Oxaliplatin-induced papilledema: Rare case report

Papilledema is the presence of bilateral optic disc edema in the presence of raised intracranial pressure and often is symmetric. We report a case of a 70-year-old male with rectal carcinoma on chemotherapy presented with minimal drop in visual acuity. The patient has bilateral disc edema and investigations including computed tomography and cerebrospinal fluid opening pressure were normal and no evidence of brain metastasis has been found. The patient was on oxaliplatin regimen and literature search has shown very few cases of platinum chemotherapy agents-induced papilledema. So far to our knowledge, oxaliplatin-induced papilledema has not been reported and knowing this condition can be sight saving for ill patients.

Objectively measured physical activity and longitudinal changes in adolescent body fatness: an observational cohort study

BACKGROUND

The data regarding prospective associations between physical activity (PA) and adiposity in youth are inconsistent.

OBJECTIVE

The objective of this study was to investigate associations between baseline levels of objectively measured PA and changes in adiposity over 2.5 years from mid-to-late adolescence.

METHODS

This was an observational cohort study in 728 school students (43% boys) from Cambridgeshire, United Kingdom. Fat mass index (FMI, kg m(-2) ) was estimated at baseline (mean ± standard deviation age: 15 ± 0.3 years) and follow-up (17.5 ± 0.3 years) by anthropometry and bioelectrical impedance. Habitual PA was assessed at baseline by ≥3 d combined heart rate and movement sensing. Average daily PA energy expenditure (PAEE) and the time (min d(-1) ) spent in light, moderate and vigorous intensity PA (LPA, MPA and VPA, respectively) was estimated. Multilevel models were used to investigate associations between baseline PA and change in FMI (ΔFMI). Adjustment for baseline age, sex, follow-up duration, area-level socioeconomic status, season of PA assessment, sedentary time, energy intake and sleep duration was made; baseline FMI was also added in a second model.

RESULTS

FMI increased significantly over follow-up (0.6 ± 1.2 kg m(-2) , P < 0.001). Baseline PAEE and LPA positively predicted ΔFMI in overfat participants (P ≤ 0.030), as did VPA in initially normal fat participants (P ≤ 0.044). There were further positive associations between PAEE and ΔFMI in normal fat participants, and between MPA and ΔFMI in both fat groups, when adjusted for baseline FMI (P ≤ 0.024).

CONCLUSIONS

Baseline PAEE and its subcomponents were positively associated with small and unlikely clinically relevant increases in ΔFMI. These counter-intuitive findings may be explained by behavioural changes during the course of study follow-up.

Fruit, vegetable and vitamin C intakes and plasma vitamin C: cross-sectional associations with insulin resistance and glycaemia in 9-10 year-old children

AIM

To examine whether low circulating vitamin C concentrations and low fruit and vegetable intakes were associated with insulin resistance and other Type 2 diabetes risk markers in childhood.

METHODS

We conducted a cross-sectional, school-based study in 2025 UK children aged 9-10 years, predominantly of white European, South-Asian and black African origin. A 24-h dietary recall was used to assess fruit, vegetable and vitamin C intakes. Height, weight and fat mass were measured and a fasting blood sample collected to measure plasma vitamin C concentrations and Type 2 diabetes risk markers.

RESULTS

In analyses adjusting for confounding variables (including socio-economic status), a one interquartile range higher plasma vitamin C concentration (30.9 μmol/l) was associated with a 9.6% (95% CI 6.5, 12.6%) lower homeostatic model assessment of insulin resistance value, 0.8% (95% CI 0.4, 1.2%) lower fasting glucose, 4.5% (95% CI 3.2, 5.9%) lower urate and 2.2% (95% CI 0.9, 3.4%) higher HDL cholesterol. HbA1c concentration was 0.6% (95% CI 0.2, 1.0%) higher. Dietary fruit, vegetable and total vitamin C intakes were not associated with any Type 2 diabetes risk markers. Lower plasma vitamin C concentrations in South-Asian and black African-Caribbean children could partly explain their higher insulin resistance.

CONCLUSIONS

Lower plasma vitamin C concentrations are associated with insulin resistance and could partly explain ethnic differences in insulin resistance. Experimental studies are needed to establish whether increasing plasma vitamin C can help prevent Type 2 diabetes at an early stage.

Trends in food consumption over 30 years: evidence from a British birth cohort

BACKGROUND/OBJECTIVES

As populations are ageing, more emphasis is placed on healthy ageing. Over the past decades, food consumption patterns and food availability have also changed drastically, and therefore this study aimed to describe these changes in an ageing population.

SUBJECTS/METHODS

Food consumption of participants from the Medical Research Council National Survey on Health and Development, a British birth cohort study, was assessed using a 5-day estimated food records at 60-64 years (2006-11), 53 years (1999), 43 years (1989) and 36 years (1982). Only those who recorded ⩾3 days at all four time points were included in the analyses, n=989 (n=438 men and n=551 women); trends were tested using the Friedman test.

RESULTS

Consumption of white bread, whole milk, fats and oils, meat and meat products, alcoholic drinks, coffee, sugar, preserves and confectionery decreased (P<0.001), whereas consumption of wholemeal and granary bread, semi-skimmed milk, fish and fruit and vegetables increased (P<0.001) over time. These observed changes in food consumption reflect a healthier diet, for example, replacement of white bread by granary and wholemeal bread, lower consumption of red and processed meats, somewhat higher consumption of fish, higher consumption of vegetables and lower consumption of coffee. This could partly be because of ageing of the cohort or compliance with dietary recommendations, facilitated by greater availability of healthier foods, such as semi-skimmed milk and wholegrain bread, in the UK.

CONCLUSIONS

The changes in food consumption in this British birth cohort over the past three decades are encouraging and reflect a healthier diet in the later years.

Irregular consumption of energy intake in meals is associated with a higher cardiometabolic risk in adults of a British birth cohort

BACKGROUND/OBJECTIVES

A potential risk factor for cardiometabolic diseases is irregular or inconsistent eating, however, research on this topic is scarce. We aimed to study associations between irregular consumption of energy intake in meals and cardiometabolic risk factors.

SUBJECT AND METHODS

Dietary intake data were derived from 5-day estimated diet diaries of 1768 participants of the National Survey of Health and Development. Energy intakes during predefined meals (breakfast, lunch, dinner, between meals) and daily totals were analyzed using a score for irregularity based on the deviation from the 5-day mean energy intake. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for having the metabolic syndrome or one of its components. Models were adjusted for sex, physical activity, socioeconomic status, marital status and smoking.

RESULTS

Irregularity scores of energy intake ranged from 0-160 and were highest for between meals. An increased risk of the metabolic syndrome was associated with more irregular energy intake during breakfast (OR=1.34 (0.99, 1.81); P trend=0.04) and between meals (OR=1.36 (1.01, 1.85); P trend=0.04). Moreover, increased waist circumference was associated with irregular energy intake during breakfast (OR=1.90 (1.47, 2.45); P trend <0.01), evening meal (OR=1.36 (1.06, 1.75); P trend=0.02) and daily total (OR=1.34 (1.04, 1.72); P trend=0.01). No significant associations were found for the other components of the metabolic syndrome.

CONCLUSIONS

Individuals with a more irregular intake of energy, especially during breakfast and between meals, appeared to have an increased cardiometabolic risk.

Diurnal eating rhythms: association with long-term development of diabetes in the 1946 British birth cohort

BACKGROUND AND AIMS

Few studies have described the association between time-of-day of macronutrient intake and diabetes. This study examined the prospective association between time-of-day and nutrient composition of eating occasions in relation to diabetes incidence in the 1946 British birth cohort.

METHODS AND RESULTS

The study included 1618 survey members who completed dietary assessment at age 43 (1989) and for whom data on glycosylated haemoglobin at age 53 years (1999) were available. Diet was assessed using 5d estimated diaries, divided into seven meal slots: breakfast, mid-morning, lunch, mid-afternoon, dinner, late evening and extras. Diabetes was defined by glycosylated haemoglobin (HbA1c) ≥ 6.5% or diabetes medication use. The association between time-of-day of macronutrient intake at age 43 years and diabetes at age 53 years was assessed using logistic multivariate nutrient density models after adjustment for potential confounders. There were 66 cases of diabetes at age 53 years. Survey members with diabetes obtained 50.4% of their energy from carbohydrate at breakfast compared to 55.9% in survey members without diabetes (P = 0.001). Increasing carbohydrate intake at breakfast at the expense of fat was related to lower odds ratio (OR) of diabetes (OR = 0.86; 95%CI = 0.79-0.93; P < 0.001). This relationship was attenuated after adjustment for body mass index and waist circumference.

CONCLUSION

Increasing energy intake from carbohydrate at the expense of fat at breakfast is inversely associated with 10-year diabetes incidence. However, further studies are required to elucidate whether the type or source of carbohydrates or fat influences the above association.

Biomarkers of diabetes risk in the National Diet and Nutrition Survey rolling programme (2008-2011)

This study describes the distribution of glycosylated haemoglobin (Hb_A1c) and glucose concentrations in the combined year 1 (2008–2009), year 2 (2009–2010) and year 3 (2010–2011) of the National Diet and Nutrition Survey (NDNS) rolling programme. The NDNS rolling programme is a nationally representative survey of food consumption, nutrient intakes and nutritional status of people aged 1.5 years and over living in England, Wales, Scotland and Northern Ireland. The study population comprised survey members who completed three or four days of dietary recording and who provided a blood sample. After excluding survey members with self-reported diabetes (n=25), there were 1016 results for Hb_A1c and 942 for glucose (not the same individuals in each case). Around 5.4% of men and 1.7% of women aged 19–64 years, and 5.1% of men and 5.9% of women aged ≥65 years had impaired fasting glucose (glucose concentrations 6.1–6.9 mmol/L). Over 20% of men aged ≥65 years had fasting glucose concentrations above the clinical cut-off for diabetes (≥7 mmol/L) compared to 2.1% of women of similar age (p=0.007). Similarly, 16.4% of men had Hb_A1c concentrations ≥6.5%, compared to 1.5% of women (p=0.003). Children and teenagers had fasting glucose and Hb_A1c values largely within the normal range. To conclude, this is the first study to provide data on the distribution of Hb_A1c and glucose concentrations in a nationally representative sample of the British population. The high prevalence of men aged ≥65 years with Hb_A1c and glucose concentrations above the clinical cut-off of diabetes warrants further attention.

Mapping low intake of micronutrients across Europe

Achieving an understanding of the extent of micronutrient adequacy across Europe is a major challenge. The main objective of the present study was to collect and evaluate the prevalence of low micronutrient intakes of different European countries by comparing recent nationally representative dietary survey data from Belgium, Denmark, France, Germany, The Netherlands, Poland, Spain and the United Kingdom. Dietary intake information was evaluated for intakes of Ca, Cu, I, Fe, Mg, K, Se, Zn and the vitamins A, B₁, B₂, B₆, B₁₂, C, D, E and folate. The mean and 5th percentile of the intake distributions were estimated for these countries, for a number of defined sex and age groups. The percentages of those with intakes below the lower reference nutrient intake and the estimated average requirement were calculated. Reference intakes were derived from the UK and Nordic Nutrition Recommendations. The impact of dietary supplement intake as well as inclusion of apparently low energy reporters on the estimates was evaluated. Except for vitamin D, the present study suggests that the current intakes of vitamins from foods lead to low risk of low intakes in all age and sex groups. For current minerals, the study suggests that the risk of low intakes is likely to appear more often in specific age groups. In spite of the limitations of the data, the present study provides valuable new information about micronutrient intakes across Europe and the likelihood of inadequacy country by country.

Time-of-day and nutrient composition of eating occasions: prospective association with the metabolic syndrome in the 1946 British birth cohort

Background:

Diet is a key modifiable factor in the prevention and treatment of the metabolic syndrome. However, few studies have examined the prospective association between time-of-day of nutrient intake and the metabolic syndrome.

Objective:

To examine the association between time-of-day and nutrient composition of eating occasions and the long-term development of metabolic syndrome in the Medical Research Council (MRC) National Survey of Health and Development (NSHD; 1946 British birth cohort).

Methods:

The analysis comprised 1488 survey members who completed at least 3 days of estimated diet records at age 43 years (1989) and for whom data on metabolic syndrome at age 53 years (1999) were available. Dietary records were divided into seven meal slots: breakfast, mid-morning, lunch, mid-afternoon, dinner, late evening and extras. Metabolic syndrome was defined by the criteria of the adult treatment panel (ATPIII8), and was modified to include glycosylated haemoglobin instead of fasting glucose. Associations between time-of-day of nutrient intake at age 43 years and prevalence of metabolic syndrome at age 53 years were assessed using multivariate nutrient density logistic models after adjustment for sex, social class, smoking status, region, alcohol intake and recreational physical activity.

Results:

There were 390 cases of metabolic syndrome at age 53 years. Substituting 5% of energy from carbohydrate for a similar amount of energy from fat at breakfast (odds ratio=0.93; 95% confidence interval=0.89–0.98; P=0.002) and mid-morning at age 43 years (odds ratio=0.96; 95% confidence interval=0.93–0.99; P=0.011) was associated with lower odds of the metabolic syndrome at age 53 years. Carbohydrate intake at breakfast or mid-morning was particularly protective against abdominal obesity (P⩽0.001). Increasing carbohydrate intake at breakfast while simultaneously decreasing fat intake was also negatively related to triacylglycerols (P⩽0.001).

Conclusions:

Increasing carbohydrate intake in the morning while simultaneously reducing fat intake could be protective against long-term development of the metabolic syndrome and its components.

Daily profiles of energy and nutrient intakes: are eating profiles changing over time?

BACKGROUND/OBJECTIVES:

Associations between timing of eating occasions and their nutrient composition and health have been described in interventional and cross-sectional studies. However, data from longitudinal data are limited. This study examined 17-year changes in energy and macronutrient intake across eating occasions in the 1946 British birth cohort.

SUBJECTS/METHODS:

Data were obtained from the 1946 British birth cohort. Cohort members completed 5d-estimated diaries at ages 36 (1982), 43 (1989) and 53 years (1999). Data from subjects who provided dietary data at all three time points were analysed (n=1253). Repeated-measures analysis of variance with post hoc Bonferroni's adjustment was used to examine changes in energy and macronutrient at breakfast, mid-morning, lunch, mid-afternoon, evening and extra meal slots between 1982 and 1999. Analyses were stratified by sex and social class.

RESULTS:

The proportion of energy and macronutrients consumed at lunch declined between 1982 and 1999, which was compensated by a greater intake in the mid-afternoon and evening. This trend was seen across sex and social class, although women and adults with a non-manual occupation reported greater energy, carbohydrate and non-starch polysaccharide intake at breakfast in 1982 and had a higher protein intake in the evening compared with men and adults with a manual occupation.

CONCLUSIONS:

The timing of energy and nutrient intake has shifted slightly over time, with a greater proportion of intake later in the day. The association between the observed sex and occupational social class differences in eating profiles and chronic disease warrants investigation.

Meat consumption after disaggregation of meat dishes in a cohort of British adults in 1989 and 1999 in relation to diet quality

BACKGROUND/OBJECTIVES

The aim of the study was to quantify more precisely the meat intake of a cohort of adults in the UK by disaggregating composite meat dishes.

SUBJECTS/METHODS

Subjects were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort. Five-day diaries were collected from 2256 men and women in 1989 and 1772 men and women in 1999. From the details provided, composite meat dishes were broken down into their constituent parts and the meat fraction was added to meat portions only. Meat intake was classified as red meat, processed meat and poultry.

RESULTS

Meat consumption without disaggregation of meat dishes resulted in a mean overestimation of 50% in men and 33% in women. Red meat consumption fell between 1989 and 1999 from 51.7 to 41.5 g per day in men and 35.7 to 30.1 g per day in women. Poultry consumption rose from 21.6 to 32.2 g per day in men and 18.2 to 29.4 g per day in women. Re-calculating red meat intakes resulted in the percentage of subjects in 1999 consuming more than the recommendation of the World Cancer Research Fund falling from 30 to 12%. Increasing consumption of red and processed meat was associated with increased intakes of energy, fat, haem iron, zinc and vitamin B(12), and lower intake of fibre. Increased sodium intake was associated with increased consumption of processed meat.

CONCLUSIONS

Disaggregation of meat dishes provided a more precise estimate of meat consumption. The quantity of red or processed meat in the diet was reflected in the nutrient content of the entire diet.

Consumption of red or processed meat does not predict risk factors for coronary heart disease; results from a cohort of British adults in 1989 and 1999

OBJECTIVES

To investigate whether a high consumption of red or processed meat is associated with increased risk of coronary heart disease (CHD).

SUBJECTS/METHODS

The subjects were 517 men and 635 women, who were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort. Assessment of diet was carried out at two time points 1989 and 1999 with outcome measures collected in 1999. Food intake data were recorded in 5-day diaries. Meat consumption was estimated by adding individual meat portions to the meat fractions of composite dishes.

RESULTS

There was no significant association between red or processed meat consumption in 1989 and 1999 and serum cholesterol concentrations and blood pressure measured in 1999. The combined intake of red and processed meat in 1999 had a significant positive association with blood pressure in men only. Red and processed meat intakes in 1989, separately and combined, had a significant positive association with waist circumference in 1999: a 10 g increase in red meat consumption accounted for a 0.3 cm increase in waist circumference; P=0.04 (men), 0.05 (women).

CONCLUSIONS

Consumption of red or processed meat assessed separately was not related to the major risk factors for CHD but contributed to increased waist circumference that has also been identified as a risk factor.

Whole grains and adiposity: little association among British adults

OBJECTIVES

To examine associations of whole-grain intake with body weight and adiposity in two nationally representative samples of British adults.

SUBJECTS/METHODS

A total of 2064 adults aged 16-64 years in 1986-1987, 1599 adults aged 19-64 years in 2000-2001. Whole-grain intake (g day(-1) and 16-g amounts) was estimated from consumption of all foods with >or=10, >or=25 or >or=51% whole-grain content, using 7-day weighed dietary records. Body weight, body mass index (BMI) and, in 2000-2001, waist circumference (WC) were measured. BMI and WC were considered as continuous and categorical variables. For each survey, associations of whole-grain intake with body weight and anthropometric indices were examined in men and women separately, before and after adjustment for age, occupational social class, smoking habit, region, season and, in 2000-2001, misreporting.

RESULTS

In 1986-1987, whole-grain intake was inversely associated with percentage of men classified using BMI as obese (P=0.008, trend), independent of other factors. However, intake was not associated with body weight or prevalence of overweight. No corresponding associations were observed among women. In 2000-2001, whole-grain intake was not associated with body weight, BMI or WC.

CONCLUSIONS

Two national surveys of British adults, with detailed quantitative estimates of whole-grain intake, provide little evidence of an association of whole-grain intake with body weight or measures of adiposity.

Haem and non-haem iron intake through 17 years of adult life of a British Birth Cohort

An investigation was carried out to determine whether there were significant changes in the intake of haem and non-haem Fe of adult men and women in the UK from 1982 (aged 36 years) to 1999 (aged 53 years). The 1253 subjects studied were members of the Medical Research Council National Survey of Health and Development; a longitudinal study of a nationally representative cohort of births in 1946. Food intake was recorded in a 5-d diary at age 36 years in 1982, 43 years in 1989 and 53 years in 1999. Outcome measures were mean intakes of total Fe, haem and non-haem Fe, by year, gender and food source. There were significant changes in total Fe, haem Fe and non-haem Fe intake over the three time points. Total Fe intake was significantly higher in 1989 than in 1982 or 1999 for both men and women but haem Fe was significantly lower in 1999 mainly due to a 40% fall in haem Fe from beef during this period. Haem Fe from processed meats fell by more than 50% between 1989 and 1999 but that from poultry rose by more than 50%. Cereal foods remained the most important source of non-haem Fe and the contribution from breakfast cereals rose relative to that of bread over the 17 years. Several factors could be responsible for these changes, particularly the importance of the epidemic of BSE from 1990. The possible advantages of a lower haem Fe intake in older subjects are discussed.

Whole-grain intake of British young people aged 4–18 years

Inverse associations between whole-grain food consumption and risk of CVD, some cancers and type 2 diabetes have been reported. However, there are few reports of whole-grain intake, particularly among young people. The objective of the present study was to estimate whole-grain intake in a nationally representative sample of young people aged 4–18 years living in Great Britain. Whole-grain intake was estimated using 7d weighed dietary records from 1583 young people who participated in the cross-sectional National Diet and Nutrition Survey in 1997. Whole-grain intake was quantified from the consumption of all foods containing ≥10% whole-grain content. Median whole-grain intake was 7g/d (interquartile range 0–19g/d), with a corresponding mean of 13 (sd18) g/d. Intake was significantly lower among young people whose head of household had a manual occupation, but did not differ significantly by sex, age, region or season. There was no whole-grain intake for 27% of participants. The percentages for less than one and less than three 16g amounts of whole-grain intake per d were 70 and 94, respectively, while corresponding percentages based on 20g amounts were 76 and 97. Foods with <51% whole-grain content provided 28% of whole-grain intake overall, with a higher percentage in older adolescents. The main sources of whole-grain intake were breakfast cereals (56%) and bread (25%). The present study provides the first quantification of absolute whole-grain intake from all significant food sources in any representative age group in the UK. Although there is some debate regarding the quantity of whole grains required for good health, whole-grain intake among British young people is low.

Use of food labels and beliefs about diet-disease relationships among university students

OBJECTIVE

The purpose of this study was to measure the reported use of nutrition information on food labels by a population of university students and to determine if label users differed from non-users in terms of gender and specific beliefs related to label information and diet-disease relationships, specifically fat and heart disease and fibre and cancer.

DESIGN

A single-stage cluster sampling technique was used. Data was obtained using a self-administered, validated questionnaire.

SETTING

The present investigation took place at the University of Saskatchewan, Canada in the autumn of 1997.

SUBJECTS

: A total of 553 students in randomly selected classes in the College of Arts and Science took part in the survey (92% response rate). The sample consisted of roughly equal numbers of males and females, most between the ages of 18 and 24.

RESULTS

There were approximately equal numbers of label users and non-users among males, while label users outnumbered non-users by almost four to one among females. The importance of nutrition information on food labels was the only belief that differed significantly between label users and non-users for both sexes. For females, no other beliefs distinguished label users from non-users. However, for males, significant differences were found between label users and non-users on the beliefs that nutrition information is truthful and that a relationship between fibre and cancer exists.

CONCLUSIONS

Females appear to use food labels more often than do males. The only consistently observed difference between label users and non-users (male and female) was that users believed in the importance of nutrition information on food labels while non-users did not.

Association between dietary fiber intake and the folate status of a group of female adolescents

The main objective of this study was to assess the association between dietary fiber intake and the folate status of Canadian female adolescents. We also assessed dietary folate intakes and evaluated the prevalence of biochemical folate deficiency in these subjects. Female adolescents aged 14-19 y (n = 224) were recruited and fasting blood samples were collected. Dietary intakes (3-d food record) were recorded and participants were classified as lactoovovegetarians, semivegetarians, or omnivores on the basis of food-consumption patterns assessed with food-frequency questionnaires. Fourteen percent, 17%, and 26% of lactoovovegetarians, semivegetarians, and omnivores, respectively, had dietary folate intakes below their predicted requirements; 1%, 4%, and 23%, respectively, had serum folate concentrations indicative of deficiency. Despite low dietary folate intakes and serum folate concentrations, few subjects had homocysteine concentrations indicative of deficiency, suggesting that the degree of folate depletion had not yet produced functional consequences. Most important, results suggest that the consumption of nonstarch polysaccharide is significantly associated with serum folate concentrations (P < 0.001). For each 1-g increase in nonstarch polysaccharide intake, a 1.8% increase in serum folate concentration is expected. In summary, we propose that an increase in nonstarch polysaccharide intake may promote the intestinal biosynthesis of folate, providing a complementary strategy to enhance the folate nutriture of humans.

Effect of green lentils on colonic function, nitrogen balance, and serum lipids in healthy human subjects

Green lentils are an increasingly popular food, but their effects on human colonic function and serum lipids have been studied little. Nine healthy males aged 19-38 y consumed for 3-wk periods a controlled Western diet and the same diet supplemented with 130 g dry lentils/d [which contained 11.8 g non-starch polysaccharide (NSP)] incorporated into loaves, cakes, and soups. Protein was equilibrated with soy protein isolate and carbohydrate with soft drinks. Radioopaque markers were used to calculate mean transit time (MTT) and to correct fecal weight for infrequency of bowel movements. Feces were collected throughout the study and blood was taken on 2 d at the end of each period. Lentils increased fecal weight from 131 +/- 12 g/d (means +/- SEM) to 189 +/- 17.4 g/d (44.9%) (P < 0.005). MTT was unchanged: 46 +/- 6 h for the control diet and 43 +/- 4 h for the lentils (NS). Fecal nitrogen was increased to 2.49 +/- 0.08 g/d for lentils compared with 1.74 +/- 0.09 g/d for the control diet (P < 0.001) and urine nitrogen decreased to 15.31 +/- 0.52 g/d with the lentils compared with 15.90 +/- 0.51 g/d for the control diet (P < 0.05); nitrogen balance was unaffected. Serum lipids were unchanged by addition of lentils to the diet. Green lentils were effective in increasing fecal weight and can therefore make a valuable contribution to a healthy diet.

Intake of carbohydrate and its components--international comparisons, trends over time, and effects of changing to low-fat diets

Carbohydrate constitutes the major source of dietary energy for all peoples of the world. However, it has been difficult to make accurate determinations of intakes of carbohydrate and its constituents because of lack of individual assessments in which carbohydrate components are included. For many countries, only food balance information is available and values for total carbohydrate are often derived by difference. Available information indicates that carbohydrate consumption decreased in many industrialized nations as prosperity led to an increased consumption of fat. Fat intakes have fallen over the past two decades and carbohydrate intakes have increased, but still do not approach the 60-70%contribution of carbohydrate to total energy in developing countries. A negative image for carbohydrate has led to a reluctance to accept it as a legitimate dietary component, particularly in North America. New evidence of the beneficial effects of starch in the diet indicates that increased consumption of carbohydrate, especially in the form of starch, should be promoted in Western countries.

The tar reduction study: randomised trial of the effect of cigarette tar yield reduction on compensatory smoking

BACKGROUND

Observational and short term intervention studies have reported that smokers of low tar cigarettes inhale more deeply (that is, compensate) than those who smoke high tar cigarettes. To quantify this effect a long term randomised trial was conducted on the effects of switching to low tar cigarettes.

METHODS

The trial was carried out between April 1985 and March 1988 among cigarette smokers in the British Civil Service, measuring blood carboxyhaemoglobin (COHb) levels and serum cotinine levels as markers of tobacco smoke intake. Volunteers first switched to a cigarette brand yielding around 10% less tar than their usual brand to identify smokers able to change brand. The 434 subjects who successfully switched were then randomly allocated to one of three groups: (a) "fast reduction" group which changed to a brand of cigarettes with a tar yield of about half that of their usual brand; (b) "slow reduction" group which reduced to the same level in steps over several months; and (c) a control group which continued smoking cigarettes with a tar yield 10% lower than their usual brand.

RESULTS

Over the course of the trial cigarette consumption declined slightly in all three groups. In both the "fast reduction" and the "slow reduction" groups, intake of COHb and cotinine was reduced, though not to the same extent as the yield reduction. Comparison of the results before randomisation with those at the end of the trial showed that a reduction in carbon monoxide yield of 45% was associated with a decrease in carbon monoxide intake of 19% (95% confidence interval 14% to 24%) and that a reduction in nicotine yield of 40% was associated with an 11% (6% to 16%) reduction in nicotine intake, reflecting relative intakes of about 1.5 for both carbon monoxide and nicotine in the "fast reduction" group. Results were similar in the "slow reduction" group with a 42% reduction in carbon monoxide yield, a 16% (11% to 22%) reduction in carbon monoxide intake, a 37% reduction in nicotine yield, and a 6% (0% to 13%) reduction in nicotine intake. Estimates of compensation derived from these results were 65% for carbon monoxide, 79% for nicotine, and 62% for tar.

CONCLUSIONS

Compensation, demonstrated when switching from a high tar cigarette to a low tar one, was incomplete. Advising people who have failed to give up smoking to switch to low tar cigarettes will reduce the intake of smoke constituents to a small extent. This would be expected to decrease their risk of smoking-related diseases, although by a smaller amount than would be achieved by giving up smoking altogether.

Whole grains--impact of consuming whole grains on physiological effects of dietary fiber and starch

Much of the present research on the physiological effects of dietary fiber and starch has been done on sources isolated from the parent material, and it is not clear whether they have the same effects if fed in the intact or whole grain. For dietary fiber, physiological effect depends on extent of fermentation in the large intestine, and this is influenced by chemical composition, solubility, physical form, and presence of lignin or other compounds. All of these factors are altered by isolation of a fiber source from the whole grain, and hence effects of eating fiber vary. Similarly, physical form and presence in the whole grain will affect digestibility of starch in the small intestine, which in turn influences the glycemic response and colonic effects determined by the extent of malabsorption and entry into the colon. Starch that enters the colon is fermented and produces short-chain fatty acids, particularly butyrate, which is necessary to maintain a healthy mucosa. Hence, their presence within the whole grain may have important implications for health for both dietary fiber and starch. Evidence indicates that such effects are beneficial and that whole-grain consumption should be encouraged.

Trends in individual fat consumption in the UK 1900-1985

Mortality from coronary heart disease is decreasing in a number of Western countries, although the pattern of the decrease differs from country to country. In the UK the mortality rate from coronary heart disease has declined since 1979, whereas in the USA mortality from this disease began to fall in 1968 and has continued since that time. Of many factors suggested as reasons for the decline, diet has been implicated, particularly dietary fat intake. However, food balance information suggests little change in fat intake. A recent examination of all published studies from the USA where individual fat intake has been reported indicated that fat intake in that country has fallen steadily since the mid 1960s. The present study describes a similar compilation of all published studies from the UK giving individual fat intakes. Ninety-seven studies, representing information for 24,045 individuals, were used. Studies ranged in size from two to 3581 individuals and were drawn from all regions of the UK. Most studies used 7 d weighed intakes as the method of dietary assessment. Quadratic regression equations were applied to the fat intakes from all studies over time, with each study weighted by the number of individuals surveyed. Data were also divided into 10-year periods and weighted fat intakes for each decade were calculated. Data were expressed for all studies, then subdivided into males, females, children and the elderly. Comparisons between Scotland and the South-East of England were made. Results indicate that fat represented 30% or less of dietary energy in the UK until the 1930s, when it began to rise. This rise was curtailed by rationing during and after the Second World War, after which the rise continued, reaching a plateau of about 40% energy in the late 1950s, with little change until the late 1970s. Trends were similar in all age-groups, but less change has occurred recently in Scotland compared with South-East England. These results differ from the pattern in the USA and suggest that if greater changes in mortality from coronary heart disease are to be seen in the UK a greater reduction in dietary fat intake will have to occur.

Molecular structures of gum exudates from Hakea species

Partial acid-hydrolysis of the gum exudates from Hakea sericea and H. gibbosa yields L-arabinose, D-galactose, D-xylose, D-mannose, D-glucuronic acid, the aldobiouronic acid GlcA (beta 1,2)Man, and a dimer of this acid alpha-linked from D-Man to O-4 of GlcA. Methylation analysis showed the modes of linkage of the sugar units to be typical of those present in plant polysaccharide exudates of the arabinogalactan type, while partial acid hydrolysis and Smith degradations established the position of linkage of the peripheral sugar assemblies at O-3 of D-Man in the interior core. Some minor differences were noted between the molecular structures of the gums from these two species of Hakea, the Gal:Ara ratio being higher for H. sericea gum.

The gum exudate of Encephalartos friderici-guilielmi

Studies of the structure of the polysaccharide gum exudate from Encephalartos friderici-guilielmi (a Cycad) confirmed its resemblance to those from other species of the same genus. Partial acid hydrolysis gave numerous products which showed a strong correlation with those from E. longifolius gum. The course of sequential Smith degradations was monitored by analysis of the molecular weights and composition of the products. The mild acid-hydrolysis step of the Smith degradation proceeded in two stages, the second being very slow but yielding a (1-->3)-D-galactan with < 20% of other residues (D-mannose, and some L-arabinose and L-rhamnose). A tentative formulation of the gum shows L-rhamnose and D-glucuronic acid residues exterior to a branched D-galactan framework; these structures are 3-linked to D-mannose, through D-galactopyranosyl or possibly L-arabinopyranosyl residues, within mannoglucuronoglycan chains. Other units occupy O-4 of D-mannose.

Trace element intakes and dietary phytate/Zn and Ca x phytate/Zn millimolar ratios of periurban Guatemalan women during the third trimester of pregnancy

Repeated 24-h recalls (9-14/subject) were conducted on 52 periurban Guatemalan pregnant women aged 25 +/- 5 y (means +/- SD). Intakes of energy, protein, calcium, zinc, copper, manganese, nonstarch polysaccharide (NSP), phytate, and millimolar ratios of phytate to zinc and (calcium x phytate) to zinc were calculated from food-composition values on the basis of chemical analysis and the literature. Mean (+/- SD) daily intakes were as follows: energy 8694 +/- 1674 kJ, protein 63.0 +/- 13.3 g, calcium 727 +/- 163, zinc 11.3 +/- 2.7, copper 1.3 +/- 0.3, manganese 2.8 +/- 0.6, phytate 2254 +/- 773 mg/d, NSP 26.6 +/- 6.9 g, phytate/zinc 18.8 +/- 4.2, (calcium x phytate)/zinc 706 +/- 21 mmol/MJ. Ninety-four percent had zinc intakes below the recommendations (15 mg) of WHO and the US recommended dietary allowances, assuming 20% absorption. Tortillas were a major source of zinc (46%), copper (20%), manganese (23%), calcium (39%), phytate (68%), and NSP (50%); 19% zinc from flesh foods. Thirty-eight percent had phytate-zinc ratios > 20; 94% had millimolar ratios of (calcium x phytate) to zinc per MJ > or = 22. The high prevalence of millimolar ratios of phytate to zinc and (calcium x phytate) to zinc per MJ above 20 and 22, respectively, may compromise zinc nutriture.

The gum exudate of Encephalartos longifolius Lehm. (female): further hydrolytic studies

Sequential, acid hydrolysis of the gum exudate from Encephalartos longifolius cones gave the neutral disaccharides beta-Gal-(1-->3)-Ara (1), beta-Gal-(1-->3)-Gal, and beta-Gal-(1-->6)-Gal; the triouronic acid beta-GlcA-(1-->6)-beta-Gal-(1-->3)-Ara (2); and the biouronic acids described earlier, namely, beta-GlcA-(1-->6)-Gal (3), beta-4-O-MeGlcA-(1-->6)-Gal, and beta-GlcA-(1-->2)-Man (4). Oligomers up to the tetramer of beta-GlcA-(1-->2)-Man alpha-linked through O-4 of GlcA characterised the inner, core region of the complex acidic polysaccharide. Alternating GlcA and Man residues were indicated by FABMS of methylated, acid-degraded gum. The presence of the constituent sugar units was confirmed by methylation of the gum and partition chromatography of the products of acid hydrolysis. Partial hydrolysis gave fractions containing terminal and in-chain GlcA attached to Gal and Man. Base-catalysed degradation of the methylated products showed Rha to be exterior to GlcA in the periphery.

Starch and dietary fibre: their physiological and epidemiological interrelationships

Until the 1980s, starch in the human diet was assumed to be totally degraded and absorbed in the small intestine. Several lines of evidence since then have indicated that this is not the case, including studies of factors controlling stool output, stool bulk on elemental diets, epidemiological studies of starch intakes in developed versus developing nations, and indications using breath hydrogen that fermentation takes place in the large intestine when starch is fed. Of the few direct estimations of starch escaping absorption in the small intestine that have been carried out, one has been conducted using intubation of healthy volunteers, where two different starch meals were fed and samples aspirated from the terminal ileum. This study demonstrated that 8-10% starch escaped absorption on average, with subjects varying from 2 to 20%. Hence a sizeable proportion of starch consumed daily may reach the large intestine, with important physiological consequences. Neither small intestinal transit time nor volume of flow were related to the extent of starch malabsorption in this study. However, many factors may play a role in the extent of malabsorption, and research is continuing to investigate physiological and food characteristics that may influence the digestion and absorption of starch.

Trends in individual consumption of dietary fat in the United States, 1920-1984

Coronary heart disease mortality has declined in the United States since 1968. Because diet has been implicated, a search was conducted of published individual assessments of food intake since 1920. One hundred seventy-one studies, ranging from 8 to 20,000 subjects and covering all ages, all ethnic groups, and both sexes, were analyzed by regression, with values weighted by number of subjects in each study. Results show fat intakes rising from approximately 34% energy in the 1930s to 40-42% in the late 1950s to mid 1960s then falling steadily to approximately 36% energy in 1984. This trend was seen for all age and sex groups. Saturated and monounsaturated fatty acid intakes fell from 18-20% energy in the early 1950s to 12-13% energy in 1984 whereas polyunsaturated fatty acid intakes rose from 2-4% energy to 7.5%. These results differ markedly from food supply trends and indicate a fall in US fat intake, which preceded the decline in heart disease mortality.

The use of bacteriophage-mediated depolymerisation in investigations of the structure of the capsular polysaccharide from Klebsiella serotype K71

The structure (1) of the heptasaccharide repeating-unit of the capsular polysaccharide from Klebsiella serotype K71 follows from methylation analysis and n.m.r. and mass-spectrometric studies of the oligosaccharides obtained on depolymerisation of the polysaccharide with a bacteriophage-borne endo-rhamnosidase. [formula; see text].

Bacteriophage-associated lyase activity against Klebsiella serotype K64 capsular polysaccharide

Bacteriophage phi 64 possesses a lyase that depolymerises the capsular polysaccharide of Klebsiella K64 into a hexasaccharide having an unsaturated derivative of glucuronic acid at the non-reducing end (1). The unsaturated hex-4-enuronic acid residue generated was characterised spectroscopically (u.v. and n.m.r.) and by g.l.c.-m.s. after hydrogenation of the double bond. Partial hydrolysis, Smith degradation, methylation analysis, and n.m.r. spectroscopy have been used to establish the structures of oligosaccharides produced from the polysaccharide. Evidence from 1H-n.m.r. spectroscopy indicates that the D-Man rho residue that undergoes fission is beta. (Formula: see text).

Effect of changing transit time on colonic microbial metabolism in man

An investigation was made of the effect of changing mean transit time (MTT) by administration of drugs which affect colonic motility on faecal microbial mass in man. Senokot was used to accelerate and codeine and/or loperamide to prolong transit in subjects maintained on a constant high fibre diet. Doses of Senokot or codeine/loperamide were adjusted to halve or double transit time measured during a three week control period on diet alone. Stools were collected throughout and analysed for bacterial mass by a gravimetric procedure. Transit was measured by a continuous marker method. Senokot decreased mean transit time from 63.9 to 25.0 hours (n = 6), with increased stool weight from 148 to 285 g/day. Bacterial mass increased in all subjects from a mean of 16.5 to 20.3 g/day (dry weight) (p less than 0.025). Codeine/loperamide increased mean transit time from 47.1 to 87.6 hours (n = 5), with decreased stool weight from 182 to 119 g/day. Bacterial mass decreased in all but one subject from a mean of 18.9 to 16.1 g/day (NS). There was a significant correlation between transit time and bacterial mass in all three periods (r = 0.77, p less than 0.001). Changes in transit time are shown to alter microbial growth in the human colon and result in altered stool output, on a constant diet. Factors which affect transit may be as important as diet in determining large bowel function and hence susceptibility to disease.

The effect of age, sex and level of intake of dietary fibre from wheat on large-bowel function in thirty healthy subjects

1. To evaluate the effect of age, sex and level of intake on the colonic response to wheat fibre, thirty healthy volunteers aged 17-62 years (nineteen men, eleven women) recruited from a local industry, were divided into four groups and given a controlled diet for two 3-week periods. The diet contained white bread during one period or one of four different amounts of bran-enriched wholemeal bread during the other (30, 60, 110, 170 g/d). 2. Wide variation was observed between subjects in stool weight on the basal diet and in response to wheat fibre. Stepwise regression analysis showed that the variation in stool weight was significantly related to sex (t 4.0, P less than 0.001) but not to age, height, weight or energy:fibre intakes on the basal diet. Stool weight in men (162 (SE 11) g/d) was approximately double that in women (83 (SE 11) g/d). Transit time and stool weight were closely related and the effect of sex on stool weight could be explained entirely by differences in transit. 3. The increase in stool weight with fibre was significantly related to dose (t 4.18, P less than 0.001) with approximately 1 g non-starch polysaccharides (the main component of dietary fibre) increasing stool weight by 5 g/d. Smaller increases in stool weight were seen in females, persons with initially low stool weights and small people. 4. Faecal carbohydrate excretion increased with the addition of bran mainly due to increased amounts of cellulose and pentose (arabinose + xylose), whilst digestibility of dietary non-starch polysaccharide fell from 77.6 (SE 2.3)% on the white bread diet to 65.6 (SE 2.4)% with the added bran (t 7.4, P less than 0.01, n26). 5. Faecal pH was more acid in men than in women and was related to methane production. Methane producers had higher faecal pH than non-producers (7.06 (SE 0.11) v. 6.65 (SE 0.1], lower stool weight (g/d; 93 (SE 12) v. 156 (SE 13] and slower transit times (h; 84.6 (SE 11.7) v. 48.6 (SE 6.6]. 6. These studies show that, when on similar diets, women have much lower stool weights and slower transit times than men. Furthermore, within the range of amounts of wheat fibre used in this and other published work, stool weight increases in linear proportion to the dose of fibre added to the diet. Methane excretion in breath is associated in this group of subjects with slow transit time and high faecal pH.

Passage of carbohydrate into the colon. Direct measurements in humans

To quantify passage of unabsorbed dietary starch into the colon, 7 healthy volunteers had a multilumen tube positioned close to the ileocecal junction. Marker solution was perfused slowly, 20-40 cm above an aspiration site, to estimate, by marker dilution, flow through the ileum. On consecutive days, subjects ate liquidized meals containing 20 or 60 g starch; ileal aspirates were analyzed for starch and glucose for 5-6 h fasting and 4-7 h postprandially. Volume and carbohydrate concentrations were used to derive total carbohydrate traversing the ileum. In different subjects, unabsorbed carbohydrate was 453-4023 mg (2.3%-20.1%, mean 9.3%) for the smaller meal and 1332-6352 mg (2.2%-10.4%, mean 6.0%) for the larger. In 4 volunteers, hydrogen breath tests were performed on separate occasions after sucrose (50 g), lactulose (26 g), and the 20-g meal. Lactulose increased hydrogen excretion; sucrose and the test meal did not. We conclude that 2%-20% of dietary starch escapes absorption in the small bowel, confirming others' results using breath tests alone. Breath tests, though more convenient than intubation studies, may be a less sensitive index of starch malabsorption.

Should we eat more fibre?

Controversy continues over the role of dietary fibre in health, and whether or not a standard fibre intake should be recommended for the UK. In this review an attempt is made to consider the evidence for and against making such a recommendation. In doing so, it is clear that many problems exist in studies examining the role of fibre in disease, such as the inherent inadequacies of epidemiological studies and distrust of such studies by some circles, or the lack of uniformity in definition of dietary fibre and in its chemical analysis. The effect of fibre on faecal bulking is given as an example of experimental verification of epidemiological findings which has led to the widespread use of fibre in treating diverticular disease and constipation. Evidence of beneficial effects for cancer of the colon and ischaemic heart disease are far less convincing. Few harmful effects of fibre have been documented, apart from continuing disagreement regarding fibre and mineral balance, a question which remains to be solved. On weighing the evidence, it is suggested that recommending higher-fibre intakes in the UK is a favourable guideline. The type of fibre to be recommended is discussed, based on new evidence of the mode of action of different types of fibre in the gastrointestinal tract, and the amount of fibre considered, in relation to intakes in other countries and in the past in the UK.