Nutritional contribution of eggs to American diets.

OBJECTIVES: The main purposes of this study were (1) to assess the nutritional significance of eggs in the American diet and (2) to estimate the degree of association between egg consumption and serum cholesterol concentration. METHODS: Data from the most recent National Health and Nutritional Examination Survey (NHANES III, 1988-94) were utilized to compare the nutritional quality indicators of diets that contained eggs (USDA food grouping system) with those that did not. Nutrient intake (from 24-hour dietary recall), egg intake (from food frequency questionnaire), sociodemographic data and blood cholesterol levels of subjects who met inclusion criteria (n = 27,378) were grouped according to the occurrence and frequency of egg consumption and were analyzed using SUDAAN. RESULTS: Daily nutrient intake of egg consumers (EC) was significantly greater than that of nonconsumers (NC) for all nutrients studied (except dietary fiber and vitamin B6). Eggs contributed < 10% of daily intake of energy and vitamin B6, 10% to 20% of folate and total, saturated and polyunsaturated fat, and 20% to 30% of vitamins A, E and B12 in EC. Compared to EC, NC had higher rates of inadequate intake (defined by Estimated Average Requirements (EAR) or < 70% Recommended Dietary Allowance (RDA)) for vitamin B12 (10% vs. 21%), vitamin A (16% vs. 21%), vitamin E (14% vs. 22%) and vitamin C (15% vs. 20%). After adjusting for demographic (age, gender and ethnicity) and lifestyle variables (smoking and physical activity), dietary cholesterol was not related to serum cholesterol concentration. People who reported eating > or = 4 eggs/wk had a significantly lower mean serum cholesterol concentration than those who reported eating < or = 1 egg/wk (193 mg/dL vs. 197 mg/dL, p < 0.01). More frequent egg consumption was negatively associated with serum cholesterol concentration (beta = -6.45, p < 0.01). CONCLUSIONS: In this cross-sectional and population-based study, egg consumption made important nutritional contributions to the American diet and was not associated with high serum cholesterol concentrations.

The PATHWAYS church-based weight loss program for urban African-American women at risk for diabetes.

OBJECTIVE: This study was carried out to test the effectiveness of PATHWAYS, a weight loss program designed specifically for urban African-American women, when administered in urban churches by trained lay facilitators. RESEARCH DESIGN AND METHODS: Thirty-nine obese women were recruited from three urban African-American churches. After randomization and the collection of baseline data on weight and lifestyle practices, subjects in the experimental group (n = 19) were assigned to receive a 14-week weight loss program (PATHWAYS) conducted by trained lay volunteers; control group subjects (n = 20) were put on a waiting list to receive the program at the conclusion of the study period. RESULTS: Of the 39 women enrolled, 15 experimental group subjects and 18 control group subjects were available for posttreatment data collection. After completing the program, PATHWAYS participants lost an average of 10.0 lb, and the control group subjects gained an average of 1.9 lb. Posttreatment difference in weight loss between the groups was statistically significant (P < 0.0001). Waist circumference among PATHWAYS participants decreased 2.5 inches, while waist circumference among control group subjects remained relatively the same. This difference between the groups was statistically significant (P < 0.05). CONCLUSIONS: A weight loss program administered by trained lay volunteers was effective in producing significant and clinically meaningful weight loss among African-American women who often do not benefit from typical weight loss programs. Ongoing research is focusing on whether the weight loss can be maintained or enhanced through monthly reinforcement sessions.

Effects on ADH activity and distribution, following selection for tolerance to ethanol in Drosophila melanogaster.

Strains of Drosophila melanogaster homozygous for either the AdhF or the AdhS allele were kept on food supplemented with ethanol for 20 generations. These strains (FE and SE) were tested for tolerance to ethanol and compared with control strains (FN and SN). The E strains showed increased tolerance to ethanol both in the adult and in the juvenile life stages. In adults the increase in tolerance was not accompanied by an increase in overall ADH activity. However, there were changes in the distribution of ADH over the body parts. Flies of the FE strain possessed significantly more ADH in the abdomen, compared with FN. Another set of FN and SN populations were started both on standard food and on ethanol food with reduced yeast concentrations. After 9 months ADH activities were determined in flies from these populations which had been placed on three different media: the food the populations had been kept on, regular food and regular food supplemented with ethanol. The phenotypic effects of yeast reduction on ADH activity were considerably, but longterm genetic effects were limited.

Influence of size and polarity of residue 31 in porcine pancreatic phospholipase A2 on catalytic properties.

Residue 31 of porcine pancreatic phospholipase A2 (PLA2) is located at the entrance to the active site. To study the role of residue 31 in PLA2, six mutant enzymes were produced by site-directed mutagenesis, replacing Leu by either Trp, Arg, Ala, Thr, Ser or Gly. Direct binding studies indicated a three to six times greater affinity of the Trp31 PLA2 for both monomeric and micellar substrate analogs, relative to the wild-type enzyme. The other five mutants possess an unchanged affinity for monomers of the product analog n-decylphosphocholine and for micelles of the diacyl substrate analog rac-1,2-dioctanoylamino-dideoxy-glycero-3-phosphocholine. The affinities for micelles of the monoacyl product analog n-hexadecylphosphocholine were decreased 9-20 times for these five mutants. Kinetic studies with monomeric substrates showed that the mutants have Vmax values which range between 15 and 70% relative to the wild-type enzyme. The Vmax values for micelles of the zwitterionic substrate 1,2-dioctanoyl-sn-glycero-3-phosphocholine were lowered 3-50 times. The Km values for the monomeric substrate and the Km values for the micellar substrate were hardly affected in the case of five of the six mutants, but were considerably decreased when Trp was present at position 31. The results of these investigations point to a versatile role for the residue at position 31: involvement in the binding and orientating of monomeric substrate (analogs), involvement in the binding of the enzyme to micellar substrate analogs and possibly involvement in shielding the active site from excess water.

The effect of DDT on the polymorphism at the G6pd and Pgd loci in Drosophila melanogaster.

For the degradation of DDT and other chlorohydrocarbon insecticides energy in the form of NADPH is needed which for the greater part is supplied by the pentose phosphate shunt. Therefore the influence of DDT on the polymorphism at the G6pd and Pgd loci in Drosophila melanogaster was investigated by studying its effect on egg to adult survival and adult survival. The results show the existence of significant differences in fitness between the different genotypes of the two loci for both components. It is found that the effect of DDT supplementation differs significantly from the effect of sodium octanoate addition. DDT treatment also increases the activity of the pentose phosphate shunt as measured by the activity of G6PD and 6PGD. In larvae a 50% increase in activity is found and in adults a 100% increase. As there is little doubt that the activities of G6PD and 6PGD are somehow correlated with the fitness of flies, the data are discussed in relation to the in vitro and in vivo differences in activity between the different allozymes of both G6PD and 6PGD.