Plasma tocopherol concentrations in response to supplemental vitamin E.

Normal healthy volunteers were studied after various doses of dl-alpha-tocopherol were ingested on different schedules. Administration of 440, 880, or 1320 mg (400, 800, or 1200 IU) of dl-alpha-tocopherol as a single dose resulted in elevation of plasma alpha-tocopherol concentrations that peaked at 12-24 h. Chronic administration of dl-alpha-tocopherol (440, 880, or 1320 mg/d for 28 d) resulted in a steady state that occurred by days 4-5 of supplementation. Discontinuation of the treatment after day 28 was associated with a decline of plasma alpha-tocopherol, which returned to the pretreatment concentrations between 12 and 20 d. The plasma elevation of alpha-tocopherol was affected by dietary fat intake. Individuals consuming a high-fat diet showed significantly greater plasma alpha-tocopherol concentrations as compared with those fed a low-fat diet. The results of this study indicate that plasma kinetics of alpha-tocopherol are similar when supplements of 440, 880, or 1320 mg dl-alpha-tocopherol are given to normal, healthy individuals.

Bioavailability of beta-carotene in humans.

Normal healthy volunteers were studied after they ingested various beta-carotene doses. Daily administration of 15 or 45 mg beta-carotene resulted in significant increase in plasma beta-carotene levels. The extent of increase and the pattern of plasma beta-carotene levels showed substantial interindividual variation. Absorption of beta-carotene was affected by dietary fat concentration. Individuals placed on a high-fat diet showed significant increases in plasma beta-carotene as compared with those placed on a low-fat diet. Pharmacological doses of beta-carotene (45 and 90 mg) were used in intermittent schedules (5-6 d intervals) without altering the steady state of beta-carotene plasma levels. Yellowing of the skin occasionally occurred during daily dosing with 45 mg beta-carotene without evidence of toxicity. The observed individual variation in bioavailability of beta-carotene raises questions regarding clinical use of this micronutrient. It appears that determination of target plasma beta-carotene concentrations is essential for effective use of this compound in prevention or treatment.

Analysis of plasma lipids and apolipoproteins in insulin-dependent and noninsulin-dependent diabetics.

Plasma triglycerides, cholesterol, high-density lipoprotein (HDL) cholesterol, and apolipoproteins (apo) A-I, A-II, C-II, and C-III were determined and analyzed in 170 diabetic patients and 46 age-matched healthy normal subjects. The diabetics were separated into two groups: insulin-dependent diabetes mellitus (IDDM, n = 78) and noninsulin-dependent diabetes mellitus (NIDDM, n = 92). Significantly increased triglycerides, low HDL cholesterol, and normal cholesterol levels were found in the diabetics. The lipid profiles were similar in the IDDM and NIDDM groups. Plasma apo A-I, but not apo A-II, was low in both groups of diabetics. However, only in the IDDM subjects was there a statistically significant decrease in apo A-I when compared to normal subjects. The decreased apo A-I level negatively correlated with plasma triglycerides. Apo C-II and apo C-III were slightly increased in the diabetics compared to normal subjects. Apo C-II and apo C-III levels significantly correlated with plasma triglycerides (apo C-II, r = 0.70, P less than 0.0001; apo C-III, r = 0.71, P less than 0.0001). Only apo C-II correlated with total cholesterol. Thirty-eight to forty-two percent of the IDDM and NIDDM subjects had a clinical diagnosis of coronary artery disease (CAD) and/or peripheral arteriovascular disease (PAD). In the IDDM subjects, but not in the NIDDM subjects the incidence of CAD and/or PAD was associated with the decreased apo A-I levels as evaluated by a univariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

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 greater than or equal to 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.

Health, laxation, and food habit influences on fiber intake of older women.

Fifty-nine elderly women interviewed about their food behavior, health, and laxation showed mean dietary fiber (DF) intakes of 14 gm. per day (range 3 to 34 gm. per day). DF intakes were lower for those in poor health and those with a tendency to constipation who took laxatives than for those who did not take laxatives or had no tendency to constipation. Factors not related to DF intake included age, participation in a meal program, living arrangements, understanding of fiber, and functional health. Cooked vegetables and bread added most to DF intakes.