Ann Yaktine

Previous research in this laboratory demonstrated elevated plasma corticosterone and reduced protein kinase C (PKC) activity and selective isoform expression in the epidermis of dietary energy-restricted mice. Because PKC is implicated in skin carcinogenesis and because both energy restriction and glucocorticoid hormone inhibit skin carcinogenesis, the purpose of the present research was to determine whether the elevated glucocorticoid hormone in

The Supplemental Nutrition Assistance Program (SNAP) increases the food purchasing power of participating households. A committee convened by the Institute of Medicine (IOM) examined the question of whether it is feasible to define SNAP allotment adequacy. Total resources; individual, household, and environmental factors; and SNAP program characteristics that affect allotment adequacy were identified from a framework developed by the IOM committee. The committee concluded that it is feasible to define SNAP allotment adequacy; however, such a definition must take into account the degree to which participants' total resources and individual, household, and environmental factors influence the purchasing power of SNAP benefits and the impact of SNAP program characteristics on the calculation of the dollar value of the SNAP allotment. The committee recommended that the USDA Food and Nutrition Service investigate ways to incorporate these factors and program characteristics into resea...

The Institute of Medicine's Food and Nutrition Board had a productive year, with important expert committee reports on the Supplemental Food Assistance Program, physical fitness, and accelerating obesity prevention efforts that provided grounding for dietary guidance and nutrition policies and programs. This summary describes Food and Nutrition Board activities, including current thinking on dietary reference intakes. The summary also highlights consensus reports on defining and measuring Supplemental Food Assistance Program benefit adequacy and on physical fitness and health outcomes in youth. In addition, current and new activities related to obesity prevention and care are addressed. What do these activities have in common? All adhere to the Institute of Medicine report model by filling gaps and by being analytical, evidence-based, and challenging.

Dioxins and related compounds are undesirable and unintended contaminants in the food supply, and dietary intake is the major route of exposure. Reducing dietary exposure to dioxins among the most vulnerable segments of the population (i.e., pregnant women, infants, and young girls) is an effective strategy for reducing body burdens in future generations. Exposure to dioxins through foods can be minimized by selecting lower-fat versions of meats, poultry, and dairy products. Consuming all foods, including fatty fish, in recommended amounts is congruent with the goal of reducing dioxin intake exposure and maintaining good health.

Dietary restriction in experimental animals enhances life span, delays disease, inhibits immunological perturbations, and ameliorates cancer. Protein kinase C (PKC) isozymes mediate signals generated by hormones, growth factors, and neurotransmitters for cell proliferation and differentiation. The results of our study showed that a C-terminally directed anti-PKC zeta antibody detected an 81-kDa band in the pancreases of control and energy-restricted hamsters. Syrian golden hamsters were fed energy-restricted diets formulated such that the hamsters received 90% (10% energy restriction (ER)), 80% (20% ER), or 60% (40% ER) of the total energy consumed by control hamsters, with the energy reduced proportionally from fat and carbohydrate. ER decreased PKC zeta isozyme levels by 40-75% in hamsters fed 10, 20, and 40% ER diets for 8 wk. PKC zeta isozyme expression was decreased by 75-80% in hamsters fed ER diets for 15 wk. Although ER caused significant decreases in PKC zeta isozyme levels compared with those of control hamsters at both time points, the relative differences in PKC zeta levels between the dietary ER groups (10, 20, and 40%) were small and not significant. A significant decrease in the body weights of ER animals compared with those of controls was observed at both time points. No differences in tomato lectin and phytohemagglutinin reactivity were observed between control animals and animals fed 10, 20, and 40% ER diets. Furthermore, the cellular expression of PKC zeta in the hamster pancreas did not differ among hamsters fed the various ER diets. These observations may be important for understanding not only the role of dietary ER in pancreatic cancers but also PKC zeta signal transduction mechanisms in normal pancreatic physiology.

The purpose of this study was to demonstrate that dietary energy restriction elevates plasma glucocorticoid hormone (GCH) levels while maintaining a circadian profile. Furthermore, we indirectly measured the effect of energy restriction on receptor activation in epidermis by determining the cellular localization of receptor protein in control-fed and energy-restricted (ER) mice. SENCAR mice were maintained on an ad libitum control diet or an ER diet that provided 60% of the total energy consumed by control-fed mice. Plasma corticosterone levels were determined by radioimmunoassay. Glucocorticoid receptor (GR) protein levels in epidermal lysates were measured by western blotting. Electron microscopy was used to identify gold-conjugated immunoreactive GR in epidermal cells of the skin in control and ER mice. Plasma corticosterone levels in ER mice were significantly increased 10 times over the levels in control mice at 0700 h, significantly increased two times over control levels at 1600 h, and not different from controls at 2300 h in the circadian cycle. The total amount of epidermal GR protein in ER mice was 140% (95% confidence interval, 104-169%) of that in controls at the early time point, not different at the midpoint, and 60% (95% confidence interval, 48-79%) of that in controls at the late time point. The distribution of gold-conjugated GR in the cytoplasmic and nuclear compartments of epidermal cells was similar in control and ER mice. Thus, we showed that dietary ER increased the level of plasma GCH without abolishing diurnal variation. However, an increase in ligand activation in epidermal cells, as indicated by nuclear localization of GR protein, was not supported by the results of this study.