Anxiety levels in dreams: relation to changes in plasma free fatty acids.

Blood samples for determination of plasma free fatty acids were obtained throughout the night by means of an indwelling catheter. The first sample was drawn at the onset of rapid eye movements and a second after 15 minutes of these movements. Subjects were then awakened and asked to relate their dreams; a third sample was drawn 15 to 25 minutes later. Anxiety scores derived from 20 dreams of nine subjects had significant positive correlations with changes in free fatty acids occurring during REM sleep. No statistically significant relation was found between anxiety and the changes in free fatty acids occurring from the time just before awakening to 15 to 25 minutes later. Presumably, anxiety in dreams triggers the release of catecholamines into the circulation, and these catecholamines mobilize proportional amounts of free fatty acids from body fat.

Reduction of blood pressure associated with dietary polyunsaturated fat.

Evidence linking the beneficial effect of dietary polyunsaturated fat on systolic and distolic blood pressure is reported. Under controlled dietary conditions, i.e., when the polyunsaturated fat to saturate fat ratio (P/S) is maintained at about 1.0, with fat providing 25% of total energy intake, blood pressure is significantly lowered in healthy males and females in the 40- to 60-year age group. The subjects selected for these studies were either normotensive or mildly hypertensive. When the subjects resumed their usual diets, their blood pressures reverted to baseline values. Body weights of the subjects remained relatively constant in these studies, and sodium chloride intakes averaged 8 to 12 g per day. It is suggested that the lowering of blood pressure by dietary linoleic acid is mediated through prostaglandins.

Lack of effect of linoleic acid on the high-density-lipoprotein-cholesterol fraction of plasma lipoproteins.

Low-fat, natural diets were fed to 11 middle-aged, healthy male subjects for two 40-d periods to determine effects on plasma lipoproteins. The diets were designed to maintain saturated and monounsaturated fatty acids at 10 en% and linoleic acid (LA) at 3.8 and 10.8 en%. When compared with baseline concentrations, total cholesterol decreased 10% at the end of the lower LA diet and 15% at the end of the higher LA diet. Low-density-lipoprotein cholesterol (LDL-C) decreased 18% and 22%, respectively, during the same periods. Plasma high-density-lipoprotein cholesterol (HDL-C) at the end of each dietary period was not significantly different but the midpoint values were lower by 12.5% on the lower LA diet and 7.3% on the higher LA diet. Apolipoprotein B decreased 27% at the end of the lower LA diet and 37% at the end of the higher LA diet whereas apolipoprotein A-I increased 18% and 24%, respectively. HDL-C was not reduced by dietary LA over a 6-wk period.

Nutrient content of the diet when the fat is reduced.

When the fat content of the typical US diet was reduced from 40 to 44% of total energy (en %) to approximately 25 en % there was a marked improvement in the overall nutrient content of the diet. Cholesterol, saturated fatty acid, and monounsaturated fatty acid intake were decreased and the polyunsaturated fatty acid content was moderately increased. This kind of dietary change was achieved without changing the usual intake of meats, dairy products, fish, and eggs. As the amount of fat was decreased, carbohydrates in the form of grains, fruits, and vegetables were increased, providing an improvement in the vitamin and mineral content of the diet. Vitamin C, thiamin, riboflavin, niacin, B-6, B-12, and folates increased in the 25 en % diet. Potassium, calcium, magnesium, phosphorus, iron, zinc, and copper intake also increased when the dietary fat decreased.

Lipid and phospholipid fatty acid composition of plasma, red blood cells, and platelets and how they are affected by dietary lipids: a study of normal subjects from Italy, Finland, and the USA.

A pilot study was conducted of males 40-45 years old from rural areas of three countries to study the long-term effects of dietary fats on the lipids of plasma, red blood cells (RBCs), and platelets. Differences were observed in cholesterol and phospholipid levels of plasma. Total phospholipids of RBCs and platelets were similar in all three countries. The pattern of individual phospholipids of RBCs in the Finnish and Italian samples differed from the American samples. In all plasma and RBC glycerolphospholipids, the monounsaturated fatty acids were highest in the Italian and the saturated fatty acids were highest in the Finnish samples; PUFAs were highest in the USA samples. Platelet glycerolphospholipids followed similar fatty acid patterns. We concluded that the fatty acid compositions of the glycerolphospholipids of plasma, RBCs, and platelets reflect the major dietary fatty acids.

Dietary stearic acid and thromboxane-prostacyclin biosynthesis in normal human subjects.

Ten male subjects were fed a diet rich in stearic acid while they were contained to a metabolic ward. There were three study periods: a 20-d baseline period followed by two 40-d intervention periods. The baseline diet contained 4.4% of energy from stearic acid; one intervention diet was high in stearic acid (7.3% of energy) and the other intervention diet was low in stearic acid (1.6% of energy). The energy contribution of protein, carbohydrate, and fat (16%, 54%, and 30%, respectively) was identical for the two diets. The fat content was distributed equally among saturated, monounsaturated, and polyunsaturated fatty acids. Urinary excretions of thromboxane B2, 2,3-dinor-thromboxane B2, 6-oxo-prostaglandin F1 alpha, and 2,3-dinor-6-oxo-prostaglandin F1 alpha were not significantly different during the two different intervention periods. This suggests that changes in dietary stearic acid do not affect in vivo thromboxane A2 or prostacyclin biosynthesis.

Effects of diets containing high or low amounts of stearic acid on plasma lipoprotein fractions and fecal fatty acid excretion of men.

Ten middle-aged males participated in a crossover study to determine the cholesterolemic effect of high amounts of stearic acid in a natural diet. They consumed a 20-d stabilization diet followed by two 40-d intervention diets containing either 1.5% of energy as stearic (18:0) acid and 7.3% of energy as palmitic (16:0) acid (low stearate: LS) or 2.4% of energy as 16:0 and 7.3% of energy as 18:0 (high stearate: HS). The experimental diets also contained approximately 10% of energy each as saturated and monounsaturated fatty acids and 7.2-8% of energy as polyunsaturated fatty acids. The primary source of 18:0 in the HS diet was sheanut oil (commercially referred to as shea butter) and palm oil and butter in the LS diet. Plasma total, low-density-lipoprotein, and high-density-lipoprotein cholesterol were significantly lower with the HS than with the LS diet. Total fecal fatty acid excretion was higher throughout the HS period. Apparent digestibility of the major dietary fatty acids showed that all of the selected fatty acids, except 18:0, were > or = 95% absorbed. These data demonstrate that feeding diets containing about two times the usual amount of stearic acid consumed in the United States, contributed to an increase in plasma lipoprotein concentrations at 40 d from an earlier decrease at 20 d. The time required to achieve stable cholesterol concentrations appears to vary depending on the kind of saturated fatty acids present in the diet.

Platelet aggregation in humans is affected by replacement of dietary linoleic acid with oleic acid.

The effect of concentrations of linoleic acid (LA) on platelet aggregation was measured in seven healthy adult males. Subjects were randomly divided into two groups; these groups were fed natural food diets of identical composition except that one was high in LA (11.5% of energy) and low in oleic acid (OA) (7.4% of energy), the other was low in LA (4.5% of energy) and high in OA (15.7% of energy). The thresholds of ADP- and collagen-induced platelet aggregation were increased significantly by the high LA diet even though the intake of total fat and saturated fatty acids did not differ in these diets.

Dietary modification of omega 6 fatty acid intake and its effect on urinary eicosanoid excretion.

A group of women were fed two separate diets in a crossover study and urinary eicosanoids were quantified. One diet contained 3.1% of total energy (en%) as polyunsaturated fatty acids (3.0 en% linoleic acid) and the other contained 8.4 en% polyunsaturated fatty acids (8.3 en% linoleic acid). Carbohydrate replaced fat in the low-polyunsaturated-fat diet. No changes were observed in the urinary excretion of 6-oxo-prostaglandin F1 alpha, its 2,3-dinor metabolite or thromboxane B2 by subjects on either of the diets. Urinary 2,3-dinor-thromboxane B2 excretion was lower (206.5 ng/24 h) when subjects were fed the high-omega 6 polyunsaturated fatty acid diet when compared with the lower-omega 6 polyunsaturated fatty acid diet (275.3 ng/24 h). Conversely, urinary prostaglandin E2 was higher (139.2 ng/g creatinine) during the higher-omega 6 polyunsaturated fatty acid diet when compared with the lower-omega 6 polyunsaturated fatty acid diet (94.4 ng/g creatinine).

Effect of dietary fat on blood pressure in a rural Finnish population.

Thirty couples living in Liperi, a community of North Karelia, aged 40 to 50 yr participated in a dietary intervention study to assess the influence of dietary fat on blood pressure and other parameters. After a weeklong base-line period the subjects consumed a low fat diet (24% of energy) with a polyunsaturated/saturated fat ratio (P/S) of 1.2 for 6 wk. After this 6-wk intervention period the subjects resumed their normal diets (36% energy from fat, P/S 0.15) for an additional 6-wk period. Body weight remained constant throughout the study and salt intakes were approximately 12 g/day. During the low fat, high P/S period a decrease of 7.5 and 2.8 mm Hg pressure occurred for systolic and diastolic blood pressure from the base-line level. When the normal diet was resumed, systolic and diastolic blood pressures increased by 7.7 and 6.3 mm Hg, respectively, from the levels observed at the end of the intervention period.

Changing the Mediterranean diet: effects on blood lipids.

A study was carried out on 48 healthy middle-age men and women habitually subsisting on a "Mediterranean type" diet in a rural area of southern Italy. Their freely chosen natural diet was modified for a period of 42 days by partially substituting animal fats for olive oil. Currently available foods were used, and the subjects maintained their habitual lifestyle. Dietary fat content changed from 33 to 37% of total energy and the polyunsaturated to saturated fatty acid ratio changed from 0.48 to 0.22. The base-line serum total cholesterol of men increased during the dietary intervention period from 214 +/- 30 mg/dl (mean and SD) to 245 +/- 33 mg (+15%). Low-density lipoprotein cholesterol increased 19%, while high-density lipoprotein cholesterol remained unmodified. Women, while exhibiting a similar trend in serum total cholesterol (+16%), showed also a 19% increase in their high-density lipoprotein cholesterol (p less than 0.001). Apoprotein B increased in parallel with low-density lipoprotein cholesterol in both sexes. The results of the study confirm the impact of the dietary factor on blood lipids. They also provide additional evidence on the response of high-density lipoprotein cholesterol to diet in free-living populations.

Dietary alpha-linolenic acid and immunocompetence in humans.

We examined the effect of dietary alpha-linolenic acid (ALA) on the indices of immunocompetence in 10 healthy free-living men (age 21-37 y) who consumed all meals at the Western Human Nutrition Research Center for 126 d. There was a stabilization period of 14 d at the start when all 10 subjects consumed basal diet (BD) and there were two intervention periods of 56 d each. Five of the subjects consumed the basal diet and the other five consumed flax-seed-oil diet (FD) during each intervention period. Feeding of FD suppressed the proliferation of peripheral blood mononuclear cells when they were cultured with phytohemagglutinin-P (P = 0.041) and concanavalin A (P = 0.054) and the delayed hypersensitivity response to seven recall antigens (NS). Concentrations of immunoglobulins in serum, C3, C4, salivary IgA, the numbers of helper cells, suppressor cells, and total T and B cells in the peripheral blood were not affected by the diets.

Changes in lactate dehydrogenase, LDH isoenzymes, lactate, and pyruvate as a result of feeding low fat diets to healthy men and women.

A study was conducted to evaluate the effects on blood lipids and lipoproteins of feeding 21 healthy volunteers, 40-60 yr old, foods commonly eaten in the United States for two 40-day periods. Activities of lactate dehydrogenase (LDH) and LDH isoenzymes, lactate, and pyruvate were monitored. Results showed that LDH activity was significantly lower in all subjects at the end of the 25% fat-calorie period (period I) than at the beginning of the study, but rose above initial levels at the end of the 35% fat-calorie period (period II). While total LDH fell during period I, relative activity of M type subunits of LDH rose significantly in relation to H type in both sexes. This rise is probably indicative of an increase in glycolytic activity as a consequence of the increased intake of dietary carbohydrate. In period I, lactate and pyruvate decreased significantly in males (pyruvate greater than lactate) but not in females. Values for males returned to near initial levels in period II. The ratio of lactate/pyruvate was elevated in both sexes after period I. The greater change in pyruvate relative to lactate with increased dietary carbohydrate suggests increased Krebs Cycle activity. There was a statistically significant positive correlation between lactate, pyruvate, and serum triglyceride for males after they ate the 25% and 35% fat-calorie diets and for females after they ate the 35% fat-calorie diet, but not between lactate, pyruvate, and serum cholesterol for either sex.

Predictors of blood pressure change in a series of controlled dietary intervention studies.

Three controlled dietary intervention studies were carried out in 1981-1983 in North Karelia, Finland, to asses the impact of dietary fat intake modification on blood pressure (BP). All these studies involved middle-aged men and women in rural or semirural areas and comprised a baseline period, a six week (or 12 weeks in the third study) intervention period and a four to six week return to baseline. During the intervention period the total fat intake was reduced from 39% to 24% of energy and the polyunsaturated/saturated (P/S) ratio increased from 0.2 to 0.4-1.2. In all groups energy intake was kept constant. For the present report data from the three studies were pooled for a series of stepwise regression analyses to predict changes in BP with different dietary changes. For both systolic (SBP) and diastolic (DBP) blood pressure, change in polyunsaturated fatty acid intake was the strongest dietary predictor of BP change. Changes in body weight, total fat intake, urinary sodium and potassium did not have significant predictive power in any of the analyses. The findings support the hypothesis that modification of dietary fat intake is a significant predictor of change in BP.

Lack of effect on blood pressure by low fat diets with different fatty acid compositions.

We compared the effects on blood pressure (BP) of three isocaloric diets with reduced total fat and saturated fatty acid (SAFA) contents but with different proportions of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Diet LF (low fat) provided 20 en% fat (7.9% SAFA, 7.8% MUFA, 3.0% PUFA); diet HP (high PUFA) 26 en% fat (7.5% SAFA, 8.2% MUFA, 8.1% PUFA), and diet HM (high MUFA) 26 en% fat (7.3% SAFA, 14.1% MUFA, 3.2% PUFA). The diets were consumed for 8 weeks (intervention) preceded by 2 weeks and followed by 8 weeks on a habitual diet (baseline/ switchback) with 33-34 en% fat (13-14% SAFA, 12% MUFA, 6% PUFA). Forty-five free-living couples were randomly allocated into the three diet groups, and 43 men and 44 women completed the study. BP was measured weekly with an automatic device. Compliance to diet was monitored by repeated food records, serum fatty acid compositions, and weekly visits to a nutritionist. Both systolic BP (SBP) and diastolic BP (DBP) remained unchanged throughout the study in all three groups. The weight-adjusted mean (s.e.m.) BP values showed changes in SBP of +1.7 (1.8), -0.4 (1.7), and +1.9 (1.9) mm Hg on the LF, HP, and HM diets, respectively (difference NS), and DBP of +0.1 (1.0), +0.6 (1.0), and -0.3 (1.0) mm Hg, respectively (difference NS) between the last 2 weeks of the baseline and intervention periods. The expected fatty acid intakes were achieved, and there were no between-group differences in change of body weight, intake of dietary fibre and potassium, and 24-h sodium excretion. A reduction in total fat and SAFA intake and changes in the proportions of dietary MUFA and PUFA did not affect the BP levels of this normotensive population with an adequate intake of PUFA at baseline.

Composition of diets containing 25 and 35 per cent calories from fat. Analyzed vs. calculated values.

In a dietary study conducted to evaluate the effects of low-fat, low-cholesterol diets on the reduction of blood lipids in man, meals were analyzed for proximate composition, ten vitamins, fourteen minerals and trace minerals, fatty acids, tocopherols, and cholesterol; Validity of the calculated nutrient composition of the diets was assessed by comparing calculated with determined values. Comparisons were also made of the determined values with 1974 Recommended Dietary Allowances. Analyzed values and those calculated from Agriculture Handbood No. 8 were exceptionally close, except for calcium; By analysis, on a per-kilogram basis, the 35-per-cent-fat-calorie diet more nearly met the Recommended Dietary Allowances for most of the nutrients than did the 25-per-cent-fat-calorie diet. However, on a per-1,000-kcal basis, there were few differences between nutrients in diets with the two levels of fat calories.

Lability of red blood cell membranes to lipid peroxidation: application to humans fed polyunsaturated lipids.

Red blood cell membranes (RBCM) were used to estimate human red blood cell lability to lipid peroxidation in vitro. RBCM were prepared from blood collected from humans fed diets with either 3 or 15% polyunsaturated fatty acids for 80 days. RBCM were isolated by centrifugation, and oxidative stress was induced by in vitro incubation with 0.1 or 0.5 mM tert-butyl hydroperoxide (t-BOOH) in the presence of 0.5 mg added hemoglobin. Lipid Peroxidation was evaluated by measurement of thiobarbituric acid-reactive substances (TBARS). Lipid peroxidation correlated with the protein content of RBCM in both noninduced and t-BOOH-induced lipid peroxidation systems. TBARS production was dependent on the amount of t-BOOH added to the RBCM. The production of TBARS by RBCM incubated with 0.5 mM t-BOOH was correlated with arachidonic acid content in the red blood cells (RBC) from which RBCM were prepared. The methodology developed was useful for comparative estimations of the lability of RBCM to lipid peroxidation.

Dietary alpha-linolenic acid alters tissue fatty acid composition, but not blood lipids, lipoproteins or coagulation status in humans.

We examined the effect of dietary alpha-linolenic acid (ALA) on the indices of lipid and coagulation status and on the fatty acid composition of serum and peripheral blood mononuclear cell (PBMNC) lipids in ten healthy men (age 21-37 yr) who consumed all their meals at the Western Human Nutrition Research Center for 126 d. There was a stabilization period of 14 d at the start when all 10 subjects consumed the basal diet (BD) containing 23.4 energy percent (en%) fat and two intervention periods of 56 d each. During the first intervention period, 5 subjects consumed the BD containing 23.4 en% fat, and 5 subjects consumed a diet providing 6.3% calories from alpha-linolenic acid [flaxseed oil (FSO) diet containing 28.8 en% fat]. Diets were crossed over between the two groups during the second intervention period. Feeding the FSO diet did not significantly alter serum triglycerides, cholesterol, high-density lipoproteins, low-density lipoproteins, apoprotein A-I and apoprotein B when compared to the corresponding values in the subjects fed the BD, nor was there any effect of the FSO diet on the bleeding time, prothrombin time and partial prothrombin time for these subjects. Feeding the ALA-containing diet did cause a significant increase in ALA concentration in serum (P < 0.001) and PBMNC lipids (P < 0.05). It also caused a significant increase (P < 0.05) in the eicosapentaenoic and docosapentaenoic acid contents of PBMNC lipids, and a decrease (P < 0.01) in linoleic and eicosatrienoic acid contents of serum lipids.(ABSTRACT TRUNCATED AT 250 WORDS)

Pilot epidemiological studies in thrombosis.

Some differences in the blood of farmers in Nurmijarvi, Finland, Canino, Italy, and Beltsville, Maryland in the United States apparently were associated with differences, among the areas, in the farmers' diets. Those associations suggested that diets that are high in saturated fats (Nurmijarvi) could predispose humans to develop intravascular disease. Such predisposition has been observed in experimental animals. Low levels of the parameters that are considered active in such predisposition apparently were associated with diets that were low in saturated fats (Canino) or with diets that were low in saturated and high in unsaturated fats (Beltsville). Within the limits of the experimental design, the data from the three population groups indicated that a more comprehensive study might establish a relation between diet and intravascular disease in humans.