James R. Hébert

Association between dietary fiber and markers of systemic inflammation in the Women's Health Initiative Observational Study

OBJECTIVE Systemic inflammation may play an important role in the development of atherosclerosis, type 2 diabetes, and some cancers. Few studies have comprehensively assessed the direct relations between dietary fiber and inflammatory cytokines, especially in minority populations. Using baseline data from 1958 postmenopausal women enrolled in the Womens Health Initiative Observational Study, we examined cross-sectional associations between dietary fiber intake and markers of systemic inflammation (including serum high-sensitivity C-reactive protein [hs-CRP], interleukin-6 [IL-6], and tumor necrosis factor-alpha receptor-2 [TNF-alpha-R2]) in addition to differences in these associations by ethnicity. METHODS Multiple linear regression models were used to assess the relation between fiber intake and makers of systemic inflammation. RESULTS After adjustment for covariates, intakes of dietary fiber were inversely associated with IL-6 (P values for trend were 0.01 for total fiber, 0.004 for soluble fiber, and 0.001 for insoluble fiber) and TNF-alpha-R2 (P values for trend were 0.002 for total, 0.02 for soluble, and <0.001 for insoluble fibers). Although the samples were small in minority Americans, results were generally consistent with those found among European Americans. We did not observe any significant association between intake of dietary fiber and hs-CRP. CONCLUSION These findings lend support to the hypothesis that a high-fiber diet is associated with lower plasma levels of IL-6 and TNF-alpha-R2. Contrary to previous reports, however, there was no association between fiber and hs-CRP among postmenopausal women. Future studies on the influence of diet on inflammation should include IL-6 and TNF-alpha-R2 and enroll participants from ethnic minorities.

Systematic Errors in Middle-Aged Women's Estimates of Energy Intake: Comparing Three Self-Report Measures to Total Energy Expenditure from Doubly Labeled Water

PURPOSE To evaluate energy intake (EI) derived from a food frequency questionnaire (FFQ), seven-day dietary recall (7DDR), and seven 24-hour dietary recall interviews (24HR) for reporting errors associated with social desirability and social approval. METHODS The FFQ and 7DDR were administered once before and once after a 14-day metabolic period during which total energy expenditure was determined using the doubly labeled water method (TEE(dlw)). Seven 24HR were conducted over the 14-day period. Data obtained from 80 healthy women (mean age = 49.1 years) were fit to linear regression models in which the EI estimates were the dependent variables and estimates of social desirability and social approval traits, body mass index [weight (kg)/ height (m)(2)], and TEE(dlw) were fit as independent variables. RESULTS indicated that in college-educated women there was an underestimate associated with social desirability on the FFQ (-42.24 kcal/day/point on the social desirability scale; 95% CI:-75.48, -9.00). For college-educated women with an average social desirability score ( approximately 17 points) this would equal an underestimate of 507 kcal/day compared to women with the minimum score (4 points). The 7DDR was associated with a differential effect of social approval when comparing by education; i.e., there was a difference of 36.35 kcal/day/point between the two groups (-14.69 in women with >/=college and 21.66 in women with <college) (95% CI: 10.25, 62.45). CONCLUSIONS Social desirability and social approval distort energy intake estimates from structured questionnaires, in a manner that appears to vary by educational status. Results observed have important implications for subject recruitment, data collection, and for methods of detection and control of biases in epidemiologic studies.

MTHFR Polymorphisms, Dietary Folate Intake, and Breast Cancer Risk: Results from the Shanghai Breast Cancer Study

Folate plays an important role in DNA methylation, synthesis, and repair; intake has been associated with breast cancer. The folate-metabolizing enzyme, methylenetetrahydrofolate reductase (MTHFR) is polymorphic at nucleotides 677 (C→T) and 1298 (A→C), resulting in allozymes with decreased activity. We evaluated these two common polymorphisms and their effects on the folate intake and breast cancer risk association in a population-based case-control study of 1144 breast cancer cases and 1236 controls using a PCR-RFLP-based assay. All subjects completed in-person interviews, which included a food frequency questionnaire. Unconditional logistic regression models were used to calculate odds ratios and their 95% confidence intervals, after adjusting for potential confounding factors. Cases and controls were similar in the distribution of MTHFR polymorphisms at codons 677 (41.4% cases and 41.8% controls carried the T allele) and 1298 (17.6% cases and 17.5% controls carried the C allele). An inverse association of breast cancer risk with folate intake was observed in all genotype groups, particularly among subjects with the 677TT genotype. Compared with those with the 677CC genotype and high folate, the adjusted odds ratios (95% confidence intervals) associated with low folate intake were 1.94 (1.15–3.26), 2.17 (1.34–3.51), and 2.51 (1.37–4.60) for subjects who had CC, CT, and TT genotypes (p for interaction, 0.05). No modifying effect of A1298C genotypes on the association of folate intake with breast cancer risk was observed. Results of this study suggest that the MTHFR C677T polymorphisms may modify the association between dietary folate intake and breast cancer risk.

Association of a Dietary Inflammatory Index With Inflammatory Indices and Metabolic Syndrome Among Police Officers

Objectives:To determine whether the dietary inflammatory index (DII) is associated with inflammatory or metabolic biomarkers and metabolic syndrome (MetSyn) among police officers. Methods:Cross-sectional data from the Buffalo Cardio-Metabolic Occupational Police Stress study were derived from saliva and fasting blood samples, anthropometric measurements, long-term shiftwork histories, and demographic, stress/depression, and food frequency questionnaires (FFQs). Metabolic syndrome was defined using standard criteria. Results:Officers in DII quartiles 2 to 4 were more likely to exceed a threshold of 3.0 mg/L for C-reactive protein (odds ratio [OR] = 1.88; 95% confidence interval [95% CI] = 1.02 to 3.45; OR = 2.17; 95% CI = 1.19 to 3.95; OR = 1.57; 95% CI = 0.85 to 2.88, respectively) compared with quartile 1. The glucose intolerance component of MetSyn was more prevalent among officers in DII quartile 4 than among those in quartile 1 (OR = 2.03; 95% CI = 1.08 to 3.82). Conclusions:A pro-inflammatory diet was associated with elevated CRP and with the glucose intolerance component of MetSyn.

Seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population

Objective:To describe seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population.Design:A longitudinal observational study.Setting:Most of the study participants were recruited from a health maintenance organization (HMO) in central Massachusetts, USA. Additional individuals of Hispanic descent were recruited from outside of the HMO population to increase the ethnic diversity of this sample.Subjects:Data from 593 participants, aged 20–70, were used for this investigation. Each participant was followed quarterly (five sampling points: baseline and four consecutive quarters) for 1-year period. Body weight measurements and three 24-h dietary and physical activity recalls were obtained on randomly selected days (including 2 weekdays and 1 weekend day) per quarter. Sinusoidal regression models were used to estimate peak-to-trough amplitude and phase of the peaks.Results:Daily caloric intake was higher by 86 kcal/day during the fall compared to the spring. Percentage of calories from carbohydrate, fat and saturated fat showed slight seasonal variation, with a peak in the spring for carbohydrate and in the fall for total fat and saturated fat intake. The lowest physical activity level was observed in the winter and the highest in the spring. Body weight varied by about 1/2 kg throughout the year, with a peak in the winter (P<0.001 winter versus summer). Greater seasonal variation was observed in subjects who were male, middle aged, nonwhite, and less educated.Conclusions:Although there is seasonal variation in diet, physical activity and body weight, the magnitude of the change is generally small in this population.Sponsorship:US National Heart, Lung and Blood Institute.

Role of Lifestyle and Aging on the Longitudinal Change in Cardiorespiratory Fitness

BACKGROUND Cardiorespiratory fitness (CRF) in adults decreases with age and is influenced by lifestyle. Low CRF is associated with risk of diseases and the ability of older persons to function independently. We defined the longitudinal rate of CRF decline with aging and the association of aging and lifestyle with CRF. METHODS We studied a cohort of 3429 women and 16 889 men, aged 20 to 96 years, from the Aerobics Center Longitudinal Study who completed 2 to 33 health examinations from 1974 to 2006. The lifestyle variables were body mass index, self-reported aerobic exercise, and smoking behavior. Cardiorespiratory fitness was measured by a maximal Balke treadmill exercise test. RESULTS Linear mixed models regression analysis stratified by sex showed that the decline in CRF with age was not linear. After 45 years of age, CRF declined at an accelerated rate. For each unit of increase in body mass index, the CRF of women declined 0.20 metabolic equivalents (METs) (95% confidence interval, -0.21 to -0.19); that of men, 0.32 METs (-0.33 to -0.20). Current smokers of both sexes also had lower CRF (-0.29 METs [95% confidence interval, -0.40 to -0.19] for women and -0.41 METS [-0.44 to -0.38] for men). Cardiorespiratory fitness was positively associated with self-reported physical activity. CONCLUSIONS Cardiorespiratory fitness in men and women declines at a nonlinear rate that accelerates after 45 years of age. Maintaining a low BMI, being physically active, and not smoking are associated with higher CRF across the adult life span.

The effects of a health promotion-health protection intervention on behavior change: the WellWorks Study

OBJECTIVES This study assessed the effects of a 2-year integrated health promotion-health protection work-site intervention on changes in dietary habits and cigarette smoking. METHODS A randomized, controlled intervention study used the work site as the unit of intervention and analysis; it included 24 predominantly manufacturing work sites in Massachusetts (250-2500 workers per site). Behaviors were assessed in self-administered surveys (n = 2386; completion rates = 61% at baseline, 62% at final). Three key intervention elements targeted health behavior change: (1) joint worker-management participation in program planning and implementation, (2) consultation with management on work-site environmental changes, and (3) health education programs. RESULTS Significant differences between intervention and control work sites included reductions in the percentage of calories consumed as fat (2.3% vs 1.5% kcal) and increases in servings of fruit and vegetables (10% vs 4% increase). The intervention had a significant effect on fiber consumption among skilled and unskilled laborers. No significant effects were observed for smoking cessation. CONCLUSIONS Although the size of the effects of this intervention are modest, on a populationwide basis effects of this size could have a large impact on cancer-related and coronary heart disease end points.

Number of 24-hour diet recalls needed to estimate energy intake

PURPOSE Twenty-four-hour diet recall interviews (24HRs) are used to assess diet and to validate other diet assessment instruments. Therefore it is important to know how many 24HRs are required to describe an individuals intake. METHOD Seventy-nine middle-aged white women completed seven 24HRs over a 14-day period, during which energy expenditure (EE) was determined by the doubly labeled water method (DLW). Mean daily intakes were compared to DLW-derived EE using paired t tests. Linear mixed models were used to evaluate the effect of call sequence and day of the week on 24HR-derived energy intake while adjusting for education, relative body weight, social desirability, and an interaction between call sequence and social desirability. RESULTS Mean EE from DLW was 2115 kcal/day. Adjusted 24HR-derived energy intake was lowest at call 1 (1501 kcal/day); significantly higher energy intake was observed at calls 2 and 3 (2246 and 2315 kcal/day, respectively). Energy intake on Friday was significantly lower than on Sunday. Averaging energy intake from the first two calls better approximated true energy expenditure than did the first call, and averaging the first three calls further improved the estimate (p=0.02 for both comparisons). Additional calls did not improve estimation. CONCLUSIONS Energy intake is underreported on the first 24HR. Three 24HRs appear optimal for estimating energy intake.

Dietary inflammatory index is related to asthma risk, lung function and systemic inflammation in asthma

Asthma prevalence has increased in recent years, and evidence suggests that diet may be a contributing factor. Increased use of processed foods has led to a decrease in diet quality, which may be creating a pro‐inflammatory environment, thereby leading to the development and/or progression of various chronic inflammatory diseases and conditions. Recently, the dietary inflammatory index (DII) has been developed and validated to assess the inflammatory potential of individual diets.

Facilitating dietary change: the patient-centered counseling model.

Recent data indicate that the patient-centered counseling model enhances long-term dietary adherence. This model facilitates change by assessing patient needs and subsequently tailoring the intervention to the patients stage in the process of change, personal goals, and unique challenges. This article describes this model, including its theoretical foundations, a 4-step counseling process, and applications. This behavioral counseling model can help nutrition professionals enhance patient adherence to nutrition care plans and dietary guidelines.