Advancing Human Nutrition Research

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The ARS human nutrition research program enhances the quality of the American diet and improves health through research. Obesity is estimated to cost $190 billion annually, and as its prevalence has increased over recent decades, ARS scientists have researched innovative ways of reversing that trend. Since agriculture primarily produces food for human consumption, integrating human nutrition research into ARS is critical for solving the biggest problems facing producers and consumers. The following accomplishments highlight ARS advances human nutrition research in FY 2019. Hyperlinked accomplishment titles point to active parent research projects.

A healthy microbiome in infants predicts better vaccine response. Vaccination is the best approach to prevent infectious diseases, but response to vaccines can be highly variable for unknown reasons, especially when given in early infancy. ARS scientists in Davis, California, conducted a study of 306 infants aged birth to 3 years to determine whether an infant that had a microbiome colonized with greater numbers of a beneficial bacteria (Bifidobacterium infantis) had better responses to four vaccines (tuberculosis, polio, hepatitis B, and tetanus) also given in early infancy. The abundance of Bifidobacterium was positively associated with better responses to the tuberculosis, tetanus, and hepatitis B vaccines when the responses were measured in early infancy and was also associated with better responses to the tuberculosis, tetanus, and polio vaccines measured at 2 to 3 years of age. This study is the first to demonstrate that bifidobacteria, which are abundant in the infant gut as a result of breastfeeding, may lead to long-term enhancement of the immune system. This observation demonstrates that early life nutrition can improve health by enhancing vaccine memory responses.

Evening snacking generally involves less healthy choices. On any given day, almost two-thirds of Americans eat or drink something after 8:00 P.M. This is of concern to researchers and policymakers because most people generally have consumed enough calories for the day by the end of their evening meals. ARS researchers in Beltsville, Maryland, analyzed data from more than 10,000 volunteers in the What We Eat in America, National Health and Nutrition Examination Survey and found that one in five adults obtained 30 percent or more of their total daily calories from late-evening consumption of foods and beverages. Those who ate late at night took in about 15 percent more calories than nonsnackers did. Snacking was most prevalent among non-Hispanic black subjects. The most commonly eaten late evening food category was “snacks and sweets” and the most commonly consumed beverage was water. Behavioral interventions for weight control or healthier diets could focus on this vulnerable time during which fewer calories and healthier choices could be selected.

Improving USDA food composition databases and launching FoodData Central. USDA food composition databases are used by a diverse community to make policy decisions, investigate the impact of diet on health, develop new foods, advise patients on improving their diets, and address the general need for more information on what is in the food we eat. The USDA has been compiling data on food composition for more than 100 years, but in recent years the amount, type, and format of the data have become outdated. To rectify this problem ARS scientists in Beltsville, Maryland, major industry partners, and the National Agricultural Library (NAL) makes available nutrition information for scientific researchers, dieticians, nutritionists, application developers, and consumers via food composition databases and FoodData Central. FoodData Central provides access to all USDA food composition information—such as expanded nutrient information, links to Special Interest Databases, and links to related agricultural and experimental research data—in a single location. The USDA databases includes legacy databases, a database used for the What We Eat in America survey, data on branded food products, and Foundation Foods (the primary source of analytical food composition data from this point forward). In fiscal 2019 NAL hosted and made available online more than 560,000 different foods with more than 8.6 million food nutrient entries in both data products. Combined, these data products generated more than 30 million page views via 4 million user sessions. Most impressively, application developers made nearly 265 million Application Programmer Interface (API) calls against these two data products in fiscal 2019, making the USDA Food Composition Database and FoodData Central APIs among the most popular in government. This new database will allow the USDA to continue to be the world’s foremost authority for nutritional data well into this century.

Brain activation in children with obesity differs from that in normal-weight children. Obesity in U.S. children has tripled over the past few decades. Understanding how normal-weight and obese young children process high-calorie food stimuli may provide ways to alter unhealthy eating behaviors. ARS-supported scientists from Little Rock, Arkansas, used functional magnetic resonance imaging (fMRI) to map activation of brain regions in 8- to 10-year-old children viewing images of high-calorie food (e.g., an ice cream sundae) or non-food (e.g., a telephone) items. Normal-weight children had significantly higher activation of two brain regions associated with cognitive control and memory than obese children; the area involved was larger and the strength of activation was higher. These results suggest that normal-weight and obese children process high-calorie food stimuli differently. The findings point to the importance of early and sustained education in children about healthy food choices.

Diet, gut bacteria, and chronic diarrhea. More than 1.2 million people in the United States suffer from inflammatory bowel disease; this disease also spontaneously occurs in monkeys. Gut bacteria aid nutrient absorption, whereas nutrients influence which gut bacteria live and die. To study this interaction, ARS researchers in Davis, California, in collaboration with University of California-Davis scientists, discovered that even though both healthy and diseased animals consumed the same foods, the “diet” of their gut microbes was not the same. Gut microbes in diseased animals consumed more of the protective mucin layer produced by intestinal cells. The microbes also participated in cross-feeding relationships in which one microbe degraded part of the protective layer, leaving another part for another microbe. These discoveries will enable new strategies to prevent chronic gastrointestinal diseases, such as ulcerative colitis, in humans.

Newly created atlas of epigenetic variation in humans. More than 15 years after scientists first mapped the human genome, most diseases still cannot be predicted based on genes, leading researchers to explore epigenetics as causes of disease. The most stable form of epigenetic regulation is DNA methylation, which changes gene conformation and gene expression, but progress on this topic has been limited by lack of information on cell type specificity. ARS-supported scientists in Houston, Texas, performed deep sequencing of genomic DNA in tissues representing the three germ layers during development followed by producing a computer algorithm to identify individual regions that vary in DNA methylation. The nearly 10,000 regions the researchers mapped out, called correlated regions of systemic interindividual variation (CoRSIVs), comprise a previously unrecognized level of molecular individuality in humans. Because epigenetic marking of genes has the power to either stably silence or activate them, any disease that has a genetic basis may also have an epigenetic component. This map forms the basis of understanding about disease processes from an epigenetic perspective.