Translation of nutrigenomic research for personalised and precision nutrition for cancer prevention and for cancer survivors

Personalised and precision nutrition uses information on individual characteristics and responses to nutrients, foods and dietary patterns to develop targeted nutritional advice that is more effective in improving the diet and health of each individual. Moving away from the conventional 'one size fits all', such targeted intervention approaches may pave the way to better population health, including lower burden of non-communicable diseases. To date, most personalised and precision nutrition approaches have been focussed on tackling obesity and cardiometabolic diseases with limited efforts directed to cancer prevention and for cancer survivors. Advances in understanding the biological basis of cancer and of the role played by diet in cancer prevention and in survival after cancer diagnosis, mean that it is timely to test and to apply such personalised and precision nutrition approaches in the cancer area. This endeavour can take advantage of the enhanced understanding of interactions between dietary factors, individual genotype and the gut microbiome that impact on risk of, and survival after, cancer diagnosis. Translation of these basic research into public health action should include real-time acquisition of nutrigenomic and related data and use of AI-based data integration methods in systems approaches that can be scaled up using mobile devices.

The Relationships of Dentition, Use of Dental Prothesis and Oral Health Problems with Frailty, Disability and Diet Quality: Results from Population-Based Studies of Older Adults from the UK and USA

OBJECTIVES

This study examined the relationships of dental status, use and types of dental prothesis and oral health problems, individually and combined, with diet quality, frailty and disability in two population-based studies of older adults.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

Men form the British Regional Heart Study (BRHS) (aged 85±4 years in 2018; n=1013) and Men and Women from the Health, Aging, and Body Composition (HABC) Study (aged 75±3 years in 1998-99; n=1975).

MEASUREMENTS

Physical and dental examinations and questionnaires were collected with data available for dental status, oral problems related to eating, diet quality, Fried frailty phenotype, disability based on mobility limitations, and activities of daily living (ADL). The associations of dental status and oral health problems, individually and combined, with risk of frailty and disability were quantified. The relationship with diet quality was also assessed.

RESULTS

In the BRHS, but not HABC Study, impaired natural dentition without the use of dentures was associated with frailty independently. This relationship was only established in the same group in those with oral problems (OR=3.24; 95% CI: 1.30-8.03). In the HABC Study, functional dentition with oral health problems was associated with greater risk of frailty (OR=2.21; 95% CI: 1.18-4.15). In both studies those who wore a full or partial denture in one or more jaw who reported oral problems were more likely to have disability. There was no association with diet quality in these groups.

CONCLUSION

Older adults with impaired dentition even who use dentures who experience self-report oral problems related to eating may be at increased risk of frailty and disability. Further research is needed to establish whether improving oral problems could potentially reduce the occurrence of frailty and disability.

Obesity and Roux-en-Y gastric bypass drive changes in miR-31 and miR-215 expression in the human rectal mucosa

Background/Objectives

Obesity increases colorectal cancer (CRC) risk. However, the effects of weight loss on CRC risk are unclear. Epigenetic mechanisms involving microRNAs that lead to dysregulated gene expression may mediate the effects of obesity and weight loss on CRC risk. We examined the effects of obesity and weight loss following Roux-en-Y gastric bypass (RYGB) on microRNA expression in the human rectal mucosa.

Subjects/Methods

We collected rectal mucosal biopsies from obese patients (n = 22) listed for RYGB and age- and sex-matched healthy non-obese Controls (n = 20), at baseline and six months post-surgery. We quantified microRNA expression in rectal mucosal biopsies using Next Generation Sequencing and bioinformatics analysis to investigate the likely functional consequences of these epigenetic changes.

Results

Compared with non-obese individuals, obese individuals showed differential expression of 112 microRNAs (p < 0.05). At six-months post-RYGB, when mean body mass had fallen by 27 kg, 60 microRNAs were differentially expressed, compared with baseline (p < 0.05). The expression of 36 microRNAs differed significantly between both i) obese and non-obese individuals and ii) obese individuals pre- and post-RYGB. Quantitative polymerase chain reaction (qPCR) demonstrated that expression of miR-31 and miR-215 was significantly (p < 0.05) higher, 143-fold and 15-fold respectively, in obese than in non-obese individuals. Weight loss, following RYGB, reduced expression of miR-31 and miR-215 to levels comparable with Controls. These differentially expressed microRNAs are implicated in pathways linked with inflammation, obesity and cancer.

Conclusion

Our findings show, for the first time, that obesity is associated with dysregulated microRNA expression in the human rectal mucosa. Further, surgically-induced weight loss may normalise microRNA expression in this tissue.

Feeding intervention potentiates the effect of mechanical loading to induce new bone formation in mice

The benefits of increased human lifespan depend upon duration of healthy, independent living; the healthspan. Bone-wasting disorders contribute significantly to loss of independence, frailty, and morbidity in older people. Therefore, there is an unmet need globally for lifestyle interventions to reduce the likelihood of bone fractures with age. Although many mechanisms are involved in disorders of bone loss, there is no single regulatory pathway and, therefore, there is no single treatment available to prevent their occurrence. Our aim in these studies was to determine whether fasting/feeding interventions alter the effect of mechanical loading on bone anabolic activities and increase bone mass. In young 17-week-old mice, 16-hour fasting period followed by reintroduction of food for 2 hours increased markedly the potency of mechanical loading, that mimics the effect of exercise, to induce new cortical bone formation. Consistent with this finding, fasting and re-feeding increased the response of bone to a loading stimulus that, alone, does not stimulate new bone formation in ad-lib fed mice. Older mice (20 months) experienced no potentiation of loading-induced bone formation with the same timing of feeding interventions. Interestingly, the pre-, prandial, and postprandial endocrine responses in older mice were different from those in young animals. The hormones that change in response to timing of feeding have osteogenic effects that interact with loading-mediated effects. Our findings indicate associations between timing of food ingestion and bone adaptation to loading. If translated to humans, such non-pharmacological lifestyle interventions may benefit skeletal health of humans throughout life-course and in older age.

Design and baseline characteristics of the Biomarkers Of Risk In Colorectal Cancer (BORICC) Follow-Up study: A 12+ years follow-up

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer worldwide. Age is the strongest non-modifiable risk factor but it is estimated that over half of CRC cases are linked with lifestyle factors such as diet. The Biomarkers Of RIsk of Colorectal Cancer (BORICC) Study recruited 363 participants in 2005 to investigate the effects of lifestyle factors on biomarkers of CRC risk.

AIM

In the present BORICC Follow-Up (BFU) Study, we are using a longitudinal study design to investigate the effects of ageing (12+ years) and lifestyle factors on biomarkers of CRC risk and on healthy ageing.

METHODS

BFU Study participants attended a study visit at North Tyneside General Hospital (UK) for collection of biological samples, including blood and rectal biopsies, and information collected included anthropometric measurements, a Health & Medications Questionnaire, physical activity and sedentary behaviour, and habitual diet. Furthermore, musculoskeletal function was assessed by heel bone densitometry, timed up and go and hand grip strength as markers of healthy ageing. The BFU Study outcomes will be similar to those measured at baseline in the BORICC Study, such as DNA methylation and mitochondrial function, with additional measurements including the gut microbiome, faecal short-chain fatty acid concentrations and expression of genes associated with CRC.

RESULTS

Participants' recruitment to BFU Study and all sample and data collection have been completed. Forty-seven of the original BORICC participants were re-recruited to the BFU Study (mean age 67 years, 51% female). The recruits included 37 initially healthy participants and 10 participants who had adenomatous polyps at baseline. Approximately 70% of participants were over-weight or obese.

CONCLUSION

Ultimately, identifying lifestyle factors that can reduce CRC risk, and understanding the underlying mechanisms for the effects of lifestyle and ageing on CRC risk, could lead to early prevention strategies.

Effects of obesity and weight loss on mitochondrial structure and function and implications for colorectal cancer risk

Colorectal cancer (CRC) is the third most common cancer globally. CRC risk is increased by obesity, and by its lifestyle determinants notably physical inactivity and poor nutrition. Obesity results in increased inflammation and oxidative stress which cause genomic damage and contribute to mitochondrial dysregulation and CRC risk. The mitochondrial dysfunction associated with obesity includes abnormal mitochondrial size, morphology and reduced autophagy, mitochondrial biogenesis and expression of key mitochondrial regulators. Although there is strong evidence that increased adiposity increases CRC risk, evidence for the effects of intentional weight loss on CRC risk is much more limited. In model systems, energy depletion leads to enhanced mitochondrial integrity, capacity, function and biogenesis but the effects of obesity and weight loss on mitochondria in the human colon are not known. We are using weight loss following bariatric surgery to investigate the effects of altered adiposity on mitochondrial structure and function in human colonocytes. In summary, there is strong and consistent evidence in model systems and more limited evidence in human subjects that over-feeding and/or obesity result in mitochondrial dysfunction and that weight loss might mitigate or reverse some of these effects.

No effect of monthly supplementation with 12000 IU, 24000 IU or 48000 IU vitamin D3 for one year on muscle function: The vitamin D in older people study

Vitamin D plays a role in muscle function through genomic and non-genomic processes. The objective of this RCT was to determine the effect of monthly supplemental vitamin D₃ onmuscle function in 70+ years old adults. Participants (n = 379) were randomized to receive, 12,000 IU, 24,000 IU or 48,000 IU of vitamin D₃ monthly for 12 months. Standardized Hand Grip Strength (GS) and Timed-Up and Go (TUG) were measured before and after vitamin D₃ supplementation. Fasting total plasma 25 hydroxyvitamin D (25OHD) and Parathyroid Hormone (PTH) concentrations were measured by Liquid Chromatography Tandem Mass Spectrometry (LC-MSMS) and immunoassay, respectively. Baseline plasma 25OHD concentrations were 41.3 (SD 19.9), 39.5 (SD 20.6), 38.9 (SD 19.7) nmol/L; GS values were 28.5 (SD 13.4), 28.8 (SD 13.0) and 28.1 (SD 12.1) kg and TUG test values were 10.8 (SD 2.5), 11.6 (SD 2.9) and 11.9 (SD 3.6) s for the 12,000 IU, 24,000 IU and 48,000 IU dose groups, respectively. Baseline plasma 25OHD concentration < 25 nmol/L was associated with lower GS (P = 0.003). Post-interventional plasma 25OHD concentrations increased to 55.9 (SD 15.6), 64.6 (SD15.3) and 79.0 (SD 15.1) nmol/L in the 12,000 IU, 24,000 IU and 48,000 IU dose groups, respectively and there was a significant dose-related response in post-interventional plasma 25OHD concentration (p<0.0001). Post-interventional GS values were 24.1 (SD 10.1), 26.2 (SD10.6) and 25.7 (SD 9.4) kg and TUG test values were 11.5 (SD 2.6), 12.0 (SD 3.7) and 11.9 (SD 3.2) s for 12,000 IU, 24,000 IU and 48,000 IU dose groups, respectively. The change (Δ) in GS and TUG from pre to post-intervention was not different between treatment groups before and after the adjustment for confounders, suggesting no effect of the intervention. Plasma 25OHD concentration was not associated with GS and TUG test after supplementation. In conclusion, plasma 25OHD concentration < 25 nmol/L was associated with lower GS at baseline. However, monthly vitamin D₃ supplementation with 12,000 IU, 24,000 IU and 48,000 IU, for 12 months had no effect on muscle function in older adults aged 70+ years. Trial Registration : EudraCT 2011-004890-10 and ISRCTN35648481.

Addressing the pitfalls when designing intervention studies to discover and validate biomarkers of habitual dietary intake

INTRODUCTION

Dietary exposure monitoring within populations is reliant on self-reported measures such as Food Frequency Questionnaires and diet diaries. These methods often contain inaccurate information due to participant misreporting, non-compliance and bias. Urinary metabolites derived from individual foods could provide additional objective indicators of dietary exposure. For biomarker approaches to have utility it is essential that they cover a wide-range of commonly consumed foods and the methodology works in a real-world environment.

OBJECTIVES

To test that the methodology works in a real-world environment and to consider the impact of the major sources of likely variance; particularly complex meals, different food formulations, processing and cooking methods, as well as the dynamics of biomarker duration in the body.

METHODS

We designed and tested a dietary exposure biomarker discovery and validation strategy based on a food intervention study involving free-living individuals preparing meals and collecting urine samples at home. Two experimental periods were built around three consecutive day menu plans where all foods and drinks were provided (n = 15 and n = 36).

RESULTS

The experimental design was validated by confirming known consumption biomarkers in urinary samples after the first menu plan. We tested biomarker performance with different food formulations and processing methods involving meat, wholegrain, fruits and vegetables.

CONCLUSION

It was demonstrated that spot urine samples, together with robust dietary biomarkers, despite major sources of variance, could be used successfully for dietary exposure monitoring in large epidemiological studies.

Maternal Red Blood Cell Folate and Infant Vitamin B12 Status Influence Methylation of Genes Associated with Childhood Acute Lymphoblastic Leukemia

SCOPE

Inadequate maternal folate intake is associated with increased childhood acute lymphoblastic leukemia (ALL) risk. Folate provides methyl groups for DNA methylation, which is dramatically disrupted in ALL. Whether or not maternal folate (and related B-vitamin) intake during pregnancy may affect ALL risk via influencing DNA methylation is investigated.

METHODS AND RESULTS

Genes in which methylation changes are reported both in response to folate status and in ALL are investigated. Folate-responsive genes (n = 526) are identified from mouse models of maternal folate depletion during pregnancy. Using published data, 2621 genes with persistently altered methylation in ALL are identified. Overall 25 overlapping genes are found, with the same directional methylation change in response to folate depletion and in ALL. Hypermethylation of a subset of genes (ASCL2, KCNA1, SH3GL3, SRD5A2) in ALL is confirmed by measuring 20 patient samples using pyrosequencing. In a nested cohort of cord blood samples (n = 148), SH3GL3 methylation is inversely related to maternal RBC folate concentrations (p = 0.008). Furthermore, ASCL2 methylation is inversely related to infant vitamin B12 levels. (p = 0.016).

CONCLUSION

Findings demonstrate proof of concept for a plausible mechanism, i.e., variation in DNA methylation, by which low intake of folate, and related B-vitamins during pregnancy may influence ALL risk.

Bioavailability of Fluoride in Drinking Water: a Human Experimental Study

It has been suggested that systemic fluoride absorption from drinking water may be influenced by the type of fluoride compound in the water and by water hardness. Using a human double-blind cross-over trial, we conducted this study to measure cmax, Tmax, and Area Under the Curve (AUC) for plasma F concentration against time, following the ingestion of naturally fluoridated hard and soft waters, artificially fluoridated hard and soft waters, and a reference water. Mean AUC over 0 to 8 hours was 1330, 1440, 1679, 1566, and 1328 ng F•min•mL−1 for naturally fluoridated soft, naturally fluoridated hard, artificially fluoridated soft, artificially fluoridated hard, and reference waters, respectively, with no statistically significant differences among waters for AUC, cmax, or Tmax. Any differences in fluoride bioavailability between drinking waters in which fluoride is present naturally or added artificially, or the waters are hard or soft, were small compared with large within- and between-subject variations in F absorption. Abbreviations used: F, fluoride; AUC, Area under the Curve for plasma F concentration against time; AUC(0-3), Area under the Curve for plasma F concentration against time for 0 to 3 hours following water ingestion; AUC(0-8), Area under the Curve for plasma F concentration against time for 0 to 8 hours following water ingestion; cmax, maximum plasma F concentration corrected for baseline plasma F and dose ( i.e., F concentration of individual waters); Tmax, time of cmax.

Serum 25-hydroxyvitamin D concentration and its determinants in the very old: the Newcastle 85+ Study

SUMMARY

Data on vitamin D status in very old adults are lacking. The aim of this study was to assess 25-hydroxyvitamin D [25(OH)D] concentrations and its predictors in 775 adults aged 85 years old living in North-East England. Low 25(OH)D was alarmingly high during winter/spring months, but its biological significance is unknown.

INTRODUCTION

Despite recent concerns about the high prevalence of vitamin D deficiency in much of the British adult and paediatric population, there is a dearth of data on vitamin D status and its predictors in very old adults. The objective of the present study was to describe vitamin D status and its associated factors in a broadly representative sample of very old men and women aged 85 years living in the North East of England (55° N).

METHODS

Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were analysed in 775 participants in the baseline phase of the Newcastle 85+ cohort study. Season of blood sampling, dietary, health, lifestyle and anthropometric data were collected and included as potential predictors of vitamin D status in ordinal regression models.

RESULTS

Median serum 25(OH)D concentrations were 27, 45, 43 and 33 nmol/L during spring, summer, autumn and winter, respectively. The prevalence of vitamin D deficiency according to North American Institute of Medicine guidelines [serum 25(OH)D <30 nmol/L] varied significantly with season with the highest prevalence observed in spring (51%) and the lowest prevalence observed in autumn (23%; P < 0.001). Reported median (inter-quartile range) dietary intakes of vitamin D were very low at 2.9 (1.2-3.3) μg/day. In multivariate ordinal regression models, non-users of either prescribed or non-prescribed vitamin D preparations and winter and spring blood sampling were associated with lower 25(OH)D concentrations. Dietary vitamin D intake, disability score and disease count were not independently associated with vitamin D status in the cohort.

CONCLUSION

There is an alarming high prevalence of vitamin D deficiency (<30 nmol/L) in 85-year-olds living in North East England at all times of the year but particularly during winter and spring. Use of vitamin D containing preparations (both supplements and medications) appeared to be the strongest predictor of 25(OH)D concentrations in these very old adults.

Associations between FTO genotype and total energy and macronutrient intake in adults: a systematic review and meta-analysis

Risk variants of fat mass and obesity-associated (FTO) gene have been associated with increased obesity. However, the evidence for associations between FTO genotype and macronutrient intake has not been reviewed systematically. Our aim was to evaluate the potential associations between FTO genotype and intakes of total energy, fat, carbohydrate and protein. We undertook a systematic literature search in OVID MEDLINE, Scopus, EMBASE and Cochrane of associations between macronutrient intake and FTO genotype in adults. Beta coefficients and confidence intervals (CIs) were used for per allele comparisons. Random-effect models assessed the pooled effect sizes. We identified 56 eligible studies reporting on 213,173 adults. For each copy of the FTO risk allele, individuals reported 6.46 kcal day(-1) (95% CI: 10.76, 2.16) lower total energy intake (P = 0.003). Total fat (P = 0.028) and protein (P = 0.006), but not carbohydrate intakes, were higher in those carrying the FTO risk allele. After adjustment for body weight, total energy intakes remained significantly lower in individuals with the FTO risk genotype (P = 0.028). The FTO risk allele is associated with a lower reported total energy intake and with altered patterns of macronutrient intake. Although significant, these differences are small and further research is needed to determine whether the associations are independent of dietary misreporting.

Instrumented assessment of test battery for physical capability using an accelerometer: a feasibility study

Recent work has identified subdomains (tests) of physical capability that are recommended for assessment of the healthy ageing phenotype (HAP). These include: postural control, locomotion, endurance, repeated sit-to-stand-to-sit and TUG. Current assessment methods lack sensitivity and are error prone due to their lack of consistency and heterogeneity of reported outcomes; instrumentation with body worn monitors provides a method to address these potential weaknesses. This work proposes the use of a single tri-axial accelerometer-based device with appropriate algorithms (referred to here as a body worn monitor, BWM) for the purposes of instrumented testing during physicality capability assessment. In this pilot study we present 14 BWM-based outcomes across the subdomains which include magnitude, frequency and spatio-temporal characteristics. Where possible, we compared BWM outcomes with manually recorded values and found no significant differences between locomotion and TUG tasks (p ≥ 0.319). Significant differences were found for the total distance walked during endurance (p = 0.037) and times for repeated sit-to-stand-to-sit transitions (p < 0.000). We identified reasons for differences and make recommendations for future testing. We were also able to quantify additional characteristics of postural control and gait which could be sensitive outcomes for future HAP assessment. Our findings demonstrate the feasibility of this method to enhance measurement of physical capacity. The methodology can also be applied to a wide variety of accelerometer-based monitors and is applicable to a range of intervention-based studies or pathological assessment.

iCap: Instrumented assessment of physical capability

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Instrumented testing of five physical capability tasks with a single accelerometer.

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Evaluated on a large cohort of older adults.

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iCap provides robust quantitative data about physical capability.

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iCap captures gait and postural control data known as sensitive to ageing/pathology.

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Methodology may have practical utility in a wide range of surveys and studies.

Objectives

The aims of this study were to (i) investigate instrumented physical capability (iCap) as a valid method during a large study and (ii) determine whether iCap can provide important additional features of postural control and gait to categorise cohorts not previously possible with manual recordings.

Study design

Cross-sectional analysis involving instrumented testing on 74 adults who were recruited as part of a pilot intervention study; LiveWell. Participants wore a single accelerometer-based monitor (lower back) during standardised physical capability tests so that outcomes could be compared directly with manual recordings (stopwatch and measurement tape) made concurrently.

Main outcome measures

Time, distance, postural control and gait characteristics.

Results

Agreement between manual and iCap ranged from moderate to excellent (0.649–0.983) with mean differences between methods low and deemed acceptable. Additionally, iCap successfully quantified (i) postural control characteristics which showed sensitivity to distinguish between 5 variations of the standing balance test and (ii) 14 gait characteristics known to be sensitive to age/pathology.

Conclusions

Our findings show that iCap can provide robust quantitative data about physical capability during standardised tests while also providing sensitive (age/pathology) postural control and gait characteristics not previously quantifiable with manual recordings. The methodology which we propose may have practical utility in a wide range of clinical and public health surveys and studies, including intervention studies, where assessment could be undertaken within diverse settings. This will need to be tested in further validation studies in a wider range of settings.

25-hydroxyvitamin D and increased all-cause mortality in very old women: the Newcastle 85+ study

OBJECTIVE

To investigate the associations between low and high concentrations of baseline serum 25-hydroxyvitamin D [25(OH)D] and all-cause mortality in very old (≥85 years) men and women over 6 years.

DESIGN, SETTING AND SUBJECTS

Prospective mortality data from 775 participants in the Newcastle 85+ Study were analysed for survival in relation to 25(OH)D (season-specific quartiles and predefined cut-off values) and sex using Cox proportional hazards models. The models were fitted to the entire and restricted (nonusers of vitamin D-containing supplements and medication) cohorts.

RESULTS

For the entire cohort, mortality was higher in both the lowest and highest 25(OH)D season-specific quartiles [SQ1: hazard ratio (HR) 1.31, 95% confidence interval (CI) 1.01-1.69, P = 0.04; SQ4: HR 1.44, 95% CI 1.12-1.85, P = 0.004] compared with the combined middle quartiles (SQ2 + SQ3), after adjustment for sociodemographic factors. The increased risk for the highest quartile remained significant after further adjustment for lifestyle variables (SQ4: HR 1.37, 95% CI 1.06-1.77, P = 0.02) and was seen only in women in sex-specific analyses. Similarly, in sensitivity analyses with predefined 25(OH)D cut-off values, the highest 25(OH)D concentration (≥75 nmol L(-1) ) was associated with a 2.4-fold increased risk of mortality in women (restricted cohort) after adjusting for all covariates.

CONCLUSION

Low and high season-specific 25(OH)D quartiles were associated with increased risks of mortality over 6 years in the very old; this effect was particularly noticeable in women, including those who reported taking vitamin D-containing supplements/medication.

Instrumenting gait with an accelerometer: a system and algorithm examination

Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required.

Serum 25-hydroxyvitamin D and cognitive decline in the very old: the Newcastle 85+ Study

BACKGROUND AND PURPOSE

Studies investigating the association between 25-hydroxyvitamin D [25(OH)D] and cognition in the very old (85+) are lacking.

METHODS

Cross-sectional (baseline) and prospective data (up to 3 years follow-up) from 775 participants in the Newcastle 85+ Study were analysed for global (measured by the Standardized Mini-Mental State Examination) and attention-specific (measured by the attention battery of the Cognitive Drug Research test) cognitive performance in relation to season-specific 25(OH)D quartiles.

RESULTS

Those in the lowest and highest season-specific 25(OH)D quartiles had an increased risk of impaired prevalent (1.66, 95% confidence interval 1.06-2.60, P = 0.03; 1.62, 95% confidence interval 1.02-2.59, P = 0.04, respectively) but not incident global cognitive functioning or decline in functioning compared with those in the middle quartiles adjusted for sociodemographic, health and lifestyle confounders. Random effects models showed that participants belonging to the lowest and highest 25(OH)D quartiles, compared with those in the middle quartiles, had overall slower (log-transformed) attention reaction times for Choice Reaction Time (lowest, β = 0.023, P = 0.01; highest, β = 0.021, P = 0.02), Digit Vigilance Task (lowest, β = 0.009, P = 0.05; highest, β = 0.01, P = 0.02) and Power of Attention (lowest, β = 0.017, P = 0.02; highest, β = 0.022, P = 0.002) and greater Reaction Time Variability (lowest, β = 0.021, P = 0.02; highest, β = 0.02, P = 0.03). The increased risk of worse global cognition and attention amongst those in the highest quartile was not observed in non-users of vitamin D supplements/medication.

CONCLUSION

Low and high season-specific 25(OH)D quartiles were associated with prevalent cognitive impairment and poorer overall performance in attention-specific tasks over 3 years in the very old, but not with global cognitive decline or incident impairment.

Early determinants of the ageing trajectory

Over the past 250 years, human life expectancy has increased dramatically and continues to do so in most countries worldwide. Genetic factors account for about one third of variation in life expectancy so that most inter-individual variation in lifespan is explained by stochastic and environmental factors. The ageing process is plastic and is driven by the accumulation of molecular damage causing the changes in cell and tissue function which characterise the ageing phenotype. Early life exposures mark the developing embryo, foetus and child with potentially profound implications for the individual's ageing trajectory. Maternal factors including age, smoking, socioeconomic status, infections, nutritional status and season of birth influence offspring life expectancy and the development of age-related diseases. Although the mechanistic processes responsible are poorly understood, many of these factors appear to affect foetal growth directly or via effects on placental development. Those born relatively small i.e. which did not achieve their genetic potential in utero, appear to be at greatest disadvantage especially if they become overweight or obese in childhood. Early life events and exposures which enhance ageing are likely to contribute to molecular damage and/or reduce the repair of such damage. Such molecular damage may produce immediate defects in cellular or tissue function that are retained into later life. In addition, there is growing evidence that early life exposures produce aberrant patterns of epigenetic marks that are sustained across the life-course and result in down-regulation of cell defence mechanisms.

Overview of genes, diet and cancer

Quantitative epidemiological analysis suggests that about one third of the variation in cancer risk can be attributed to variation in dietary exposure but it has proved difficult, using conventional epidemiological approaches, to identify which dietary components, in what amounts and over what time-scales are protective or potentially hazardous. Work in this area has been hampered by the lack of robust surrogate endpoints. However, the rapidly accumulating knowledge of the biological basis of cancer and the application of post-genomic technologies are helping the development of novel biomarkers of cancer risk. Genomic damage resulting in aberrant gene expression is the fundamental cause of all cancers. Such damage includes mutations, aberrant epigenetic marking, chromosomal damage and telomere shortening. Since both external agents and normal cell functions, such as mitosis, subject the genome to frequent and diverse insults, the human cell has evolved a battery of defence mechanisms which (a) attempt to minimize such damage (including inhibition of oxidative reactions by free radical scavenging and the detoxification of potential mutagens), (b) repair the damage or (c) remove severely damaged cells by shunting them into apoptosis. When such defences fail and a tumour becomes established, further genomic damage and further alterations in gene expression enable the tumour to grow, to cope with anoxia, to develop a novel blood supply (angiogenesis), to escape from the confines of its initiation site and to establish colonies elsewhere in the body (metastasis). All of these processes are potentially modifiable by food components and by nutritional status. In addition, interactions between dietary (and other environmental and lifestyle) factors and genetic make-up [seen principally in the assembly of single nucleotide polymorphisms (SNPs) which is unique to each individual] contributes to interindividual differences in cancer risk.

Diet induced epigenetic changes and their implications for health

Dietary exposures can have consequences for health years or decades later and this raises questions about the mechanisms through which such exposures are 'remembered' and how they result in altered disease risk. There is growing evidence that epigenetic mechanisms may mediate the effects of nutrition and may be causal for the development of common complex (or chronic) diseases. Epigenetics encompasses changes to marks on the genome (and associated cellular machinery) that are copied from one cell generation to the next, which may alter gene expression, but which do not involve changes in the primary DNA sequence. These include three distinct, but closely inter-acting, mechanisms including DNA methylation, histone modifications and non-coding microRNAs (miRNA) which, together, are responsible for regulating gene expression not only during cellular differentiation in embryonic and foetal development but also throughout the life-course. This review summarizes the growing evidence that numerous dietary factors, including micronutrients and non-nutrient dietary components such as genistein and polyphenols, can modify epigenetic marks. In some cases, for example, effects of altered dietary supply of methyl donors on DNA methylation, there are plausible explanations for the observed epigenetic changes, but to a large extent, the mechanisms responsible for diet-epigenome-health relationships remain to be discovered. In addition, relatively little is known about which epigenomic marks are most labile in response to dietary exposures. Given the plasticity of epigenetic marks and their responsiveness to dietary factors, there is potential for the development of epigenetic marks as biomarkers of health for use in intervention studies.

DNA methylation, induced by beta-carotene and arachidonic acid, plays a regulatory role in the pro-angiogenic VEGF-receptor (KDR) gene expression in endothelial cells

DNA methylation is a potent regulator of gene expression. The influence of beta-carotene (BC) and arachidonic acid (AA) on angiogenesis--a new blood vessel formation, was reported. The tyrosine kinase VEGFR-2 receptor (KDR) activation by vascular endothelial growth factor is one of the main angiogenic mechanisms. This study was aimed to investigate a possible role of CpG island methylation on regulation of the pro-angiogenic KDR gene expression after incubation of human endothelial cells with BC and/or AA.

METHODS

Human umbilical vein endothelial cells (HUVEC) were incubated with BC (1-10 microM) and/or 3 microM AA for 24 hours. The CpG island methylation was quantified using the COBRA method and restriction enzymes' digestion (NewEngland BioLabs). Intracellular protein concentrations were determined by Western blot analysis using the specific antibodies (Santa Cruz).

RESULTS

Incubation with BC and AA, decreased methylation of the KDR promoter region. These results well-correlated with the detected, by qRT-PCR, up-regulation of KDR gene expression by BC (p=0.035) as well as by AA. Incubation with BC (p=0.02) and AA (p=0.0014) increased the KDR protein levels in HUVECs.

CONCLUSION

The changes in CpG island methylation of the KDR the pro-angiogenic gene promoter, represents one of the mechanisms involved in regulation of angiogenic response by BC and AA.

Diet, ageing and genetic factors in the pathogenesis of diverticular disease

Diverticular disease (DD) is an age-related disorder of the large bowel which may affect half of the population over the age of 65 in the UK. This high prevalence ranks it as one of the most common bowel disorders in western nations. The majority of patients remain asymptomatic but there are associated life-threatening co-morbidities, which, given the large numbers of people with DD, translates into a considerable number of deaths per annum. Despite this public health burden, relatively little seems to be known about either the mechanisms of development or causality. In the 1970s, a model of DD formulated the concept that diverticula occur as a consequence of pressure-induced damage to the colon wall amongst those with a low intake of dietary fiber. In this review, we have examined the evidence regarding the influence of ageing, diet, inflammation and genetics on DD development. We argue that the evidence supporting the barotrauma hypothesis is largely anecdotal. We have also identified several gaps in the knowledge base which need to be filled before we can complete a model for the etiology of diverticular disease.

Measurement of dietary exposure: a challenging problem which may be overcome thanks to metabolomics?

The diet is an important environmental exposure, and its measurement is an essential component of much health-related research. However, conventional tools for measuring dietary exposure have significant limitations being subject to an unknown degree of misreporting and dependent upon food composition tables to allow estimation of intakes of energy, nutrients and non-nutrient food constituents. In addition, such tools may be inappropriate for use with certain groups of people. As an alternative approach, the recent techniques of metabolite profiling or fingerprinting, which allows simultaneous monitoring of multiple and dynamic components of biological fluids, may provide metabolic signals indicative of food intake. Samples can be analysed through numerous analytical platforms, followed by multivariate data analysis. In humans, metabolomics has been applied successfully in pharmacology, toxicology and medical screening, but nutritional metabolomics is still in its infancy. Biomarkers of a small number of specific foods and nutrients have been developed successfully but less targeted and more high-throughput methods, that do not need prior knowledge of which signals might be discriminatory, and which may allow a more global characterisation of dietary intake, remain to be tested. A proof a principle project (the MEDE Study) is currently underway in our laboratories to test the hypothesis that high-throughput, non-targeted metabolite fingerprinting using flow injection electrospray mass spectrometry can be applied to human biofluids (blood and urine) to characterise dietary exposure in humans.

Cell kinetics and gene expression changes in colorectal cancer patients given resistant starch: a randomised controlled trial

OBJECTIVE

This study investigated the effects of oral supplementation of resistant starch (RS) on tumour cell and colonic mucosal cell kinetics and on gene expression in patients with colorectal cancer (CRC), and its potential role in colon cancer prevention.

METHODS

65 patients with CRC were randomised to treatment with RS or ordinary starch (OS) and were given starch treatment for up to 4 weeks. Pretreatment and post-treatment biopsies were obtained from the tumour and colonic mucosa, and the effects of the starch treatment on cell proliferation and expression of the cell cycle regulatory genes CDK4 (cyclin-dependent kinase 4) and GADD45A (growth arrest and DNA damage-inducible, alpha) were investigated.

RESULTS

The proportion of mitotic cells in the top half of the colonic crypt was significantly lower following RS treatment (3.1 (1.5), mean (SEM)) as compared with OS treatment (13.7 (3.2)) (p = 0.028). However, there was no effect of RS treatment on crypt dimensions and tumour cell proliferation index. There was significant upregulation in expression of CDK4 (p<0.01) and downregulation in expression of GADD45A (p<0.001) in the tumour tissue when compared with macroscopically normal mucosa. Following RS treatment, CDK4 expression in tumours (0.88 (0.15)) was twofold higher than that in the OS group (0.37 (0.16)) (p = 0.02). The expression of GADD45A, which was downregulated in the presence of cancer, was significantly upregulated (p = 0.048) following RS treatment (1.41 (0.26)) as compared with OS treatment (0.56 (0.3)). However, there were no significant differences in the expression of these genes in the normal mucosa following starch treatment.

CONCLUSIONS

Cell proliferation in the upper part of colonic crypts is a premalignant marker and its reduction by RS supplementation is consistent with an antineoplastic action of this food component. Differential expression of the key cell cycle regulatory genes may contribute to the molecular mechanisms underlying these antineoplastic effects of RS.

A review of dietary factors and its influence on DNA methylation in colorectal carcinogenesis

Colorectal cancer (CRC) is the most common cancer in non-smokers posing a significant health burden in the UK. Observational studies lend support to the impact of environmental factors especially diet on colorectal carcinogenesis. Significant advances have been made in understanding the biology of CRC carcinogenesis in particular epigenetic modifications such as DNA methylation. DNA methylation is thought to occur at least as commonly as inactivation of tumor suppressor genes. In fact compared with other human cancers, promoter gene methylation occurs most commonly within the gastrointestinal tract. Emerging data suggest the direct influence of certain micronutrients for example folic acid, selenium as well as interaction with toxins such as alcohol on DNA methylation. Such interactions are likely to have a mechanistic impact on CRC carcinogenesis through the methylation pathway but also, may offer possible therapeutic potential as nutraceuticals.

Beta-carotene and arachidonic acid induced DNA methylation and the regulation of pro-chemotactic activity of endothelial cells and its progenitors

DNA methylation is one of the important mechanisms regulating gene expression. Since beta-carotene (BC) was shown to have pro-chemotactic activity and stimulates expression of pro-angiogenic genes, this study was undertaken to define the possible changes in DNA methylation in endothelial cell and its progenitors in the presence of BC. The culture medium for human umbilical vein endothelial cells (HUVEC) and endothelial progenitor cells (EPC) was supplemented with BC (1 - 10 microM) with the presence of arachidonic acid (AA) (3 microM). Global DNA methylation tended to be lower in both endothelial cell lines, after incubation with BC and AA. HUVEC incubated with AA demonstrated the lowest DNA methylation. The decrease of DNA methylation in EPC, induced by BC, was concentration-dependent. The microarray study revealed, that the angiogenesis and homing-related genes were mostly influenced by BC and AA in investigated cells. Our results indicate that BC and AA-induced DNA hypomethylation in EPC and HUVEC, might be a mechanism which may alter gene expression in endothelial cells what in certain conditions may be connected with the suggested pro-malignant effect of this compounds.

Evidence that a polymorphism within the 3'UTR of glutathione peroxidase 4 is functional and is associated with susceptibility to colorectal cancer

Low selenium (Se) status has been associated with increased risk of colorectal cancer (CRC). Se is present as the amino acid selenocysteine in selenoproteins, such as the glutathione peroxidases. Se incorporation requires specific RNA structures in the 3' untranslated region (3'UTR) of the selenoprotein mRNAs. A single nucleotide polymorphism (SNP) occurs at nucleotide 718 (within the 3'UTR) in the glutathione peroxidase 4 gene. In the present study, Caco-2 cells were transfected with constructs in which type 1 iodothyronine deiodinase coding region was linked to the GPx4 3'UTR with either C or T variant at position 718. Higher reporter activity was observed in cells expressing the C variant compared to those expressing the T variant, under either Se-adequate or Se-deficient conditions. In addition, a disease association study was carried out in cohorts of patients with either adenomatous polyps, colorectal adenocarcinomas and in healthy controls. A higher proportion of individuals with CC genotype at the GPx4 T/C 718 SNP was present in the cancer group, but not in the polyp group, compared with the control group (P < 0.05). The present data demonstrate the functionality of the GPx4 T/C 718 SNP and suggest that T genotype is associated with lower risk of CRC.

The nutrition knowledge of older adults living in sheltered housing accommodation

BACKGROUND

Nutrition knowledge enables informed dietary choices. This paper reports on the nutrition knowledge of older adults residing in sheltered housing accommodation in socially deprived areas of north-east England.

METHOD

As part of a cluster randomized dietary intervention trial, a validated questionnaire measured the knowledge of current dietary recommendations, nutrient sources, ability to select healthy meal options and knowledge of associations between diet and diseases of older adults aged 60 years and over residing in sheltered accommodation.

RESULTS

Completed questionnaires were obtained from 177 (59%) subjects (147 female, 30 male), of whom 76% were overweight/obese and 2% underweight. The mean (SD) age was 76.4 (8.0) years. Of a possible score of 47, the mean score was 23.2, indicating that approximately 50% of questions were answered incorrectly. Knowledge of associations between diet and diseases was particularly poor; 90% of subjects being unaware of the benefits of high fruit and vegetable consumption. Respondents in the highest 10% of the nutrition knowledge score had a significantly higher intake of fruit and vegetables compared with those in the lowest 10%.

CONCLUSION

A high proportion of older adults had little basic nutrition knowledge; this presents a barrier to healthier eating that should be addressed.

Children's estimates of food portion size: the development and evaluation of three portion size assessment tools for use with children

A number of methods have been developed to assist subjects in providing an estimate of portion size but their application in improving portion size estimation by children has not been investigated systematically. The aim was to develop portion size assessment tools for use with children and to assess the accuracy of children's estimates of portion size using the tools. The tools were food photographs, food models and an interactive portion size assessment system (IPSAS). Children (n 201), aged 4–16 years, were supplied with known quantities of food to eat, in school. Food leftovers were weighed. Children estimated the amount of each food using each tool, 24 h after consuming the food. The age-specific portion sizes represented were based on portion sizes consumed by children in a national survey. Significant differences were found between the accuracy of estimates using the three tools. Children of all ages performed well using the IPSAS and food photographs. The accuracy and precision of estimates made using the food models were poor. For all tools, estimates of the amount of food served were more accurate than estimates of the amount consumed. Issues relating to reporting of foods left over which impact on estimates of the amounts of foods actually consumed require further study. The IPSAS has shown potential for assessment of dietary intake with children. Before practical application in assessment of dietary intake of children the tool would need to be expanded to cover a wider range of foods and to be validated in a ‘real-life’ situation.

Nutrition and DNA Repair - Potential Molecular Mechanisms of Action

At its most fundamental, cancer is a genetic disease in the sense that the primary events in tumorigenesis involve damage to the genome. The genome is subject to damage continuously from both exogenous agents and endogenous processes but this becomes functionally important only if the damage is not detected and resolved in a timely and effective manner. In mammals there are 5 DNA repair pathways, encoded by approximately 150 genes, which appear to have arisen early in evolution and which are highly conserved. Given the substantial epidemiological and experimental evidence that variation in dietary intake accounts for a significant proportion of the variance in cancer prevalence, an a priori case can be made that dietary factors may influence the effectiveness of DNA repair. A review of the literature has identified 4 observational and 8 intervention studies in human subjects where DNA repair (or a component thereof) has been measured in relation to nutrition. This rather limited evidence base precludes drawing definitive conclusions, but the fact that there were significant effects of dietary supplements in 5 out of the 8 intervention studies suggests that food components and/or nutritional status may influence DNA repair. This review considers possible molecular mechanisms through which such factors could modulate repair.

Children's estimates of food portion size: the effect of timing of dietary interview on the accuracy of children's portion size estimates

For food intakes to be converted into nutrient intakes a measure or estimate of the amount of food consumed is required. A number of methods have been developed to assist subjects in providing an estimate of portion size. Children's ability to use perception, conceptualisation and memory skills to estimate food portion size has not been investigated systematically. The aim of the present study was to test the effect of the timing of a dietary interview on the accuracy of estimates of food portion sizes made by children, using food photographs, food models and an interactive portion size assessment system, developed for use with children and based on portion sizes of foods consumed by children. Children (n 108) aged 4–14 years were supplied with known quantities of foods and asked to estimate the portion size of each food using each of the three portion size assessment tools. Interviews took place (a) with the food in view, (b) just after the child had eaten the food or (c) 24 h after the child had eaten the food. There were no significant differences in children's ability to estimate food portion size (either as served or as eaten) with timing of interview. That is, children were as accurate in their estimates of portion size 24 h after consuming the food as when the food was in view. Under these conditions many children were able to estimate food portion size utilising perception, conceptualisation and memory skills.

Changes in consumption of sugars by English adolescents over 20 years

OBJECTIVE

Dietary surveys of 11- to 12-year-old Northumbrian children in 1980 and 1990 revealed that consumption of non-milk extrinsic sugars (NMES) was 16-17% of energy intake. This study reports dietary sugars consumption in 2000 and compares it with data collected in 1980 and 1990, using identical methods.

DESIGN

A repeat cross-sectional dietary survey of children aged 1-12 years attending the same schools as in the 1980 and 1990 surveys.

SETTING

Seven middle schools in south Northumberland.

SUBJECTS

All children aged 11-12 years old attending the seven schools.

METHOD

Food consumption was recorded using two 3-day diet diaries. Food composition tables were used to calculate energy and nutrient intakes. NMES, and milk and intrinsic sugars were calculated using previously described methods.

RESULTS

The numbers of children completing the surveys in 1980, 1990 and 2000 were 405, 379 and 424, respectively; approximately 60-70% of eligible children. Total sugars provided 22% of energy consistently over the three surveys. NMES consumption in 2000 provided 16% of energy compared with 16% in 1980 and 17% in 1990. Sources of NMES changed over the three surveys. NMES from soft drinks doubled from 15 to 31 g day(-1), and from breakfast cereals increased from 2 to 7 g day(-1) over the 20 years. Confectionery and soft drinks provided 61% of NMES. Over 20 years, the proportion of energy from fat decreased by 5% and from starch increased by 4%, creating a welcome tilt in the fat-starch see-saw, without an adverse effect on sugars intake.

CONCLUSIONS

Consumption of NMES in 2000 was substantially higher than recommended, and there has been little change over 20 years. Continued and coordinated efforts are required at a national, community and individual level to reduce the intake of NMES.

Dietary and genetic modulation of DNA repair in healthy human adults

The DNA in all cells of the human body is subject to damage continuously from exogenous agents, internal cellular processes and spontaneous decomposition. Failure to repair such damage is fundamental to the development of many diseases and to ageing. Fortunately, the vast majority of DNA damage is detected and repaired by one of five complementary DNA repair systems. However, recent studies have shown that even in healthy individuals there is a wide inter-individual variation in DNA repair capacity. Part of this variation can be accounted for by polymorphisms in the genes encoding DNA repair proteins. However, it is probable that environmental factors, including dietary exposure as well as diet-gene interactions, are also responsible for much of the difference in repair capacity between individuals. Whilst there is some evidence from human studies that generalised malnutrition or low intakes of specific nutrients may affect DNA repair, as yet there is limited understanding of the molecular mechanisms through which nutrients can modulate this key cellular process.

Zinc Transporters in the Mouse Placenta Show a Coordinated Regulatory Response to Changes in Dietary Zinc Intake

The aim of the study was to determine if the expression of zinc transporters in the mouse placenta is regulated by dietary zinc, commensurate with regulating the supply of zinc to the fetus. Mice were fed diets differing only in the concentration of zinc (moderately zinc-restricted (ZnR)--15 mg Zn/kg; zinc-adequate (ZnA)--50 mg Zn/kg; zinc-supplemented (ZnS)--150 mg Zn/kg) from the onset of pregnancy until collection of tissue at day 17. Compared with mice fed the other diets, fetal weight was reduced in the ZnR group and total non-embryonic weight gain was reduced in mice fed the ZnS diet. Transcript levels of metallothionein and the zinc transporters ZnT1, ZnT4 and ZIP1 were reduced in the placenta of mice fed both the ZnR and ZnS diets compared with mice fed the ZnA diet. Placental ZnT7 and fetal liver metallothionein transcript levels did not differ significantly between mice fed the three diets and placental ZnT5 was reduced in mice fed the ZnS compared with the ZnA diet but did not differ significantly between the ZnA and ZnR diets. The pattern of mRNA expression in placenta was reflected at the protein level for ZnT1. Levels of ZnT5 protein were also highest in mice fed the ZnA diet. Both ZnT1 and ZnT5 were detected in the human villous syncytiotrophoblast by immunohistochemistry. The data indicate that the expression of zinc transporters in mouse placenta is responsive to dietary zinc supply but this modulation of expression is insufficient to maintain optimum fetal nutrition at even a modest level of dietary zinc restriction.

Methylation of the ESR1 CpG island in the colorectal mucosa is an 'all or nothing' process in healthy human colon, and is accelerated by dietary folate supplementation in the mouse

ESR1 is frequently silenced by CGI (CpG island) methylation, both in human colorectal tumours and, in an age-dependent manner, in healthy mucosa. It is not clear, however, whether methylation of individual cytosines occurs randomly within the epithelial genome, or preferentially within individual cells as an 'all-or-nothing' phenomenon. CGI methylation can be quantified in human DNA residues recovered from faecal samples. We used bisulphite genomic sequencing of human DNA from this source and from a colorectal cancer cell line (SW48) to show that the ESR1 CGI is methylated in an allele-specific manner. This provides support for the 'all or none' mechanism for methylation of this gene, and shows how age-dependent methylation of the ESR1 CGI leads rapidly to silencing of the gene within the cells, and hence the colonic crypt within which it occurs. Preliminary studies with a rodent model suggest the rate of age-dependent methylation of ESR1 is modifiable by dietary folate.

DNA mismatch repair status may influence anti-neoplastic effects of butyrate

HNPCC (hereditary non-polyposis colon cancer) is an autosomal-dominant disorder characterized by early-onset CRC (colorectal cancer). HNPCC is most often associated with mutations in the MMR (mismatch repair) genes hMLH1, hMSH2, hMSH6 or hPMS2. The mutator phenotype of a defective MMR system is MSI (microsatellite instability), which also occurs in approx. 15-25% of sporadic CRC cases, where it is associated with the hypermethylation of the promoter region of hMLH1. Dietary factors, including excessive alcohol consumption, ingestion of red meat and low folate intake, may increase the risk of MSI high tumour development. In contrast, aspirin may suppress MSI in MMR-deficient CRC cell lines. Butyrate, a short-chain-fatty-acid end product of carbohydrate fermentation in the colon, shares a number of anti-neoplastic properties with aspirin, including inhibiting proliferation and inducing apoptosis of CRC cells. Recent in vitro studies suggest that physiological concentrations of butyrate (0.5-2 mM) may have more potent anti-neoplastic effects in CRC cell lines deficient in MMR, but mechanisms for such a differential response remain to be established.

Homeostatic regulation of zinc transporters in the human small intestine by dietary zinc supplementation

BACKGROUND

The role of intestinal transporter regulation in optimising nutrient absorption has been studied extensively in rodent and cell line models but not in human subjects.

AIMS

The aim of the present study was to investigate the response in vivo of zinc transporters in the human enterocyte to dietary zinc supplementation.

SUBJECTS

Eighteen patients who had previously undergone ileostomy, all free of any symptoms of inflammatory bowel disease.

METHODS

Subjects took a daily zinc supplement of 25 mg for 14 days in a double blind, placebo controlled, crossover trial. The effect of the supplement on expression in ileal biopsies of the zinc transporters SLC30A1, SLC30A4, SLC30A5, SLC39A1, SLC39A4, and metallothionein was measured by reverse transcription-polymerase chain reaction RT-PCR. Expression of SLC30A1, SLC30A5, and SLC39A4 was also examined by immunoblotting.

RESULTS

The zinc supplement reduced SLC30A1 mRNA (1.4-fold) together with SLC30A1, SLC30A5, and SLC39A4 protein (1.8-fold, 3.7-fold, and to undetectable levels, respectively) in ileal mucosa and increased metallothionein mRNA (1.7-fold). The supplement had no effect on expression of SLC30A4 or SLC39A1 mRNA. Localisation of SLC30A5 at the apical human enterocyte/colonocyte membrane and also at the apical membrane of Caco-2 cells was demonstrated by immunohistochemistry. Commensurate with these observations in zinc supplemented human subjects, SLC30A1, SLC30A5, and SLC39A4 mRNA and protein were reduced in Caco-2 cells cultured at 200 muM compared with 100 muM zinc.

CONCLUSIONS

These observations indicate that, in response to variations in dietary zinc intakes, regulated expression of plasma membrane zinc transporters in the human intestine contributes to maintenance of zinc status.

Folate and DNA methylation during in utero development and aging

DNA methylation is one of several epigenetic mechanisms that play a regulatory role in genome programming and imprinting during embryogenesis. Aberrant DNA methylation has been implicated in the pathogenesis of a number of diseases associated with aging, including cancer and cardiovascular and neurological diseases. Evidence is accumulating that dietary factors in utero modulate disease risk in later life. Although folic acid is a key component of DNA methylation, the impact of folic acid availability in utero on DNA methylation patterns and disease risk in adulthood is at present poorly characterized. This review describes the relationship between folic acid and DNA methylation, and the association between DNA methylation during in utero development and aging.

Changes over 20 years in macronutrient intake and body mass index in 11- to 12-year-old adolescents living in Northumberland

Monitoring adolescent diets over time enables the assessment of the effectiveness of public health messages which are particularly important in vulnerable groups such as adolescents. In 2000, 424 children aged 11-12 years old completed two 3 d estimated dietary records. On the fourth day one nutritionist interviewed each child to clarify the information in the diary and foods were quantified with the aid of food models. Nutrient intake was calculated using computerised food tables. These children attended the same seven schools in the same Northumberland area as the 11- to 12-year-old children who recorded their diet using the same method in 1980 (n 405) and 1990 (n 379), respectively. Height and weight, and parental occupation were recorded in all three surveys for each child. Height and weight were used to calculate BMI, weight was used to estimate BMR and parental occupation was used to determine social class. Comparing the macronutrient intakes in 2000 with 1980 and 1990, energy intakes (EI) fell in boys (to 8.45 MJ) and girls (to 7.60 MJ). This fall may, at least in part, be due to an increase in low energy reporting. For 1980, 1990 and 2000 the percentage of boys with EI:BMR below 1.1 was 6, 15 and 23 %, respectively; for girls, 3, 14 and 18 %, respectively. Percentage energy from fat was unchanged between 1980 and 1990 but fell to 35 % (about 76 g/d) in 2000, alongside a 3 % increase in percentage energy from starch (30 %). Percentage energy from non-milk extrinsic sugars remained above recommendations (16 %; about 82 g/d). The number of overweight and obese children increased from 11 % to 30 % between 1980 and 2000. Positive changes have occurred in the Northumbrian adolescent diet but social inequalities, reported in previous surveys, remain.

Changes in water intake of Northumbrian adolescents 1980 to 2000

OBJECTIVES

To determine: total water intake in young English adolescents; the relative importance of sources of water intake; and changes in water intake and sources of water between 1980 and 2000.

DESIGN

A cross-sectional observational study of the diets of 11-12-year-old children attending seven schools in south Northumberland, UK. The information obtained was compared with results from a similar survey carried out 20 years previously.

METHODS

All children attending these schools were invited to participate. They completed a three-day diet diary with an interview on the fourth day, on two occasions during the school year. Standard UK food composition tables were used and water intake from various sources calculated. Anthropometric and social class information was obtained.

RESULTS

Four hundred and twenty-four children completed all aspects of the study (64% of those eligible). The mean total water intake was 1,130 g d(-1), approximately the same as that recorded 20 years before. Water intake in relation to energy intake: water intake was 139 g MJ(-1) in boys and 143 g MJ(-1) in girls. Sixty-five per cent of water came from drinks and 35% from foods; very similar to proportions 20 years before. The sources of water in drinks had changed considerably, with a marked increase in consumption of soft drinks (especially carbonated drinks) and a decrease in consumption of hot drinks and milk. There were a few differences between sexes but little difference between social groups.

CONCLUSIONS

Total water intake was similar to that recorded 20 years previously and lower than intakes reported in other countries. Changes in the sources of water meant that less water consumed was likely to come from the tap in the house and more from drinks made elsewhere, than 20 years previously. These changes have implications for estimating fluoride intake in fluoridated areas.

A lifecourse study of risk for hyperinsulinaemia, dyslipidaemia and obesity (the central metabolic syndrome) at age 49-51 years

AIMS

Suboptimal maternal nutrition and catch-up growth in early childhood predispose to insulin resistance and other components of metabolic syndrome in later life. A central metabolic syndrome (CMS) has been identified comprising obesity, dyslipidaemia and insulin resistance. This study was designed to investigate determinants of risk for CMS.

METHODS

Persons born in Newcastle in May and June 1947 (n = 358) were followed to 1996-1998. A lifecourse approach was used to estimate the proportion of variance in a summary measure of CMS at age 49-51 years accounted for by factors operating at different stages of life.

RESULTS

After adjustment for other early life variables, childhood catch-up growth in men accounted for significant variation in the CMS score independent of adult lifestyle. In adulthood, exercise level in men and smoking in both genders were independently associated with CMS. Over two-thirds of explained variation in the CMS score in women, and almost half in men, was accounted for exclusively by factors measured in adulthood.

CONCLUSIONS

While risk for CMS in men is compounded by early life disadvantage, promotion of a healthier adult lifestyle and a reduction in the number of people taking up smoking would appear to be the public health interventions most likely to reduce the prevalence of CMS in middle age.

Curcumin modifies Apc(min) apoptosis resistance and inhibits 2-amino 1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced tumour formation in Apc(min) mice

Curcumin, the active ingredient of the rhizome of Curcuma longa, promotes apoptosis and may have chemopreventive properties. This study investigates the effects of curcumin on apoptosis and tumorigenesis in male Apc(min) mice treated with the human dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Intestinal epithelial apoptotic index in response to PhIP treatment was approximately twice as great in the wild-type C57BL/6 APC(+/+) strain than in Apc(min) mice (3.7% Apc(+/+) versus 1.9% Apc(min); P < 0.001). PhIP promoted tumour formation in Apc(min) proximal small intestine (4.6 tumours per mouse, PhIP treated versus 2.1 tumours per mouse, control untreated; P < 0.05). Curcumin enhanced PhIP-induced apoptosis (4.0% curcumin + PhIP versus 2.1% PhIP alone; P < 0.01) and inhibited PhIP-induced tumorigenesis in the proximal small intestine of Apc(min) mice (2.2 tumours per mouse, curcumin + PhIP versus 4.6 tumours per mouse PhIP alone; P < 0.05). This study shows that the Apc(min) genotype is associated with resistance to PhIP-induced apoptosis in intestinal epithelium. Curcumin attenuates Apc(min) resistance to PhIP-induced apoptosis and inhibits PhIP-induced tumorigenesis in proximal Apc(min) mouse small intestine.

Susceptibility markers in colorectal cancer

Many susceptibility factors contribute to an individual's risk of developing colorectal cancer. Family history of colorectal cancer (particularly with early age of onset), maleness and increasing age are all factors associated with increasing risk. About three quarters of colorectal cancers are thought to be due to somatic mutations, and both high- and low-penetrance predisposing genes contribute to the remaining quarter of cases. Many of the highly penetrant dominant genes are known, but others remain to be identified. Describing the contribution of individual genes is likely to be very complex, as some modify the impact of other genes and other environmental factors rather than incurring a direct, easily attributable effect. The two dominant predisposing syndromes are familial adenomatous polyposis and Lynch syndrome, the first due to a mutant tumour-suppressor gene APC, and the second due to mutations in a number of genes responsible for mismatch repair in DNA at cell division. Establishing genetic susceptibility for colorectal cancer will soon be possible, and could save lives by allowing targetting of screening and the encouragement of preventive behaviours. However, there will always be a risk of making healthy people "sick" through the identification of predisposing genes, and there are many potential ways by which a gene carrier may be stigmatized by society, insurance companies and employers.

Randomised controlled trial evaluating the effectiveness of behavioural interventions to modify cardiovascular risk factors in men and women with impaired glucose tolerance: outcomes at 6 months

AIMS

To evaluate the efficacy of interventions to promote a healthy diet and physical activity in people with impaired glucose tolerance (IGT).

METHODS

A randomised controlled trial in Newcastle upon Tyne, UK, 1995-98. Participants included 67 adults (38 men; 29 women) aged 24-75 years with IGT. The intervention consisted of regular diet and physical activity counselling based on the stages of change model. Main outcome measures were changes between baseline and 6 months in nutrient intake; physical activity; anthropometric and physiological measurements including serum lipids; glucose tolerance; insulin sensitivity.

RESULTS

The difference in change in total fat consumption was significant between intervention and control groups (difference -21.8 (95% confidence interval (CI) -37.8 to -5.8) g/day, P=0.008). A significantly larger proportion of intervention participants reported taking up vigorous activity than controls (difference 30.1, (95% CI 4.3--52.7)%, P=0.021). The change in body mass index was significantly different between groups (difference -0.95 (95% CI -1.5 to -0.4) kg/m(2), P=0.001). There was no significant difference in change in mean 2-h plasma glucose between groups (difference -0.19 (95% CI -1.1 to 0.71) mmol/l, NS) or in serum cholesterol (difference 0.02 (95% CI -0.26 to 0.31) mmol/l, NS). The difference in change in fasting serum insulin between groups was significant (difference -3.4 (95% CI -5.8 to -1.1) mU/l, P=0.005).

CONCLUSIONS

After 6 months of intensive lifestyle intervention in participants with IGT, there were changes in diet and physical activity, some cardiovascular risk factors and insulin sensitivity, but not glucose tolerance. Further follow-up is in progress to investigate whether these changes are sustained or augmented over 2 years.

Comparative gastrointestinal and plasma cholesterol responses of rats fed on cholesterol-free diets supplemented with guar gum and sodium alginate

The present study investigated the digestion and cholesterol-lowering effects of the water-soluble NSP guar gum (GG) and sodium alginate (SA) in laboratory animals. Groups of five male Wistar strain rats were fed semi-purified cholesterol-free diets containing 0, 50 or 100 g NSP source/kg for 21 d which comprised a 14-d adaptation period followed by a 7-d balance period. Weight gain over the balance period and food conversion ratio decreased linearly with increasing NSP intake ( and respectively). DM digestibility decreased with increasing NSP intake and this effect was greater for SA-containing diets compared with GG-containing diets At the lower inclusion rate, 0.9-1.0 of the additional NSP was digested, but this value fell to 0.8 for both NSP sources at the 100 g/kg inclusion rate, implying that the capacity for near complete digestion of the test NSP had been exceeded. Intestinal tissue mass was increased in response to inclusion of both NSP sources. Caecal digesta pH decreased linearly with additional GG, but increased slightly with consumption of SA. Total caecal short-chain fatty acid concentrations (micromol/g caecal contents) increased markedly with 50 g GG/kg but did not increase further with 100 g GG/kg, and were slightly lower than control values in rats consuming SA. Plasma cholesterol concentration fell linearly with increasing NSP in the diet and the effect was similar for both GG and SA. Total output of faecal bile acids rose in rats fed 50 g GG/kg and 50 g SA/kg (59 micromol/7 d v. 24 micromol/7 d for control rats) with no further increase at the higher inclusion rate. These results show that SA has a strong hypocholesterolaemic effect in rats which is similar to that of GG, and that this effect is most likely to be mediated through an interruption in the entero-hepatic circulation of bile acids and not through increased hepatic supply of propionate from fermentation of the NSP in the large bowel.

Colonic crypt cell proliferation state assessed by whole crypt microdissection in sporadic neoplasia and familial adenomatous polyposis

BACKGROUND

It has yet to be established whether proliferative activity in the macroscopically normal colonic mucosa is causally correlated with neoplastic risk. Measurement of proliferative activity in human subjects is of necessity usually undertaken using indirect methods with inherent limitations, and relatively little has been published on the effect of normal biological variables on such indices.

AIMS

To establish the validity of mitosis counts following whole crypt microdissection as an index of the crypt cell proliferative state (CCPS) and to examine the effect of normal biological variables (age, sex, and colonic site) and colonic neoplasia on the mitotic index in macroscopically normal human colon.

SUBJECTS

Mucosal samples were obtained at colectomy or colonoscopy from 107 individuals (24 controls, 23 sporadic adenoma patients, 31 sporadic carcinoma patients, and 29 patients with familial adenomatous polyposis (FAP)).

METHODS

Mucosal specimens were hydrated, hydrolysed, and small groups of crypts separated from the main specimen under a dissecting microscope. The total number of mitoses/crypt were counted by one observer for each of 10 complete crypts.

RESULTS

Validation work established that whole crypt mitoses counts were reliable and reproducible. There was no relation between age and mean mitoses/crypt (Pearson correlation coefficient -0.1). The CCPS count was higher for males than for females (difference in means 2.8 (95% confidence interval 0.80-4.66)) among controls but there was no gender difference in the three disease groups. For all disease groups and controls, the crypt mitotic count showed a significant linear increase (p=0.004) from the rectum to the caecum. Biopsies from within 5 cm of the macroscopic margin of a carcinoma (near) gave a mean mitosis count of 12.6 while those from more than 10 cm (far) were lower but not significantly so (p=0.12) with a count of 9.0. The mean mitoses/crypt were similar for the controls and adenomas (5.6 and 4.7, respectively) but greater for the cancers and especially for FAP (8.3 and 14.2, respectively). Statistical analysis confirmed that there were significant differences (p<0.05) between controls and all disease groups together, between sporadic disease and FAP, and between adenoma and carcinoma subjects at each of the four colonic sites. Post hoc comparison by t test showed significantly greater CCPS for FAP compared with controls (p<0.001) and for sporadic cancer versus controls (p=0.04).

CONCLUSIONS

Whole crypt microdissection and mitosis counting is a reliable, reproducible, and robust technique for assessing CCPS in the human colon. CCPS is unaffected by age but increases from the distal to the proximal colon. CCPS is increased if a sporadic cancer is present and markedly increased in FAP. However, the precise relation of an increased CCPS to the neoplastic process remains uncertain.

Dietary strategies to reduce the burden of cancer and cardiovascular disease in the UK

The importance attributed to dietary change as a means of helping to achieve the major goals of the UK's public health policy as articulated in the Health of the Nation White paper (Department of Health, 1992) is less apparent in the most recent strategy document (Department of Health, 1999). Greater emphasis is given to amelioration of the socio-economic circumstances that are believed to contribute to inequalities in health. Better understanding of the elements of foods and diets which help protect health together with better evidence of effective dietary interventions are essential if the opportunities to use diet to reduce the burden of non-communicable diseases are to be realised. This is likely to need new research strategies that take advantage of emerging information from genomics and proteomics to produce evidence of safety, efficacy and applicability. Ethical exploitation of the rapid growth in interest in 'functional foods' by the food industry will require a level of investment in biomedical research unusual in the past.

Evidence for altered control of glucose disposal after total colectomy

Colonic fermentation of organic matter to short-chain fatty acids has been implicated in the improvement in insulin sensitivity achieved by feeding diets rich in complex carbohydrates. The present study assessed the potential role of the colon in determining postprandial glucose kinetics. Metabolic responses to a complex-carbohydrate test meal were determined in conjunction with a primed continuous infusion of D-[6,6-2H]glucose in a group of ileostomists and sex-matched controls. Glucose disposal (GD) was computed using Steele's (1959) non-steady-state kinetics on a single compartment model. Insulin sensitivity was derived using cumulative GD as the dependent variable, and time and the integrated insulin concentration as independent variables. The ileostomist group had a significantly higher postprandial plasma insulin concentration ( P = 0.034) compared with the control group, but no difference in the plasma glucose concentration. Total GD was similar in each group, although the insulin-dependent GD was substantially lower in the ileostomists (0.46 v. 0.13 mg glucose/min per pmol, P = 0.015). The ileostomist group also showed a 50% lower rate of glucose oxidation in the postprandial period (p = 0.005), although the rate of non-oxidative GD was not significantly affected. The present study indicates that loss of the colon is associated with several characteristics of the insulin resistance syndrome, and favours a view that the colon has a role in the control of postprandial glucose.

Changes to the quantity and processing of starchy foods in a western diet can increase polysaccharides escaping digestion and improve in vitro fermentation variables

This study investigated how readily achievable changes to the quantity and processing of starchy foods in a typical Western diet: (1) were reflected in levels of resistant starch (RS) and NSP excreted from the small intestine; and (2) more favourable profiles of butyrate, NH3 and phenol production. Two diets, a low-starch diet (LSD) and a high-starch, low-fat diet (HSLFD) were compared. The LSD with 20% total energy (%E) from starch was based on a 'typical' Australian diet, while the HSLFD (40%E as starch) was the same Australian diet modified by an increased content of legumes, starchy foods and coarsely-ground cereals and by a reduced fat content. Four subjects with iliostomies consumed each diet for 2 d, with ileal effluent collection on the second day. On the HSLFD compared with the LSD, RS in ileal effluent increased from from 0.49 to 1.7 g/MJ per d (P < 0.005) while ileal NSP excretion increased from 2.0 to 3.3 g/MJ per d (P < 0.05). Ileal effluents obtained after each diet were incubated for 24 h in vitro with a human faecal innoculum. After fermentation, ileal effluent from the HSLFD produced more butyrate relative to other short-chain fatty acids (17.5 v. 15.8 molar %, P < 0.005) and less phenol (2.3 v. 5.7 mg/l, P < 0.05) and NH3 (20.3 v. 23.1 mmol/l, P < 0.005) than the LSD diet. The HSLFD also generated a lower pH (6.15 v. 6.27, P < 0.05). On a wt/wt basis, RS was 2.3-fold higher in the HSLFD effluent while NSP did not increase, suggesting that the change in RS largely contributed to the fermentation effects. Changes in in vitro variables when the HSLFD ileal effluent was ground before fermentation indicated the importance of physical structure in determining ileal excretion of RS. We conclude that: (1) readily achievable modifications to the amount and processing of starchy foods in an Australian diet would produce potential benefits for in vitro fermentation variables; and (2) the physical structure of grains and cereals is important in determining access by colonic bacteria to a carbohydrate substrate.