Biomedical subjects
S N Gershoff
Publications and source records attributed to S N Gershoff.
National Dairy Council Award for Excellence in Medical/Dental Nutrition Education Lecture, 1996: nutrition education--success or failure?
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Nutrition evaluation of dietary fat substitutes.
In response to US dietary guidelines and health goals, the food industry has introduced a variety of innovative food products designed to help the American public lower its fat intake. The physical characteristics and safety considerations of these products are reviewed, as well as their association with chronic disease prevention.
Prophylactic vitamin C: misplaced zeal.
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Maternal education and child feeding practices in rural Bangladesh.
This study in rural lowland Bangladesh used spot and event observations from 185 children aged 4-27 months in order to examine whether child feeding practices differed with mother's education and with household education. Each child and his/her caretakers were observed for a mean of 20 hr over 6 months from February to July 1986. Only 25% of mothers and 51% of fathers had had any formal education. Exploratory partial correlations and stepwise multiple regression analyses revealed significant behavioral differences with both maternal and household measures of education while controlling for wealth. Caretakers in families with education were found to feed the children more frequently, with fresher food, and in cleaner, more protected places. They did not allow their children to eat food intended for someone else as often, and were more observant when their children's food dropped during the feeding. These caretakers also used more cups and bottles for feedings, breastfed their children less frequently, and their mothers terminated the breastfeedings more often. These behaviors suggested a shift from less attentive feeding practices and less frequent feedings to more frequent feedings in which the caretaker took more control of the child's feeding sessions. They also suggest a commitment to more labor-intensive child care. These associations between education and child feeding practices are mechanisms through which maternal education may improve child health and growth. They suggest the need for promoting more formal and nonformal education.
A longitudinal study of the impact of behavioural change intervention on cleanliness, diarrhoeal morbidity and growth of children in rural Bangladesh.
A community-based intervention was developed through direct participation of the target population in assessment and iterative trials to improve hygiene practices and to reduce childhood diarrhoea in lowland rural Bangladesh. A total of 185 (98%) households with children ages 0-18 months in five contiguous villages were targeted for the interventions. A comparison site was selected for a detailed observational study and for use as a control for the intervention. About 97% of all households with children ages 0-18 months were enrolled for study at the control site. Children in this age group were targeted because at this developmental stage they were most vulnerable to diarrhoeal morbidity and malnutrition (related to unhygienic practices). The intervention was implemented with the assistance of village leaders through a "Clean Life" campaign by local project workers and volunteer mothers who were chosen from the target households. The intervention activities started in January 1986 and lasted for 7 months. Higher adoption rates of the intervention were associated with better cleanliness status, which was related to lower diarrhoea and malnutrition rates in the intervention site. The results of between-site longitudinal analyses showed that after the intervention, the intervention site had substantially higher cleanliness scores, lower diarrhoeal morbidity, and better growth status compared to those of the control site, with differences increasing over time. The findings suggest that this type of community-based intervention can be very beneficial in modifying hygiene behaviours and lowering childhood diarrhoea and malnutrition.
Comparison of the costs of compliance with nutrition education messages to improve the diets of Bangladeshi breastfeeding mothers and weaning-age children.
Local market prices in rural Bangladesh were used to compute the costs of filling the nutrient gaps between actual intakes and safe nutrient requirements, and the costs of compliance with nutrition messages, for 78 lactating mothers and 61 weaning-age breastfed children. (The gap is the difference between the requirement and the amount of nutrient consumed.) To fill the mother's energy gap of approximately 1050 kcal (4393 kJ) would cost an additional 21% of the daily wage, or almost double the value of food she was presently eating. Given social reality, these costs would probably be much greater, as the mother would also need to increase the allocation of food to other household members. The weaning-age children's energy gap could theoretically be closed for less than one-third of the cost of improving the mothers' diets, or about 8% of the daily wage. The increase in food intake equivalent to 2% of the daily wage actually achieved through nutrition education resulted in a significant improvement in child weight gain, though not ideal. These findings suggest that, in the absence of programs which reduce economic barriers, it is economically feasible for families to close the nutrient gaps for weaning-age breastfed children in Bangladesh, but not for lactating women. Thus, education to improve women's diets should be incorporated into programs that make these improvements affordable, whereas education to improve weaning-age children's diets can be implemented with or without other program supports.
Prevalence of riboflavin deficiency among Guatemalan elderly people and its relationship to milk intake.
Six groups of elderly subjects from central Guatemala were assessed for riboflavin status by using the erythrocyte glutathione reductase activity coefficient (EGRAC). The prevalence of riboflavin deficiency ranged from 50% to 76% among the free-living rural elderly subjects. Milk intake data that were collected from some of the subjects showed a significant correlation (P < 0.0001) between frequency of milk intake and riboflavin status. In a short-term riboflavin supplementation experiment in which nine riboflavin-deficient subjects were given 10 mg riboflavin/d for 3 d, all the subjects' EGRACs were normalized by the supplementation. However, they returned to a state of deficiency within 2 wk while consuming their usual diets without supplementation. It appears that the high prevalence of riboflavin deficiency in elderly Guatemalan people is caused by inadequate intake of riboflavin-rich foods such as dairy products, and that sufficient amounts of riboflavin need to be ingested regularly to maintain satisfactory riboflavin status.
Riboflavin requirement of healthy elderly humans and its relationship to macronutrient composition of the diet.
The riboflavin requirements of two groups of riboflavin-deficient, but otherwise healthy, Guatemalan elderly persons over the age of 60 y were studied by varying the fat:carbohydrate ratio in two diets. The first group consumed a diet similar in macronutrient content to a Western-type diet with low carbohydrate and high fat; the second group consumed a typical Guatemalan diet with high carbohydrate and low fat. Energy and protein intakes of both groups were similar. Riboflavin status was monitored by weekly measurements of erythrocyte glutathione reductase activity coefficient (EGRAC) and urinary riboflavin excretion. Increasing increments of riboflavin were added to the subjects' diets until their status was normalized, as indicated by EGRAC of < 1.34 and a sharp increase in urinary riboflavin excretion. Using the EGRAC method, the mean value of riboflavin intake at which the subjects' EGRAC reached the limit of normality was 1.37 +/- 0.03 mg/d in the first phase and 1.29 +/- 0.03 mg/d in the second phase. The sharp increase in urinary excretion occurred at riboflavin intakes of 1.13 and 1.03 mg/d for Groups 1 and 2, respectively. Thus, the differences between the two groups suggest that diets with a lower fat:carbohydrate ratio can decrease the dietary need for riboflavin. The dietary requirement of riboflavin, as estimated by the more reliable urinary excretion method, was 1.1-1.3 mg/d for those consuming the Western-type diet, which is similar to values found over 40 y ago in young adults. We conclude that the dietary requirements of riboflavin in the elderly do not differ from those of young adults.
Vitamin C (ascorbic acid): new roles, new requirements?
There is an enormous amount of literature on vitamin C intake and health in animals, cell cultures, and humans. Beyond its function in collagen formation, ascorbic acid is known to increase absorption of inorganic iron, to have essential roles in the metabolism of folic acid and of some amino acids and hormones, and to act as an antioxidant. In recent years, research has increasingly focused on this latter function, stimulated by suggestions that "oxidative stress" may be a causal factor in the etiology of such diverse and important disorders of aging as cancer, cardiovascular disease, and cataract formation. The present evidence is strong enough to have convinced nutritionists that daily vitamin C intake should be many times higher than the amount needed to protect against scurvy, and this is reflected in the present Recommended Dietary Allowances. Suggestions that the recommended levels should be higher still are largely based on extrapolations from results of animal and tissue culture studies. How much ascorbic acid is necessary to achieve in humans the effects seen in animal studies is not clear. In general, the limited human studies have not been persuasive. The data are incomplete, and many of the studies have serious flaws. There are no toxicity studies of the type done for new compounds being considered for approval as therapy for major disease conditions. Intervention studies will be difficult, but are essential, and methods for tissue saturation measurement must be defined before new recommendations for the public are designed.
Effect of vitamin B-6 deficiency on fasting plasma homocysteine concentrations.
The catabolism of homocysteine through cystathionine synthesis requires pyridoxal-5'-phosphate, thus the effect of vitamin B-6 deficiency on plasma homocysteine concentrations was evaluated. Total fasting plasma homocysteine concentrations were measured in 11 elderly subjects aged 64.4 +/- 1.7 y (mean +/- SE) who consumed a vitamin B-6-deficient diet for less than or equal to 20 d. Only 1 of the 11 subjects was found to have elevated homocysteine concentrations even though all subjects exhibited high urinary xanthurenic acid concentrations after a tryptophan load, a measure indicative of vitamin B-6 deficiency. In a supporting study, fasting plasma homocysteine concentrations were measured in 3- and 23-mo-old rats fed vitamin B-6-deficient diets and were compared with those of vitamin B-6-replete, pair-fed controls. There was no difference in homocysteine concentrations between deficient and pair-fed animals after 6 wk of the dietary regimen for either age group; after 9 wk a modest elevation was observed in the 3-mo-old deficient rats whereas no difference was observed for the 23-mo-old rats. It is concluded that fasting plasma homocysteine concentrations are not initially elevated in vitamin B-6 deficiency and therefore fasting plasma homocysteine concentrations are not a good indicator of vitamin B-6 status.
Evaluation of the impact of weaning food messages on infant feeding practices and child growth in rural Bangladesh.
In rural Bangladesh, a community-based weaning intervention used volunteers to teach complementary feeding to families of 62 breast-fed infants aged 6-12 mo. Over 5 mo, treatment children gained on average 0.46 SD (approximately 460 g) more in weight-for-age (WAZ) than the 55 control subjects, and were approximately 0.5 kg heavier at the final measure. The differences were statistically significant (P < 0.001). The percent median weight-for-age (WAPM) of treatment children held steady at 76% of the National Center for Health Statistics' reference, whereas the WAPM of control subjects dropped from 78% to 72%. The increase in percentage points of severe malnutrition (below -3 WAZ) was only 5% in the treatment group compared with 26% in the control subjects. Treatment children consumed a significantly greater percent of their energy and protein requirements from complementary foods than did control subjects. The affordable complementary foods consisted mainly of cereal porridge with oil and brown sugar. These findings suggest that educational interventions teaching families to feed hygienic, simple, cheap, energy-enriched complementary foods to breast-fed infants after 5-6 mo can improve child growth, even under impoverished conditions.
The politics of hunger: when science and ideology clash.
In recent years the WIC program, a federal nutrition program for poor mothers and babies, has become a major playing field for ideological forces hoping to shape public opinion and Congressional action on matters of domestic social policy. WIC's highly positive benefits have been distorted, research results from its scientific evaluation altered by high-level federal officials, and its public support undermined by an academic spokesman with ties to the White House and a stated desire to kill the program. While strong bipartisan support on Capitol Hill makes it likely that WIC will survive and even grow, distortion of its record provides insight into how ideological forces contaminate the well of reasoned discourse for their preconceived ends.
Nutrition and behavioral characteristics and determinants of plasma cholesterol levels in men and women.
The National Cholesterol Education Program advocates dietary interventions in persons with high and moderate blood cholesterol levels and in the general population as a preventive measure for coronary heart disease. For these efforts to be successful, it is necessary to understand consumer characteristics and behaviors, including nutrient intake and dietary patterns. We studied the relationship of plasma cholesterol levels to consumer characteristics and dietary behaviors by examining 127 men (aged 20 through 71 years) and 187 women (aged 18 through 67 years) as part of a cholesterol screening project in the administrative offices and academic departments of Boston University from March 1988 through June 1988. Our results showed that specific consumer characteristics and dietary behaviors significantly differentiated male and female groups with low, moderate, and high cholesterol levels. Factors that should be considered in planning dietary interventions aimed at cholesterol reduction in men include spouse involvement and support in lipid-lowering interventions; weight reduction; increase in exercise; reduction in beef intake; and increases in dietary fiber and carbohydrates, particularly fruits. For women, recommendations include weight reduction; possible interventions aimed at reducing blood pressure (ie, behavioral modification aimed at reducing stress, increasing exercise, and cooking low-salt meals); reduction in beef intake, dietary fat, and saturated fat; and increases in carbohydrates and dietary fiber.
Vitamin B-6 deficiency impairs interleukin 2 production and lymphocyte proliferation in elderly adults.
The effect of vitamin B-6 deficiency on immune response was studied in eight healthy elderly adults. The protocol consisted of a 5-d baseline (BL) period; a vitamin B-6-depletion period of less than or equal to 20 d; three stages of vitamin B-6-repletion, each lasting 21 d; and a 4-d final phase. The amounts of vitamin B-6 ingested during the different phases of the study were 3.00, 15.00, 22.50, and 33.75 micrograms.kg body wt-1.d-1, respectively. During the final phase the subjects ingested 50 mg vitamin B-6/d. Fasting blood was collected at the end of each period. Vitamin B-6 depletion significantly decreased percentage and total number of lymphocytes, mitogenic responses of peripheral blood lymphocytes to T- and B-cell mitogens, and interleukin 2 production. These indices returned to BL values after the third vitamin B-6-repletion period, when the total vitamin B-6 intakes were 1.90 +/- 0.18 mg/d for women and 2.88 +/- 0.17 mg/d for men. Vitamin B-6 deficiency impairs in vitro indices of cell-mediated immunity in healthy elderly adults. This impairment is reversible by vitamin B-6 repletion.
Vitamin B-6 requirements of elderly men and women.
The vitamin B-6 requirements of 12 men and women over 60 y old were studied. The protocol consisted of a 5-d baseline period and four experimental periods during which the subjects successively received 0.003, 0.015, 0.0225 and 0.03375 mg of vitamin B-6/(kg body wt.d). Dietary protein was 1.2 or 0.8 g/(kg body wt.d). At 5- or 6-d intervals, xanthurenic acid (XA) after a 5-g L-tryptophan load and 4-pyridoxic acid (4-PA) in 24-h urine, erythrocyte aspartate aminotransferase activity coefficient (EAST-AC) and plasma pyridoxal-5'-phosphate (PLP) were measured. These measurements were abnormal during vitamin B-6 depletion but returned to normal during repletion. Men who ingested approximately 120 g protein/d required 1.96 +/- 0.11 mg of vitamin B-6 to normalize XA; women who ingested 78 g protein/d required 1.90 +/- 0.18 mg of vitamin B-6 to normalize XA. To attain normal levels of EAST-AC and 4-PA in men, 2.88 +/- 0.17 mg of vitamin B-6 were needed; to normalize PLP, 1.96 +/- 0.11 mg of vitamin B-6 were required. Women required 1.90 +/- 0.18 mg or more of vitamin B-6 to normalize these measurements. Vitamin B-6 requirements were not decreased in two of three subjects who ingested 54 g of protein daily. Thus, vitamin B-6 requirements of elderly men and women are about 1.96 and 1.90 mg/d, respectively.
Aging and vitamin B-6 depletion: effects on plasma pyridoxal-5'-phosphate and erythrocyte aspartate aminotransferase activity coefficients in rats.
Plasma pyridoxal-5'-phosphate (PLP) and erythrocyte aspartate aminotransferase activity coefficients were longitudinally determined in rats. Blood was obtained at weeks 0, 1, 2, 4, 6, 9, and 11 from rats initially aged 3 wk, 3 mo, 12 mo, and 23 mo (weeks 0, 1, 4, 6, and 9 only). The diet groups were ad libitum control (ALC), deficient (DEF), and pair-fed control (PF). Plasma PLP concentrations of controls were highest at 3 mo, intermediate at 3 wk and 12 mo, and lowest at 23 mo. When an additional group of 22-mo-old rats was fed a high-vitamin B-6 diet for 4 wk, their low baseline plasma PLP concentrations did not increase significantly. Plasma PLP decreased significantly within 1 wk and activity coefficients increased significantly by week 4 in all DEF rats. Depletion was most rapid and severe in the youngest DEF rats and least in 12-mo-old DEF rats. Mechanisms for the low plasma PLP control values and resistance to depletion in aged rats remain to be determined.
The paradox of hunger and economic prosperity in America.
Within a period of twenty years, America discovered that many of its citizens were hungry, acted to greatly reduce this problem through an array of federal programs, and, in the 1980s, learned that hunger has reappeared in epidemic proportions. The return of hunger to the U.S. is associated with economic and tax policies that have reallocated income distribution from poor and middle-income groups to the wealthy, and with a corresponding failure to utilize the federal government to protect high-risk population groups from undernutrition associated with growing economic deprivation in the nation.