Diet, nutrition, and avoidable cancer

In a 1981 review, Doll and Peto estimated that approximately 35% of cancer deaths in the United States were potentially avoidable by the modification of diet but that this percentage might be as low as 10% or as high as 70%. Since that time, the epidemiologic literature on diet and cancer has grown greatly, as has understanding of the mechanisms of carcinogenesis. In general, this expanded literature has not provided reason to alter the Doll and Peto estimate substantially. For colon cancer, evidence has accumulated that some of the international differences that were attributed to diet are probably due to physical activity. For breast cancer, the concept that fat intake per se is the primary reason for differences in rates among countries has not been supported by prospective studies. Although several lines of evidence suggest that caloric restriction and slow growth rates may contribute importantly to the low rates of breast cancer found outside Western countries, this may not translate directly to practical means of prevention. In contrast to breast cancer, more recent data have supported a causative role for red meat in the development of colon and prostate cancers, although perhaps not entirely due to its fat content. Whereas earlier thinking about nutrition and cancer emphasized the adverse effects of fat and other components in the diet, the most compelling evidence of the last decade has indicated the importance of protective factors, largely unidentified, in fruits and vegetables. Considering the more recent evidence, it is roughly estimated that about 32% of cancer may be avoidable by changes in diet; however, it now seems unlikely that less than 20% or more than 42% of cancer deaths would be avoidable by dietary change

trans-Fatty Acid Isomers in Adipose Tissue Have Divergent Associations with Adiposity in Humans

The aim of this study was to evaluate the association between adipose tissue trans-fatty acid isomers and adiposity. This cross-sectional study included 1,785 subjects from Costa Rica. Fatty acid concentrations (as a percentage of the total fatty acids) in subcutaneous adipose tissue were assessed by gas–liquid chromatography. Dietary intakes were assessed with a food frequency questionnaire. Multivariate linear regression models were used to relate adipose tissue trans-fatty acid content to BMI, waist circumference, and skinfold thickness while adjusting for age, sex, and area of residence. To account for variations in lifestyle, we adjusted for smoking, physical activity, income, self-reported history of diabetes and hypertension, and for adipose tissue alpha-linolenic acid and energy intake in a third model. After adjustments, positive associations were found between 18:2t-fatty acids (primarily from partially hydrogenated oils) and BMI, waist circumference, and skinfold thickness (P for each association  0.05). Inverse associations were found between 16:1n-7t-fatty acids and skinfold thickness and between 18:1t-fatty acids and BMI and waist circumference (P < 0.0001). This study suggests that individual trans-fatty acid isomers may have divergent effects on adiposity. 18:2t-fatty acids show consistent positive associations with measures of adiposity. These isomer-specific associations are an interesting new finding. Other prospective and intervention studies are necessary to examine these relationships further

Prenatal vitamin intake during pregnancy and offspring obesity

Background/Objectives: In animal studies, exposure to multi-vitamins may be associated with obesity in the offspring; however, data in humans is sparse. We therefore examined the association between prenatal vitamin intake during pregnancy and offspring obesity. Subjects/Methods: We investigated the association between prenatal vitamin intake and obesity among 29 160 mother-daughter dyads in the Nurses’ Health Study II. Mothers of participants provided information on prenatal vitamin use during pregnancy with the nurse daughter. Information on body fatness at ages 5 and 10, body mass index (BMI) at age 18, weight in 1989 and 2009, waist circumference, and height was obtained from the daughter. Polytomous logistic regression was used to predict BMI in early adulthood and adulthood, and body fatness in childhood. Linear regression was used to predict waist circumference in adulthood. Results: In utero exposure to prenatal vitamins was not associated with body fatness, either in childhood or adulthood. Women whose mothers took prenatal vitamins during pregnancy had a covariate-adjusted odds ratio of being obese in adulthood of 0.99 (95% CI 0.92–1.05, P-value=0.68) compared to women whose mothers did not take prenatal vitamins. Women whose mothers took prenatal vitamins during pregnancy had a covariate-adjusted odds ratio of having the largest body shape at age 5 of 1.02 (95% CI 0.90–1.15, P-value=0.78). In additional analyses, in utero exposure to prenatal vitamins was also unrelated to adult abdominal adiposity. Conclusions: Exposure to prenatal vitamins was not associated with body fatness either in childhood or in adulthood

Parental smoking during pregnancy and risk of overweight and obesity in the daughter

Objective: Emerging evidence suggests that prenatal exposures may affect long-term health outcomes. In utero exposure to smoking is associated with an increased risk of overweight and obesity in children and adolescents. However, few studies have examined how prenatal exposure to parental smoking influences risk of obesity in adulthood and whether these associations are independent of childhood and adolescent adiposity. The aim of the current study was to investigate whether prenatal exposure to parental smoking influences body size in adulthood and whether any association may be mediated by childhood and adolescent body size. Methods: We investigated the association between parental smoking during pregnancy and risk of overweight and obesity in adulthood and at age 18, and adiposity during childhood among 35,370 participants in the Nurses’ Health Study II. Data on smoking during pregnancy and socioeconomic variables were provided by the mothers, and anthropometric data and adult risk factors were reported by participants. Results: After adjustment for socioeconomic and behavioral variables, maternal smoking during pregnancy was associated with adiposity at ages 5–10, age 18, and during adulthood. For age 18 overweight the ORs (95% CIs) for 1–14, 15–24, and 25+cigarettes/day were 1.13 (1.18–1.50), 1.40 (1.20–1.64), and 1.15 (0.79–1.69) and for obesity were 1.41 (1.14–1.75), 1.69 (1.31–2.18), and 2.36 (1.44–3.86). The corresponding ORs (95% CIs) for obesity in adulthood were 1.26 (1.16–1.37), 1.46 (1.30–1.63), and 1.43 (1.10–1.86). Risk of adiposity was not increased among daughters whose mothers stopped smoking during the first trimester (OR [95% CI] for overweight (1.03 [95% CI 0.90–1.17] and obesity (1.12 [95% CI 0.97–1.30]). Women whose fathers smoked during pregnancy were also at increased risk of overweight and obesity in adulthood with covariate-adjusted ORs (95% CIs) for obesity of 1.19 (1.11–1.29) for 1–14 cigarettes/day, 1.27 (1.18–1.37) for 15–24 cigarettes/day, and 1.40 (1.27–1.54) for 25+ cigarettes/day compared to fathers who did not smoke (ptrend<0.0001). Paternal smoking during pregnancy was also associated with an increased risk of obesity at age 18 among those whose fathers smoked 15 or more cigarettes/day but was not associated with childhood body size. Conclusions: Maternal smoking during pregnancy was associated in a dose-response manner with overweight and obesity in the daughter through adolescence and adult life. Smoking cessation during the first trimester appears to mitigate this excess risk. Paternal smoking was also associated with risk of overweight and obesity of the adult daughter and this association persisted after adjustment for maternal smoking

Dietary flavonoid intake and weight maintenance: three prospective cohorts of 124,086 US men and women followed for up to 24 years

Objective: To examine whether dietary intake of specific flavonoid sub-classes is associated with weight change over time, including flavonols, flavones, flavanones, flavan-3-ols, anthocyanins, and flavonoid polymers. Design: Three prospective cohort studies. Setting: Health professionals in the United States. Participants: 124,086 men and women participating in the Health Professionals Follow-up Study (HPFS), Nurses’ Health Study (NHS), and Nurses’ Health Study II (NHS II). Main outcome measure: Self-reported change in weight over multiple 4-year time intervals between 1986 and 2011. Results: Increased consumption of most flavonoid sub-classes, including flavonols, flavan-3-ols, anthocyanins, and flavonoid polymers was inversely associated with weight change over 4-year time intervals, after adjustment for simultaneous changes in other lifestyle factors including other aspects of diet, smoking status, and physical activity. In the pooled results, the greatest magnitude of association was observed for anthocyanins (-0.22 lbs, 95% CI -0.30 to -0.15 lbs per additional SD/day, 10 mg), flavonoid polymers (-0.18 lbs, 95% CI -0.28 to -0.08 lbs per additional SD/day, 138 mg), and flavonols (-0.16 lbs, 95% CI -0.26 to -0.06 lbs per additional SD/day, 7 mg). After additional adjustment for fiber intake associations remained significant for anthocyanins, proanthocyanidins, and total flavonoid polymers but were attenuated and no longer statistically significant for other sub-classes. Conclusions: Higher intake of foods rich in flavonols, flavan-3-ols, anthocyanins, and flavonoid polymers, may contribute to weight maintenance in adulthood, and may help to refine dietary recommendations for the prevention of obesity and its potential sequelae

Obesity epidemic has emerged among Nigerians

Background: Data from the WHO shows that the prevalence of overweight and obesity increased by ~20% between 2002 and 2010 in Nigeria. We conducted this study to examine the correlates of this fast growing epidemic. Methods: We conducted a cross-sectional study among a random sample of 1058 adults, who were visitors and staff of a government worksite in Abuja, an urban city in Nigeria. The study participants had varying socio-economic status and a wide range of occupations, including skilled labor and professionals. Log-binomial regression models were used to estimate the multivariable-adjusted associations of potential determinants with the prevalence of overweight and obesity. Result The mean age and body-mass index of the study population were 42 years ± (9.3) and 27 kg/m2 ± (4.8). The overall prevalence of overweight or obesity (body-mass index ≥ 25 kg/m2) was 64% (74% of the women and 57% of the men). For women compared to men, the prevalence ratio (PR) and (95% confidence interval, CI) was 1.24 (95% CI 1.08, 1.43, p = 0.004), for overweight, and 2.54 (95% CI 2.08, 3.10, p = <0.0001), for obesity. Individuals aged 40 – 49 years were more likely to be overweight or obese. The PR for overweight and obesity was 1.45 (95% CI 1.07, 1.97), p for age trend = 0.002 and 8.07(95% CI 3.01, 21.66, p for age trend = <0.0001) for those aged 40 – 49 years, compared with those aged <30 years. Compared with the individuals in the lower socio-economic status, the PR for obesity among those in the middle and high socio-economic statuses, were 1.39 (95% CI 1.13, 1.72) and 1.24 (95% CI 0.97, 1.59) respectively, p for trend = 0.003. Conclusion: About two-thirds of urban, professional, high socio-economic status Nigerian adults are either overweight or obese. The prevalence of overweight and obesity among this population of adult Nigerians, is as high as it is in the United Kingdom. Female gender and older age were independent predictors of overweight and obesity; while middle or high socio-economic status were independently associated with obesity

Prospective Study of Pre-Gravid Sugar-Sweetened Beverage Consumption and the Risk of Gestational Diabetes Mellitus

OBJECTIVE: Consumption of sugar-sweetened beverages (SSBs) was related to an elevated risk of type 2 diabetes and insulin resistance in several recent studies among middle- or older-aged populations. Studies on SSB consumption and glucose intolerance among pregnant women, however, are lacking. We therefore examined the association between regular SSB consumption before pregnancy and the risk of gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: This was a prospective study among 13,475 U.S. women who reported at least one singleton pregnancy between 1992 and 2001 in the Nurses' Health Study II. GDM was self-reported and validated by medical record review in a subsample. Cox proportional hazards models with multivariate adjustments were applied to examine the association of SSB consumption with GDM risk. RESULTS: During 10 years of follow-up, 860 incident GDM case subjects were identified. After adjustment for age, parity, race, physical activity, smoking, alcohol intake, prepregnancy BMI, and Western dietary pattern, intake of sugar-sweetened cola was positively associated with the risk of GDM, whereas no significant association was found for other SSBs and diet beverages. Compared with women who consumed <1 serving/month, those who consumed ≥5 servings/week of sugar-sweetened cola had a 22% greater GDM risk (relative risk 1.22 [95% CI 1.01–1.47]). CONCLUSIONS: Findings from this study suggest that prepregnancy higher consumption of sugar-sweetened cola (≥5 servings/week) is associated with an elevated GDM risk, whereas no significant association with GDM risk was observed for other SSBs and diet beverages

Food Predictors of Plasma Carotenoids

Empirical prediction models that weight food frequency questionnaire (FFQ) food items by their relation to nutrient biomarker concentrations may estimate nutrient exposure better than nutrient intakes derived from food composition databases. Carotenoids may especially benefit because contributing foods vary in bioavailability and assessment validity. Our objective was to develop empirical prediction models for the major plasma carotenoids and total carotenoids and evaluate their validity compared with dietary intakes calculated from standard food composition tables. 4180 nonsmoking women in the Nurses’ Health Study (NHS) blood subcohort with previously measured plasma carotenoids were randomly divided into training (n = 2787) and testing (n = 1393) subsets. Empirical prediction models were developed in the training subset by stepwise selection from foods contributing ≥0.5% to intake of the relevant carotenoid. Spearman correlations between predicted and measured plasma concentrations were compared to Spearman correlations between dietary intake and measured plasma concentrations for each carotenoid. Three to 12 foods were selected for the α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, lycopene, and total carotenoids prediction models. In the testing subset, Spearman correlations with measured plasma concentrations for the calculated dietary intakes and predicted plasma concentrations, respectively, were 0.31 and 0.37 for α-carotene, 0.29 and 0.31 for β-carotene, 0.36 and 0.41 for β-cryptoxanthin, 0.28 and 0.31 for lutein/zeaxanthin, 0.22 and 0.23 for lycopene, and 0.22 and 0.27 for total carotenoids. Empirical prediction models may modestly improve assessment of some carotenoids, particularly α-carotene and β-cryptoxanthin