The Human Nutrition National Program (NP 107) addresses high-priority problems of national importance, as outlined in Strategic Goal 5 of the ARS Strategic Plan for FY2006-2011 which is to improve the Nation’s nutrition and health. Specifically, this program contributes to Objective 5.2: promote healthier eating habits and lifestyles. This is being done throughout the program but is highlighted by our increased emphasis on obesity prevention research. The goal of NP 107 is to define the role of food and its components in maintaining health throughout the life cycle.
During the past year, NP 107 underwent a retrospective review of the previous five years’ accomplishments by an extramural panel of distinguished scientists. The executive summary of that report is available on this Web site. In February 2007, a Stakeholder Workshop was held which was attended by 140 individuals representing stakeholders, customers, and ARS. Input from that workshop was used by teams of ARS scientists and the National Program Leaders to develop a new Action Plan for the years 2009-2013. The current action plan remains in effect until the end of 2008.
There are seven research components in the current program:
- Composition of Foods
- Bioavailability of Nutrients and Food Components
- Nutrition Monitoring
- Nutrient Requirements
- Health Promoting Properties of Plant and Animal Foods
- Relationship between Diet, Genetics, Lifestyle, and the Prevention of Obesity and Disease
- Health Promoting Intervention Strategies for Targeted Populations
Selected accomplishments completed during FY2007 are listed below. Several of these represent combined efforts of two or more of the Human Nutrition Research Centers. Links to publicly available documentation are provided after each finding.
Breakfast and meal patterns are important to health and performance. Scientists at the ARS Center in Little Rock, Arkansas, found that children who skipped breakfast were less attentive and had slower visual cue response times than children who ate breakfast. These findings suggest that breakfast facilitates brain and motor processes that are important for learning in school. Using data from the USDA “What We Eat in America/NHANES” national dietary survey, ARS scientists in Beltsville, Maryland, found that 80% of Americans consume breakfast on any given day. On average breakfast was found to be proportionately lower in calories and higher in vitamins and minerals than other meals, demonstrating the importance of breakfast to the overall quality of American diets. Further, other ARS scientists at Beltsville, Maryland, demonstrated that consuming a single meal per day, in contrast to several meals per day, adversely influences risk for diabetes and cardiovascular disease. Such meal pattern information has broad implications for federal and state nutrition policy and programs.
Publications: Pivik RT, Dykman RA. Event-related variations in alpha band activity during an attentional task in preadolescents: Effects of morning nutrition. Clin Neurophysiol. 2007; 118:615-32.
Carlson O, Martin B, Stote KS, Golden E, Maudsley S, Najjar SS, Ferrucci L, Ingram DK, Longo DL, Rumpler WV, Baer DJ, Egan J, Mattson MP. Impact of reduced meal frequency without caloric restriction on glucose regulation in healthy, normal-weight middle-aged men and women. Metabolism. 2007;56:1729-34.
Rebuilding bone strength in young women with calcium-rich foods. For years it has been thought that insufficient calcium consumption during adolescence increases a woman’s risk for bone fracture during the post-menopausal years. However, ARS scientists in Grand Forks, North Dakota, demonstrated in female rats that the damaging effects of a severe calcium deficiency on bone structure and strength during adolescence could be completely reversed by adequate calcium nutrition during the early adult years. This finding suggests that young women with inadequate calcium intake during the teen years may be able to rebuild their bones by increasing consumption of calcium-rich foods in early adulthood. Today, animal products are the primary source of unfortified, calcium-rich foods. ARS scientists in Houston, Texas, reported that it is possible to improve the calcium bioavailability of plant foods by reducing the formation of calcium oxalate content in plants. This has important implications as plants are the major calcium source for much of the world’s population.
Publication: Morris J, Nakata PA, McConn M, Brock A, Hirschi KD. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate. Plant Mol Biol. 2007;64:613-8.
Folic acid fortification and increased cancer risk. Mandatory fortification of the food supply in the U.S. and Canada began in the late 1990’s to reduce the risk of certain birth defects. It was also expected that cancer rates would drop as a result. In contrast, ARS scientists in Boston, Massachusetts, noted a rise in colorectal cancer that coincided with this change to the food supply. This reversed a prolonged decline in incidence of this type of cancer. This observation is being followed up with folic acid analysis of 1,000 colon biopsies in people with or without cancer to determine if this association is truly cause and effect.
Publication: Mason JB, Dickstein A, Jacques PF, Haggarty P, Selhub J, Dallal G, Rosenberg IH. A temporal association between folic acid fortification and an increase in colorectal cancer rates may be illuminating important biological principles: a hypothesis. Cancer Epidemiol Biomarkers Prev. 2007;16:1325-9.
Zinc levels in blood predict pneumonia in elderly. A study of 617 people over 65 years old living in 33 nursing homes was conducted to determine if vitamin E supplements prevented pneumonia, one of the leading causes of death in this population. While vitamin E had small effects, subjects with normal blood zinc levels had decreased incidence (by almost half) and duration of pneumonia, needed fewer antibiotics, and had reduced total mortality. All of these reductions were statistically significant. This study, conducted by ARS scientists in Boston, Massachusetts, suggests that many elderly could benefit from diets higher in zinc and/or zinc supplements.
Publication: Meydani SN, Barnett JB, Dallal GE, Fine BC, Jacques PF, Leka LS, Hamer DH. Serum zinc and pneumonia in nursing home elderly. Am J Clin Nutr. 2007; 86:1167-73.
Maternal overweight programs obesity in offspring. Observational studies of people indicate a link between obesity in mothers and development of overweight in children. Due to interaction of genetics and environment, it is almost impossible to establish causal relationships in human studies. ARS researchers in Little Rock, Arkansas, used an animal model to find that obese females gave birth to normal weight offspring but the progeny were much more susceptible to becoming overweight in later life than offspring from normal weight mothers. These results may partially explain the rapid increase in obesity seen in the U.S. over the last 30 years and afford the ability to test biological mechanisms and dietary interventions relatively quickly.
Helping underweight women have healthier pregnancies. Successful pregnancy requires expansion of blood volume and blood vessels. This is achieved through production of the signal molecule, nitric oxide, which is derived from the amino acid arginine. ARS researchers in Houston, Texas, discovered that underweight women produced more arginine and more nitric oxide early in pregnancy compared with normal weight women but did not respond with the expected expansion of blood volume. These findings suggest that underweight women need more arginine and nitric oxide than normal weight women to maintain increased blood volume during pregnancy and this may be achieved by alterations in dietary precursors
Texas school lunch nutrition policy changes improve the nutrition of school children. Scientists at the ARS Center in Houston, Texas, tracked the dietary intakes of middle-school children before and after enactment of the Texas Public School Nutrition Policy in 2004 that was designed to improve the nutrition of school children. Children consuming mostly foods from the National School Lunch Program (NSLP) had higher intakes of most nutrients, milk, fruit and vegetables, and lower intakes of sweetened beverages, snack chips, candy than students eating non-NSLP foods. However, findings also indicate the need to reduce saturated fat and sodium in the NSLP.
Publication: Cullen KW, Watson K, Zakeri I. Improvements in middle school student dietary intake after implementation of the Texas Public School Nutrition Policy. Am J Public Health. 2007.
Beneficial bacteria improve intestinal function. Probiotics are helpful bacteria that live in the intestine. ARS scientists Beltsville, Maryland, found that ingestion of these bacteria improved both intestinal immune function and the barrier function that keeps harmful bacteria from entering the body while scientists in Little Rock, Arkansas reported that diet regulates development of immune tissue in the gastrointestinal tract of neonatal pigs. These studies have potential to provide better advice for infant feeding and healthier dairy products that naturally contain probiotic bacteria.
Publication: Helm RM, Golden C, McMahon M, Thampi P, Badger TM, Nagarajan S. Diet regulates the development of gut-associated lymphoid tissue in neonatal piglets. Neonatology. 2007;91:248-55.
Moderate exercise program reduces the risk for diabetes in sedentary obese adolescents. The USDA/DHHS Dietary Guidelines for Americans recommends 60 minutes of physical activity most days of the week for children. Scientists at the ARS Center in Houston, Texas, demonstrated that a controlled, moderate exercise training program without weight loss resulted in increased fitness, reduced fat accumulation in the abdomen and surrounding vital organs, and improved insulin sensitivity in obese adolescents. This program can be adapted for use in schools and obesity clinics as a strategy to delay or reduce the risk of type-2 diabetes in children and adolescents.
New database release on the antioxidant capacities of fruits, nuts, vegetables and spices. ARS scientists at Beltsville, Maryland, and Little Rock, Arkansas, collaborated on the development of a new database on the Oxygen Radical Absorbance Capacity (ORAC) of about 300 selected foods. ORAC is one approach to evaluating the antioxidant capacity of foods. Such information is essential to scientists investigating the role of food antioxidants in promoting health and preventing risk for chronic diseases.
Available on the Web: ORAC of Selected Foods