No association between alcohol supplementation and autoantibodies to DNA damage in postmenopausal women in a controlled feeding study

Alcohol consumption is linked to increased breast cancer risk. Since oestrogens increase breast cancer risk, possibly through oxidative damage, and we have shown that alcohol consumption increases serum oestrogens, we tested whether moderate alcohol supplementation increased oxidative DNA damage among healthy postmenopausal women not on hormone replacement therapy in a randomized controlled crossover study. We used serum 5-hydroxymethyl-2-deoxyuridine (5-HMdU) autoantibodies (aAbs) as a marker of oxidative DNA damage. The results showed no evidence for increased or decreased levels of oxidative DNA damage among women who consumed 15 g or 30 g alcohol per day for 8 weeks compared with women in the 0 g alcohol group. We conclude that among healthy women, it is possible that an 8-week trial of moderate alcohol supplementation might be too short to make enough 5-HMdU aAbs to compare differences by alcohol dose. In future studies, a panel of biomarkers for DNA damage should be used.

Effects of moderate alcohol consumption on folate and vitamin B(12) status in postmenopausal women

BACKGROUND

Although alcohol intake has been positively associated with breast cancer risk in epidemiologic studies, a causal relationship has not been established, and the mechanisms mediating this association are speculative. Alcohol may act through altered status of folate and vitamin B(12), two vitamins required for DNA methylation and nucleotide synthesis, and thus cell integrity. Although the effects of heavy alcohol intake on folate and vitamin B(12) status have been well-documented, few studies have addressed the effects of moderate alcohol intake in a controlled setting.

OBJECTIVE

The objective of this study was to determine the effects of moderate alcohol intake on folate and vitamin B(12) status in healthy, well-nourished, postmenopausal women.

DESIGN

The study design was a randomized, diet-controlled crossover intervention. Postmenopausal women (n=53) received three 8-week alcohol treatments in random order: 0, 15, and 30 g/day. Treatment periods were preceded by 2-5-week washout periods. Blood collected at baseline and week 8 of each treatment period was analyzed for serum folate, vitamin B(12), homocysteine (HCY), and methylmalonic acid (MMA) concentrations.

RESULTS

After adjusting for body mass index (BMI), a significant 5% decrease was observed in mean serum vitamin B(12) concentrations from 0 to 30 g of alcohol/day (461.45+/-30.26 vs 440.25+/-30.24 pg/ml; P=0.03). Mean serum HCY concentrations tended to increase by 3% from 0 to 30 g of alcohol/day (9.44+/-0.37 vs 9.73+/-0.37 micromol/l; P=0.05). Alcohol intake had no significant effects on serum folate or MMA concentrations.

CONCLUSIONS

Among healthy, well-nourished, postmenopausal women, moderate alcohol intake may diminish vitamin B(12) status.

Moderate alcohol consumption and levels of antioxidant vitamins and isoprostanes in postmenopausal women

BACKGROUND

Although alcohol intake has been positively associated with breast cancer risk in epidemiologic studies, the mechanisms mediating this association are speculative.

OBJECTIVE

The Postmenopausal Women's Alcohol Study was designed to explore the effects of moderate alcohol consumption on potential risk factors for breast cancer. In the present analysis, we evaluated the relationship of alcohol consumption with antioxidant nutrients and a biomarker of oxidative stress.

DESIGN

Participants (n=53) consumed a controlled diet plus each of three treatments (15 or 30 g alcohol/day or a no-alcohol placebo beverage), during three 8-week periods in random order. We measured the antioxidants, vitamin E (alpha (alpha)- and gamma (gamma)-tocopherols), selenium, and vitamin C in fasting blood samples which were collected at the end of diet periods, treated and frozen for assay at the end of the study. We also measured 15-F(2t)-IsoP isoprostane, produced by lipid peroxidation, which serves as an indicator of oxidative stress and may serve as a biomarker for conditions favorable to carcinogenesis.

RESULTS

After adjusting for BMI (all models) and total serum cholesterol (tocopherol and isoprostane models) we observed a significant 4.6% decrease (P=0.02) in alpha-tocopherol and a marginally significant 4.9% increase (P=0.07) in isoprostane levels when women consumed 30 g alcohol/day (P=0.06 and 0.05 for overall effect of alcohol on alpha-tocopherol and isoprostanes, respectively). The other antioxidants were not significantly modified by the alcohol treatment.

CONCLUSIONS

These results suggest that moderate alcohol consumption increases some biomarkers of oxidative stress in postmenopausal women.

Diet interviews of subject pairs: how different persons recall eating the same foods

OBJECTIVE

To compare qualitative descriptions of the same food items eaten by different persons using 24-hour dietary recall interviews.

DESIGN

Eleven pairs of subjects were interviewed twice using 24-hour dietary recalls such that each member of the pair described the same day's foods. Each pair shared a home and ate at least 2 meals together daily. After each interview, subjects were asked to identify the foods reported during the interview that they observed the other member of their pair consuming and to note when a particular food was the only item of that type available in the house. Qualitative descriptions of the foods were compared, differences in descriptions were noted, and calculations were made of the potential energy error produced if a subject erred in reporting a food item.

SUBJECTS/SETTING

Subjects were randomly selected from a database of persons who have participated in other studies at the Beltsville Human Nutrition Research Center. Ten pairs were husbands and wives and 1 pair was sisters. Each pair reported eating at least 2 meals per day together. Dietary recall interviews were done at the Research Center and were conducted by a trained dietitian in a quiet room free of distractions.

RESULTS

Discrepancies in qualitative food descriptions were identified for every subject pair interviewed. Men were found to be more likely to omit food items than women, snack items were more likely to be omitted than meal items, meat items were likely to be described inaccurately, and first interviews were likely to contain more errors than second interviews.

APPLICATIONS/CONCLUSIONS

This analysis shows which types of food items are most likely to be omitted or inaccurately described, and that dietetics professionals may improve the accuracy of dietary intake interviews by asking questions related to meat, milk, and snacks very carefully. The analysis also showed reductions in recall inconsistencies from the first recall to the second recall, suggesting that the learning associated with repeated interviews may be helpful in accurately identifying what a person consumes.

Serum hormones and the alcohol-breast cancer association in postmenopausal women

BACKGROUND

Alcohol ingestion is associated with an increased risk of breast cancer in most epidemiologic studies. Results, however, are heterogeneous at lower levels of alcohol intake, and a biologic mechanism for the association has not been clearly identified. To determine whether alcohol consumption by postmenopausal women elevates serum levels of hormones associated with an increased risk of breast cancer, we performed a controlled feeding study.

METHODS

Participants were 51 healthy postmenopausal women not using hormone replacement therapy. Each participant rotated through three 8-week dietary periods in which she consumed 15 or 30 g of alcohol per day or an alcohol-free placebo beverage. The order of assignment to the three alcohol levels was random. During the dietary periods, all food and beverages were supplied by the study, and energy intake was adjusted to keep body weight constant. Levels of estradiol, estrone, estrone sulfate, testosterone, androstenedione, progesterone, dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), and androstenediol were measured by radioimmunoassays in serum collected at the end of each dietary period. All statistical tests are two-sided.

RESULTS

When women consumed 15 or 30 g of alcohol per day, respectively, estrone sulfate concentrations increased by 7.5% (95% confidence interval [CI] = -0.3% to 15.9%; P =.06) and 10.7% (95% CI = 2.7% to 19.3%; P =.009) and DHEAS concentrations increased by 5.1% (95% CI = 1.4% to 9.0%; P =.008) and 7.5% (95% CI = 3.7% to 11.5%; P<.001) relative to levels when women consumed placebo. None of the other hormones measured changed statistically significantly when women consumed alcohol.

CONCLUSIONS

Results suggest a possible mechanism by which consumption of one or two alcoholic drinks per day by postmenopausal women could increase their risk of breast cancer.

Effects of margarine compared with those of butter on blood lipid profiles related to cardiovascular disease risk factors in normolipemic adults fed controlled diets

Effects of butter and 2 types of margarine on blood lipid and lipoprotein concentrations were compared in a controlled diet study with 23 men and 23 women. Table spreads, added to a common basal diet, provided 8.3% of energy as fat. Diets averaged 34.6% of energy as fat and 15.5% as protein. Each diet was fed for 5 wk in a 3 x 3 Latin-square design. One margarine (TFA-M) approximated the average trans monoene content of trans fatty acid-containing margarines in the United States (17% trans fatty acids by dry wt). The other margarine (PUFA-M) was free of trans unsaturated fatty acids; it contained approximately twice the polyunsaturated fatty acid content of TFA-M (49% compared with 27% polyunsaturated fatty acids). The tub-type margarines had similar physical properties at ambient temperature. Fasting blood lipids and lipoproteins were determined in 2 samples taken from the subjects during the fifth week of each dietary treatment. Compared with butter, total cholesterol was 3.5% lower (P=0.009) after consumption of TFA-M and 5.4% lower (P< 0.001) after consumption of PUFA-M. Similarly, LDL cholesterol was 4.9% lower (P=0.005) and 6.7% lower (P< 0.001) after consumption of TFA-M and PUFA-M, respectively. Neither margarine differed from butter in its effect on HDL cholesterol or triacylglycerols. Thus, consumption of TFA-M or PUFA-M improved blood lipid profiles for the major lipoproteins associated with cardiovascular risk when compared with butter, with a greater improvement with PUFA-M than with TFA-M.

Plasma lipoprotein (a) levels in men and women consuming diets enriched in saturated, cis-, or trans-monounsaturated fatty acids

Studies that have shown adverse effects of trans-unsaturated fatty acids on plasma lipoprotein (a) [Lp(a)] levels have used levels of trans-fatty acid that are higher than those in the average U.S. diet. This study was conducted to clarify the effects on Lp(a) of trans-fatty acids levels commonly found in U.S. diets. Lp(a) levels were measured in a double-blind study of 29 men and 29 women who ate 4 controlled diets in random order for 6 weeks each. Fatty acids represented 39% to 40% of energy. The diets were: (1) Oleic (16.7% of energy as oleic acid); (2) Moderate trans (3.8% of energy as trans-monoenes, approximately the trans content of the U.S. diet); (3) High trans (6.6% of energy as trans-monoenes); (4) Saturated (16.2% of energy as lauric plus myristic plus palmitic acids). The Saturated diet lowered Lp(a) levels significantly (by 8% to 11%). Compared to the Oleic diet, the trans diets had no adverse effect on Lp(a) levels when all subjects were considered collectively. A subset with initially high levels of Lp(a) (> or = 30 mg/dL), however, responded to the High trans diet with a slight (5%) increase in Lp(a) levels relative to the Oleic and Moderate trans diets. Thus, in amounts commonly found in the typical U.S. diet, saturated fatty acids consistently decrease Lp(a) concentrations. The adverse effects of replacing cis- with trans-fatty acids are only suggestive and are restricted to high trans intakes in subjects with high Lp(a) levels.

Individual variability in lipoprotein cholesterol response to National Cholesterol Education Program Step 2 diets

The effects of National Cholesterol Education Program (NCEP) Step 2 diets on plasma lipoprotein profiles in 72 men [mean (+/- SD) age: 44 +/- 15 y, range: 19-81 y] and 48 women (mean age: 50 +/- 21 y, range: 21-78 y) participating in five previously published studies were examined. Subjects were placed on a baseline diet similar to an average American diet (35-41% total fat, 13-16% saturated fat, 31-45 mg cholesterol/MJ) and then on an NCEP Step 2 diet (18-29% total fat, 4-7% saturated fat, 11-20 mg cholesterol/MJ) under isoenergetic conditions. All food and drink were provided. Compared with the baseline diet, consumption of the NCEP Step 2 diets was associated with significant decreases in concentrations of low-density-lipoprotein (LDL) cholesterol (-18.9% and -15.6%, respectively) and high-density-lipoprotein (HDL) cholesterol (-17.0% and -11.2%, respectively) in both men and women. Men with the apolipoprotein (apo) E 3,4 phenotype had a significantly greater decrease in LDL cholesterol (-24.2%) with the NCEP Step 2 diets than men with the apo E 3,3 phenotype (-17.7%). Men with the apo A-IV 1,2 phenotype tended to have less LDL cholesterol lowering (-12.8%) than men with the apo A-IV 1,1 phenotype (-19.6%), but this difference was not significant. No differences were seen by apo E and A-IV phenotype in women. A large variability in lipid response to the diet was observed, with changes in LDL cholesterol ranging from +3% to -55% in men and and from +13% to -39% in women. Forty-eight percent of the variability in LDL-cholesterol response (in mmol/L) to the diet could be accounted for by baseline LDL concentrations and age in men, and 13% by age in women.

Effects of dietary fat and fiber on plasma and urine androgens and estrogens in men: a controlled feeding study

We conducted a controlled feeding study to evaluate the effects of fat and fiber consumption on plasma and urine sex hormones in men. The study had a crossover design and included 43 healthy men aged 19-56 y. Men were initially randomly assigned to either a low-fat, high-fiber or high-fat, low-fiber diet for 10 wk and after a 2-wk washout period crossed over to the other diet. The energy content of diets was varied to maintain constant body weight but averaged approximately 13.3 MJ (3170 kcal)/d on both diets. The low-fat diet provided 18.8% of energy from fat with a ratio of polyunsaturated to saturated fat (P:S) of 1.3, whereas the high-fat diet provided 41.0% of energy from fat with a P:S of 0.6. Total dietary fiber consumption from the low- and high-fat diets averaged 4.6 and 2.0 g.MJ-1.d-1, respectively. Mean plasma concentrations of total and sex-hormone-binding-globulin (SHBG)-bound testosterone were 13% and 15% higher, respectively, on the high-fat, low-fiber diet and the difference from the low-fat, high-fiber diet was significant for the SHBG-bound fraction (P = 0.04). Men's daily urinary excretion of testosterone also was 13% higher with the high-fat, low-fiber diet than with the low-fat, high-fiber diet (P = 0.01). Conversely, their urinary excretion of estradiol and estrone and their 2-hydroxy metabolites were 12-28% lower with the high-fat, low-fiber diet (P < or = 0.01). Results of this study suggest that diet may alter endogenous sex hormone metabolism in men.

Relation of energy, fat, and fiber intakes to plasma concentrations of estrogens and androgens in premenopausal women

To evaluate whether diet may influence the incidence of hormone-dependent cancers through an effect on blood estrogen and androgen concentrations, we analyzed diet-blood hormone relations in a cross-sectional study. Dietary energy, fat, and fiber intakes were estimated from 7-d food records completed by 90 premenopausal women on days 14-20 of their menstrual cycles. Fasting blood specimens were collected on days 5-7, 12-15, and 21-23 of each participant's cycle and pooled to create follicular-, midcycle-, and luteal-phase samples, respectively, for analysis. Energy intake was associated inversely with plasma androstenedione and dehydroepiandrosterone sulfate (DHEAS), averaged across the three menstrual cycle phases, and directly with the probability of a luteal-phase rise in progesterone. For each additional 1 MJ (239 kcal) consumed, androstenedione decreased by 6.0% (95% CI: -8.4%, -3.6%), DHEAS decreased by 5.1% (95% CI: -9.6%, -0.4%), and the probability of a progesterone rise increased by 60% (95% CI: 5%, 145%). After energy intake was adjusted for, the ratio of polyunsaturated to saturated fat (P:S) in the diet was significantly inversely associated with plasma estradiol and estrone during the luteal phase of the menstrual cycle. For each 0.1 increment in the P:S, there was a 7.6% (95% CI: -14.3%, -0.5%) decrease in estradiol and a 6.8% (95% CI: -12.7%, -0.6%) decrease in estrone. Results of this cross-sectional study support a relation between both energy and fat ingestion and plasma sex hormone concentrations in premenopausal women.

Lean and heavy women may not use energy from alcohol with equal efficiency

To assess whether energy from alcohol is efficiently utilized to maintain body mass, we examined changes in energy intake of young women when they drank alcohol. The women ate controlled diets typical of the American diet with regard to macronutrients. Body weights were controlled to within 1 kg of entry level weights. The subjects were given alcohol (30 g/d) and no alcohol treatments for 3 mo each in a crossover design. The treatments were isoenergetic; for the no alcohol treatment alcohol energy was replaced with energy from carbohydrate. The average change in energy intake associated with the alcohol treatment was negligible when all subjects were considered collectively. There was, however, a divergence in response between lean and heavy subjects. Fifteen women required, on average, an additional 886 +/- 147 (mean +/- SEM) kJ/d to maintain body weight during the alcohol treatment, and these women were leaner (body mass index 22.6 +/- 0.8 kg/m2 vs. 25.2 +/- 1.0, P < 0.05) than the 22 women who required, on average, 559 +/- 139 fewer kJ/d when on the alcohol treatment. This study suggests that all subjects do not use energy from alcohol with equal efficiency.

Selective responses of hormones involved in carbohydrate and lipid metabolism and properties of erythrocyte membranes during the menstrual cycle in premenopausal women consuming moderate amounts of alcohol

The effects of chronic consumption of moderate amounts of alcohol on hormones associated with lipid and carbohydrate metabolism, plasma concentrations of triacylglycerol and cholesterol, insulin receptors on erythrocyte membranes, and erythrocyte membrane fluidity were studied during three phases of the menstrual cycle in 37 premenopausal women. Subjects were given either 30 g ethanol or an equienergetic fruit juice for three menstrual cycles in a crossover design. Blood samples were analyzed during the luteal, midcycle, and follicular phases. Administration of alcohol induced a significant rise in plasma glucagon and cortisol uniformly across the entire menstrual cycle. A similar rise in plasma growth hormone was observed at midcycle during the period when subjects consumed alcohol. A marginal effect was observed on cholesterol and somatomedin C concentrations. Insulin binding to erythrocyte ghosts was not affected by either alcohol or menstrual-cycle phase. Erythrocyte membranes were more fluid during the follicular phase than during the luteal phase of the menstrual cycle when the women were consuming the alcohol. There were no perceptible interactions between alcohol and phases of the menstrual cycle for the indexes studied, except membrane fluidity.

Effect of alcohol consumption on plasma carotenoid concentrations in premenopausal women: a controlled dietary study

This 6-mo controlled dietary study compared the effect of 30 g alcohol/d for three menstrual cycles with three alcohol-free cycles on plasma carotenoid concentrations in 18 nonsmoking, premenopausal women. Participants were randomly allocated within a crossover design to either phase and consumed approximately 6 mg total carotenoids/d under isoenergetic conditions. Blood was drawn during the third menstrual cycle of each alcohol phase. After adjustment for the mean daily specific carotenoid and energy intakes for each alcohol phase, the paired differences in mean plasma alpha- and beta-carotene concentrations were significantly higher by 19% (P = 0.027) and 13% (P = 0.034), respectively, during the alcohol-intake phase of the study. The paired difference in mean plasma lutein/zeaxanthin concentration was significantly lower by 17% (P = 0.031) when the participants consumed alcohol than when they did not. This is the first reported study in women to document the independent effect of alcohol on plasma carotenoid concentrations without the potential interaction of smoking under controlled dietary conditions.

Relationships of age and reproductive characteristics with plasma estrogens and androgens in premenopausal women

We used data from a cross-sectional study of 107 premenopausal women to evaluate the relation of age, menarcheal age, parity, and age at first live birth with plasma estrogen and androgen levels in premenopausal women. Fasting blood specimens were collected on each of days 5-7, 12-15, and 21-23 of menstrual cycles of the participants and pooled to create follicular, midcycle, and luteal phase samples, respectively, for each woman. Age was associated significantly and positively with plasma estradiol levels during the follicular phase [percentage difference/year = 2.6; 95% confidence interval (CI) = 1.0-4.2] and midcycle (percentage difference/year = 2.7; 95% CI = 0.9-4.7) but not the luteal phase (percentage difference/year = -0.4; 95% CI = -1.9-1.3) of the menstrual cycle. The relation of age to plasma estradiol varied by parity, with significant interactions during midcycle and luteal phase. Among nulliparous women, plasma estradiol levels increased with age midcycle and during the luteal phase, but among parous women estradiol levels decreased with age during these phases of the menstrual cycle. Plasma estrone increased with age in all women during the follicular phase of the menstrual cycle (percentage difference/year = 1.5; 95% CI = 0.2-2.8). During the luteal phase there was a significant interaction with parity; estrone levels in nulliparous women varied only slightly with age, but levels in parous women decreased significantly as age increased. The androgens, androstenedione and dehydroepiandrosterone sulfate decreased, and sex hormone-binding globulin increased as age increased. The results of this cross-sectional study suggest that pregnancy may modify age-related changes in plasma estrogen levels.

Effects of alcohol consumption on lipoproteins of premenopausal women. A controlled diet study

A substantial portion of American women consume alcohol, but controlled studies of alcohol-induced changes in lipoproteins of women are rare. In this study, the effects of alcohol consumption (equivalent to two drinks per day) on the lipoprotein profiles of 34 premenopausal women were measured while controlling subjects' diet and various other potentially confounding variables including phase of the menstrual cycle. Alcohol and no-alcohol treatments were administered in a crossover design, and blood samples were obtained during the early follicular phase of the third month of treatment. With alcohol, HDL cholesterol levels increased 10%, LDL levels decreased 8%, and levels of lipoprotein(a) were unchanged. The increase in HDL cholesterol was due to an increase in both HDL2 and HDL3, and the overall size of HDL particles was increased. HDL particles containing apolipoprotein (apo) A-I and apoA-II as well as those containing apoA-I but no apoA-II were elevated in response to alcohol. Although these observations are limited to a single phase of the menstrual cycle, the alcohol-induced changes in lipoproteins are consistent with changes that are thought to confer protection against coronary heart disease.

The relation of body size to plasma levels of estrogens and androgens in premenopausal women (Maryland, United States)

We analyzed data from a cross-sectional study of 107 premenopausal women to evaluate the relations of height, weight, and body mass index (BMI) with plasma hormone levels. Participants were 20- to 40-year old women residing in Maryland (United States), whose reported menstrual cycle lengths were not more than 35 days and whose measured weights for height were 85 to 130 percent of 'desirable' based on 1983 Metropolitan Life Insurance tables. Fasting blood specimens were collected on each of days 5-7, 12-15, and 21-23 of every participant's menstrual cycle and pooled to create follicular, midcycle, and luteal phase samples, respectively, for analysis. Adjusted for age, taller women had significantly higher follicular-phase plasma-estradiol levels (percent difference/cm = 1.5, 95 percent confidence interval [CI] = 0.3-2.7, and heavier women had significantly lower plasma sex-hormone binding globulin (SHBG) levels averaged across the menstrual cycle phases (percent difference/kg = -1.2; CI = -1.9-(-0.6). Body weight within the range studied, however, was not related significantly to the concentration of SHBG-bound estradiol during any phase of the menstrual cycle. The results of this cross-sectional study suggest a possible mechanism by which height may influence breast cancer risk.

Effect of apolipoprotein E phenotype on diet-induced lowering of plasma low density lipoprotein cholesterol

The National Cholesterol Education Program (NCEP) has recommended that dietary total fat, saturated fat, and cholesterol intake be reduced to < or = 30% of calories, < 10% of calories, and < 300 mg/day, respectively (Step 1 diet) in the general population to reduce plasma low density lipoprotein (LDL) cholesterol levels and heart disease risk. We examined the LDL cholesterol-lowering response to such a diet (26% fat, 8% saturated fat, and 201 mg/day of cholesterol) as compared to an average American diet (39% fat, 15% saturated fat, and 435 mg/day of cholesterol) in 128 subjects using diet periods of 4-24 weeks for each diet phase. The mean LDL cholesterol reduction was 15% in males (n = 83) and 8% in post-menopausal females (n = 45). The effect of apolipoprotein (apo) E phenotype on responsiveness was examined. LDL cholesterol lowering in males was 14% for 60 apoE3/3 subjects, 23% for 10 apoE3/4 subjects, and 16% for 13 apoE3/2 subjects. Male apoE3/4 subjects had a significantly greater LDL cholesterol reduction (P = 0.006) and a greater decrease in the LDL/HDL ratio (P = 0.047) than apoE3/3 subjects. In females, 7% lowering in LDL cholesterol was observed in 34 apoE3/3 subjects and 11% lowering was observed in 7 apoE3/4 subjects (P = 0.12). A meta-analysis of data from published studies supports this conclusion. These data indicate that apoE phenotype modulates the LDL cholesterol-lowering response to a diet meeting NCEP Step 1 criteria, and that male subjects carrying the apoE4 allele are more responsive than other subjects.

Relationship between dietary intake and plasma concentrations of carotenoids in premenopausal women: application of the USDA-NCI carotenoid food-composition database

The diet-plasma relationships for carotenoids were examined in a group of 98 nonsmoking premenopausal women who participated in the cross-sectional phase of the National Cancer Institute (NCI)-US Department of Agriculture (USDA) diet study on alcohol-hormone metabolism, 1988-90. With use of the newly developed USDA-NCI carotenoid food-composition database, the mean daily intakes of carotenoids were significantly higher when estimated from the food-frequency questionnaire (FFQ) than from the 7-d diet records. Lycopene (mean = 0.58 mmol/L), lutein plus zeaxanthin (mean = 0.46 mmol/L), and beta-carotene (mean = 0.34 mmol/L) were the major plasma carotenoids. After adjustment for body mass index, energy and alcohol intakes, and total plasma cholesterol concentration, the following significant correlation (P < 0.05) were observed between the diet record and the FFQ-estimated carotenoid intakes and their respective plasma concentrations: alpha-carotene (r = 0.58 vs 0.49), beta-carotene (r = 0.51 vs 0.49), beta-cryptoxanthin (r = 0.49 vs 0.36), lutein plus zeaxanthin (r = 0.31 vs 0.37), lycopene (r = 0.50 vs 0.26), and total carotenoids (r = 0.57 vs 0.49). These data indicate that plasma carotenoid concentrations are reflective of dietary intake, but the magnitude of the correlation varies depending on the specific carotenoid and on the dietary assessment tool.

ApoA-IV phenotype affects diet-induced plasma LDL cholesterol lowering

The National Cholesterol Education Program (NCEP) recommends that dietary total fat, saturated fat, and cholesterol intake be reduced to < or = 30% of calories, < 10% of calories, and < 300 mg/d, respectively (step 1 diet), in the general population to reduce plasma low-density lipoprotein cholesterol (LDL-C) levels and heart disease risk. We examined the LDL-C-lowering response to such a diet (26% fat, 8% saturated fat, and 201 mg/d cholesterol) compared with an average American diet (39% fat, 15% saturated fat, and 435 mg cholesterol/d) in 153 subjects using diet periods of 4 through 24 weeks for each diet phase. The mean LDL-C reduction was 13% in men (n = 93) and 7% in postmenopausal women (n = 60). The effect of apolipoprotein (apo) A-IV phenotype on responsiveness was examined. LDL-C lowering in men was significantly (P < .005) less (7%) for 17 apoA-IV (1/2) subjects than for 76 apoA-IV (1/1) subjects (16%). In women, 7% lowering was observed in both 12 apoA-IV (1/2) subjects and 48 apoA-IV (1/1) subjects. ApoA-IV phenotype had a significant effect on plasma high-density lipoprotein cholesterol levels during both dietary periods; women carrying the apoA-IV-2 allele had higher levels than those homozygous for the apoA-IV-1 allele. The opposite was true for triglyceride levels, but only during the period when the subjects consumed the high-fat, high-cholesterol diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary trans fatty acids: effects on plasma lipids and lipoproteins of healthy men and women

Effects of cis and trans monounsaturated fatty acids (TFA) and saturated fatty acids were assessed in 29 men and 29 women consuming controlled diets. Subjects ate each diet for 6 wk in a Latin square design. The diets, each with 39-40% of energy as fat were: 1) high oleic (16.7% of energy as oleic acid), 2) moderate TFA (3.8% of energy as TFA), 3) high TFA (6.6% of energy as TFA), 4) and saturated (16.2% of energy as lauric+myristic+palmitic acids). Compared with the oleic diet, LDL cholesterol increased 6.0%, 7.8%, and 9.0% after moderate TFA, high TFA, and saturated diets, respectively. HDL cholesterol was unchanged after moderate TFA, but was slightly lower (2.8%) after high TFA. HDL cholesterol after the saturated diet was 3.5% higher than after the oleic diet. Changes in apolipoproteins B and A-I corresponded with changes in the lipoprotein cholesterols. Thus, compared with oleic acid, dietary TFAs raise LDL cholesterol, but to a slightly lesser degree than do saturates, and high TFA concentrations may result in minor reductions of HDL cholesterol.

The relation of reported alcohol ingestion to plasma levels of estrogens and androgens in premenopausal women (Maryland, United States)

We undertook a cross-sectional study in 107 premenopausal women in Maryland (United States) of alcohol intake and hormonal status in order to evaluate whether plasma hormone levels might mediate the reported positive relation between alcohol ingestion and breast cancer risk. Alcohol ingestion was estimated using a drinking pattern questionnaire, a food frequency questionnaire, and seven-day food records. Fasting blood specimens were collected on days 5-7, 12-15, and 21-23 of each participant's menstrual cycle and pooled to create follicular, midcycle, and luteal phase samples, respectively, for analysis. Estrone, estrone sulfate, estradiol, androstenedione, and dehydroepiandrosterone sulfate (DHEAS) in plasma were measured by radioimmunoassay, and sex-hormone binding globulin (SHBG) was measured by an immunoradiometric assay. After adjusting for age, weight, and total energy intake, alcohol ingestion was not associated with plasma estrogens in the follicular, midcycle, or luteal phases of the menstrual cycle, nor with the level of SHBG or DHEAS in plasma averaged from the three phases of the cycle. Alcohol, however, was significantly positively associated with the average level of plasma androstenedione. Based on these cross-sectional findings among premenopausal women, the increased risk of breast cancer related to alcohol ingestion does not appear to be mediated by elevated plasma estrogen levels. Androstenedione, however, may mediate the alcohol/breast cancer-association.

Dietary fish oil-induced changes in the distribution of alpha-tocopherol, retinol, and beta-carotene in plasma, red blood cells, and platelets: modulation by vitamin E

Healthy men (ages 24-57 y) were fed a controlled basal diet supplemented with 15 g/d of placebo oil (PO) for 10 wk followed by 15 g/d of fish-oil concentrate (FO) (fortified with 15 mg all-rac-tocopherol) for 10 wk without additional alpha-tocopherol and the last 8 wk with 200 mg alpha-tocopherol/d (FO+E). Compared with PO, FO raised plasma malondialdehyde; lowered alpha-tocopherol in plasma, red blood cells, and platelets; and raised plasma and platelet beta-carotene. Supplementation with additional alpha-tocopherol (FO+E) not only restored tocopherol concentrations but also reversed the rise in beta-carotene. The response in retinol, particularly in platelets, showed an inverse relationship to beta-carotene, alpha-tocopherol exhibiting a modulating effect on these changes. From these observations it is postulated that platelets may be a significant extraintestinal site of retinol formation from beta-carotene.

Effects of alcohol consumption on plasma and urinary hormone concentrations in premenopausal women

BACKGROUND

Most epidemiologic studies of the relationship between alcohol consumption and breast cancer risk over the past decade have shown that persons who consume a moderate amount of alcohol are at 40%-100% greater risk of breast cancer than those who do not consume alcohol. Dose-response effects have been observed, but no causal relationship has been established.

PURPOSE

This study examines the hypothesis that alcohol consumption affects levels of reproductive hormones.

METHODS

A controlled-diet study lasting for six consecutive menstrual cycles was conducted. Participants were randomly assigned to two groups, and a crossover design was used. During the last three menstrual cycles, alcohol consumption of the two groups was reversed. Thirty-four premenopausal women, aged 21-40 years, with a history of regular menstrual cycles, consumed 30 g of ethanol (equivalent to approximately two average drinks) per day for three menstrual cycles and no alcohol for the other three. All food and alcohol consumed were provided by the study. Caloric intake was monitored to ensure that each woman would maintain body weight at approximately the baseline level. Hormone assays were performed on pooled plasma or 24-hour urine specimens collected during the follicular (days 5-7), peri-ovulatory (days 12-15), and mid-luteal (days 21-23) phases of the third menstrual cycle for subjects on each diet.

RESULTS

Alcohol consumption was associated with statistically significant increases in levels of several hormones. Plasma dehydroepiandrosterone sulfate levels were 7.0% higher in the follicular phase (P = .05). In the peri-ovulatory phase, there were increases of 21.2% (P = .01) in plasma estrone levels, 27.5% (P = .01) in plasma estradiol levels, and 31.9% (P = .009) in urinary estradiol levels. In the luteal phase, urinary estrone levels rose 15.2% (P = .05), estradiol levels increased 21.6% (P = .02), and estriol levels rose 29.1% (P = .03). No changes were found in the percent of bioavailable estradiol, defined by the sum of percent free estradiol and percent albumin-bound estradiol. However, increased total estradiol levels in the peri-ovulatory phase suggest elevated absolute amounts of bioavailable estradiol.

CONCLUSION

This study has shown increases in total estrogen levels and amount of bioavailable estrogens in association with alcohol consumption in premenopausal women.

IMPLICATION

This possible explanatory mechanism for a positive association between alcohol consumption and breast cancer risk merits further investigation.

Ingestion of marine oil reduces excretion of 11-dehydrothromboxane B2, an index of intravascular production of thromboxane A2

We evaluated the effect of anchovy oil supplementation on the endogenous production of thromboxane A2 by measuring the excretion of its stable metabolite, 11-dehydrothromboxane B2 (11-DTXB2), in 24-h urine. In a longitudinal study, 35 male volunteers consumed a controlled basal diet for two experimental periods lasting a total of 20 weeks. During period 1 (10 weeks) the diet was supplemented with placebo (PO) capsules (15 x 1 g/d) consisting of a blend of fats approaching the fatty acid profile of the basal diet. During period 2 the subjects received 15 x 1 g/d capsules of fish oil concentrate (FOC). PO and FOC capsules contained 1 mg alpha-tocopherol per gram of fat as antioxidant. A 38% reduction of 11-DTXB2 excretion was observed after 10 weeks of FOC supplementation (period 2, n-6/n-3 PUFA ratio = 2.3), compared to an identical period of PO supplementation (period 1, n-6/n-3 = 12.5), p = 0.0001. The 11-DTXB2 excretion reduction (delta) fits the quadratic equation delta = 136.0038-0.3178(tx1)-0.0002(tx1)2, (R2 = 0.8944), where tx1 is the excretion rate at the end of period 1. This finding supports the hypothesis that the antithrombotic effect of marine oil is mediated, at least in part, by diet-induced shifts in the eicosanoid system.

Effect of dietary fat on length of the follicular phase of the menstrual cycle in a controlled diet setting

The length of the follicular phase of the menstrual cycle (defined as the time from the first day of menses until the day of urinary LH peak, inclusive) was examined in 30 healthy, premenopausal women. The women consumed defined, weight maintaining diets, with a ratio of polyunsaturated to saturated fatty acids (P/S ratio) of either 0.3 or 1.0. Both P/S groups consumed a high fat diet (40% energy from fat) for 4 menstrual cycles, followed by 4 menstrual cycles of a low fat diet (20% energy from fat). There was a significant increase (P less than 0.006) in the length of the follicular phase of the menstrual cycle during consumption of the low fat diet. Two thirds of the women showed increases in follicular phase length with an average increase of 1.9 days.

Plasma lipid and lipoprotein concentrations of men consuming a low-fat, high-fiber diet

This study assessed the influence of a low-fat, high-fiber diet on blood lipid concentrations of 42 men with desirable or moderately elevated cholesterol concentrations. A low-fat diet (19% fat, 4% saturated fatty acids, 4.6 g fiber/MJ) was compared with a high-fat diet (41% fat, 15% saturated fatty acids, 2.0 g fiber/MJ) and with subjects' self-selected diets. Substituting the low-fat for the high-fat diet decreased total, low-density-lipoprotein, and high-density-lipoprotein cholesterol by 17-20%. Lipid changes between 6 and 10 wk were minor. A reduction in plasma cholesterol of greater than 0.52 mmol/L was achieved with the low-fat diet in 59% of men changing from their self-selected diets and in 79% changing from the high-fat diet. Percent reduction was independent of subjects' cholesterol classification. Results indicate that significant reductions in plasma cholesterol can be achieved by the majority of men committing to a low-fat, high-fiber diet.

Increased vitamin E intake restores fish-oil-induced suppressed blastogenesis of mitogen-stimulated T lymphocytes

We sought to determine whether fish-oil supplementation would suppress blastogenesis in vitro of concanavalin A (ConA)-stimulated peripheral blood mononuclear cells (PBMCs) and, if so, whether it could be reversed with increased intake of vitamin E. Healthy males ate a controlled basal diet providing a total of 40% of energy from fat when fed in conjunction with 15 g/d of either placebo oil (PO) or fish-oil concentrate (FOC) fortified with 15 mg alpha-tocopherol/d for three periods. The subjects were supplemented with PO for 10 wk (PO), with FOC for 10 wk (FOC), and with FOC plus an additional 200 mg alpha-tocopherol/d for 8 wk (FOC+E). During FOC supplementation mitogenic responsiveness of PBMCs to ConA was suppressed, but this effect was reversed by concurrent supplementation with all-rac-alpha-tocopherol (FOC+E). There was a significant positive relationship (P less than 0.001) between plasma alpha-tocopherol concentrations and responsiveness of T lymphocytes to ConA.

Effects of omega 3 fatty acids and vitamin E on hormones involved in carbohydrate and lipid metabolism in men

Forty healthy men were fed diets providing 40% of energy from fat and a minimum of 25 mg vitamin E for 28 wk. During the first 10 wk diets were supplemented with placebo, 15 g mixed fat/d. During the second 10 wk placebo was replaced by 15 g fish-oil concentrate/d. During the last 8 wk 200 mg vitamin E/d was added to fish oil. Compared with placebo, fish-oil feeding significantly increased plasma glucose and decreased triacylglycerol, insulin, glucagon, growth hormone, and somatomedin C. The changes in plasma cholesterol, cortisol, and dehydroepiandrosterone sulphate (DHEA-S) were not significant. Fish oil plus vitamin E further decreased insulin, growth hormone, and DHEA-S and reversed the effect of fish-oil on somatomedin C. The changes in glucose, glucagon, growth hormone, and cortisol were not significant. Thus, changes in plasma glucose and lipids caused by dietary fish oil alone and with fish oil plus vitamin E appear to be due to alterations in hormones involved in carbohydrate and lipid metabolism.

PGE1 compared to PGE2/PGF2 alpha ratio as a marker for seminal fluid contamination of urine in studies of renal prostaglandin biosynthesis

Occasional and unpredictable seminal plasma leakage (SPL) into the urinary system severely limits the usefulness of primary prostaglandin (PG) excretion rates as markers of renal synthesis in male subjects. Although reports to this effect appeared first some 10 years ago, no specific study has been done to define the magnitude of the problem, while several investigators persisted in the use of primary PG excretion rates, disregarding SPL as a confounding factor. We conducted a systematic study with a group of 5 healthy adult subjects who collected 24-h urine with an average frequency of one collection every other week for a total of 20 weeks. 35% of the urine collected contained seminal plasma. It is imperative to be able to disqualify compromised urine specimens in biological studies. With this objective in mind, we developed a method to identify contaminated samples based on the presence of PGE1. This is a major prostanoid in seminal plasma but is normally absent in 'clear' urine.

What are people really eating? The relation between energy intake derived from estimated diet records and intake determined to maintain body weight

Two hundred sixty-six free-living human volunteers, 21-64 y old, were trained by dietitians to record daily their food intake for at least 7 d. Subsequently, they were fed diets of conventional foods adjusted in amounts to maintain their body weight for greater than or equal to 45 d. Comparing their estimated energy intake with the intake determined to maintain weight yielded mean differences of 2365 and 1792 kJ (565 and 428 kcal) in men and women, respectively, representing an underreporting of 18%. Twenty-two individuals (8%) overestimated and 29 (11%) were accurate to within 419 kJ (100 kcal) of their maintenance requirement. The remaining 215 individuals (81%) reported their habitual intake at 2930 +/- 1586 kJ (700 +/- 379 kcal) below that subsequently determined as their maintenance requirement. These findings suggest caution in the interpretation of food-consumption data.

Effect of fish oil supplementation on the excretion of the major metabolite of prostaglandin E in healthy male subjects

We investigated the effect of fish oil supplementation on the synthesis of prostaglandin E (PGE) in vivo by measuring the excretion of its catabolite, PGE-M, in 24-hr urine by gas chromatography/mass spectrometry. Forty healthy male volunteers (24-57 years of age) consumed a controlled basal diet providing 40% of energy from fat (P/S ratio about 0.8:1), 130 mg/1000 kcal cholesterol, and a minimum of 22 mg/day of alpha-tocopherol (alpha-T), for three experimental periods lasting a total of 28 weeks. During period 1 (10 weeks) the diet was supplemented with placebo (PO) capsules (15 X 1 g/day) consisting of a blend of fats approaching the fatty acid profile of the basal diet. This was followed by a second 10-week period during which the subjects received 15 X 1 g/day capsules of fish oil concentrate (FOC). During period 3 (8 weeks) they continued the 15 g/day intake of FOC but received an additional 200 mg/day of alpha-T. PO and FOC capsules contained 1 mg alpha-T/g fat as antioxidant. A 14% reduction of PGE-M excretion was observed after 10 weeks of FOC supplementation (period 2), compared to an identical period of placebo supplementation (period 1), P = 0.009. PGE-M excretion during the last week of period 3 was not significantly different from that at the end of period 2. The reduction in PGE synthesis in response to the relatively high marine oil supplementation was large in many subjects participating in this study.

Quantitative assessment of the genotoxicity of fecapentaenes

Fecapentaenes are a group of fecal mutagens of microbial origin isolated from human stools. Fecapentaene-12 (F-12) and fecapentaene-14 (F-14), differing only in two carbon atoms in the side chain, are glyceryl ethers with a highly reactive chromophoric aliphatic side chain incorporating a conjugated pentaene moiety. Although these compounds are known for their genotoxicity, no test systems have been developed to precisely assess their relative genotoxicity. In this study F-12 and F-14 were assayed for their genotoxicity using the SOS Chromotest in which the induction of beta-galactosidase in E. coli PQ37 was used as a quantitative measure of biological activity. The activity obtained with F-12 and F-14 was compared with that of 4-nitroquinoline oxide (4-NQO) as the reference standard of a direct acting mutagen. While F-14 was almost as active as 4-NQO, F-12 was only about 25% as active as F-14, the higher analog.

Dietary fat and hormonal influences on lipoprotein fluidity and composition in premenopausal women

LDL and HDL became more fluid when health, free-living, premenopausal women were fed reduced fat diets with higher proportions of polyunsaturated fatty acids. Lipoproteins were isolated from plasma of 31 female subjects fed one of two sets of diets from typical U.S.A. foods with P/S ratios of 0.3 or 1.0. All subjects were fed high-fat diets (40% of energy) for the duration of four menstrual cycles followed by low-fat diets (20% of energy) for the next four cycles. Blood samples were collected during mid-follicular and mid-luteal phases of the fourth menstrual cycle of each diet period to assess interactive dietary and hormonal control of lipoprotein fluidity. LDL was significantly more fluid, as determined by DPH fluorescence, upon reducing fat consumption from 40 to 20% of energy for subjects eating foods with P/S = 1.0 or 0.3. Generally LDL was more fluid during the follicular phase than the luteal phase of the cycles, thus indicating hormonal influences on LDL fluidity. HDL results were similar but not as pronounced as with LDL. Lipoprotein phospholipid (PL) and cholesteryl ester (CE) fatty acyl compositions were also subject to dietary and hormonal influences. Effects were noted in several fatty acids depending upon diet and hormonal state; however, generally diet fat reduction resulted in reduced linoleate and increased oleate contents. Regression analyses showed that fluidity was more dependent upon the lipoprotein cholesterol content than upon fatty acyl composition.

Influence of dietary fat on fecal mutagenicity in premenopausal women

A dietary intervention study was conducted on 31 premenopausal women (age: 20-40 years) to investigate the relationship between dietary fat and fecal mutagenicity. After a free-living period (baseline) of one menstrual cycle, the subjects were placed on a high-fat diet (40% calories from fat) for 4 menstrual cycles, followed by a low-fat diet (20% calories from fat) for 4 menstrual cycles. One-half of the subjects were randomly assigned throughout the study to a diet with a P:S ratio of 1.0 while the other half was assigned to one with a P:S ratio of 0.3; body weight by group remained constant. Three-day stool samples were collected at the mid-follicular period during the free-living phase and during the 4th menstrual cycle of each of the 2 controlled diet periods. Mutagenicity was assayed by the SOS chromotest. Reduction of dietary fat was accompanied by a significant decrease in fecal mutagenicity in both P:S groups. Combined values, i.e., both P:S groups, were 20.3 units for high-fat diets vs. 8.78 for low-fat diets.

Relationship of dietary fat to plasma fatty acids, blood pressure, and urinary eicosanoids in adult men

This experiment was conducted to determine the relationships between modest changes in dietary linoleate, blood pressure (BP) response, and levels of eicosanoid synthesis in humans. Products of eicosanoids which appear in blood were measured in urine: PGI2, 6-keto-PGF1 alpha (KPGI2); TXA2, (TXB2); PGF2 alpha, 13,14-dihydro-15-keto-PGF2 alpha, (MPGF2 alpha). Twenty-three adult men were fed controlled diets having 25 energy percent fat, and having P/S ratios of either 0.3 (low-PUFA) or 1.0 (high-PUFA), for a total of 12 weeks, with a switchover between P/S ratios at 6 weeks. The results showed that, under the conditions of this study, BP was significantly reduced by reducing dietary fat intake from about 37 to 25 energy percent. However, no further effects on BP were produced by increasing the P/S ratio from 0.3 to 1.0. KPGI2 excretion was significantly lowered on both controlled diets as compared to the self-selected (SS) diet. However, MPGF2 alpha was lowered only on the low-PUFA diet as compared to the self-selected diet. No significant decrease in TXB2 excretion was observed. Both MPGF2 alpha and KPGI2 excretion were positively correlated with urine volume and sodium excretion. On the SS diet, but not on the controlled diets, MPGF2 alpha excretion was negatively correlated with plasma linoleate and positively correlated with stearate. On the low-PUFA diet, MPGF2 alpha excretion increased with the intake of linoleate, while, on the high-PUFA diet, it decreased. This may have been due to the limited amounts of linoleate available in the low-PUFA diet (3.2-3.4 energy percent) as compared to that in the high-PUFA diet. Both KPGI2 and MPGF2 alpha excretion were positively correlated with systolic and diastolic BP. These results suggest that the amount of dietary linoleate is an important factor in the regulation of prostaglandin synthesis in humans.

Dietary fat and menstrual-cycle effects on the erythrocyte ghost insulin receptor in premenopausal women

The effect of high- and low-fat diets with different levels of fatty acid unsaturation on insulin receptors of erythrocyte ghosts was studied during different phases of the menstrual cycle in 31 healthy premenopausal women. Subjects were divided into two groups and consumed controlled diets containing 39% fat with a ratio of polyunsaturated to saturated fatty acids (P:S) of either 0.30 or 1.00 for four menstrual cycles. They were switched to 19% fat at the same P:S for another four cycles. Fasting blood samples were collected during the follicular and luteal phases. Insulin receptors were measured from right-side-out ghosts. Insulin binding was significantly lower due to fewer receptors when subjects were fed the low-fat, high-carbohydrate diet compared with the high-fat, low-carbohydrate diet. There was no significant effect of level of unsaturation or time of menstrual cycle on insulin binding. Thus, insulin receptors on erythrocytes respond to dietary lipids.

Dietary fat and hormonal effects on erythrocyte membrane fluidity and lipid composition in adult women

Erythrocyte ghost membrane fluidity and phospholipid linoleate were significantly increased when higher levels of polyunsaturated fats were fed to healthy, free living, premenopausal women. Fluidity was assessed by diphenylhexatriene (DPH) fluorescence polarization measurements with hypotonically lysed red blood cells from 31 female subjects fed one of two sets of diets, which were formulated from typical US foods to contain polyunsaturate to saturate ratios (P/S) of 1.0 or 0.3. Both groups of women were fed diets with 40% of energy as fat for four menstrual cycles followed by low-fat diets having 20% of energy as fat for the next four menstrual cycles. Blood was sampled during the fourth cycle of each dietary period at times estimated to correspond to maximum secretions of estrogen and progesterone to assess interactive hormonal and dietary effects on membrane composition and fluidity. Red blood cell membranes were most fluid following higher levels of linoleate intake, either by higher (40%) total fat or higher P/S levels. Membrane fluidity was directly related to the phospholipid oleate and linoleate contents and inversely related to the molar cholesterol/phospholipid ratio. Hormonal status effects on the membranes were not extensive. Membrane fluidity in cells from women fed P/S = 0.3 diets was higher at 40% than at 20% fat during the luteal phase of the fourth cycle. In contrast, women fed the P/S = 1.0 diets had more fluid red cells at 40% fat during the follicular phase of the cycle. Regression analysis showed a direct linear correlation between membrane fluidity and red cell membrane insulin binding demonstrating a relation between receptor binding and cell membrane fluidity in the human female.

Modulating influence of dietary lipid intake on the prostaglandin system in adult men

We evaluated the effect of moderate dietary changes on the prostaglandin system by measuring the urinary excretion of 7 alpha-hydroxy-5,11-dioxo-tetranorprostane-1,16-dioic acid (PGE-M). In a crossover design, twenty-four free-living male subjects in good health (24 to 54 years of age) were fed two diets: (i) Regular (R) diet, 41% energy (en%) from fat, P/S 0.59, M/S 0.96; (ii) Experimental (E) diet, 19 en% from fat, P/S 1.31, M/S 1.48. Diet R contained 13.9 g/day of neutral detergent fiber (NDF) and about 600 mg/day of cholesterol per 3200 kcal; Diet E contained 35.5 g/day NDF and about 280 mg/day cholesterol. Each controlled-diet period lasted ten weeks. The menu cycle was 7 days, and all diets were calculated to provide adequate amounts of essential nutrients. The PGE-M excretion rates were determined in 24-hr urine by stable-isotope dilution gas chromatography-mass spectrometry in the selected ion-monitoring mode. Low-fat Diet E, with an intake of 6.6 en% from polyunsaturates, was associated with an average 14.2% reduction in PGE-M daily output, compared to high-fat Diet R with a 9.3 en% from polyunsaturates (P = 0.046). These results support the view that dietary lipid changes can significantly alter the in vivo production of E-series prostaglandins. We cannot conclude, however, if this apparent diet effect was brought about by the change in linoleate intake alone or was the result of complex biochemical interactions among individual fatty acids, both saturated and unsaturated.

Caloric and selected nutrient intakes and estimated energy expenditures for adult women: identification of non-sedentary women with lower energy intakes

Dietary intakes and energy expenditures of healthy adult women were studied. Phase I (no. = 98): 37 women (38% of Phase one subjects) reported 3-day intakes of less than 1,600 kcal/day; low nutrient intakes were associated with less than 1,600 kcal/day for women who did not take supplements. Phase II (no. = 18): group mean energy expenditures assessed by activity diaries matched 7-day intake records for 8 women who had consumed greater than 1,800 kcal/day during Phase I but not for 10 women who had consumed less than 1,600 kcal/day during Phase I. Phase III: duplicate food composites and records supported previous intake records. The data from this study suggest that some non-sedentary women maintain consistently low energy/nutrient intakes and that calculation of energy expenditure from standard tables is not appropriate for those women.

Effects of low fat diets differing in degree of fat unsaturation on plasma lipids, lipoproteins, and apolipoproteins in adult men

The effects of two low fat diets with differing ratios of polyunsaturated to saturated fatty acids (P/S) on blood lipids, lipoproteins (LP), and apolipoproteins (Apo) were studied in 23 adult men, 30-60 years old, using a crossover design. Both test diets had 25% fat calories with either a P/S of 0.3 (Diet 1) or a P/S of 1.0 (Diet 2) and equivalent amounts of cholesterol. The study consisted of four periods: a 5-week prestudy on self-selected diet (SS), two 6-week test diet periods followed by a second 5-week post-study period on the SS diet. When compared with the SS diet, Diet 2 lowered the mean plasma total cholesterol (TC) by about 20% (P less than 0.01). Low density lipoprotein (LDL) cholesterol was also decreased by about 18% by Diet 2 (P less than 0.01). The high P/S diet did not cause a change in total cholesterol in the high density lipoprotein (HDL) subclass2 (HDL2) when compared to the SS diet. Levels of triglycerides (TG) were slightly reduced in HDL2 but showed a greater reduction in HDL3 in both diets. Phospholipids (PL) were significantly reduced in HDL2 and in HDL3, but the reduction in HDL3 PL was not statistically significant. Apo A-I levels were not changed by either diet when compared with the SS diet, but Apo A-II levels of HDL2 and HDL3 were significantly decreased by the low fat diets, and there was no P/S effect. No other consistent changes in apoprotein levels occurred. Our data suggest that, in men with normal lipid levels, practical dietary changes involving a moderate increase in P/S from 0.3 to 1.0 in a low fat, low cholesterol diet do influence lipoprotein composition and apoprotein distribution in a short time. The reduction in cholesterol in total lipid composition and in LDL lipids which accompanied the reduction of dietary fat and cholesterol are considered to be beneficial.

Vitamin E and relationships among tocopherols in human plasma, platelets, lymphocytes, and red blood cells

Plasma, RBC, platelets, and lymphocytes from human subjects on graded intakes of vitamin E were analyzed for tocopherols to determine which humoral compartment most closely followed changes in the dietary intake. Relative merits of the various blood elements to reflect changes in vitamin E intake were calculated by the sensitivity concept of Mandel and Stiehler (ie, rate of change of tocopherol levels with dose divided by the standard deviation). Sensitivities of alpha-tocopherol levels of the various blood components to vitamin E intake decreased in the order platelets greater than RBC greater than plasma lipids greater than plasma greater than lymphocytes. Changes in tocopherol levels in platelets most closely followed changing dietary intakes of vitamin E when compared with data from RBC, lymphocytes, and plasma. Furthermore, for studying the effects of diets on vitamin E status, tocopherol levels of platelets appear to be a better measure than tocopherol levels of either RBC, lymphocytes, or plasma lipids.

Cheek cell fatty acids as indicators of dietary lipids in humans

Analysis of cheek cell lipids has been suggested as a noninvasive method for monitoring the fatty acid composition of diets in humans. In a pilot study conducted to determine the validity of the method, cheek cell samples were collected from subjects consuming a low fat (20% of calories) diet consisting of fatty acids with either a 1.0 or 0.3 P/S ratio. Neither total lipid nor polar lipid fatty acids in cheek cells consistently reflected the P/S ratio of the diets. However, there were trends, particularly in the nonpolar lipids, suggesting that cheek cell fatty acid ratios might be useful for monitoring the fatty acid composition of the diets. The diet with the higher P/S ratio (1.0 vs 0.3) consistently resulted in cheek cell lipids with lower ratios of 18:1/saturated fatty acids and greater 18:2/20:4, 18:2/18:1 and 18:2/18:0 fatty acid ratios.

Menstrual cycle effect on plasma lipids

In a study of 31 healthy women in which dietary intake and body weight were controlled, a significantly higher mean plasma cholesterol was observed in the follicular phase of the menstrual cycle compared to the luteal phase (mean difference of 8.4% during controlled dietary periods). Higher mean plasma triglycerides (mean difference of 7.4%) and lower HDL-cholesterol (mean difference of 5.8%) were also observed in the follicular phase of the controlled dietary study, although these differences were not consistently significant.

Influence of dietary fat on menstrual cycle and menses length

Menstrual cycle and menses lengths were determined in 31 healthy premenopausal women randomized into one of two sets of weight-maintaining diets, those with a ratio of polyunsaturated to saturated fatty acids (P/S ratio) of 1.0 and those with a P/S ratio of 0.3. After a baseline interval of one menstrual cycle, both groups were fed a high fat diet (40 per cent energy from fat) for four menstrual cycles per subject, followed by a similar interval on a low fat diet (20 per cent energy from fat). There was a significant increase of 1.3 d (P = 0.02) in the average menstrual cycle length and 0.5 d (P = 0.01) in menses length on the low fat diet. Although no significant differences were evident between the P/S groups, the effect of low fat on menstrual cycle and menses length was most pronounced in the P/S = 1.0 group.

Dietary linoleate increases fluidity and influences chemical composition of plasma low density lipoprotein in adult men

Dietary linoleate was effective to increase LDL fluidity in adult men but did not significantly influence VLDL or HDL fluidities. Lipoproteins were isolated ultracentrifugally from plasma of sixteen healthy, free living male volunteers consuming controlled diets formulated from typical U.S.A. foods to have 35 energy % fat with 10 g (diet L) or 30 g (diet H) linoleate per day, 30-50 g saturated fatty acids/day and the balance mainly monounsaturated fatty acids. Calculated cholesterol intakes were 500 mg/day at each calorie level. Changes in LDL fluidity were detected as differences in diphenylhexatriene (DPH) fluorescence polarization upon crossover between the two controlled diets. Thermotropic measurement of DPH fluorescence anisotropy and compositional analyses indicated that LDL and HDL fluidities were dependent upon phospholipid and triacylglycerol concentrations, respectively, and were modulated by the presence of cholesteryl esters. Fatty acid analyses of the major lipid classes of the isolated lipoproteins indicated that changes, upon diet crossover, in DPH fluorescence anisotropy, were a linear function of the incremental change in LDL phospholipid linoleate. The fluorescent probe described an environment corresponding to the fatty acyl moieties of the phospholipids on the LDL periphery, which composition is apparently under dietary control. It is suggested that the diet induced fluidity changes may affect the conformation of the apoprotein moiety on the LDL surface and thus the potential for LDL interaction with cellular LDL receptors.

Influence of caloric contribution and saturation of dietary fat on plasma lipids in premenopausal women

Total cholesterol, HDL cholesterol, and triglycerides were measured in 31 premenopausal women randomized into one of two diet groups: one diet with a P:S ratio of 1.0 and one diet with a P:S ratio of 0.3. Both groups were fed a high-fat diet (40% of energy from fat) for four menstrual cycles per subject followed by a similar interval on a low-fat diet (20% of energy from fat). Changing from the high-fat to the low-fat diet resulted in a nonsignificant mean decrease of 7% in total cholesterol. HDL-cholesterol response to the low-fat regimen was influenced by the P:S ratio. Women in the high P:S group showed no change; mean HDL cholesterol in women in the low P:S group decreased 12%. Plasma triglycerides increased in both groups on the low-fat diet although the increase was greatest in the low P:S group.

Vitamin E in foods from high and low linoleic acid diets

As part of a human diet study, vitamin E activity was estimated in foods used in seven daily menus. Each menu was designed to contain 35% fat calories with either 10 or 30 gm/day of linoleic acid (18:2) and 500 mg/day of cholesterol. To estimate vitamin E activity, each food used in the menus was analyzed for alpha and gamma tocopherol content by high-pressure liquid chromatography with fluorescence detection. This article reports the alpha and gamma tocopherol contents of those foods, tocopherol contributions from each food in one sample 2,400-kcal menu, and the mean daily vitamin E activity (milligram alpha tocopherol equivalents) of all seven menus at five caloric levels. Major sources of alpha tocopherol (greater than 10% of the RDA) common to both diets (10 and 30 gm linoleic acid) were olive oil and a few fruits and vegetables. Additional major sources in the 30-gm linoleic acid diets were polyunsaturated fatty acid (PUFA) vegetable oils and margarine. Contrary to a common assumption, increasing the level of PUFA in the menus did not necessarily result in higher milligram equivalents of alpha tocopherol because soybean oil, with a tocopherol composition that is predominantly gamma tocopherol, was the major source of linoleic acid in the diets. Thus, vitamin E activity was not necessarily increased when soybean oil was substituted for a less saturated fat such as olive oil, which has mostly alpha tocopherol.

Effects of low fat diets varying in P/S ratio on nutrient intakes, fecal excretion, blood chemistry profiles, and fatty acids of adult men

Twenty-three apparently healthy volunteers aged 35 to 60 years consumed closely monitored self-selected (SS) diets for five weeks followed by two low fat controlled diets (25% energy) for two six-week periods followed by another five-week SS diet. The two low fat diets, fed in a crossover design to one-half of the subjects per controlled diet period, had a polyunsaturated/saturated (P/S) fat ratio of either 0.3 or 1.0. Results are reported for bi-weekly measurements of energy and nutrients; blood profiles and plasma fatty acids; and for end-of-period values for stool characteristics. Blood chemistry profiles differed in the two groups. The low P/S diet produced significant increases not only in cholesterol, but in 16:0, 16:1, and percent saturated fatty acids and decreases in 18:2 and omega 6 fatty acids. The reverse was seen with the high P/S diet. The essential fatty acid (EFA) linoleic acid returned in the poststudy period to prestudy levels (all subjects), but arachidonic acid did not. The explanation for negative correlation between magnesium intake or excretion and percent plasma linoleic acid must await further research.