Diet and short term plasma lipoprotein-lipid changes after exercise in trained Men.

To test the effect of diet on the short-term lipid response to exercise, fourteen moderately trained (VO2max: 50.2 +/- 6.7 ml/kg/min), healthy men (mean age: 28 +/- 4 years) were alternately fed a high fat (60 +/- 6.7% fat) and a high carbohydrate (63 +/- 3.2% carbohydrate) isoenergetic diet for 2 weeks in a randomized crossover design. During the last 4 days of the treatments, fasting total cholesterol, triglyceride, HDL-cholesterol, and HDL3-cholesterol were measured the day before, and again immediately, 24 hr, and 48 hr after exercise (4190 kJ, 70% VO2max). LDL-cholesterol and HDL2-cholesterol were calculated. Lipid concentrations were adjusted for plasma volume changes after exercise. A 2 (diet) x 4 (time) ANOVA with repeated measures revealed no significant interaction between the diet and exercise treatments. Furthermore, diet alone did not influence lipid concentrations in these trained men. Exercise resulted in an increase in HDL-C (10.7%) and HDL3-C (8.5%) concentrations and a concomitant fall in triglyceride (-25%) and total cholesterol (-3.5%). Thus, we conclude that diet composition does not affect the short-term changes in blood lipids and lipoproteins that accompany a single session of aerobic exercise in moderately trained men.

The effects of menopausal status and exercise training on serum lipids and the activities of intravascular enzymes related to lipid transport.

The study purpose was to compare the effect of exercise training on serum lipid and apolipoprotein concentrations and the activities of intravascular enzymes related to lipid transport in previously untrained eumenorrheic, premenopausal (PRM) women (n = 21; mean age, 36 +/- 3 years) and estrogen-free postmenopausal (POM) women (n = 16; mean age, 68 +/- 8 years). Subjects trained at a progressive intensity and duration (50% to 75% maximal O2 consumption [VO2max], 200 to 300 kcal/session) 4 d/wk for 12 weeks. Before and after training, VO2max, body weight, relative body fat, and fasting blood samples were obtained following 2 weeks on a standardized diet designed to maintain body weight and during the early follicular stage for the PRM group. Blood samples were analyzed for serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), the cholesterol content of the HDL3 subfraction, apolipoprotein (apo)A-I and apoB, lipoprotein(a), and the activity of lecithin:cholesterol acyltransferase (LCAT). Total and hepatic triglyceride lipase activity (HTGLA) were determined from plasma samples obtained after heparin administration. The cholesterol content of the low-density lipoprotein (LDL) and HDL2 subfractions and endothelial-bound lipoprotein lipase activity (LPLA) were calculated. A two (group) x two (time) multivariate ANOVA (MANOVA), with repeated measures for time indicated that the exercise-induced changes in physiological measurements, serum lipid or apolipoprotein concentrations, or enzyme activities did not differ between groups. Serum concentrations of TC, LDL-C, and HDL3 cholesterol, TG, and apo A-I and apoB were higher in POM women compared with the PRM group (P < .05 for all). For the combined groups, body weight and relative body fat did not change with training, but VO2max increased an average of 18.5% (P < .05). LPLA, HTGLA, and LCAT activity were unaltered with exercise training. Except for a small but significant decrease in HDL-C (-5.5%) and an elevation in apoB (4.3%; P < .05 for both), the concentrations of serum lipids and apolipoproteins did not change over the training period. We conclude that in previously untrained women, menopausal status does not influence the exercise training response of serum lipids or apolipoproteins or activities of intravascular enzymes related to lipid transport.

Training intensity, blood lipids, and apolipoproteins in men with high cholesterol.

Twenty-six hypercholesterolemic men (mean cholesterol, 258 mg/dl; age, 47 yr; weight, 81.9 kg) completed 24 wk of cycle ergometer training (3 days/wk, 350 kcal/session) at either high (n = 12) or moderate (n = 14) intensity (80 and 50% maximal O2 uptake, respectively, randomly assigned) to test the influence of training intensity on blood lipid and apolipoprotein (apo) concentrations. All physiological, lipid, and apo measurements were completed at 0, 8, 16, and 24 wk. Lipid data were analyzed via two x four repeated-measures analysis of variance (alpha = 0.0031). Training produced a significant decrease in body weight and increase in maximal O2 uptake. No interactions between intensity and weeks of training were noted for any lipid or apo variable, and no between-group differences were significant before or throughout training. Therefore, intensity did not affect the training response. Regardless of intensity, apo AI and apo B fell 9 and 13%, respectively, by week 16 and remained lower through week 24 (P < 0.0003). Total cholesterol fell transiently (-5.5%) by week 16 (P < 0.0021) but returned to initial levels by week 24. Triglyceride, low-density-lipoprotein cholesterol, and high-density-lipoprotein (HDL) cholesterol did not change with training. In contrast, HDL2 cholesterol rose 79% above initial levels by week 8 and 82% above initial levels by week 24 (P < 0.0018); HDL3 cholesterol fell 8 and 13% over the same training intervals (P < 0.0026). These data show that changes in blood lipid and apo concentrations that accompany training in hypercholesterolemic men are not influenced by exercise intensity when caloric expenditure is held constant.

Effects of training and a single session of exercise on lipids and apolipoproteins in hypercholesterolemic men.

To differentiate between transient (acute) and training (chronic) effects of exercise at two different intensities on blood lipids and apolipoproteins (apo), 26 hypercholesterolemic men (cholesterol = 258 mg/dl, age = 47 yr, weight = 81.9 kg) trained three times per week for 24 wk, 350 kcal/session at high (80% maximal O2 uptake, n = 12) or moderate (50% maximal O2 uptake, n = 14) intensity. Serum lipid and apolipoprotein (apo) concentrations (plasma volume adjusted) were measured before and immediately, 24, and 48 h after exercise on four different occasions corresponding to 0, 8, 16, and 24 wk of training. Data were analyzed using three-way repeated-measures multivariate analysis of variance followed by analysis of variance and Duncan's procedures (alpha = 0.05). A transient 6% rise in low-density-lipoprotein cholesterol measured before training at the 24-h time point was no longer evident after training. Triglycerides fell and total cholesterol, high-density-lipoprotein cholesterol (HDL-C), HDL3-C, apo A-I, and apo B rose 24-48 h after exercise regardless of training or intensity. Total cholesterol, HDL3-C, apo A-I, and apo B were lower and HDL2-C was higher after training than before training. Thus exercise training and a single session of exercise exert distinct and interactive effects on lipids and apolipoproteins. These results support the practice of training at least every other day to obtain optimal exercise benefits.

Characterization and quantitation of the apoproteins of high-density lipoprotein by capillary electrophoresis.

A method has been developed using capillary electrophoresis (CE) to quantitate plasma levels of apoprotein A-I (apoA-I) and apoprotein A-II (apoA-II) in high-density lipoprotein (HDL) samples. ApoA-I and apoA-II are resolved by CE in delipidated and non-delipidated HDL samples. Concentrations of apoA-I and apoA-II were calculated from their peak areas in the electropherogram. Results of the analysis of Sigma plasma standards (Controls 1 and 2) using CE are in good agreement with values obtained by Sigma using immunoturbidimetric assay. CE and reverse-phase high-performance liquid chromatography (RP-HPLC) were found to be complementary in the study of apoA-I and apoA-II. RP-HPLC resolves the isoforms of purified apoA-I and apoA-II, but it cannot resolve mixtures of them because the retention times of the isoforms overlap. CE separates apoA-I from apoA-II, but it does not resolve the isoforms. Matrix-assisted laser desorption/ ionization mass spectrometry was used to identify the isoforms of apoA-I and apoA-II by their molecular weight (M(r)) in fractions collected from RP-HPLC.

Calcium supplementation modifies the relative amounts of bile acids in bile and affects key aspects of human colon physiology.

Use of calcium supplements has increased dramatically in recent years yet little is known about the effect of calcium supplementation on colon physiology. We supplemented 22 individuals with a history of resected adenocarcinoma of the colon, but currently free of cancer, with 2000 or 3000 mg calcium for 16 wk. The effects of supplementation on duodenal bile acids and important fecal characteristics including total fecal output, wet and dry weight, pH, bile acids (in solids and in fecal water), and concentrations and total excretion of calcium, magnesium, phosphates (organic and inorganic), unesterified fatty acids and total fat were determined. Calcium supplementation significantly decreased the proportion of water in the stool (P = 0.03), doubled fecal excretion of calcium (P = 0.006), and increased excretion of organic phosphate (P = 0.035) but not magnesium. Calcium supplementation significantly decreased the proportion of chenodeoxycholic acid in bile (P = 0.007) and decreased the ratio of lithocholate to deoxycholate in feces (P = 0.06). The concentration of primary bile acids in fecal water decreased after 16 wk Ca supplementation. Together with other reports of a "healthier" bile acid profile with respect to colon cancer when changes such as those observed in this study were achieved, these results suggest a protective effect of calcium supplementation against this disease.

Changes in serum lipids and apolipoproteins after exercise in men with high cholesterol: influence of intensity.

The purpose of this study was to characterize the short-term changes in blood lipid and apolipoprotein concentrations in healthy hypercholesterolemic men after high-intensity [80% maximal O2 uptake (VO2max); n = 20] or moderate-intensity (50% VO2max; n = 19) cycle ergometer exercise balanced for caloric expenditure (350 kcal). The men's age, height, weight, %fat, and VO2max were 46 +/- 2 yr, 173 +/- 7 cm, 82.7 +/- 2.2 kg, 28 +/- 1%, and 31.1 +/- 1.0 ml O2.kg-1.min-1, respectively. Blood samples were drawn before exercise, immediately after exercise, then 24 and 48 h later, and concentrations of all variables were adjusted for changes in plasma volume. Significant changes (P < 0.0016) were as follows: total and low-density lipoprotein cholesterol fell by 4% immediately after exercise and then rose by 5-8% by 48 h. Triglycerides were 18 and 15% lower at 24 and 48 h, respectively. HDL-cholesterol, high-density lipoprotein3-cholesterol, and apolipoprotein B rose 8-9% by 24 h and remained elevated. High-density lipoprotein2-cholesterol rose by 27% by 48 h after exercise, but this change was not significant. Apolipoprotein A-I did not change with exercise. The response patterns were not affected by exercise intensity. These data show that a single session of exercise performed by untrained hypercholesterolemic men alters blood lipid and apolipoprotein concentrations. Furthermore, the postexercise response patterns are not influenced by exercise intensity, as long as caloric expenditure is held constant.

Acute effects of walking on serum lipids and lipoproteins in women.

The purpose of this study was to characterize and evaluate the acute effects of walking performed of fairly light (50% VO2max) and moderate (70% VO2max) intensities on serum lipids and lipoproteins in a group of premenopausal (n = 11) and a group of postmenopausal (n = 10) women. Premenopausal women were (x +/- SEM) 34.5 +/- 1.1 years of age, had 22.8 +/- 1.7% body fat and a 2.47 +/- 0.08 l.min-1 VO2max. Postmenopausal women were 54.8 +/- 2.5 years of age, had 37.9 +/- 0.9% body fat and a 2.06 +/- 0.15 l.min-1 VO2max. All subjects walked on a motor-driven treadmill at each respective intensity of exercise for a total duration sufficient to expend 350 kcal of energy. Dependent variables included total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and its subfractions HDL2-C and HDL3-C, low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). Blood samples were obtained at baseline (pre-exercise), immediately post-exercise (IPE), and at 24 hours and 48 hours post-exercise. A repeated measures design was employed controlling for diet, menstrual cycle periodicity, natural menopause, and plasma volume shifts. A 2 x 4 ANOVA was used to test for differences among means for each group separately. Significant (p < 0.05) time exercise intensity interactions were found for TC and LDL-C for the premenopausal women. This non-parallel change across exercise intensity condition created significant differences at IPE for both TC and LDL-C. Furthermore, an IPE increase in TG (p < 0.05) was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol metabolism is altered when rats are fed either beef tallow as the only dietary fat or fat containing the lipid extracts of beef.

This study was designed to evaluate tissue cholesterol concentrations in rats fed the nonpolar component or the polar component of the lipid extracted from beef. Comparisons were made to tissue cholesterol concentrations of rats fed either whole beef or beef tallow. The nonpolar component was predominantly triacylglycerol with a fatty acid composition similar to that of the beef tallow. Rats consuming the diet containing the nonpolar component had a plasma cholesterol concentration similar to those of rats in the other treatment groups. However, their plasma HDL cholesterol concentration was significantly greater and their hepatic cholesterol concentration was significantly less than for rats fed the diet with beef tallow but not rats fed the diet with beef or the polar component of beef lipid. Rats fed the diet with the polar component had a plasma cholesterol concentration that was significantly less than that of the beef tallow-fed group but similar to those of the other treatment groups; however, their plasma HDL cholesterol concentration was not different from that of any other group. Comparing electrophoretic lipoprotein profiles among diet groups demonstrated enhanced proportions of HDL in rats fed beef or the nonpolar component rather than beef tallow. These data suggest a novel effect of endogenous nonpolar beef lipid on cholesterol metabolism, which seems to depend upon factor(s) other than properties that are similar to the properties of beef tallow, i.e., fatty acid composition and lipid polarity.

Influence of dietary egg and soybean phospholipids and triacylglycerols on human serum lipoproteins.

Human serum lipid and lipoprotein concentrations and compositions were compared in ten healthy middle-aged men consuming phospholipids from egg or from soybean or triacylglycerol mixtures with fatty acid compositions similar to that of the phospholipids. All subjects followed each of the four treatments: egg phospholipids (EP), soybean phospholipids (SP), an oil of fatty acid composition similar to that of EP, and an oil similar in fatty acid composition to SP for six weeks with "wash-out" periods of similar duration between treatment periods. The phospholipids, 15 g/d, and the oils, 12 g/d, which contained approximately equivalent quantities of fatty acids were provided to the subjects in gelatin capsules and were taken before meals. Diet intake was monitored by three-day food records. Serum lipoproteins (Lp) were separated by ultracentrifugation into very low density lipoproteins, low density lipoproteins (LDL), high density lipoproteins (HDL)2 and HDL3. Lp fractions and whole serum were analyzed for triacylglycerols, cholesterol (CH), phospholipids (PL), and protein. HDL cholesterol was determined in whole serum. Cholesteryl esters were determined in some Lp fractions. Lipid compositions of Lp were expressed in mmol/g protein. Apoprotein B was measured in whole serum and in LDL; apoprotein A-I in whole serum and in HDL3. In whole serum, CH and PL were significantly lower after the SP compared to EP treatment periods. CH, but not PL, was lower after SPTG compared to EP. CH in HDL2 was significantly higher after SP compared to SPTG. Also, PL in HDL2 were significantly higher after SP compared to all other treatments and to baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of dietary soybean and egg lecithins on lipid responses in cholesterol-fed guinea pigs.

The comparative influence on plasma and tissue lipids of dietary soybean and egg lecithins, which have contrasting fatty acid compositions, was studied in the hypercholesterolemic guinea pig. The polyunsaturated to saturated fatty acid (P/S) ratios of the soybean and egg lecithins were 3.4 and 0.38, respectively. Hypercholesterolemia was induced by feeding guinea pigs a purified diet that contained 15% lard enriched with 0.5% cholesterol. Subsequently, guinea pigs were fed for six wk the same diet supplemented with either soybean or egg lecithin as 7.5% of the diet. A control group continued to be fed the lecithin-free diet. Parameters measured included body weight and relative liver weight; in plasma, total cholesterol, high density lipoprotein cholesterol (HDLC), phospholipid, and nonesterified cholesterol; in liver, total fat, cholesterol, and the specific activity of the catabolic enzyme cholesterol 7 alpha-hydroxylase; (EC 1.14.13.17); and in the aorta, cholesterol. Among the most noteworthy observations were the 49% decrease in total plasma cholesterol of the soybean lecithin group without decreasing HDLC and the 177% increase in HDLC of the egg lecithin group without a significant increase in total cholesterol compared with those values in the control group. These data suggest that dietary lecithin is particularly effective in increasing the HDLC/total cholesterol ratio in plasma. However, the absolute concentrations of those plasma lipids seem to depend upon the fatty acid composition of the lecithin.

Plasma lipid and lipoprotein response of humans to beef fat, coconut oil and safflower oil.

This study's purpose was to evaluate the fasting human plasma lipid and lipoprotein responses to dietary beef fat (BF) by comparison with coconut oil (CO) and safflower oil (SO), fats customarily classified as saturated and polyunsaturated. Nineteen free-living normolipidemic men aged 25.6 +/- 3.5 yr consumed centrally-prepared lunches and dinners of common foods having 35% fat calories, 60% of which was the test fat. The test fats were isocalorically substituted, and each fed for five weeks in random sequences with intervening five weeks of habitual diets. Plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) concentrations among individuals follows the same relative rank regardless of diet. Triglycerides (TG) concentrations among individuals also maintain their relative rank regardless of diet but in a different order from that of the cholesterols. Plasma TC, HDL-C, and LDL-C responses to BF were significantly lower and TG higher than to CO. As compared to SO, BF produced equivalent levels of TG, HDL-C, and LDL-C and marginally higher TC. Thus, the customary consideration of BF as "saturated" and grouping it with CO appears unwarranted.

Influence of early weaning and dietary fat on immune responses in adult rats.

Equal numbers of female rats, either prematurely weaned at 14 days of age or allowed to nurse for 21 days, were pair-fed a diet containing either vegetable oil or cholesterol-enriched animal fat for 95 days. Thereafter all animals received the animal fat diet until 11 months of age. Rats were then immunized with sheep erythrocytes and the antibody response quantified. There was no significant effect of early weaning or diet on the number of plaque-forming splenocytes or on serum hemolysins. A significant positive correlation between HDL cholesterol and both plaque-forming cells and hemolysin titres was detected in the groups fed animal fat. Significant impairment in splenocyte blastogenic response to phytohemagglutinin was observed in rats receiving animal fat prior to 95 days. Separate groups of rats were infected 5 days before death with Listeria monocytogenes. Splenocyte blastogenesis was impaired in the group fed animal fat to a degree similar to that observed in uninfected rats fed the same diet, and there were increased numbers of bacteria recovered from the spleen and kidney of animals whose early diet contained animal fat. We conclude that the fat content of the early postweaning diet has an impact on immune responses which persists into adulthood.

The influence of premature weaning and the nature of the fat in the diet during development on adult plasma lipids and adipose cellularity in pair-fed rats.

Long-term effects of the nature of the fat in the diet of developing rats on plasma lipids and adipose cellularity were investigated. During the developmental period (less than 95 days of age) rats were fed purified diets containing either polyunsaturated vegetable oil (VO) or cholesterol-supplemented animal fat (AF). Half of the rats of each diet fat group was weaned at 14 days of age (PW). From age 95 days to the time of death at 333 days all of the rats were fed the AF diet. In both early diet fat groups PW and normally suckled (MN) rats were pair-fed after 21 days of age. Adult MN rats fed the AF diet had the lowest total plasma cholesterol concentration of any group and a lower level of high density lipoprotein cholesterol than MN rats fed the VO diet during development. All four groups of rats had approximately the same average body weight at 333 days, but MN rats that had been fed the VO diet had significantly fewer, but larger, adipocytes per gram of ovarian fat pad than any other group. Despite virtually equivalent food consumption and no known nutrient deficiencies or excesses, these data demonstrate some significant adult metabolic responses to variations in early diet.

Cholesterolemic responses of rats to human-type diet ingredients.

The average serum cholesterol level of rats fed a human-type diet that contained 28% (wt/wt) beef fat and 0.5% added cholesterol and that was low in non-digestible constituents was lower than that of rats fed an equivalent diet prepared from purified ingredients, 94 mg/dl and 163 mg/dl, respectively. In order to identify the hypocholesterolemic ingredients in the human-type diet, the sources of protein and carbohydrate in the purified diet, casein and cornstarch, were substituted for the corresponding sources in the human-type diet, beef tenderloin, bread, and rice. These prepared diets were fed to female Sprague-Dawley rats for 10 weeks. Diets containing casein were hypercholesterolemic compared to stock rat diet, but rats fed the bread with the casein had the lowest serum cholesterol level, 112 mg/dl, of any casein diet group. The cholesterolemic response of rats fed the beef and bread diet was the same as that of stock-fed rats, 94 mg/dl and 86 mg/dl, respectively. The level of cholesterol in the liver of rats fed the beef and bread diet was lower than that of rats fed the purified diet, 7.7 mg/g and 28.5 mg/g, respectively, but it was higher than that of rats fed the stock diet, 3.8 mg/g. The hypocholesterolemic effect of beef and bread may be related to reduced cholesterol absorption. These data demonstrate the sensitive control on cholesterol metabolism of nonlipid diet ingredients.

Hepatic 3-hydroxy-3-methylglutaryl coenzyme-a reductase of rats fed semipurified and stock diets.

Rat hepatic 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMG-CoA reductase) was found to be lower in rats fed a semipurified diet of sucrose, casein, and cellulose with a mixture of safflower oil and stripped lard than those fed a stock diet: 0.115 versus 0.447 nmoles mevalonic acid formed/minute/mg microsomal protein. Efforts were made to find the substances in the stock diet responsible for the higher enzyme activity. Neither the addition of small amounts of cholesterol or plant sterols to the semipurified diet, nor the substitution of corn oil or the lipids extracted from the stock diet for the safflower oil-stipped lard mixture, significantly raised the enzyme level. Replacement of sucrose by starch also had no effect on the enzyme activity. The substitution of soybean protein for the casein did increase the specific activity of the enzyme from 0.115 to 0.247, still well below the 0.447 level response to stock rat diet ingestion. Substitution of the safflower oil-stripped lard fat mixture for the extracted fat of the stock feed had no significant effect on the response of the rats to the stock feed. However, substitution of part of the cellulose in the semi-purified diet with citrus pectin resulted in HMG-CoA levels of 0.553, approximately equal to that produced by the stock diet. In the latter study, the total fecal bile acids of the rat fed the stock, semipurified-cellulose, and semipurified-pectin diets were 2.34, 1.28, and 2.22 mg/g feces respectively, and the total fecal neutral sterols 1.86, 1.50, and 2.42 mg/g feces. Thus, the constituent nonutritive fiber appears responsible for differences in steroid excretion and elevated hepatic HMG-CoA levels, possibly by binding bile acids and increasing the turnover rate of blood and liver cholesterol.