Substantial experimental evidence suggests that several flavonoid classes are involved in glucose metabolism, but few clinical or epidemiologic studies exist that provide supporting human evidence for this relationship. The objective of this study was to determine if habitual intakes of specific flavonoid classes are related to incidence of type 2 diabetes (T2D). We followed 2915 members of the Framingham Offspring cohort who were free of T2D at baseline from 1991 to 2008. Diabetes was defined by either elevated fasting glucose (≥7.0 mmol/L) or initiation of hypoglycemic medication during follow-up. Dietary intakes of 6 flavonoid classes and total flavonoids were assessed using a validated, semiquantitative food frequency questionnaire. We observed 308 incident cases of T2D during a mean follow-up period of 11.9 y (range 2.5–16.8 y). After multivariable adjusted, time-dependent analyses, which accounted for long-term flavonoid intake during follow-up, each 2.5-fold increase in flavonol intake was associated with a 26% lower incidence of T2D [HR = 0.74 (95% CI: 0.61, 0.90); P-trend = 0.003] and each 2.5-fold increase in flavan-3-ol intake was marginally associated with an 11% lower incidence of T2D [HR = 0.89 (95% CI: 0.80, 1.00); P-trend = 0.06]. No other associations between flavonoid classes and risk of T2D were observed. Our observations support previous experimental evidence of a possible beneficial relationship between increased flavonol intake and risk of T2D.
This paper, based on the symposium “Is ‘Processed’ a Four-Letter Word? The Role of Processed Foods in Achieving Dietary Guidelines and Nutrient Recommendations in the U.S.” describes ongoing efforts and challenges at the nutrition–food science interface and public health; addresses misinformation about processed foods by showing that processed fruits and vegetables made important dietary contributions (e.g., fiber, folate, potassium, vitamins A and C) to nutrient intake among NHANES 2003–2006 participants, that major sources of vitamins (except vitamin K) were provided by enrichment and fortification and that enrichment and fortification helped decrease the percentage of the population below the Estimated Average Requirement for vitamin A, thiamin, folate, and iron; describes how negative consumer perceptions and consumer confusion about processed foods led to the development of science-based information on food processing and technology that aligns with health objectives; and examines challenges and opportunities faced by food scientists who must balance consumer preferences, federal regulations, and issues surrounding food safety, cost, unintended consequences, and sustainability when developing healthful foods that align with dietary guidelines.
More than half of US adults use dietary supplements. Some reports suggest that supplement users have higher vitamin intakes from foods than nonusers, but this observation has not been examined using nationally representative survey data.
The purpose of this analysis was to examine vitamin intakes from foods by supplement use and how dietary supplements contribute to meeting or exceeding the Dietary Reference Intakes for selected vitamins using data from the National Health and Nutrition Examination Survey among adults (aged ≥19 years) in 2003–2006 (n=8,860).
Among male users, mean intakes of folate and vitamins A, E, and K from food sources were significantly higher than among nonusers. Among women, mean intakes of folate and vitamins A, C, D, and E from foods were higher among users than nonusers. Total intakes (food and supplements) were higher for every vitamin we examined among users than the dietary vitamin intakes of nonusers. Supplement use helped lower the prevalence of intakes below the Estimated Average Requirement for every vitamin we examined, but for folic acid and vitamins A, B-6, and C, supplement use increased the likelihood of intakes above the Tolerable Upper Intake Level.
Supplement use was associated with higher mean intakes of some vitamins from foods among users than nonusers, but it was not associated with the prevalence of intakes less than the Estimated Average Requirement from foods. Those who do not use vitamin supplements had significantly higher prevalence of inadequate vitamin intakes; however, the use of supplements can contribute to excess intake for some vitamins.
Dietary supplements; NHANES; Vitamins; Users and non-users of supplements
Food composition databases are critical to assess and plan dietary intakes. Dietary supplement databases are also needed because dietary supplements make significant contributions to total nutrient intakes. However, no uniform system exists for classifying dietary supplement products and indexing their ingredients in such databases. Differing approaches to classifying these products make it difficult to retrieve or link information effectively. A consistent approach to classifying information within food composition databases led to the development of LanguaL™, a structured vocabulary. LanguaL™ is being adapted as an interface tool for classifying and retrieving product information in dietary supplement databases. This paper outlines proposed changes to the LanguaL™ thesaurus for indexing dietary supplement products and ingredients in databases. The choice of 12 of the original 14 LanguaL™ facets pertinent to dietary supplements, modifications to their scopes, and applications are described. The 12 chosen facets are: Product Type; Source; Part of Source; Physical State, Shape or Form; Ingredients; Preservation Method, Packing Medium, Container or Wrapping; Contact Surface; Consumer Group/Dietary Use/Label Claim; Geographic Places and Regions; and Adjunct Characteristics of food.
LanguaL; Government; Dietary supplements; Databases; Indexing; Structured vocabulary; Thesaurus; Food analysis; Food composition
Elite adolescent figure skaters must accommodate both the physical demands of competitive training and the accelerated rate of bone growth that is associated with adolescence, in this sport that emphasizes leanness. Although, these athletes apparently have sufficient osteogenic stimuli to mitigate the effects of possible low energy availability on bone health, the extent or magnitude of bone accrual also varies with training effects, which differ among skater disciplines.
We studied differences in total and regional bone mineral density in 36 nationally ranked skaters among 3 skater disciplines: single, pairs, and dancers.
Bone mineral density (BMD) of the total body and its regions was measured by dual energy x-ray absorptiometry (DXA). Values for total body, spine, pelvis and leg were entered into a statistical mixed regression model to identify the effect of skater discipline on bone mineralization while controlling for energy, vitamin D, and calcium intake.
The skaters had a mean body mass index of 19.8 ± 2.1 and % fat mass of 19.2 ± 5.8. After controlling for dietary intakes of energy, calcium, and vitamin D, there was a significant relationship between skater discipline and BMD (p = 0.002), with single skaters having greater BMD in the total body, legs, and pelvis than ice dancers (p < 0.001). Pair skaters had greater pelvic BMD than ice dancers (p = 0.001).
Single and pair skaters have greater BMD than ice dancers. The osteogenic effect of physical training is most apparent in single skaters, particularly in the bone loading sites of the leg and pelvis.
Elite adolescent female figure skaters compete in an aesthetic-based sport that values thin builds and lithe figures. To conform to the sport’s physical requirements, skaters may alter their eating patterns in unhealthful directions. This study assesses the eating attitudes and dietary intakes of elite adolescent female figure skaters to assess the potential nutritional risks among them.
Thirty-six elite competitive adolescent female figure skaters (mean age 16 ± 2.5 SD years) completed self-administered three-day records of dietary intake and simultaneous physical activity records during training season. Two months later, they attended a national training camp during which they completed the Eating Attitudes Test (EAT-40), provided fasting blood samples, and had heights and weights measured.
Participants’ mean body mass index (BMI) was 19.8 ± 2.1 SD. Their BMIs were within the normal range, and the majority (70%) did not report a history of recent weight loss. The mean EAT-40 score was normal (19.5 ± 13.5 SD) and below the cut-off score of 30 that indicates clinically significant eating pathology. However, one-quarter of the skaters had EAT-40 scores above 30. The skaters reported a mean energy intake of 1491 ± 471 SD kcal/day (31 ± 10 SD kcal/kg), with 61.6% of calories from carbohydrate, 14.6% from protein, and 23.7% from fat. Their reported dietary intakes were high in carbohydrates but low in total energy, fat, and bone-building nutrients.
Although these highly active young women compete in a sport that prizes leanness, they had appropriate weights. The athletes reported dietary intakes that were far below estimated energy needs and were at moderate risk of disordered eating. Anticipatory guidance is warranted to improve their dietary intakes, particularly of bone-building nutrients.
Eating attitudes; Female athletes; Disordered eating; EAT scores; Dietary intake; BMI
Increased interest in the potential societal benefit of incorporating health economics as a part of clinical translational science, particularly nutrition interventions, led the Office of Dietary Supplements at the National Institutes of Health to sponsor a conference to address key questions about economic analysis of nutrition interventions to enhance communication among health economic methodologists, researchers, reimbursement policy makers, and regulators. Issues discussed included the state of the science, such as what health economic methods are currently used to judge the burden of illness, interventions, or health care policies, and what new research methodologies are available or needed to address knowledge and methodological gaps or barriers. Research applications included existing evidence-based health economic research activities in nutrition that are ongoing or planned at federal agencies. International and U.S. regulatory, policy and clinical practice perspectives included a discussion of how research results can help regulators and policy makers within government make nutrition policy decisions, and how economics affects clinical guideline development.
cost-benefit analysis; primary prevention; nutrition policy; medical economics; nutrition therapy
To examine the relationship between adherence to prescribed folic acid supplements and folic acid intake, serum folate and plasma homocysteine in hemodialysis patients. The effects of change in adherence patterns from enrollment to one year later on changes in these same measures were also assessed.
Secondary data analysis
Eighty six hemodialysis patients who participated in the Hemodialysis (HEMO) Study’s Homocysteine ancillary study.
Main Outcome Measures
Folic acid supplement intake, serum folate and plasma homocysteine.
Eighty-eight percent of patients at enrollment and 91% one year later were adherent to prescribed folic acid supplements. Non-adherers had lower intakes of folic acid at both enrollment and one year later and lower serum folate levels at enrollment. Percent change was significantly different between the 3 adherence change groups for folic acid intake (p=0.001) and plasma homocysteine (p<0.001) from enrollment to one year later. The non-adherent group at enrollment had the lowest intakes and serum folate levels, and the highest plasma homocysteine levels. When they became adherent one year later, they had the greatest change in folic acid intake (5461%; p=0.03), coupled with a 69% increase in serum folate (p=0.04) and a 29% decrease in plasma homocysteine (p=0.03).
Hemodialysis patients who were non-adherent to folic acid supplement prescriptions had low folic acid intakes, low serum folates and high homocysteine levels. When their adherence improved, folic acid intakes rose, serum folates increased and plasma homocysteine levels decreased, although mild hyperhomocysteinemia persisted.
Adherence; folic acid; supplements; hemodialysis; homocysteine
folic acid; folate; NHANES; folic acid fortification
We reviewed lignan physiology and lignan intervention and epidemiological studies to determine if they decreased the risks of cardiovascular disease in Western populations. Five intervention studies using flaxseed lignan supplements indicated beneficial associations with C-reactive protein and a meta-analysis, which included these studies, also suggested a lowering effect on plasma total and low-density lipoprotein cholesterol. Three intervention studies using sesamin supplements indicated possible lipid and blood pressure lowering associations. Eleven human observational epidemiological studies examined dietary intakes of lignans in relation to cardiovascular disease risk. Five showed decreased risk with either increasing dietary intakes of lignans or increased levels of serum enterolactone (an enterolignan used as a biomarker of lignan intake), five studies were of borderline significance, and one was null. The associations between lignans and decreased risk of cardiovascular disease are promising, but are yet not well established, perhaps due to low lignan intakes in habitual Western diets. At the higher doses used in intervention studies, associations were more evident.
lignans; cardiovascular disease; review
online resources; government; dietary supplements; databases
To assess whether use of folic acid vitamin supplements reduces cardiac and stroke mortality in hemodialysis patients. Further, we examined whether consumption of folic acid from vitamin supplements greater than 1000 μg compared to standard 1000 μg, and 1000 μg compared to either lower dose or no consumption were associated with reduced cardiac and stroke mortality risk.
Secondary analysis of data from the Hemodialysis (HEMO) Study, a randomized clinical trial examining dialysis treatment regimens over three years follow-up. Participants: One thousand eight hundred and forty-six hemodialysis patients previously participating in the HEMO study.
Main Outcome Measure
Cardiac and stroke mortality.
From time-dependent Cox proportional hazard regression models, folic acid consumption from vitamin supplements, above or below the standard 1000 μg dose was not associated with decrease or increase in cardiac mortality (P = 0.53 above vs. standard dose and P = 0.46, below vs. standard dose). There was also no association between folic acid consumption and mortality from stroke (P = 0.27, above vs. standard dose and P = 0.64, below vs. standard dose).
Consumption of higher than the standard 1000 μg prescribed dose of folic acid was not beneficial in reducing cardiac or stroke mortality in hemodialysis patients. Similarly, consumption of lower than standard dose was not associated with an increase in either cardiac or stroke mortality.
Folic acid; cardiac; stroke; mortality; hemodialysis
Limited data are available on the source of usual nutrient intakes in the United States. This analysis aimed to assess contributions of micronutrients to usual intakes derived from all sources (naturally occurring, fortified and enriched, and dietary supplements) and to compare usual intakes to the Dietary Reference Intake for U.S. residents aged ≥2 y according to NHANES 2003–2006 (n = 16,110). We used the National Cancer Institute method to assess usual intakes of 19 micronutrients by source. Only a small percentage of the population had total usual intakes (from dietary intakes and supplements) below the estimated average requirement (EAR) for the following: vitamin B-6 (8%), folate (8%), zinc (8%), thiamin, riboflavin, niacin, vitamin B-12, phosphorus, iron, copper, and selenium (<6% for all). However, more of the population had total usual intakes below the EAR for vitamins A, C, D, and E (34, 25, 70, and 60%, respectively), calcium (38%), and magnesium (45%). Only 3 and 35% had total usual intakes of potassium and vitamin K, respectively, greater than the adequate intake. Enrichment and/or fortification largely contributed to intakes of vitamins A, C, and D, thiamin, iron, and folate. Dietary supplements further reduced the percentage of the population consuming less than the EAR for all nutrients. The percentage of the population with total intakes greater than the tolerable upper intake level (UL) was very low for most nutrients, whereas 10.3 and 8.4% of the population had intakes greater than the UL for niacin and zinc, respectively. Without enrichment and/or fortification and supplementation, many Americans did not achieve the recommended micronutrient intake levels set forth in the Dietary Reference Intake.
A higher body mass index is associated with better outcomes in hemodialysis patients; however, this index does not differentiate between fat and muscle mass. In order to clarify this, we examined the relationship between measures of fat and muscle mass and mortality in 1709 patients from the Hemodialysis Study. Triceps skin-fold thickness was used to assess body fat and mid-arm muscle circumference was used to assess muscle mass. Cox regression was used to evaluate the relationship between measures of body composition with all-cause mortality after adjustments for demographic, cardiovascular, dialysis, and nutrition-related risk factors. During a median follow-up of 2.5 years, there were 802 deaths. In adjusted models with continuous covariates, higher triceps skin-fold thickness and higher body mass index were significantly associated with decreased hazards of mortality, while higher mid-arm muscle circumference showed a trend toward decreased mortality. In adjusted models, lower quartiles of triceps skin-fold thickness, mid-arm muscle circumference, and body mass index were all significantly associated with higher all-cause mortality. These studies show that body composition in end-stage renal disease bears a complex relationship to all-cause mortality.
body mass index; dialysis; mortality; obesity
The NIH sponsored a scientific workshop, “Soy Protein/Isoflavone Research: Challenges in Designing and Evaluating Intervention Studies,” July 28–29, 2009. The workshop goal was to provide guidance for the next generation of soy protein/isoflavone human research. Session topics included population exposure to soy; the variability of the human response to soy; product composition; methods, tools, and resources available to estimate exposure and protocol adherence; and analytical methods to assess soy in foods and supplements and analytes in biologic fluids and other tissues. The intent of the workshop was to address the quality of soy studies, not the efficacy or safety of soy. Prior NIH workshops and an evidence-based review questioned the quality of data from human soy studies. If clinical studies are pursued, investigators need to ensure that the experimental designs are optimal and the studies properly executed. The workshop participants identified methodological issues that may confound study results and interpretation. Scientifically sound and useful options for dealing with these issues were discussed. The resulting guidance is presented in this document with a brief rationale. The guidance is specific to soy clinical research and does not address nonsoy-related factors that should also be considered in designing and reporting clinical studies. This guidance may be used by investigators, journal editors, study sponsors, and protocol reviewers for a variety of purposes, including designing and implementing trials, reporting results, and interpreting published epidemiological and clinical studies.
The mechanisms by which diet affects breast cancer (BC) risk are poorly understood but a positive relationship between fat and a negative association with fiber intake and BC risk have been demonstrated. Here we study the association between dietary fat/fiber ratio and estrogen metabolism. Fifty women were recruited, 22 were included in the low fat/high fiber and 22 were in the high fat/low fiber and 6 did not meet our criteria. Estrogens (determined in plasma, urine and feces) and dietary records were collected during 3 following days. All data were collected in winter and in summer. The high fat/low fiber group had significantly higher urinary total estrogens, estriol-3-glucuronide, 2-hydroxyestradiol, 16α-hydroxyestrone, and a higher 2-hydroxyestrone/4-hydroxyestrone ratio. Total fat intake correlated significantly with plasma estrone, estradiol, urinary 2-hydroxyestrone, 2-hydroxyestradiol, 2-hydroxyestrone/4-hydroxyestrone ratio, and total urinary estrogens, even after adjustment for total fiber intake. The high fat/low fiber diet was associated with high values both for catechol and 16α-hydroxylated estrogens and a high 2-hydroxyestrone/4-hydroxyestrone ratio, but 2-hydroxyestrone/16α-hydroxyestrone ratio was not different between the groups. Our results suggest that fat affects estrogen metabolism more than does fiber and that one mechanism resulting in high estrogen values is an increased reabsorption of biliary estrogens.
Diet; Estrogens; Breast cancer risk; Women
In response to the need to assess both food and supplemental sources of nutrients, we have expanded the capabilities of Nutrition Data System for Research (NDSR) software to allow for assessing dietary supplement use. A Dietary Supplement Assessment Module allows for the automated collection and coding of dietary supplement use. The module is designed for use in conjunction with the software’s 24-hour dietary recall features. The medication inventory method, commonly used in pharmaceutical research, served as the basis for the module’s assessment approach. In adapting this approach for use in our software we designed a tiered structure that involves first screening for use of dietary supplements, then collecting product detail (e.g. full name of product, number of times taken, etc.), and finally reviewing the information with the participant. Preliminary results from a demonstration study being conducted to evaluate the Module indicate the assessment approach is acceptable to both participants and interviewers. Collecting dietary supplement use information significantly increases interview time, especially for those using multiple products. A validation study is needed to determine whether the new method results in accurate estimation of nutrient intake from supplemental sources.
Dietary supplements; Dietary assessment