Lipid In Men Research Articles

Coffee Intake and Serum Lipids in Men

To the Editor.— On perusal, my first reaction to the article, Coffee Intake and Elevated Cholesterol and Apolipoprotein B Levels in Men, 1 was that it would stimulate a flood of letters to JAMA . Such a topic always does. My objections to the article are somewhat different and are directed at JAMA as much as at the authors. I understand methodology and statistics as well as the majority of JAMA readers, and I contend that that majority have not the faintest idea of how to interpret (or criticize) those data. This is not to suggest that the statistics are superfluous; indeed, they are the essence of the article. However, I question their deserving the status of a lead

Coffee intake and serum lipids in men

Coffee intake and serum lipids in men

Evidence for a regional component of body fatness in the association with serum lipids in men and women

Four hundred and seventy-two subjects (234 women and 238 men), 18 to 50 years of age, participated in percent body fat determination from underwater weighing, assessment of 6 subcutaneous skinfold thicknesses, and a 12-hour fast blood sampling for measurement of serum triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), total cholesterol (CHOL), and HDL-C CHOL ratio. Even though women were significantly fatter than men, they had lower TG, CHOL, and higher values of HDL-C CHOL ratio. Correlational and variance analyses showed that body fatness seemed to be more closely associated with serum lipids in men than in women. Moreover, the relationship between each skinfold and serum lipids indicated that subscapular and abdominal fat depots are more closely associated with serum lipids than other fat depots in men. In women, correlations were lower and regional differences attenuated. Furthermore, the regional trend observed in men remained significant after correction for concomitant variables such as age, cigarette smoking, habitual energy intake and energy expenditure, maximal aerobic power, and alcohol consumption. However, no effect of increasing body fatness was noted on HDL-C levels in women. Results of this study suggest that measurement of subscapular and abdominal fat should be considered when interpreting the blood lipid profile, particularly in males. A higher percentage of fat must be present in women than in men to observe alterations in serum lipids.

The effect of vigorous treadmill exercise on plasma lipoproteins and hepatic lipoprotein production in Zucker rats

Chronic exercise has been shown to alter plasma lipids in man and animals, but the mechanism(s) responsible for this phenomenon have not been clarified. In the present study we have examined the role of the liver in the production of lipoproteins following an intensive exercise regimen in lean and obese Zucker rats. Four-week-old lean and obese male Zucker rats were subjected to a vigorous exercise regimen of running on a motor-driven treadmill for 10 weeks. Hepatic lipoprotein cholesterol production was then assessed using liver perfusion techniques. Plasma cholesterol concentration was significantly lower in both lean and obese runners versus appropriate non-exercised controls. This decrease was due to a decline in both chylomicron and HDL cholesterol. Exercise had no affect on plasma VLDL and LDL cholesterol concentrations. Hepatic VLDL cholesterol production was elevated in obese rats versus lean rats and was not affected by exercise in runners of either phenotype. Hepatic HDL cholesterol production was higher in lean runners but was unchanged in obese runners. Plasma triglyceride was reduced by 50% in exercised obese rats. In summary, intense exercise decreased plasma triglyceride, cholesterol, and HDL cholesterol concentrations in lean and obese Zucker rats. Since hepatic HDL cholesterol production was increased and hepatic VLDL cholesterol production was unaffected by exercise, the changes in plasma lipid levels observed following exercise appear to be mediated by extrahepatic mechanisms.

Aberrations in lipoprotein lipids in men with coronary artery disease and the influence of obesity, smoking and beta-adrenoceptor blocking drugs

In this study 74 men, 40–60 years old, with incapacitating angina pectoris and angiographically verified coronary artery disease (CAD) were compared to an equal number of randomly sampled healthy men matched for age, occupation and place of living. Obesity and smoking were more common in patients than in controls. The patients had elevated cholesterol (C), triglycerides (TG), and phospholipid (PL) levels dependent on raised concentrations of these lipids in the VLDL and LDL. The C and PL levels in the HDL fraction were decreased. Obesity had a significant influence on the VLDL and HDL levels. Also after taking this influence into account, the CAD patients had higher VLDL and LDL levels and a lower HDL concentration than the controls. Furthermore, regardless of the influence of the TG concentration, the HDL level was reduced in the patients. Smoking habits had no significant influence on the lipoprotein levels. Treatment with beta-adrenoceptor blocking drugs was not associated with any significant alteration of the VLDL or the HDL level. The results strengthen the importance of lipoprotein aberrations as risk factors for coronary heart disease also if observed in association with obesity, smoking and treatment with beta-adrenoceptor blocking drugs.

Lipolytic activity in the placentas of chronically deprived fetuses.

Intracellular lipolytic activity and lipoprotein lipase activity were determined in healthy human placental tissue, in placentas obtained from patients with severe pre-eclampsia, and from cases of intra-uterine growth retardation. The level of lipoprotein lipase, which is responsible for the transfer of fatty acids across membranes, was found to be much higher compared with the intracellular lipase and had increased further during pregnancy. Lipoprotein lipase activity was significantly greater in placentas of pre-eclamptic women and in the placentas of intra-uterine growth retarded fetuses. The intracellular lipolytic activity was significantly lower, however, than in controls. The levels of triglycerides and cholesterol were significantly higher in the cord blood of newbornes of women who had pre-eclampsia and in the intra-uterine growth retarded fetuses. The present study indicates that in situations causing fetal distress there are changes in the placenta leading to an increased supply of free fatty acids to the fetus. The role of lipids in fetal metabolism and their transfer across the placenta are poorly understood. The main precursor of fetal lipids in man is believed to be either carbohydrate (5) or maternal blood lipids (10). There is no evidence for the trans-placental flow of intact triglycerides. The plasma free fatty acids (FFA) constitute the only lipid fraction known to cross the placenta and could supply a significant proportion of the fetal requirements (8, 19).

Mathematical model of biliary lipid secretion: a quantitative analysis of physiological and biochemical data from man and other species.

We propose a simple mathematical model to account for the coupling of secretion rates of bile salts, lecithin, and cholesterol into bile. The model assumes that: 1) molecules of "biliary" lecithin and cholesterol enter a functional compartment located in the endoplasmic reticulum of the hepatocyte from which they are secreted into bile, and in the case of cholesterol, also catabolized to bile salts; 2) the rates at which lecithin and cholesterol enter the "secretory" compartment are regulated independently by feedback loops that control their synthesis and/or uptake; 3) lecithin secretion is coupled by an unknown transport mechanism, possibly micellar or vesicular, to the flux of bile salts passing through the compartment; 4) cholesterol secretion is coupled by a similar mechanism to lecithin secretion and not to bile salt secretion directly; and 5) bile salt synthesis is proportional to the cholesterol content of the compartment. The model predicts that in the steady state the dependences, lecithin secretion vs bile salt secretion; cholesterol secretion vs lecithin secretion; and cholesterol secretion vs bile salt secretion, will all have the form of rectangular hyperbolae. Four independent parameters related to the postulated mechanisms of biliary lipid synthesis, uptake, and transport determine the quantitative features of these hyperbolae. These four "secretion parameters" also determine how the biliary lipid composition of hepatic and "fasting" gallbladder bile varies with bile salt secretion rate. A quantitative analysis of biochemical and physiological data on biliary lipid secretion in rat, dog, and man confirms the general predictions of the model. Deductions of the secretion parameters are made for each species and are compared with other relevant data on biliary lipid metabolism. From this analysis, we offer new insights into: i) the species differences in biliary lipid secretion and bile composition; ii) the influence of obesity on biliary lipid secretion in man; and iii) the causes of cholesterol super-saturation in fasting gallbladder bile.

Adrenergic mechanisms in the control of plasma lipids in man

The effects on plasma lipids of beta-blocking antihypertensive agents with differing degrees of selectivity and intrinsic sympathomimetic activity were studied. The interrelationship between changes in lipid factors, lipoprotein lipase function, the degree of response, and pretreatment characteristics were examined. Beta-adrenergic blockade increased plasma triglycerides but decreased high-density lipoprotein cholesterol. Cardioselective drugs (atenolol and metoprolol) had less effect on triglyceride and very low-density lipoprotein cholesterol than the nonselective beta blockers (propranolol and oxprenolol). Inhibition of lipoprotein lipase was suggested by a reduction of the fractional removal rate of triglyceride in conjunction with increased total and very low-density lipoprotein cholesterol levels and reduced high-density lipoprotein cholesterol. Consistent decreases in free fatty acids lend argument against elevated triglyceride synthesis.

Studies on the effect of prazosin on blood pressure and serum lipids in Japanese hypertensive patients

The introduction of the western diet and lifestyle to Japan has been associated with changes in body build, lipid levels, and disease pattern. An increased incidence of coronary heart disease parallels increased fat intake. Thiazide diuretics and beta blockers may have adverse effects on blood lipids in man leading to an increase in the risk of coronary heart disease; therefore, for many patients these drugs may not offer the optimum treatment strategy. Hence, prazosin, a drug that effectively lowers blood pressure without adversely affecting lipid metabolism, has been evaluated in nine studies within Japan. Prazosin showed adequate antihypertensive effects even at doses as low as 1 to 3 mg per day. Sustained constant blood pressure reductions were achieved with maintenance doses of 3 to 6 mg per day without significant side effects. Even when given in low doses, prazosin increased high-density lipoprotein cholesterol while inhibiting elevations of total cholesterol and decreasing triglycerides. In view of these findings, prazosin as a single agent can be considered for monotherapy of hypertension.

Gastric emptying and intragastric distribution of lipids in man. A new scintigraphic method of study.

We measured gastric emptying of fat and water from a solid-liquid meal in healthy volunteers using a tubeless scintigraphic method. Selenium-75 glycerol triether, incorporated in butter, was the lipid-phase marker, and technetium-99m, ingested with 250 ml water, the non-lipid phase marker. In seven of these subjects we also measured the gastric emptying of solids and liquids with technetium-99m bound to cooked egg whites as the solid-phase marker and indium-111 ingested with 250 ml water as the marker of the solid and aqueous phases. Emptying and intragastric repartition of each marker were measured by detection of radioactivity changes over the abdominal area using a gamma-camera. The stability and the specificity of the labeling was checked for each marker. Mean gastric emptying rate (expressed as percentage ingested marker emptied per hr) of lipids (17.4 +/- 2.4) was much lower than that of the rest of the meal (34.2 +/- 1.8) and slightly, but significantly, lower than that of solids (22.8 +/- 1.8). An intragastric layering of fat above nonlipids was observed only after the first postprandial hour and remained moderate. Thus, lipids are emptied more slowly than any other component of an ordinary meal, and this is not due only to layering of fat above water.

The effects of age, body wight and family relationships on plasma lipoproteins and lipids in men, women and children of randomly selected families.

Two hundred thirty-three families were randomly selected from a designated population base. Data from 619 persons ages 6--65 years had distributions of lipid and anthropometric values typical for the U.S. population. The typical rise in plasma cholesterol and triglyceride with age was also demonstrated. The plasma cholesterol and low-density lipoprotein (LDL) correlated more strongly with age than body weight, whereas the plasma triglyceride was more related to body weight than to age. High-density lipoprotein (HDL) was inversely correlated with weight and plasma triglyceride. Family membership accounted for approximately 20% of the variability in cholesterol, LDL, HDL and weight. Related family members (father-child, mother-child and siblings) had strong correlations for plasma cholesterol, LDL and HDL. These measurements did not correlate in the spouse pairs. The plasma triglyceride did not correlate for the family as a whole nor for the individual family members. This study indicates the importance of both chronic environmental factors and genetic family relationships on plasma lipids and lipoproteins.

Influence of Dietary Cholesterol and Fat on Serum Lipids in Men

The effect of changes in dietary cholesterol and fat on serum lipids was studied in 32 healthy men (mean age = 24.8 years). Subjects were fed a controlled diet for 10 days providing 42 to 45% of the total calories from fat, a P/S ratio of 0.3 to 0.5 and two eggs per day. During the next eight weeks, 16 subjects received each of the following diets for four weeks in a crossover design: 1) a control diet with two eggs per day or 2) the control diet with eggs replaced by a cholesterol-free egg substitute. The remaining 16 subjects received each of the following diets in a similar crossover design: 1) a modified-fat diet containing 35% of the total calories from fat, a P/S ratio ≥ 1.0 and two eggs per day or 2) the same modified-fat diet with the egg substitute replacing the eggs. The two-week cycle of menus repeated throughout the study included a wide variety of foods commonly consumed in this country. Although the response of individual subjects varied, analysis of variance showed a significant decrease in serum total cholesterol related to replacement of eggs with the egg substitute and to modification in the type and amount of dietary fat. A significant diet-treatment interaction or sequencing effect was not found. Change in cholesterol intake related to addition or deletion of two eggs in the daily diet had no significant effect on serum triglycerides, high density lipoprotein cholesterol, or relative lipoprotein concentrations.serum lipids dietary cholesterol dietary fat

Serum lipids in humans fed diets containing beef or fish and poultry

One half of a group of 129 men and women (74 men and 55 women), in a cross-over design at, within a self-selected diet, one egg and at least 5 oz of beef daily for 3 months while the other half at one egg and at least 5 oz of poultry and fish daily. Then they reversed their diets for 3 months. Blood samples were drawn by venipuncture before the study started and at the end of the 3 and 6 months, for analyses of serum total cholesterol, triglycerides, and high density lipoprotein cholesterol. No statistically significant changes were found in serum lipids in men. In women serum triglycerides but not other serum lipids were significantly higher when poultry and fish had been ingested.

A simple and accurate routine procedure for qualitative analysis of skin surface lipids (SSL) in man

A new routine testing procedure of qualitative analysis of skin surface lipids in man is proposed. This method combines the easiness of sampling, by direct contact between ground glass plates and skin fat, with accurate thin layer chromatographic analysis of the five basic parameters (cholesterol, free fatty acids, triglycerides, wax esters, squalene) without any treatment of the samples. Such procedure can be applied to any region of the body.

Les methodes d'évaluation quantitative des lipides de surface chez l'homme. Présentation d'une nouvelle procédure

SynopsisIl existe trois méthodes permettant de mesurer l'excrétion sébacée chez l'homme. Ces méthodes ne sont pas équivalentes sur le plan de la précision et de leur utilisation routinière. Une application de la méthode de Schaefer et Kuhn‐Bussius est proposée, permettant une détermination rapide et precise des taux des lipides de surface chez l'homme. Une expérimentation, avec cette méthode, chez trente‐deux personnes, permet de préciser le mécanisme du prélèvement ainsi que la définition quantitative des types de peau.SummaryThree main methods to measure quantitatively surface lipids in man have been used. A comparison of the information they produce and their routine practicabilities are given.Adaptation and standardization of the Schaeffer and Kuhn‐Bussius method, using a photoelectric absorptiometer and ground glass plates are described.This procedure, applied to thirty‐two adults, demonstrated the quantitative nature of the sampling mechanism. A mathematical approach gives the precise definition of the casual‐level. This procedure shows that casual‐level values appear to be correlated with skin types.

Type IV hyperlipoproteinemia: effects of a caloric restricted type IV diet versus physical training plus isocaloric type IV diet

Serum lipids, plasma insulin and glucagon, aerobic capacity, and body composition were examined in middle-aged men (X age = 44.2 years) with type IV hyperlipoproteinemia to determine the relative effectiveness of a caloric restricted type IV hyperlipoproteinemia diet (group A) versus physical training plus an isocaloric type IV diet (group B). After 9 weeks of the above interventions, reductions (P less than 0.01) in mean cholesterol levels from 213 to 186 (12% change) and from 205 to 185 mg/dl (9% change), and in triglyceride levels from 332 to 211 (29% change) and from 263 to 138 mg/dl (42% change) were found for groups A and B, respectively. A small reduction in mean fasting insulin level was found only in group B; this reduction appeared inversely associated with increases in aerobic capacity in group B (r = -0.66). Both interventions were without effect on fasting glucagon levels. The physical training program prescribed resulted in a 12% increase in aerobic capacity (group B). Significant mean body weight reductions of 7.7 lb (P less than 0.01) and 2.9 lb (P less than 0.01) were seen for groups A and B, respectively; these absolute body weight reductions differed significantly (P less than 0.05) between groups. Both groups significantly lost body fatness (P less than 0.01). These reductions in body weight and body fatness appeared independent of changes in lipid levels. These results demonstrate that both interventions reduce serum lipids in men with type IV hyperlipoproteinemia but that physical training plus an isocaloric type IV diet may be the more advantageous of the two regimens, since a greater percentage decrease and a more sustained reduction in serum triglyceride levels, and a greater reduction of fasting hyperinsulinemia were observed in group B.

Plasma hormones and lipids in men at different risk for coronary heart disease

Plasma hormones and lipids in men at different risk for coronary heart disease

Effects of feeding cholic acid and chenodeoxycholic acid on cholesterol absorption and hepatic secretion of biliary lipids in man.

Chenodeoxycholic acid (CDCA), in contrast to cholic acid (CA), reduces cholesterol saturation of bile. The mechanisms for these differences were the object of this study. Investigations were carried out in nine white men; three nonobese subjects and one obese subject were fed a weight-maintenance diet, and five obese patients had a reduced caloric intake for weight reduction. They were given a daily dose of 750-1000 mg CDCA or CA for one month after which they received the other bile acid for another month. The effects of both bile acids on bile acid pool size and hepatic secretion rates of biliary lipids were determined. Total bile acid pools were increased markedly by both CDCA and CA, but to about the same degree for each. Thus, the superior action of CDCA for lowering saturation of bile could not be explained by its effect on the pool sizes of bile acids. On the other hand, hepatic secretion of cholesterol, both during feeding and fasting, was found to be reduced to a greater extent by CDCA than by CA. A theoretical mechanism by which CDCA might lower hepatic outputs of cholesterol is the inhibition of cholesterol absorption. To examine this possibility, cholesterol absorption was estimated by use of an intestinal perfusion technique. No differences were obtained between the two treatment periods for either percentage or net absorption of cholesterol; thus it is unlikely that decreased absorption could account for the reduced cholesterol secretion. Another possibility is that CDCA might affect the interrelations of the three biliary lipids differently than CA. This was explored by measurements of hepatic secretion rates of these lipids. We observed a linear relationship between the secretion rates of bile acids and cholesterol, cholesterol and phospholipids, and bile acids during both treatment periods. However, cholesterol:phospholipid ratios were higher during CA therapy than with CDCA, and they increased still more during fasting in most CA-treated subjects, but not with CDCA. This indicated that there is a marked difference between the two bile acids in the degree of coupling of cholesterol and phospholipids in fasting. We suggest that the reduction in bile sa;uration on CDCA is most likely the result of changes in the interrelations of the different biliary lipids at the site of their secretion and/or inhibition of cholesterol output from the liver because of suppressed cholesterol synthesis in this organ.

Dependence of the effects of dietary cholesterol and experimental conditions on serum lipids in man I. Effects of dietary cholesterol in a linoleic acid-rich diet

In this experiment the effect of dietary cholesterol in a linoleic acid-rich diet on serum cholesterol was tested. In a cross-over design 41 young healthy students received a linoleic acid-rich diet for 4 weeks at two levels of dietary cholesterol. The diet contained 14 to 15 energy% linoleic acid. The high cholesterol diet was obtained by adding two egg yolks a day to the rations. Supplementation of the linoleic acid-rich diet with the egg yolk cholesterol caused a significant rise of serum cholesterol of about 11 mg/100 ml (0.29 mmole/liter). The dietary cholesterol did not influence serum triglyceride levels. The influence on serum cholesterol was much less than expected, based on several predictive formulas. It is concluded that the presence of a high content of linoleic acid in the diet reduces the effect of dietary cholesterol on serum cholesterol if the cholesterol is provided as egg yolk.

Dependence of the effects of dietary cholesterol and experimental conditions on serum lipids in man III. The effect on serum cholesterol of removal of eggs from the diet of free-living habitually egg-eating people

Forty-four healthy free living volunteers were used to study the effect of the removal of eggs from a habitual egg-rich diet. The subjects, recruited by advertising, normally consumed at least 1 egg per day. During the 3-week experimental period they were not allowed to eat any eggs or products containing large amounts of eggs, except cakes and tarts. Elimination of eggs from a habitual egg-rich diet did result in a small but significant decrease in serum cholesterol levels in all subjects. No correlation could be demonstrated between changes in serum cholesterol levels and the age of the subjects and between changes in serum cholesterol levels and the numbers of eggs eaten per week before the experimental period. A significant negative correlation was found between changes in serum cholesterol levels and the Quételet index for obesity and between changes in serum cholesterol levels and the serum cholesterol levels before the experimental period. The results indicate that a very variable response is present in a human population toward dietary cholesterol. More research seems to be necessary to describe and select the population of hyperresponders, the subjects who are more sensitive to changes in dietary cholesterol, and the hyporesponders. The results moreover indicate that effects of dietary changes in a free-living population are much smaller than can be accomplished in populations under controlled conditions.