Nutrient intakes; biochemical and risk indices associated with Type 2 diabetes and glycosylated haemoglobin, in the British National Diet and Nutrition Survey of people aged 65 years and over

Tomatoes: An Extensive Review of the Associated Health Impacts of Tomatoes and Factors That Can Affect Their Cultivation

Simple Summary

The research outlined in this review paper discusses potential health benefits associated with a diet enriched with tomatoes and tomato products. This includes details of previous studies investigating the anticancer properties of tomatoes, protection against cardiovascular and neurodegenerative diseases and diabetes, maintenance of a healthy gut microbiome, and improved skin health, fertility, immune response, and exercise recovery. The specific parts of a tomato fruit that contribute these health benefits are also outlined. The potential disadvantages to a tomato-rich diet are detailed, especially the consumption of supplements that contain compounds found in tomatoes, such as lycopene. This review also discusses how the cultivation of tomato plants can affect the nutritional value of the fruit harvested. Different environmental growing conditions such as light intensity, growing media, and temperature are explained in terms of the impact they have on the quality of fruit, its nutrient content, and hence the potential health benefits acquired from eating the fruit.

Abstract

This review outlines the health benefits associated with the regular consumption of tomatoes and tomato products. The first section provides a detailed account of the horticultural techniques that can impact the quality of the fruit and its nutritional properties, including water availability, light intensity, temperature, and growing media. The next section provides information on the components of tomato that are likely to contribute to its health effects. The review then details some of the health benefits associated with tomato consumption, including anticancer properties, cardiovascular and neurodegenerative diseases and skin health. This review also discusses the impact tomatoes can have on the gut microbiome and associated health benefits, including reducing the risk of inflammatory bowel diseases. Other health benefits of eating tomatoes are also discussed in relation to effects on diabetes, the immune response, exercise recovery, and fertility. Finally, this review also addresses the negative effects that can occur as a result of overconsumption of tomato products and lycopene supplements.

Vitamin C Status in People with Types 1 and 2 Diabetes Mellitus and Varying Degrees of Renal Dysfunction: Relationship to Body Weight

Diabetes mellitus is a chronic metabolic disorder and is associated with depleted vitamin C status. The underlying aetiologies and pathogeneses responsible for this association are poorly understood. This retrospective study explored the vitamin C status of 136 adult outpatients with types 1 and 2 diabetes mellitus (T1DM/T2DM), with a focus on indices of renal function and metabolic health, including body weight. In the T1DM group (n = 73), the median plasma vitamin C concentration was 33 (18, 48) µmol/L, with 37% hypovitaminosis C and 12% deficiency. In the T2DM group (n = 63), the median plasma concentration was 15 (7, 29) µmol/L, with 68% hypovitaminosis C and 38% deficiency. Lower vitamin C was associated with macroalbuminuria (p = 0.03), renal dysfunction (p = 0.08), and hypertension (p = 0.0005). Inverse associations were also observed between plasma vitamin C and various other metabolic health parameters (p < 0.05), especially body weight (p < 0.0001), which was higher in those with hypovitaminosis C (<23 µmol/L; p = 0.0001). The association with bodyweight remained, even after multivariable analysis. In summary, body weight was a significant predictor of low vitamin C status in people with diabetes. This suggests that people with both diabetes and a high body weight may have greater than average vitamin C requirements.

Interactions Between Diet and Exposure to Secondhand Smoke on Glycated Hemoglobin Levels Among US Children: Results From NHANES 2007-2012

Introduction

Antioxidant-rich diets may lessen the adverse metabolic responses triggered by exposure to secondhand smoke (SHS), but no studies have investigated these potential interactions.

Objective

To examine the interaction between diet and exposure to SHS on glycated hemoglobin (HbA1c) levels among 2551 children, ages 12-19 years, who participated in the 2007-2012 National Health and Nutrition Examination Survey (NHANES).

Methods

Exposure to SHS was assessed by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), cotinine, and self-report. Weighted linear regression models evaluated the cross-sectional association between exposure to SHS and HbA1c levels. Additive interaction was assessed by introducing product terms (with SHS) of individual nutrients (dietary fiber, eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA], vitamin C, and vitamin E) to separate models.

Results

Over half of the children had NNAL or cotinine levels above the limit of detection (56% and 71%, respectively). The median HbA1c level was 5.2% (95% confidence interval: 5.17%, 5.23%). The interaction results suggest that the effects of exposure to SHS and certain dietary nutrients (EPA, DHA, vitamin C) on HbA1c levels may not be independent. For example, although there was only a slight difference in adjusted mean HbA1c levels across NNAL categories among children with high EPA intakes, the adjusted mean HbA1c level was 0.09% higher for high NNAL as compared to low NNAL among children with low EPA intakes.

Conclusions

Further research is needed to inform public health strategies for limiting increases in HbA1c levels among children. Messages may need to focus both on reducing exposure to SHS and improving diets to obtain the maximum benefit.

Implications

Our results suggest that the effects of exposure to SHS and diet on HbA1c levels may not be independent. For example, although there was little effect of exposure to SHS on HbA1c levels among children with high EPA intakes, high exposure to SHS was associated with an increase in HbA1c levels among children with low EPA intakes. Further research is necessary; however, based on these joint effects, strategies for limiting increases in HbA1c levels that focus both on reducing exposure to SHS and improving diets may achieve the largest public health benefits.

Influence of smoking and diet on glycated haemoglobin and 'pre-diabetes' categorisation: a cross-sectional analysis

BACKGROUND

The new HbA1c criteria for diagnosis of pre-diabetes have been criticised for misdiagnosis. It is possible that some elevation of HbA1c is not driven by hyperglycaemia. This study assesses associations of HbA1c, commonly assumed to relate solely to glucose concentration, with (i) smoking, a major source of reactive oxygen species (ROS) and (ii) fruit & vegetables consumption associated with improved redox status.

METHODS

One-way ANOVA, Chi-squared and multivariate linear regressions, adjusted for all known confounders were used to explore associations of HbA1c with self-reported smoking status and fruit & vegetables consumptions in the Scottish Health Surveys 2003-2010, among individuals without known diabetes and HbA1c < 6.5%.

RESULTS

Compared to non-smokers (n = 2831), smokers (n = 1457) were younger, consumed less fruit & vegetables, had lower physical activity levels, lower BMI, higher HbA1c and CRP (p < 0.05). HbA1c was higher in smokers by 0.25 SDs (0.08%), and 0.38 SDs higher (0.14%) in heavy smokers (>20 cigarettes/day) than non-smokers (p < 0.001 both). Smokers were twice as likely to have HbA1c in the 'pre-diabetic' range (5.7-6.4%) (p < 0.001, adj.model). Pre-diabetes and low grade inflammation did not affect the associations. For every extra 80 g vegetable portion consumed, HbA1c was 0.03 SDs (0.01%) lower (p = 0.02), but fruit consumption did not impact on HbA1c, within the low range of consumptions in this population.

CONCLUSION

This study adds evidence to relate smoking (an oxidative stress proxy) with protein glycation in normoglycaemic subjects, with implications for individuals exposed to ROS and for epidemiological interpretation of HbA1c.

Role of oxidative stress in physiological albumin glycation: a neglected interaction

Protein glycation is a key mechanism involved in chronic disease development in both diabetic and nondiabetic individuals. About 12-18% of circulating proteins are glycated in vivo in normoglycemic blood, but in vitro studies have hitherto failed to demonstrate glucose-driven glycation below a concentration of 30mM. Bovine serum albumin (BSA), reduced BSA (mercaptalbumin) (both 40g/L), and human plasma were incubated with glucose concentrations of 0-30mM for 4 weeks at 37°C. All were tested preoxidized for 8h before glycation with 10nM H2O2 or continuously exposed to 10nM H2O2 throughout the incubation period. Fructosamine was measured (nitroblue tetrazolium method) at 2 and 4 weeks. Oxidized BSA (both preoxidized and continuously exposed to H2O2) was more readily glycated than native BSA at all glucose concentrations (p = 0.03). Moreover, only oxidized BSA was glycated at physiological glucose concentration (5mM) compared to glucose-free control (glycation increased by 35% compared to native albumin, p < 0.05). Both 5 and 10mM glucose led to higher glycation when mercaptalbumin was oxidized than when unoxidized (p < 0.05). Fructosamine concentration in human plasma was also significantly higher when oxidized and exposed to 5mM glucose, compared to unoxidized plasma (p = 0.03). The interaction between glucose concentration and oxidation was significant in all protein models (p < 0.05). This study has for the first time demonstrated albumin glycation in vitro, using physiological concentrations of albumin, glucose, and hydrogen peroxide, identifying low-grade oxidative stress as a key element early in the glycation process.

Diabetes and frailty: an emerging issue. Part 1: Sarcopaenia and factors affecting lower limb function

Frailty and sarcopaenia are commonly used terms in the medical management of older people but their relationship to those with diabetes has not been explored in great detail. In this review, we hypothesise that diabetes and frailty are related conditions, and we attempt to explain the nature of this relationship, and consider the possibility that sarcopaenia is an intermediate step.

The quality of midday meals eaten at school by adolescents; school lunches compared with packed lunches and their contribution to total energy and nutrient intakes

OBJECTIVE

To compare food and nutrient intakes from midday meals provided by schools with those from packed lunches and to estimate the contribution from food eaten at midday to the total daily energy and nutrient intakes of teenagers.

DESIGN

Dietary data were recorded in 4 d estimated diaries of which 2 d were school days. The school day data were analysed for total and midday energy and nutrient intakes. The latter were compared with the recommendations of the Caroline Walker Trust (CWT).

SETTING

Cambridgeshire, UK, 2006.

SUBJECTS

Teenagers (n 757) aged 14-15 years, from eighteen secondary schools, who reported food eaten at school.

RESULTS

The contribution to total daily energy intake from all lunches eaten at school was 29 % (boys) and 28 % (girls). School meals provided greater quantities of protein, starch, carotene and folate but also more saturated fats and Na than packed lunches. Intakes of energy and several nutrients fell below the CWT recommendations for both types of lunch. School meals and packed lunches provided different types of foods; greater quantities of rice, pasta and vegetables in school meals; more yoghurt, cheese, fruit and juices but also more confectionery and soft drinks in packed lunches.

CONCLUSIONS

There has been concern that schoolchildren who are not opting for lunch provided by schools are compromising the overall quality of their diet, but the present study showed small differences in nutrient content between packed and school lunches. These data were collected in 2005–2007 before the government programme of improvements reached secondary schools.

Dietary restriction of lycopene for a period of one month resulted in significantly increased biomarkers of oxidative stress and bone resorption in postmenopausal women

BACKGROUND AND OBJECTIVES

Lycopene is a carotenoid commonly found in tomatoes and tomato products which acts as an antioxidant to decrease oxidative stress and osteoporosis risk. We wanted to determine the effects of a lycopene-restricted diet on oxidative stress parameters and bone turnover markers in postmenopausal women.

SETTING

St. Michael 's Hospital, Toronto, ON, Canada. PARTICIPANTS AND STUDY DESIGN: 23 healthy postmenopausal women, 50-60 years old, provided blood samples at baseline and following a one-month lycopene-depletion period.

MEASUREMENTS

Serum samples were analyzed for carotenoids; the oxidative stress parameters protein thiols and thiobarbituric-malondialdehyde reactive substances; the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and the bone turnover markers bone alkaline phosphatase and crosslinked N-telopeptide of type I collagen (NTx). A paired t-test was used to test for significant differences in bone turnover markers, oxidative stress parameters and antioxidant status after lycopene restriction.

RESULTS

Dietary lycopene restriction resulted in significantly decreased serum lycopene (p < 0.0001), lutein/zeaxanthin (p < 0.01), and α -/β -carotene (p < 0.05). GPx (p < 0.01), lipid and protein oxidation increased (not significant), while CAT and SOD were significantly depressed (p < 0.05 and p < 0.005, respectively). These changes coincided with significantly increased NTx (p < 0.05).

CONCLUSIONS

These findings suggest that the daily consumption of lycopene may be important as it acts as an antioxidant to decrease bone resorption in postmenopausal women and may therefore be beneficial in reducing the risk of osteoporosis.

Biochemical risk indices, including plasma homocysteine, that prospectively predict mortality in older British people: the National Diet and Nutrition Survey of People Aged 65 Years and Over

Predictive power, for total and vascular mortality, of selected indices measured at baseline in the British National Diet and Nutrition Survey (community-living subset) of People Aged 65 Years and Over was tested. Mortality status and its primary and underlying causes were recorded for 1100 (mean age 76.7 (sd 7.5) years, 50.2% females) respondents from the baseline survey in 1994-5 until September 2008. Follow-up data analyses focussed especially on known predictors of vascular disease risk, together with intakes and status indices of selected nutrients known to affect, or to be affected by, these predictors. Total mortality was significantly predicted by hazard ratios of baseline plasma concentrations (per sd) of total homocysteine (tHcy) (95% CI) 1.19 (1.11, 1.27), pyridoxal phosphate 0.90 (0.81, 1.00), pyridoxic acid 1.10 (1.03, 1.19), alpha1-antichymotrypsin 1.21 (1.13, 1.29), fibrinogen 1.14 (1.05, 1.23), creatinine 1.20 (1.10, 1.31) and glycosylated Hb 1.23 (1.14, 1.32), and by dietary intakes of energy 0.87 (0.80, 0.96) and protein 0.86 (0.77, 0.97). Prediction patterns and significance were similar for primary-cause vascular mortality. The traditional risk predictors plasma total and HDL cholesterol were not significant mortality predictors in this age group, nor were the known tHcy-regulating nutrients, folate and vitamin B12 (intakes and status indices). Model adjustment for known risk predictors resulted in the loss of significance for some of the afore-mentioned indices; however, tHcy 1.34 (1.04, 1.73) remained a significant predictor for vascular mortality. Thus, total and primary vascular mortality is predicted by energy and protein intakes, and by biochemical indices including tHcy, independent of serum folate or vitamin B12.

Diet and glycosylated haemoglobin in the 1946 British birth cohort

OBJECTIVES

Raised glycosylated haemoglobin (HbA(1c)) concentration is a recognized risk factor for diabetes, the incidence of which is rising worldwide. The intake of certain foods has been related to HbA(1c) concentration. The aim of this study was to investigate whether nutrient intake, sourced by these foods, was predictive of raised glycosylated haemoglobin (HbA(1c)) concentration in a British cohort.

SUBJECTS

The subjects were 495 men and 570 women who were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort.Diet was assessed from 5-day records in 1982, 1989 and 1999. HbA(1c) was measured in blood samples collected in 1999. Individuals in whom concentration of HbA(1c) was > or =6.3% were identified as being 'at risk' and their nutrient intake was compared with those whose concentration of HbA(1c) was within the normal range (< or =6.2%).

RESULTS

Lower intakes of protein, carbohydrate, non-starch polysaccharide, iron, folate, vitamin B(12) and a higher percentage energy from fat in 1989 were significantly predictive of high HbA(1c) status in 1999. In 1999, there were no nutrient intakes that were predictive of HbA(1c) status. Global tests of whether the intakes of energy, carbohydrate, sodium, iron, riboflavin and vitamin B(12) at all three time points were related to HbA(1c) status in 1999, were significant.

CONCLUSION

An increased intake of energy, carbohydrate, sodium, iron, riboflavin and vitamin B(12) over 10 years was predictive of raised HbA(1c) status. Increased energy intake may have resulted in increase in body weight, which is a risk factor for diabetes.

Associations of plasma carotenoids with risk factors and biomarkers related to cardiovascular disease in middle-aged and older women

BACKGROUND

Cardiovascular disease (CVD) risk factors may potentially influence plasma concentrations of carotenoids. However, data on the association of plasma carotenoids with CVD related biomarkers are only limited.

OBJECTIVE

We examined the cross-sectional association of plasma carotenoids with blood lipids, glycated hemoglobin (Hb A(1c)), and C-reactive protein (CRP) in middle-aged and older women initially free of CVD and cancer.

DESIGN

Participants from 3 nested case-control studies in the Women's Health Study were pooled. Baseline plasma carotenoids, including alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein-zeaxanthin, blood lipids, Hb A(1c), and CRP were available for 2895 women.

RESULTS

Women who were current smokers or obese had lower plasma concentrations of most carotenoids expect for lycopene. After adjusting for age, race, lifestyle factors, clinical factors, plasma total cholesterol, and dietary carotenoids, an increase of 30 mg/dL in LDL cholesterol was associated with a 17% increase in alpha-carotene, a 16% increase in beta-carotene, and an 8.5% increase in lycopene; an increase of 10 mg/dL in HDL cholesterol was associated with a 5.3% decrease in lycopene; an increase of 0.3% in Hb A(1c) was associated with a 1.4% increase in lycopene; and an increase of 2 mg/L in CRP was associated with a 1.3% decrease in beta-carotene (all P < 0.01).

CONCLUSIONS

In middle-aged and older women free of CVD and cancer, plasma carotenoids were associated with smoking, obesity, LDL cholesterol, HDL cholesterol, Hb A(1c), and CRP. The associations differ among individual carotenoids, possibly reflecting metabolic effects of lifestyle and physiologic factors on plasma carotenoids, and may partially explain the inverse association of plasma carotenoids with CVD outcomes observed in epidemiologic studies.

Management of Diabetes in Older Adults

Enhanced life expectancy and the aging of society have conspired with rising rates of obesity and physical inactivity to cause an unprecedented increase in diabetes prevalence worldwide. The disease and its chronic complications have unique presentations and challenges in the elderly. Postprandial hyperglycemia may be the predominant manifestation, comorbid health conditions are often present, and the risk of cardiovascular disease is vastly increased. Periodic screening is essential for early diagnosis and proper treatment. The principles of multidisciplinary management emphasizing nutrition, exercise, education, psychosocial care, attention to concomitant metabolic risk factors, and prudent use of pharmacologic agents are the mainstay of therapy for older adults. Treatment should be tailored to the individual patient, and the assistance of family and caregivers should be combined with rational utilization of community resources. An evidence-based, comprehensive, and proactive approach is needed to reduce the burden of morbidity and mortality from diabetes in the elderly.

Plasma lycopene, other carotenoids, and the risk of type 2 diabetes in women

The authors conducted a nested case-control study from 1992 to 2003 among US women aged 45 years or older and free from cardiovascular disease and cancer to examine the prospective association among plasma lycopene, other carotenoids, and the risk of developing type 2 diabetes. During 10 years of follow-up, 470 cases of incident type 2 diabetes were selected and individually matched on age (+/- 1 year) and follow-up time to 470 nondiabetic controls. Baseline plasma levels of lycopene, alpha-carotene, beta-carotene, beta-cryptoxanthin, and lutein/zeaxanthin were similar in cases and controls (all p > 0.05). A possible crude inverse association between plasma lycopene and risk of type 2 diabetes was attenuated upon multivariate adjustment. After control for plasma total cholesterol and known diabetes risk factors, the multivariate odds ratios of type 2 diabetes in the highest versus the lowest quartile of plasma carotenoids were 1.13 (95% confidence interval (CI): 0.60, 2.13) for lycopene, 1.27 (95% CI: 0.63, 2.57) for alpha-carotene, 1.10 (95% CI: 0.57, 2.13) for beta-carotene, 0.91 (95% CI: 0.46, 1.81) for beta-cryptoxanthin, and 1.35 (95% CI: 0.68, 2.69) for lutein/zeaxanthin. There was no prospective association between baseline plasma carotenoids and the risk of type 2 diabetes in middle-aged and older women.

The consumption of lycopene and tomato-based food products is not associated with the risk of type 2 diabetes in women

Lycopene is a major carotenoid with potent antioxidant properties that may provide protection against the development of type 2 diabetes mellitus (DM). In this study we examined the association between baseline dietary intakes of lycopene, lycopene-containing foods, and the subsequent development of type 2 DM in a large prospective cohort study. We analyzed a total of 35,783 women from the United States, aged > or =45 y and free from self-reported cardiovascular disease, cancer, and DM at baseline. Intakes of lycopene and total and individual tomato-based food products were assessed by a 131-item-validated semiquantitative food-frequency questionnaire. During a median follow-up of 10.2 y, 1544 cases of incident type 2 DM were documented. After adjusting for age, total energy intake, randomized treatment assignment, body mass index, and other known DM risk factors, the multivariate-adjusted relative risks and 95% CI of type 2 DM across increasing quintiles of dietary lycopene, were 1.00 (baseline), 1.10 (0.94-1.29), 1.10 (0.94-1.29), and 1.07 (0.91-1.26) (P linear trend = 0.56). Compared with women who consumed <1.5 servings/wk total tomato-based food products, women who consumed 1.5 to <4, 4 to <7, 7 to <10, and > or =10 servings/wk had multivariate relative risks (95% CI) of 1.03 (0.88-1.20), 1.02 (0.87-1.20), 1.09 (0.89-1.33), and 1.04 (0.80-1.36), respectively (P linear trend = 0.54). The associations for individual tomato-based food products were similar to the results for the combination of all tomato products. Our study found little evidence for an association between dietary intake of lycopene or lycopene-containing foods and the risk of type 2 DM.