Food sources of energy and nutrients among adults in the US: NHANES 2003–2006

Major food sources contributing to energy intake – a nationwide survey of Brazilians aged 10 years and older

Identification of major sources of energy in the diet helps to implement dietary recommendations to reduce obesity. To determine the food sources of energy consumed by Brazilians, we used the traditional method of ranking energy contribution of selected food groups and also compared days with and without consumption of specific food groups. Analysis was based on two non-consecutive days of dietary record from the Brazilian National Dietary Survey, conducted among 34 003 Brazilians (aged 10 years or more), taking into account the complex design of the survey. Comparison of days with and without consumption gave more consistent results, with sweets and cookies as the most important contributors to energy intake, increasing 992 kJ/d (95 % CI 883, 1096) for those days when consumption of cakes, cookies and desserts was reported compared to days without their consumption. Savoury snacks, cheese and sugar-sweetened beverages (SSB) also increase energy intake by about 600 kJ. The only group associated with decreased energy intake was vegetable ( − 155 kJ; 95 % CI − 272, − 37). Consumption of beans, milk and fruits increased the energy intake by about 210 kJ. In total, the mean energy intake of the group was 8000 kJ. Except for the consumption of vegetables, all of the other ten food groups analysed were associated with increased energy intake. Sweets and cookies may increase the energy intake by 12 % and SSB by 7 %, indicating that these two groups are major targets for improving healthy eating by reducing energy intake; whereas vegetable intake is associated with the reduction of energy content of the diet.

Associations between objective and self-reported physical activity and vitamin D serum levels in the US population

PURPOSE

Both low levels of vitamin D and of physical activity are associated with all-cause, cancer, and cardiovascular disease mortality. There is some evidence based on self-reported activity levels that physically more active individuals have higher vitamin D serum levels. The aim was to investigate associations between objectively measured and self-reported physical activity, respectively, and vitamin D serum concentrations in the US population.

METHODS

Data from NHANES 2003-2006 (n = 6,370, aged ≥ 18 years) were analyzed using multiple regression analyses. A total of 6,370 individuals aged 18 years and older with valid data on vitamin D serum levels and physical activity were included. Objective physical activity was assessed using accelerometers; self-reported physical activity was based on the NHANES physical activity questionnaire.

RESULTS

An increase of 10 min of objectively measured and self-reported moderate-to-vigorous activities per day was associated with an increase in circulating vitamin D of 0.32 ng/ml (95% CI 0.17, 0.48) and of 0.18 ng/ml (95% CI 0.12, 0.23), respectively. The odds ratio for being vitamin D deficient (< 20 ng/ml) if being insufficiently active compared with being sufficiently active was 1.32 (1.11, 1.57). Associations were not stronger for self-reported outdoor activities compared with indoor activities.

CONCLUSIONS

Physical activity may be a way to achieve higher vitamin D serum levels in the population. Factors other than sun exposure that may be responsible for higher vitamin D levels in more active individuals need further investigation.

Low-carbohydrate diet and type 2 diabetes risk in Japanese men and women: the Japan Public Health Center-Based Prospective Study

Objective

Evidence is sparse and contradictory regarding the association between low-carbohydrate diet score and type 2 diabetes risk, and no prospective study examined the association among Asians, who consume greater amount of carbohydrate. We prospectively investigated the association of low-carbohydrate diet score with type 2 diabetes risk.

Methods

Participants were 27,799 men and 36,875 women aged 45–75 years who participated in the second survey of the Japan Public Health Center-Based Prospective Study and who had no history of diabetes. Dietary intake was ascertained by using a validated food-frequency questionnaire, and low-carbohydrate diet score was calculated from total carbohydrate, fat, and protein intake. The scores for high animal protein and fat or for high plant protein and fat were also calculated. Odds ratios of self-reported, physician-diagnosed type 2 diabetes over 5-year were estimated by using logistic regression.

Results

During the 5-year period, 1191 new cases of type 2 diabetes were self-reported. Low-carbohydrate diet score for high total protein and fat was significantly associated with a decreased risk of type 2 diabetes in women (P for trend <0.001); the multivariable-adjusted odds ratio of type 2 diabetes for the highest quintile of the score were 0.63 (95% confidence interval 0.46–0.84), compared with those for the lowest quintile. Additional adjustment for dietary glycemic load attenuated the association (odds ratio 0.75, 95% confidence interval 0.45–1.25). When the score separated for animal and for plant protein and fat, the score for high animal protein and fat was inversely associated with type 2 diabetes in women, whereas the score for high plant protein and fat was not associated in both men and women.

Discussion

Low-carbohydrate diet was associated with decreased risk of type 2 diabetes in Japanese women and this association may be partly attributable to high intake of white rice. The association for animal-based and plant-based low-carbohydrate diet warrants further investigation.

Ten-year trends in fiber and whole grain intakes and food sources for the United States population: National Health and Nutrition Examination Survey 2001-2010

Current U.S. dietary guidance includes recommendations to increase intakes of both dietary fiber and whole grain (WG). This study examines fiber and WG intakes, food sources and trends from 2001 to 2010 based on National Health and Nutrition Examination Survey (NHANES) data for children/adolescents (n = 14,973) and adults (n = 24,809). Mean fiber intake for children/adolescents was 13.2 (±0.1) g/day. Mean fiber intake for adults 19–50 years (y) was 16.1 (±0.2) g/day and for adults 51+ was 16.1 (±0.2) g/day. There were significant increases in fiber intake from 2001–2010 for children/adolescents and for adults 51+ y. Mean WG intake for children/adolescents was 0.52 (±0.01) oz eq/day. Mean WG intake for adults 19–50 y was 0.61 (±0.02) oz eq/day and for adults 51+ 0.86 (±0.02) oz eq/day. There were no significant changes in WG intake for any age group from 2001–2010. The main food groups contributing to dietary fiber intake for children/adolescents were vegetables (16.6%), grain mixtures (16.3%), other foods (15.8%) and fruits (11.3%). For adults 19+ y, the main sources of dietary fiber were vegetables (22.6%), other foods (14.3%), grain mixtures (12.0%) and fruits (11.1%). Major WG sources for children/adolescents included ready-to-eat cereals (RTEC) (31%), yeast breads/rolls (21%) and crackers and salty grain snacks (21%). The main sources of WG for adults 19+ were yeast breads/rolls (27%), RTEC (23%) and pastas/cooked cereals/rice (21%). Recommending cereals, breads and grain mixtures with higher contents of both dietary fiber and WG, along with consumer education, could increase intakes among the United States (U.S.) population.

Dietary mineral intakes of rural midlife to older adult women with prehypertension in Midwestern United States

OBJECTIVES

Midlife to older rural women with prehypertension are at increased risk for hypertension and its impact on cardiovascular health with advancing age. Because modification of dietary factors could help alleviate risk, the objective of this study was to explore calcium, magnesium, potassium and sodium intakes of midlife to older rural women, with identification of their top food sources.

DESIGN

Survey of baseline dietary intake data of women and comparison to standard recommendations.

SETTING

Rural Midwestern United States.

PARTICIPANTS

289 rural women, age 40-69, with prehypertension who volunteered for lifestyle modification to reduce blood pressure.

MEASUREMENTS

Baseline nutrition data using the Block Health Habit and History Questionnaire were collected over a twelve-month rolling enrollment period from rural women with prehypertension. Mineral intakes were calculated and compared to recommended standards. Top ten foods contributing to each mineral were identified.

RESULTS

The percent of women who met the Recommended Dietary Allowance (RDA)/Adequate Intake (AI) recommendations for their age groups ranged from a high 42.9% for magnesium to a low of 4.2% for potassium. Mean intakes of calcium, magnesium and potassium were all below recommended levels and sodium intakes were above recommendation.

CONCLUSION

Midlife to older rural US women with prehypertension were eating some of the foods that would help them meet mineral recommendations. As a preventive approach to reducing hypertension risk, clinical practice could include advising on ways to increase both commonly and less commonly consumed nutrient-rich foods with awareness of what is typically available in the rural area.

Ethnic disparities among food sources of energy and nutrients of public health concern and nutrients to limit in adults in the United States: NHANES 2003-2006

Background

Identification of current food sources of energy and nutrients among US non-Hispanic whites (NHW), non-Hispanic blacks (NHB), and Mexican American (MA) adults is needed to help with public health efforts in implementing culturally sensitive and feasible dietary recommendations.

Objective

The objective of this study was to determine the food sources of energy and nutrients to limit [saturated fatty acids (SFA), added sugars, and sodium] and nutrients of public health concern (dietary fiber, vitamin D, calcium, and potassium) by NHW, NHB, and MA adults.

Design

This was a cross-sectional analysis of a nationally representative sample of NWH (n=4,811), NHB (2,062), and MA (n=1,950) adults 19+ years. The 2003–2006 NHANES 24-h recall (Day 1) dietary intake data were analyzed. An updated USDA Dietary Source Nutrient Database was developed using current food composition databases. Food grouping included ingredients from disaggregated mixtures. Mean energy and nutrient intakes from food sources were sample-weighted. Percentages of total dietary intake contributed from food sources were ranked.

Results

Multiple differences in intake among ethnic groups were seen for energy and all nutrients examined. For example, energy intake was higher in MA as compared to NHB; SFA, added sugars, and sodium intakes were higher in NHW than NHB; dietary fiber was highest in MA and lowest in NHB; vitamin D was highest in NHW; calcium was lowest in NHB; and potassium was higher in NHW as compared to NHB. Food sources of these nutrients also varied.

Conclusion

Identification of intake of nutrients to limit and of public health concern can help health professionals implement appropriate dietary recommendations and plan interventions that are ethnically appropriate.

Dietary protein and fiber in end stage renal disease

Prior to the availability of hemodialysis, dietary protein restriction played a large part in the treatment of uremia. This therapy was based on observations that uremic symptoms increased with high protein intake. Early investigators thus presumed that "uremic toxins" were derived from the breakdown of dietary protein; its restriction improved uremic symptoms but caused malnutrition. After the availability of hemodialysis, protein restriction was no longer recommended. Studies in healthy subjects have shown that an intake of 0.6-0.8 g/kg/day is adequate to prevent protein malnutrition. Guidelines for hemodialysis patients, however, currently recommend higher protein intakes of 1.2 g/kg/day. A downside to higher intake may be increased production of protein-derived uremic solutes that caused the symptoms observed by early investigators. Some of these solutes are produced by colon microbes acting on protein which escapes digestion in the small intestine. Increasing dietary fiber may reduce the production of colon-derived solutes in hemodialysis patients without adverse effects of protein restriction. Fiber comprises carbohydrates and related substances that are resistant to digestion in the small intestine. Upon delivery to the colon, fiber is broken down to short chain fatty acids, providing energy to both the microbes and the host. With an increased energy supply, the microbes can incorporate dietary protein for growth rather than breaking them down to uremic solutes. Increasing fiber intake in hemodialysis patients has been shown to reduce the plasma levels of selected colon-derived solutes. Further studies are needed to test whether this provides clinical benefit.

Sandwiches are major contributors of sodium in the diets of American adults: results from What We Eat in America, National Health and Nutrition Examination Survey 2009-2010

Efforts to sharpen the focus of sodium reduction strategies include identification of major food group contributors of sodium intake. Although sandwiches are a staple of the American diet, previous examinations of their contribution to sodium intake captured only a small subset of sandwiches. One day of dietary intake data from 5,762 adults aged 20 years and older in What We Eat in America, National Health and Nutrition Examination Survey 2009-2010 was analyzed. Sandwiches were defined in a manner that more accurately reflected their frequency of consumption. Two-sided t tests were used to compare percentages of men and women reporting sandwiches; contributions of sandwiches to energy and sodium intakes (amounts in kilocalories and milligrams, respectively, and percent of daily totals) by sex; and total energy, total sodium, and sodium density (mg/1,000 kcal) by sandwich reporting status (reporter/nonreporter). On any given day, 49% of American adults ate sandwiches. A significantly higher percentage of men than women reported sandwiches (54% vs 44%, respectively; P<0.001), and sandwiches accounted for higher percentages of men's total energy and sodium intakes. Compared with individuals who did not report a sandwich on the intake day, sandwich reporters had significantly higher energy and sodium intakes; however, sodium density of the diet did not vary by sandwich reporting status. Although much national attention is appropriately focused on reducing sodium in the food supply, consumer choices still play a vital role. Due to sandwiches' frequent consumption and considerable contributions to sodium intake, substituting lower-sodium for higher-sodium ingredients in sandwiches could significantly influence sodium intakes.

Dietary and non-dietary factors associated with serum zinc in Indian women

Women in low-income settings, common in India, are at risk of inadequate zinc intake due to poor diet quality and low consumption of flesh foods rich in zinc. The aims of this study were to assess the prevalence of zinc status of non-pregnant rural and tribal women living in central India and to identify dietary and non-dietary factors associated with the biochemical zinc status of these women. Rural and tribal non-pregnant women 18-30 years of age were selected using proportion to population sampling near Nagpur, Maharashtra, India. Sociodemographic, biochemical (serum zinc), clinical, and dietary data (1-day interactive 24-h recall) were collected. The mean age of women (n = 109; rural = 52; tribal = 56) was 23.2 years and mean BMI was 17.9 kg/m(2). The majority of the participants identified as being non-vegetarian (72 %). The mean ± SD serum zinc concentration was 10.8 ± 1.6 μmol/L, and 52 % of participants had a low serum zinc concentration according to the International Zinc Nutrition Consultative Group (IZiNCG). The median (first and third quartile) energy, zinc intake, and phytate/zinc molar ratio was 5.4 (4.2, 6.7) MJ/day, 5.3 (3.8, 7.0) mg/day, and 26 (22, 28), respectively. Zinc intakes were well below IZiNCG recommendations for dietary zinc of 9 mg/day for non-pregnant women aged 14-18 years and 7 mg/day for non-pregnant women aged ≥ 19 years. Using linear regression analysis to identify non-dietary and dietary factors associated with serum zinc, a significant association was only found for current lactation (p = 0.012) and energy intake (p < 0.001). Diets low in energy with poor bioavailability of dietary zinc are likely to be the primary cause of the high proportion of Indian women with zinc deficiency.

Income and race/ethnicity influence dietary fiber intake and vegetable consumption

Grains, fruits, and vegetables are the primary sources of dietary fiber (DF), with the white potato contributing nearly 7% of the DF to the US food supply. The DF composition of the white potato-with or without the skin and regardless of cooking method-compares well with the DF content of other vegetables. Many health benefits, including improved gastrointestinal health, are attributed to greater DF consumption; however, less than 3% of males and females have an adequate intake of DF. Because of this population-wide shortfall, DF is considered to be a nutrient of concern. In this study, using data from the National Health and Nutrition Examination Survey 2009 to 2010, we examined the mean intake of DF across sex, age, race/ethnicity, family income, and poverty threshold. This study shows that mean intake of DF is far below recommendations, with children and adolescents aged 2 to 19 years consuming an average of less than 14 g of DF per day. Adults 20+ years old consume, on average, about 17 g of DF per day, and men consume significantly more DF than women. Non-Hispanic black adults consume significantly less DF compared with other race/ethnic groups. Lower family income and living at less than 131% of poverty were associated with lower DF intakes among adults. Federal and local government policies should encourage consumption of all vegetables, including the white potato, as an important source of DF.

Race and gender disparities in nutrient intake are not related to metabolic syndrome in 20- to 59-year-old US adults

BACKGROUND

The goal of this study was to examine the relationship between macronutrient and micronutrient intake and metabolic syndrome within race and gender cohorts of young US adults.

METHODS

The 2007-2010 National Health and Nutrition Examination Survey (NHANES) data for adults (n=2440) aged 20-59 were analyzed. Two 24-hr dietary recalls were used to measure intake of total calories, macronutrients, and 20 vitamins and minerals. Metabolic syndrome and its components were defined by the National Heart, Lung and Blood Institute criteria. Differences in statistical tests were noted when significant at P<0.05.

RESULTS

Prevalence of metabolic syndrome among 20- to 59-year-old adults was 30.4% [95% confidence interval 27.6-33.2]. Among cohorts, metabolic syndrome was highest in black women and white men, and lowest in black men and white women. Regression analysis indicated that no macronutrients were associated with greater risk of metabolic syndrome. For relative macronutrient intake, men with metabolic syndrome consumed more polyunsaturated fats, whereas women with metabolic syndrome consumed more total, saturated and monounsaturated fats and less fiber and starch than women without metabolic syndrome. Among races, white men and women consumed greater absolute quantities of all macronutrients except carbohydrates and sugar. Micronutrient intake was greatest for white men and women; women without metabolic syndrome had greater micronutrient adequacy than women with metabolic syndrome.

CONCLUSION

Nutrient intake varied between race/gender cohorts; however, there were few clinically significant differences in nutrient intake between those with and without metabolic syndrome. Diet may be marginally related to diagnosis of metabolic syndrome.

Inclusion of red meat in healthful dietary patterns

Dietary patterns are an important concept in dietary recommendations. The Western pattern is most commonly defined as a diet characterized by high intakes of refined grains, sugar and red meat, and has been shown to be associated with increased risks for certain types of cancer, coronary heart disease, diabetes, and obesity. However, isolating the independent effects of individual foods on health outcomes is central to helping individuals choose foods to build healthier dietary patterns to which they can adhere. Red meat is a popular source of high quality protein and provides a variety of essential nutrients that improve overall diet quality. It is also a source of saturated fatty acids, which observational evidence suggests are associated with heart disease, although recent data challenge this. Several studies have shown that lean red meat can be successfully included in recommended heart-healthy dietary patterns without detriment to blood lipids. Furthermore, increased dietary protein has been shown to promote healthy body weight and composition, in part by increasing satiety, and to improve vitality and stamina.

Total dietary fiber intakes in the US population are related to whole grain consumption: results from the National Health and Nutrition Examination Survey 2009 to 2010

Whole grain (WG) foods have been shown to reduce chronic disease risk and overweight. Total dietary fiber is associated with WG and its health benefits. The purpose was to determine whether associations exist between WG intake (no-WG intake, 0 ounce equivalent [oz eq]; low, >0-<3 oz eq; high, ≥3 oz eq) and total dietary fiber intake among Americans 2 years and older. One-day food intake data from the US National Health and Nutrition Examination Survey 2009 to 2010 (n = 9042) showed that only 2.9% and 7.7% of children/adolescents (2-18 years) and adults (≥19 years) consumed at least 3 WG oz eq/d, respectively. For children/adolescents and adults, individuals in the high WG intake group were 59 and 76 times more likely to fall in the third fiber tertile, respectively, compared with those with no-WG intake. Total dietary fiber intake from food sources varied by WG intake group for children/adolescents and adults with more total dietary fiber consumed from ready-to-eat (RTE) and hot cereals and yeast breads/rolls in the high WG intake group compared with the no-WG intake group. Major WG sources for children/adolescents and adults included yeast bread/rolls (24% and 27%, respectively), RTE cereals (25% and 20%, respectively), and oatmeal (12% and 21%, respectively). Among those with the highest WG intake, WG RTE cereal with no added bran was the greatest contributor to total dietary fiber compared with other RTE cereal types. Whole grain foods make a substantial contribution to total dietary fiber intake and should be promoted to meet recommendations.

Candy consumption in childhood is not predictive of weight, adiposity measures or cardiovascular risk factors in young adults: the Bogalusa Heart Study

BACKGROUND

There are limited data available on the longitudinal relationship between candy consumption by children on weight and other cardiovascular risk factors (CVRF) in young adults. The present study investigated whether candy consumption in children was predictive of weight and CVRF in young adults.

METHODS

A longitudinal sample of children 10 years (n = 355; 61% females; 71% European-Americans, 29% African-Americans) who participated in cross-sectional surveys from 1973 to 1984 (baseline) and in one of two surveys (follow-ups) as young adults [19-38 years; mean (SD) = 23.6 (2.6) years] in Bogalusa, LA, were studied. Dietary data were collected using 24-h dietary recalls at baseline and at one follow-up survey; a food frequency questionnaire was used in the other follow-up survey. Candy consumers were those consuming any amount of candy. Candy consumption was calculated (g day(-1) ) from baseline 24-h dietary recalls, and was used as a covariate in the adjusted linear mixed models. Dependent variables included body mass index (BMI) and CVRF measured in young adults.

RESULTS

At baseline, 92% of children reported consuming candy [46 (45) g day(-1)]; the percentage decreased to 67% [20 (30) g day(-1)] at follow-up. No longitudinal relationship was shown between baseline candy consumption and BMI or CVRF in young adults, suggesting that candy consumption was not predictive of health risks later in life.

CONCLUSIONS

The consumption of nutrient rich foods consistent with dietary recommendations is important, although modest amounts of candy can be added to the diet without potential adverse long-term consequences to weight or CVRF. Additional studies are needed to confirm these results.

Lactose intolerance and health disparities among African Americans and Hispanic Americans: an updated consensus statement

Dairy foods contribute nine essential nutrients to the diet including calcium, potassium and vitamin D; nutrients identified by the 2010 Dietary Guidelines for Americans as being "of public health concern" within the U.S. population. Milk and milk product intake is associated with better diet quality and has been associated with a reduced risk of chronic diseases or conditions including hypertension, cardiovascular disease, metabolic syndrome, Type 2 Diabetes and osteoporosis. Some research also indicates dairy food intake may be linked to reduced body fat, when accompanied by energy-restriction. On average, both African Americans and Hispanic Americans consume less than the recommended levels of dairy foods, and perceived or actual lactose intolerance can be a primary reason for limiting or avoiding dairy intake. True lactose intolerance prevalence is not known because healthcare providers do not routinely measure for it, and no standardized assessment method exists. Avoiding dairy may lead to shortfalls of essential nutrients and increased susceptibility to chronic disease. This updated Consensus Statement aims to provide the most current information about lactose intolerance and health, with specific relevance to the African American and Hispanic American communities. Topics covered include diagnostic considerations, actual and recommended dairy food intake and levels of consumption of key dairy nutrients among African Americans and Hispanic Americans; prevalence of self-reported lactose intolerance among various racial/ethnic groups; the association between dairy food intake, lactose intolerance and chronic disease; and research-based management recommendations for those with lactose intolerance.

Systematic review of clinical studies related to pork intake and metabolic syndrome or its components

Globally, both the incidence of type 2 diabetes and the consumption of meat, in particular pork meat, have increased, concurrently. Processed meats have been associated with an increased risk for diabetes in observational studies. Therefore, it is important to understand the possible mechanisms of this association and the impact of meats from different species. The goal of this systematic review was to assess experimental human studies of the impact of pork intake compared with other protein sources on early markers for the development of diabetes, ie, insulin resistance, glucose intolerance, and the components of the metabolic syndrome. A systematic review was conducted searching PubMed and EMBASE and using the Cochrane and PRISMA guidelines. Eight studies were eligible and critically reviewed. Five studies were based on a single meal or single day exposure to pork, as compared with other sources of protein. The glucose-insulin response following the pork meals did not differ compared with beef, shrimp, or mixed sources of proteins. However, compared with eggs, ham (processed meat) led to a larger insulin response in nonobese subjects. Compared with whey, ham led to a smaller insulin response and a larger glucose response. These findings suggest possible mechanisms for the association between processed meat and the development of diabetes. Nonprocessed pork meats were not compared with eggs or whey. The three longer interventions (11 days to 6 months) did not show a significant impact of pork on the components of the metabolic syndrome, with the exception of a possible benefit on waist circumference and high-density lipoprotein cholesterol (one study each with significant limitations). Most of the findings are weak and there is a lack of solid evidence. The literature on the topic is limited and important research gaps are identified. Considering recent trends and projections for diabetes and pork intake, this is an important global public health question that requires more attention in order to provide improved evidence-based dietary recommendations.

Iron and zinc nutrition in the economically-developed world: a review

This review compares iron and zinc food sources, dietary intakes, dietary recommendations, nutritional status, bioavailability and interactions, with a focus on adults in economically-developed countries. The main sources of iron and zinc are cereals and meat, with fortificant iron and zinc potentially making an important contribution. Current fortification practices are concerning as there is little regulation or monitoring of intakes. In the countries included in this review, the proportion of individuals with iron intakes below recommendations was similar to the proportion of individuals with suboptimal iron status. Due to a lack of population zinc status information, similar comparisons cannot be made for zinc intakes and status. Significant data indicate that inhibitors of iron absorption include phytate, polyphenols, soy protein and calcium, and enhancers include animal tissue and ascorbic acid. It appears that of these, only phytate and soy protein also inhibit zinc absorption. Most data are derived from single-meal studies, which tend to amplify impacts on iron absorption in contrast to studies that utilize a realistic food matrix. These interactions need to be substantiated by studies that account for whole diets, however in the interim, it may be prudent for those at risk of iron deficiency to maximize absorption by reducing consumption of inhibitors and including enhancers at mealtimes.

Major food sources of calories, added sugars, and saturated fat and their contribution to essential nutrient intakes in the U.S. diet: data from the National Health and Nutrition Examination Survey (2003-2006)

BACKGROUND

The risk of chronic disease cannot be predicted simply by the content of a single nutrient in a food or food group in the diet. The contribution of food sources of calories, added sugars and saturated fat (SFA) to intakes of dietary fiber and micronutrients of public health importance is also relevant to understanding the overall dietary impact of these foods.

OBJECTIVE

Identify the top food sources of calories, added sugars and SFA in the U.S. diet and quantify their contribution to fiber and micronutrient intakes.

METHODS

Single 24-hour dietary recalls (Day 1) collected from participants ≥2 years (n = 16,822) of the What We Eat in America, National Health and Nutrition Examination Survey (WWEIA/NHANES 2003-2006) were analyzed. All analyses included sample weights to account for the survey design. Calorie and nutrient intakes from foods included contributions from disaggregated food mixtures and tabulated by rank order.

RESULTS

No one food category contributes more than 7.2% of calories to the overall U.S. diet, but half of the top 10 contribute 10% or more of total dietary fiber and micronutrients. Three of the top 10 sources of calories and SFA (beef, milk and cheese) contribute 46.3% of the calcium, 49.5% of the vitamin D, 42.3% of the vitamin B12 as well as other essential nutrients to the American diet. On the other hand, foods categorized as desserts, snacks, or beverages, contribute 13.6% of total calories, 83% of added sugar intake, and provide little or no nutritional value. Including food components of disaggregated recipes more accurately estimated the contribution of foods like beef, milk or cheese to overall nutrient intake compared to "as consumed" food categorizations.

CONCLUSIONS

Some food sources of calories, added sugars and SFA make major contributions to American dietary fiber and micronutrient intakes. Dietary modifications targeting reductions in calories, added sugar, or SFA need to take these key micronutrient sources into account so as not to have the unintended consequence of lowering overall dietary quality.

Strategies for vitamin B6 biofortification of plants: a dual role as a micronutrient and a stress protectant

Vitamin B6 has an essential role in cells as a cofactor for several metabolic enzymes. It has also been shown to function as a potent antioxidant molecule. The recent elucidation of the vitamin B6 biosynthesis pathways in plants provides opportunities for characterizing their importance during developmental processes and exposure to stress. Humans and animals must acquire vitamin B6 with their diet, with plants being a major source, because they cannot biosynthesize it de novo. However, the abundance of the vitamin in the edible portions of the most commonly consumed plants is not sufficient to meet daily requirements. Genetic engineering has proven successful in increasing the vitamin B6 content in the model plant Arabidopsis. The added benefits associated with the enhanced vitamin B6 content, such as higher biomass and resistance to abiotic stress, suggest that increasing this essential micronutrient could be a valuable option to improve the nutritional quality and stress tolerance of crop plants. This review summarizes current achievements in vitamin B6 biofortification and considers strategies for increasing vitamin B6 levels in crop plants for human health and nutrition.