Douglas S. Lewis

A College Nutrition Science Course As An Intervention To Prevent Weight Gain In Female College Freshmen

The objective of this study was to test the hypothesis that a nutrition course that stresses fundamental principles of human physiology, energy metabolism, and genetics helps prevent weight gain during the first 16 months of college life. A randomized control trial was conducted from January 1997 to May 1998 using volunteers. Forty female college freshmen participated in the intervention (college course, n = 21) and control (no course, n = 19) groups. The intervention was a one-semester nutrition science college course. Body weight, nutrient intakes, and knowledge were measured at baseline, the end of the intervention (4 months from baseline), and 1 year later (16 months from baseline). Statistical analysis was conducted using a repeated-measure analysis of variance. Higher Body Mass Index (BMI) students (BMI > 24) in the intervention group (n = 11) reported lower fat (p =.04), protein (p =.03), and carbohydrate (p =.008) intakes compared with the higher BMI students in the control group (n = 6). Dietary changes reported by the higher BMI intervention students were associated with the maintenance of baseline body weight for 1 year in contrast with the higher BMI control students who gained 9.2 6.8 kg (p =.012). The findings suggest that nutrition education emphasizing human physiology and energy metabolism is an effective strategy to prevent weight gain in at-risk college students.

Resveratrol promotes atherosclerosis in hypercholesterolemic rabbits

The hypothesis was tested that resveratrol, a compound in red wine, would inhibit atherosclerotic development in rabbits fed 0.5% cholesterol for 60 days. Rabbits were supplemented with or without oral resveratrol. During the study, body weights and food consumption were similar for the two groups. The lack of differences between liver weights and a series of serum parameters indicative of liver disease suggest that liver function was similar in the two groups. The diet produced hypercholesterolemia in both groups, but no differences in lipoprotein-cholesterol concentrations. The electrophoretic mobility of plasma low-density lipoprotein (LDL) and plasma LDL after induced oxidation also was not different between the groups. Staining of atherosclerotic lesions in the control and resveratrol-treated groups revealed that the resveratrol-treated rabbits had significantly more aortic surface area covered by atherosclerotic lesions (P < 0.02). Therefore, resveratrol promoted atherosclerotic development, rather than protect against it, by a mechanism that is independent of observed differences in gross animal health, liver function, plasma cholesterol concentrations, or LDL oxidative status.

Isoflavone-rich soy protein prevents loss of hip lean mass but does not prevent the shift in regional fat distribution in perimenopausal women.

ObjectiveMenopause-induced estrogen deficiency increases the risk of cardiovascular disease, which is related to a shift in regional fat distribution. We tested the hypothesis that estrogen-like isoflavones in soy protein isolate (SPI+) would lessen both regional fat gain and lean loss compared with isoflavone-poor soy (SPI−). DesignPerimenopausal participants (N = 69) were randomly assigned (double-blind) to 24 weeks of treatment (40 g soy or whey protein per day): SPI+ (n = 24), SPI− (n = 24), or whey control (n = 21); each participant had blood drawn in the fasted (12 hours) state, had physical activity assessed, and kept a 5-day food diary. Dual-energy x-ray absorptiometry was used to examine the effects of SPI+ on regional fat and lean tissue distribution changes in the waist, hip, and thigh regions. ResultsMean body mass increased (P < 0.01) in each group, but treatment had no effect on gain in overall body mass, fat mass, or lean mass using analysis of variance. In all treatment groups combined, lean mass increased in each region; fat mass increased only in the waist region. Treatment had an effect (P = 0.039) on hip lean mass and a marginal effect (P = 0.077) on thigh fat. Regression analyses revealed that SPI+ diminished the increase in thigh fat (P = 0.018) and heightened the increase in hip lean (P = 0.035) mass. Carbohydrate intake (P = 0.006) and cohort (reflective of season; P = 0.011) contributed to the gain in thigh fat. Total protein intake (P = 0.0012), plasma insulin (P = 0.0034), and physical activity (P = 0.047) contributed to the gain in hip lean mass. ConclusionsGain in hip lean mass was greater (P = 0.014) in SPI+ than other groups, but SPI+ did not reduce the disease-promoting menopausal shift in regional fat mass.

Cats increase fatty acid oxidation when isocalorically fed meat-based diets with increasing fat content.

This study tested the hypothesis that sedentary cats have the ability to adapt to high-fat carnivore diets by increasing fat oxidation. Twenty-four hour indirect calorimetry was used to determine total energy expenditure (TEE) and macronutrient oxidation in six vasectomized male (VAS) and six ovariectomized female (OVX) cats isocalorically fed lower-fat (53% fat, 45% protein) and higher-fat (71% fat, 26% protein) meat-based diets at maintenance for 8 days. Fat oxidation increased linearly with fat intake with a mean slope of 0.91 g fat oxidized/g fat intake (P < 0.001), with no change in TEE. However, VAS male cats were able to more precisely match fat oxidation with fat intake than OVX female cats (P < 0.02). Body fat content did not significantly influence fat oxidation. These results demonstrate that cats maintain body weight during short-term isocaloric feeding of a high-fat carnivore-type diet in part by increasing fat oxidation commensurate with increases in fat intake. This ability may be an important mechanism underlying the resistance of cats to obesity, despite habitual consumption of high-fat diets.This study tested the hypothesis that sedentary cats have the ability to adapt to high-fat carnivore diets by increasing fat oxidation. Twenty-four hour indirect calorimetry was used to determine total energy expenditure (TEE) and macronutrient oxidation in six vasectomized male (VAS) and six ovariectomized female (OVX) cats isocalorically fed lower-fat (53% fat, 45% protein) and higher-fat (71% fat, 26% protein) meat-based diets at maintenance for 8 days. Fat oxidation increased linearly with fat intake with a mean slope of 0.91 g fat oxidized/g fat intake ( P < 0.001), with no change in TEE. However, VAS male cats were able to more precisely match fat oxidation with fat intake than OVX female cats ( P < 0.02). Body fat content did not significantly influence fat oxidation. These results demonstrate that cats maintain body weight during short-term isocaloric feeding of a high-fat carnivore-type diet in part by increasing fat oxidation commensurate with increases in fat intake. This ability may be an important mechanism underlying the resistance of cats to obesity, despite habitual consumption of high-fat diets.

Preweaning Diet Programs Postweaning Plasma Thyroxine Concentrations in Baboons

Abstract We tested the hypothesis that breast- and formula-feeding of infant baboons affect postweaning plasma thyroid hormone concentrations and that differences in thyroid hormone concentrations are associated with long-term effects of infant diet on lipoprotein concentrations and cholesterol metabolism. Newborn baboons were breast-fed (n = 12) or fed formulas with a high polyunsaturated/saturated (P/S) fat ratio (n = 11) or with a low P/S ratio (n = 12) similar to baboon breast milk. Baboons were weaned at 14 weeks of age to a high cholesterol, saturated fat diet. Plasma thyroid hormone concentrations were measured in this group of baboons until about 223 weeks of age. Thyroid hormones were also measured at 400 weeks in a second group of adult baboons (n = 80) that as infants were either breast-fed or fed formulas with varying levels of cholesterol. Baboons breast-fed as infants averaged 11% higher (P < 0.03) thyroxine (T4) concentrations from 34 to 400 weeks of age compared with those fed formulas. From 70 to 400 weeks of age breast-fed baboons had 10% lower T3/T4 ratios (P < 0.03). Breast- versus formula-feeding did not affect postweaning T3 and fT3 concentrations. Postweaning thyroid hormone concentrations were not significantly affected by the P/S ratio or the cholesterol level of the infant formulas. The rank correlation of the means of the sire progeny groups for T4 and HDL-C concentrations was statistically significant (ra = −0.83; P < 0.05). Partial correlations of T4 concentrations with body weight, feed intake, or measures of cholesterol metabolism were not significant. T4 concentrations were significantly correlated with T3 concentrations (r = 0.42; P < 0.02), and T3 concentrations were correlated with bile acid synthesis rate (r = 0.47; P < 0.01), acyl-CoA cholesterol acyltransferase (r = 0.66; P < 0.001), and plasma HDL,-C levels (r = −0.49; P < 0.007). These effects suggest that altered thyroid hormone homeostasis may partially mediate the long-term differences in cholesterol metabolism caused by breast- versus formula-feeding.

Sensory Evaluation of Barley Chocolate Chip Cookies by Consumers with Different Demographic Background and Eating Patterns

ABSTRACT Health organizations have recommended an increase in consumption of whole grains, total dietary fiber, and soluble fiber to help reduce the potential risk factor for the development of type-2 diabetes, obesity, and cardiovascular disease, among others. The purpose of this project was to determine the sensory characteristics of chocolate chip (CC) cookies containing a high-soluble fiber whole barley flour (HSFWB). Cookies with 0, 30, 50, and 70% HSFWB were evaluated for appearance, color, flavor, texture, and overall acceptability using a 9-point hedonic scale. Forty-nine students, faculty, and staff tested the cookies on three different days. Demographic and behavioral data on age, gender, ethnicity, frequency of eating CC cookies, daily effort to consume fiber (FD), consumption of reduced-fat (RF) cookies, and texture preference (TP) of CC cookies were collected. The 50% HSFWB cookie could be potentially marketed among older consumers (22+), males, Hispanics, individuals who consume CC cookies a...