Effects of soybean polysaccharide on plasma lipids.

Free-living volunteers with mild to moderate hypercholesteremia added 25 gm soybean polysaccharide or starch placebo in crouton or cookie form to their normal, daily diets. A total of 31 persons completed the blind, crossover design, 8-week, experimental protocol. Subjects ingesting soybean polysaccharide prior to placebo showed an 11% decrease (from 252 to 224 mg/dl) in total plasma cholesterol; those who followed placebo with fiber showed a 5% decrease (from 241 to 230 mg/dl). Starch placebo was associated with a 2% decrease in total cholesterol when consumed first and a 4% increase when consumed following the fiber consumption period. High-density-lipoprotein (HDL) cholesterol decreased 8% and 6% from initial values during the first period for the fiber and starch groups, respectively. HDL cholesterol increased 2% but decreased 1% during the second period for starch and fiber, respectively. No significant changes in triglyceride levels occurred. The data indicate that soybean polysaccharide fiber promotes a significant decrease in plasma cholesterol in persons with mild to moderate hypercholesteremia. The addition of fiber may represent an important adjunct to traditional fat- and cholesterol-controlled diets for such persons.

Effects of different liquid diets and sustained ethanol release on alcohol metabolism.

The effects of two liquid diets, Sustacal and Shorey-AIN, on liver alcohol dehydrogenase (ADH) activity and ethanol clearance were tested in rats under conditions of high ethanol exposure for nine days. High blood ethanol levels (BEL) were produced through a combination of an initial intubated dose of ethanol sustained ethanol release tube (SERT), and ethanol as 37% of total energy in the liquid diet. Under free-feeding conditions, rats consumed slightly more ethanol per unit body weight in the Shorey-AIN diet, a diet formulated for rodent nutrition, than in the Sustacal diet, a diet originally intended for human consumption. However, BEL were significantly higher in the Sustacal group than in the Shorey-AIN group. No differences in ethanol clearance rates were observed between the groups. On the other hand, total liver ADH activity was significantly reduced in both the Shorey AIN/ethanol and the Sustacal/ethanol groups, compared to lab chow controls. When the Sustacal diet was fortified with casein and methionine so that the protein content matched that of the Shorey AIN diet, the BEL were no longer significantly higher than those produced by the Shorey AIN/ethanol diet. The results demonstrate the effect of nutritional factors on BEL under conditions of high ethanol load. However, these factors do not appear to alter major characteristics of ethanol metabolism and clearance in our short-term experiments.

Effect of zinc supplementation on plasma high-density lipoprotein cholesterol and zinc.

The recent report by Hooper PL, et al. (JAMA 1980;244:1960-1) that pharmacological doses (160 mg) of zinc lowered high-density lipoprotein (HDL)-cholesterol in men and that zinc might be an atherogenic agent prompted this report of the effect of zinc supplementation on HDL-cholesterol in women. Four levels of zinc supplements (0, 15, 50, or 100 mg/day) were given to 32 women for 8 wk. Fasting plasma HDL-cholesterol and zinc were measured at biweekly intervals. Plasma zinc increased in the supplemented groups, peaked at wk 4, then decreased toward initial values. The decline in plasma zinc regardless of continuing zinc administration may reflect a homeostatic response. No significant differences were seen in HDL-cholesterol over the 8 wk except in the 100 mg group at wk 4 when a transient decrease, -8.4% (57 to 48 mg/dl, p less than 0.04) was observed. Thus we conclude that in women the reduction in HDL-cholesterol in response to the pharmacological doses of zinc used in this study was transient and not dose-related.

The interaction of ethanol and swimming upon cardiac mass and mitochondrial function.

Four groups of female Sprague-Dawley rats received a nutritionally adequate liquid diet formulated for rats. Two groups, one ethanol diet and one control diet swam 6 days/wk for 6 weeks and were designated swim ethanol (SWM-E) and swim control (SWM-C) respectively. Their swimming time increased from 15 min/day on the first day to 2 hrs/day during the final week. One sedentary group received an ethanol diet (SED-E) while another sedentary group received a control diet (SED-C). In the ethanol diet 35% of the calories as ethanol isoenergetically replaced dextrin. The group mean body weights were not different at the end of 6 weeks. The left ventricles of both swimming groups showed similar gains in weight, 13% for the ethanol and 15% for the control. Mitochondrial respiration in the ethanol groups showed a significant depression across substrates and across both pupulations of mitochondria (subsarcolemmal and intermyofibrillar). The swimming-ethanol interaction in the SWM-E group caused an atrophy of the gastrocnemius-plantaris muscle as evidenced by the 13% loss in weight of the muscle. We conclude that chronic ingestion of ethanol will suppress mitochondrial respiration in sedentary and swimming exercised rats, but will not suppress cardiac hypertrophy in the swimming exercised rats. Muscles that are not chronically overloaded by swimming, such as the gastrocnemius-plantaris muscles will undergo atrophy during the swimming protocol of 6 weeks.

Determinants of hypocholesterolemic response to soy and animal protein-based diets.

The effect of substituting soy for animal protein in mixed diets was determined in young men with mildly elevated plasma cholesterol, 218 to 307 mg/dl. The diets were low in cholesterol, 200 mg/day, with 13 to 16% of energy as protein, 30 to 35% as fat, and a polyunsaturated to saturated fat ratio of 0.5. Of protein 65% was from either mixed animal proteins or isolated soy protein products made comparable by the addition of extracted animal fats. Fresh egg yolk was added to balance the cholesterol content of the diets. Proteins from grains and vegetables were identical in both menus and contributed about 35% of dietary protein. Twenty of 24 subjects decreased plasma cholesterol at the end of the protocol. Subjects were classified as responders or nonresponders as a function of greater or lesser than mean reduction in cholesterol for the groups. Mean decreases in plasma cholesterol, 16 and 13%, for responders in the animal and soy groups were significant, p less than 0.01 and 0.05, respectively. Responders in both groups had higher initial plasma cholesterol values than nonresponders. Although plasma high-density lipoprotein cholesterol decreased slightly, the high-density lipoprotein cholesterol to cholesterol ratio (high-density lipoprotein cholesterol/total cholesterol) remained constant for most individuals. The hypocholesterolemic effects were similar for both animal and soy protein (p less than 0.05) and fat (p less than 0.05) while on the experimental diet. All groups significantly decreased dietary cholesterol (p less than 0.001).

Ethanol dependence produced in rats by nutritionally complete diets.

Nutritionally complete diets formulated according to American Institute of Nutrition guidelines were used to make rats dependent upon ethanol. When intubated with a diet-ethanol solution for four days maintained initial body weight. When forced to consume the solution as the sole source of nutrients and water for nineteen days, rats gained weight. All animals developed severe withdrawal signs as measured by the intensity of tremors and spastic rigidity. The diet ingredients did not alter the absorption of the ethanol. The results demonstrate that physical dependence on ethanol can be induced in the rat without nutritional impairment.

Induction of physical dependence on and tolerance to ethanol in rats fed a new nutritionally complete and balanced liquid diet.

Rats offered a nutritionally balanced and complete liquid diet containing 35% of energy as ethanol, 12% as fat, 21% as protein, and the balance as carbohydrate consumed greater than 9 g/kg ethanol after 10 days. Rats displayed signs of physical dependence and tolerance while showing a net gain in weight. Physical dependence was indicated by severe intensity of the following signs during withdrawal from ethanol: Muscle rigidity; tail tremors; caudal tremors; and general tremors. Severity of these signs reached a maximum intensity by 19 h after withdrawal of ethanol. Tolerance was exhibited by chronically treated rats as measured by significantly reduced time off the belt after 7 days. Concentrations of ethanol in blood were documented on selected mornings and were observed to increase. These data suggest that physical dependence and tolerance can be induced through voluntary consumption of ethanol by rats and without nutritional compromises or weight loss.

Effects of ethanol on growth. Consumption of food, and body composition of weanling rats.

Ethanol administered to weanling rats in various concentrations as the sole drinking fluid in conjunction with a semipurified dry diet was consumed at a level of not more than 20% of total energy. Suppression of fluid intake and concomitant reduction of food intake resulted in decreased growth. Analysis of body composition indicated that the difference in weight in rats given 20% solutions of ethanol as the sole drinking fluid and in rats pair-fed diets without ethanol was primarily due to dehydration. With total liquid formulations having good resistance to separation, there were no significant differences in weight gain between rats given 20% or 30% of total energy as ethanol and rats pair-fed diets without ethanol. Ethanol fed at 40% of total energy caused inhibition of growth which could not be ascribed solely to decreased consumption of food and water. These data indicate that the method of administering ethanol to weanling rats affects not only the levels at which ethanol is toxic but also the amount of ethanol voluntarily consumed by the rats. The use of pair-feeding techniques and of homogenous liquid formulations is essential for studies of the metabolic effects of ethanol.

Efficacy of diet and exercise in the reduction of serum cholesterol and triglyceride in free-living adult males.

Young males with levels of serum cholesterol or triglyceride in the upper quartile of the distribution for volunteers tested, participated in a program designed to determine the effect of diet and exercise on serum lipids. Dietary modifications involved caloric restriction superimposed on either the National Institutes of Health (NIH) recommendations for type II or IV hyperlipoproteinemia, as appropriate, or superimposed on a fat-controlled regimen in which fat of an unspecified nature was restricted to 30% of total calories. Participants with elevated levels of cholesterol responded significantly better when instructed in the diet meeting NIH criteria, 21% change in cholesterol, than when instructed in a diet controlled in fat, 11% change in cholesterol. For those with elevated levels of triglyceride, the NIH type IV diet was no more effective at the end of 6 months than the diet controlled in fat where caloric restriction was a part of both dietary regimens. The mean change in triglyceride for this group was 32%. Those with elevated levels of both cholesterol and triglyceride were less amenable to change than those with a single hyperlipidemia. For some diagnostic types, the results were suggestive of a beneficial effect of exercise in addition to diet in accelerating or maintaining reductions in serum lipids.