A national program workshop is scheduled for March 8-10, 2000. The purpose of the workshop is to establish long-term national priorities for the ARS Human Nutrition Program.

Diet records may not accurately reflect energy expenditure. When compared to total energy expenditure, diet records underestimated energy requirement by 29 percent in a rural elderly population. Diet records were assessed for 3 days and total energy expenditure was measured by doubly labeled water and resting energy expenditure was measured by indirect calorimetry. Activity recall estimates were not significantly different from total energy expenditure in elderly women, but they overestimated energy requirement by 14 percent in elderly men.

Release of CD-ROM set for CSFII/DHKS 1994-96. The CD-ROM contains the 3-year combined 1994-96 Continuing Survey of Food Intakes by Individuals (CSFII)/Diet and Health Knowledge Survey (DHKS) data set, technical support files, a data set containing intakes of fatty acids, and a data set containing servings based on USDA's Food Guide Pyramid. Approximately 250 data tables summarizing the information in the data sets were released on the World Wide Web. This information is useful to nutritionists, researchers, and policy-makers.

Collecting dietary intake data by telephone is feasible. A telephone food intake survey conducted using random-digit dialing with a sample of 700 women (20-49 years of age) was not statistically significantly different in selected evaluation measures compared to in-person interviews of data collected in the 1994-96 CSFII study. This information has been used in the planning of a full-scale nationwide food survey. This will result in considerable cost savings for future USDA nationwide food surveys. In addition, the Lower Mississippi Delta Nutrition Intervention Research Initiative completed a Foods of Our Delta Validation and pilot study in three counties in Arkansas, Louisiana, and Mississippi, and determined that a telephone interview could be used in the rural Delta. Dietary intake data were not statistically different from those obtained from in-person interviews in both telephone and nontelephone households. This study was a validation study for a larger nutrition assessment survey planned for 1999.

New isoflavone database established. A database of values for the isoflavone content of foods was developed in collaboration between ARS scientists and scientists at Iowa State University. For the first time, this database will allow investigators to determine the relationship of foods containing these low- and/or antiestrogenic compounds with risk for cardiovascular and other diseases. The database is available on the Web, www.nal.usda.gov/fnic/foodcomp.

Release of Standard Reference 12. The Nutrient Database for Standard Reference (SR) 12 was released in March 1998. This is the major product of the National Nutrient Databank System and provides the basis of all other food composition databases, including government, private sector, and academia. It is available on the Web, www.nal.usda.gov/fnic/foodcomp. SR12 provides estimates of composition for up to 81 food components and 5, 976 foods, including revised estimates for folic acid in foods; values for selenium in foods was added for the first time.

New lignans identified in food. The isolation and characterization of the lignans, isolariciresinol, pinoresinol, secoisolariciresinol, and matairesinol from flax meal were accomplished. This is the first report of isolariciresinol and pinoresinol being identified in a food. Secoisolariciresinol and matairesinol may have potent phytoestrogenic activity, and all of them may have other important biological activities, including antioxidant activity.

National Food and Nutrient Analysis Program initiated. ARS scientists initited this new program to generate new analytical data for 1,000 key foods and ingredients. During 1998, the Nutrient Data Laboratory developed the program protocol to include statistically based nationwide sampling of foods to be followed by chemical analyses. The result will be a body of current, representative values in foods to be added to the National Nutrient Databank. This project is being partly supported by the National Heart, Lung, and Blood Institute and other Institutes within the National Institutes of Health.

Restricted zinc intake adversely affects energy utilization during exercise. An intake of 3 mg/day zinc compared to 18 mg/day in young men was associated with significant alterations in energy production and respiratory function during progressive peak exercise on a cycle ergometer. This finding provides the first evidence of impaired physiological function when dietary zinc is fed in an amount similar to that consumed by some physically active individuals. In addition, carbonic anhydrase activity in red blood cells was decreased in response to low dietary zinc, which suggests that the activity of this zinc-containing enzyme may be a new blood biochemical marker for assessment of human zinc nutritional status.

Kinetic model for copper and Molybdenum metabolism in humans developed. Dietary copper intake of 0.4 mg/day is too low to maintain copper status, and indices of copper decline were shown. Diets too low in copper may impair immune status and the activity of lysyl oxidase was decreased, which may aid in understanding the adverse effects of copper deficiency on bone and integumentary tissue. In addition, the first computer model of molybdenum metabolism from studies conducted under controlled conditions was developed.

Dietary depletion of vitamin K has a detrimental impact on bone metabolism. In a 15-day dietary restriction of all forms of vitamin K in men and women, a subclinical deficiency was obtained. Classic measures of coagulation were maintained at normal levels throughout the depletion period. However, there were significant increases in abnormal forms of prothrombin and osteocalcin. In addition, there was a significant increase in a urinary marker of bone resorption during depletion. A subsequent 10-day repletion period of the naturally occurring form of vitamin K restored function of the vitamin K-dependent proteins, and bone resorption levels returned to baseline.

Possible mechanism for vitamin E protective role against atherosclerosis and cancer. Vitamin E contributes to the decreased risk of these chronic diseases through modulation of immune and endothelial cell interaction, production of several chemokines including IL-8 and MCP-1, proinflammatory cytokine IL-6, and modulation of angiogenesis. The inhibitory effect of vitamin E on suppression of monocyte adhesion to endothelial cells was also observed with lycopene, which is abundant in tomatoes. However, gamma-tocopherol, a form of vitamin E found in cooking oil and other carotenoids do not exert the same effect as alpha-tocopherol or lycopene.

Zinc may improve some aspects of cognitive function. Short-term supplementation with zinc, along with other micronutrients, improved cognitive function in school-aged Mexican-American children who are at increased risk for zinc deficiency primarily due to high intakes of dietary phytate. This is complementary to the work in which the researchers found that cognitive and psychomotor function of Chinese children with a high incidence of zinc deficiency primarily due to inadequate zinc intakes were improved with a similar dietary treatment. These research findings may be used in formulating school meal programs.

cDNA of maltase-glucoamylase (MGA) cloned and sequenced. cDNA MGA expression in mammalian cells has been documented. A genomic MGA clone is now being sequenced. This information will permit the full understanding of the terminal steps in starch digestion and how the message level of this enzyme is regulated in response to the diet.

Two new fiber and fat replacement sources reduce glycemic response. Nu-trims from oat and barley developed by ARS were subjected to the first controlled human study. They were found to reduce glucose and insulin responses. The barley extract, which was from a cultivar with triple the amount of soluble beta glucan as the oat extract, was much more effective in lowering glucose and insulin responses in both men and women. Thus, these extracts have potential for development of low-fat high-fiber foods with health promoting benefits.

Protein extracted from soybeans and used in infant formulas reduces the risk of certain cancers. The protein extracted from soybeans and used as the exclusive protein source for over 95 percent of the world's soy-based infant formulas was found to reduce the risk of breast and colon cancer in rats.

Fruit and vegetable consumption affects antioxidant status. For the first time, ARS scientists demonstrated that antioxidant status in humans can be altered with increased fruit and vegetable consumption. This was assessed by measuring plasma antioxidant capacity using the Oxygen Radical Absorbance Capacity Assay.

Development and validation of an in vitro method to assess iron bioavailability. This method is based on the measurement of ferritin, the intracellular iron storage protein which forms in response to iron uptake. This methodology, which precludes radiolabeling of food iron for in vitro digestion studies, will expand research in iron nutrition as it enables scientists to determine food iron availability without the costs and limitations of using radioistotopes.

Bioavailability of carotenoids from tomatoes. Two lesser known carotenoids, phytofluene and phytoene, are much more bioavailable from tomato juice than is the dominant carotenoid, lycopene. The bioavailability of phytofluene and phytoene are more than would be expected based on the content of these carotenoids in tomato products. The potential of these carotenoids to protect human health is unknown and has not been studied. However, studies suggest that they should be investigated for health effects rather than focusing solely on lycopene as the primary component of the tomato responsible for cancer prevention.

Food matrix in which carotenoids are found affects their bioavailability. The bioavailability of lutein and zeaxanthin to plasma was examined in moderately hypercholesterolemic adults consuming diets comprised of corn oil or beef tallow as the principal fat and then later supplemented with chicken egg yolks. The lutein and zeaxanthin content of the egg yolks was characterized, and egg yolk supplementation to the diets was found to significantly increase plasma concentration of these carotenoids. The concentrations of plasma beta-carotene and lycopene were not significantly affected by the diets. Thus, chicken eggs may serve as a rich dietary source of bioavailable lutein and zeaxanthin, possibly due to the lipid matrix of the yolk in which they are located.

Potential intervention strategy identified to block the effects of aging. A number of tissues loose their ability to respond to growth stimuli with age. The loss of proliferative capacity with age was examined at the molecular level using hepatocyte mitogen, epidermal growth factor. Liver cells (hepatocytes) from old rats were found to have a defect in their ability to stimulate a major mitogenic signal transduction pathway. These data shed new light on mechanisms of aging. Potential interventions include the use of antioxidants to alter phosphatase activity.

Diminishing risk for developing cataracts. Supplementing with vitamin C was associated with significant diminution in cataract risk in individuals who used supplements for over 10 years.