Dietary supplementation with n-3 fatty acids increases gluconeogenesis from glycerol but not hepatic glucose production in patients with non-insulin-dependent diabetes mellitus.

Fish-oil supplementation decreases serum triacylglycerols but may worsen hyperglycemia in patients with non-insulin-dependent diabetes mellitus. The reason for the possible deterioration of glycemia is unclear. We examined whether inhibition of triacylglycerol synthesis by n-3 fatty acids changes lipolysis, glycerol gluconeogenesis, or fatty acid oxidation. Nine obese patients with non-insulin-dependent diabetes mellitus participated in a randomized double-blind crossover study in which 6 wk of n-3 fatty acid supplementation (12 g fish oil) was compared with 6 wk of corn plus olive oil. Serum triacylglycerols decreased by 30% during n-3 fatty acid supplementation. Glycerol gluconeogenesis ([U-14C]glycerol) increased by 32%. However, overall glucose production ([3-3H]glucose), glycemic control, and fatty acid oxidation remained unchanged. Thus, 6 wk of n-3 fatty acid supplementation lowers triacylglycerols in patients with non-insulin-dependent diabetes mellitus without worsening glycemic control. However, n-3 fatty acid supplementation increases glycerol gluconeogenesis, which could contribute to deterioration of glycemic control during long-term treatment with high doses of fish-oil supplements.

Metabolic and dietary determinants of serum lipids in obese patients with recently diagnosed non-insulin-dependent diabetes.

The aim of the study was to ascertain the metabolic and dietary determinants of changes in serum lipids during a 15-month diet therapy of obese patients (n = 71, 41 males, 30 females) with recently diagnosed Type 2 (non-insulin-dependent) diabetes. The subjects lost weight and improvement in glycaemic control was observed, but due to variation in individual responses the mean serum total cholesterol or non-HDL cholesterol did not change significantly. The proportion of palmitic acid decreased and that of linoleic acid increased in serum lipids during the study, and serum triglycerides decreased and HDL-cholesterol increased. In univariate analyses, decreased serum triglyceride level was associated with serum triglycerides at baseline, decreases in body mass index, fasting blood glucose and palmitic acid proportion of serum triglycerides, and the intake of saturated fats and dietary fibre, but in multiple regression analyses the determinants for decreased serum triglycerides were high serum triglycerides at baseline and a decreased proportion of palmitic acid in serum triglycerides. In univariate analysis, increased HDL-cholesterol was associated with the baseline HDL-cholesterol, decrease in the triceps/subscapularis ratio and the intake of saturated and mono-unsaturated fatty acids, but none of these variables had an independent contribution to the increase in serum HDL-cholesterol in multiple regression analysis. In conclusion, a reduction of palmitic acid in the serum lipids, which was probably due to reduction of dietary saturated fatty acids, had beneficial effects on serum lipids in obese patients with Type 2 diabetes, independently of weight loss and improvement in glycaemic control.

Identity of the cholesterol-raising factor from boiled coffee and its effects on liver function enzymes.

Boiled coffee contains an unidentified lipid that raises serum cholesterol. We studied the effects of the ingestion of coffee oil fractions of increasing purity in volunteers in order to identify the cholesterol-raising factor. In 15 volunteers who ingested 0.75 g/d of a non-triglyceride-fraction from coffee oil for 4 weeks, mean cholesterol increased by 48 mg/dl (1.2 mmol/l) relative to placebo. In contrast, a coffee oil stripped of the non-triglyceride lipids cafestol and kahweol had no effect. In three volunteers, purified cafestol (73 mg/d) plus kahweol (58 mg/d) increased cholesterol by 66 mg/dl (1.7 mmol/l) after 6 weeks. Oil from Robusta beans, which contains cafestol but negligible kahweol, also raised serum cholesterol. These findings show that cafestol is at least partly responsible for the cholesterol-raising effect of boiled coffee. Coffee oils and brews containing cafestol consistently increased serum triglycerides and alanine amino-transferase, and depressed serum creatinine and gamma-glutamyl-transferase (GGT). After withdrawal GGT activity rose above baseline. Norwegians who habitually consumed 5-9 cups of boiled coffee per day had higher serum cholesterol levels and lower GGT but no higher alanine aminotransferase activity than controls. Thus, serum cholesterol is raised by cafestol and possibly also kahweol, both natural components of coffee beans. The mechanism of action is unknown but is accompanied by alterations in liver function enzymes.

Fatty acid composition of serum cholesterol esters, and erythrocyte and platelet membranes as indicators of long-term adherence to fat-modified diets.

Dietary adherence to four different fat-modified diets was examined in 160 subjects by determining the fatty acid composition of serum cholesterol esters (CEs) and erythrocyte (ER) and platelet (PT) membranes in addition to food records. Subjects were randomly assigned to one of the following diet groups: 1) high-sat--35/14:104 (% of energy from total/saturated:monounsaturated:polyunsaturated fatty acids in the actual diet) 2) AHA (American Heart Association) type--32/10:8:8 3) monoene-enriched--34/11:11:5, or 4) low-fat--30/12:8:3 for 6 mo. Decreases in the proportions of palmitic acid in CEs were found in the AHA-type and monoene-enriched-diet groups. An increased proportion of linoleic acid in CEs was found in the AHA-type group. The differences in the proportions of palmitic acid in CEs and linoleic and palmitoleic acids in PTs were significant in the AHA-type and monoene-enriched-diet groups compared with the high-sat group. An increase in alpha-linolenic acid in CEs was an indicator of the use of low erucic acid rapeseed oil, which was the main source of monoenes in the monoene-enriched-diet group.

Long-term effects of three fat-modified diets in hypercholesterolemic subjects.

Altogether 160 free living subjects (aged 30-60 years) most of whom had moderate hypercholesterolemia were randomised into the following diet groups to find out long-term effects of different fat-modified diets: (1) control diet 35/14:10:4 (energy percents from fat/saturated:monounsaturated:polyunsaturated fatty acids in actual diets); (2) AHA type diet 32/10:8:8; (3) monoene-enriched diet 34/11:11:5; (4) reduced-fat diet 30/12:8:3. LDL cholesterol fell equally with the AHA type diet (4.54 +/- 0.97 vs. 4.21 +/- 0.89 mmol/l (mean +/- S.D., 0 vs. 6 months), P = 0.001) and with the monoene-enriched diet (4.55 +/- 0.95 vs. 4.25 +/- 0.95 mmol/l, P = 0.004) during the 6-month study. Moderate amounts of polyenes or monoenes as part of natural diets did not decrease HDL cholesterol level in the long term. Serum lipid values remained unchanged with the reduced-fat diet. Analysis by apolipoprotein E phenotypes showed a decrease in LDL cholesterol only in subjects with phenotype 3/3 in the monoene-enriched group (-8.6 +/- 8.7 vs. +1.3 +/- 15.4, percent change in LDL cholesterol E 3/3 vs. E 4/3 + 4/4), but in the AHA type group LDL cholesterol decreased similarly in phenotypes E 3/3 and E 4/3 + 4/4 (-6.9 +/- 10.1 vs -6.9 +/- 16.5).

Impact of intensified dietary therapy on energy and nutrient intakes and fatty acid composition of serum lipids in patients with recently diagnosed non-insulin-dependent diabetes mellitus.

Compliance with dietary recommendations and the effect of intensified dietary therapy on energy and nutrient intakes and fatty acid composition of serum lipids were studied in 86 obese subjects (aged 40 to 64 years) with recently diagnosed non-insulin-dependent diabetes mellitus (NIDDM). After three months of basic education, the subjects were randomly separated into an intervention group (n = 40) and a conventional treatment group (n = 46). Members of the intervention group participated in 12 months of intensified education; those in the conventional group visited local health centers. Compliance with dietary instructions was monitored through food records. Intensified dietary therapy resulted in greater weight loss, better metabolic control, and a less atherogenic lipid profile than conventional treatment. Intake of energy and saturated fatty acids tended to decline in the intervention group. A higher percentage of patients in the intervention group had a total fat intake of 30% of energy or less after 15 months (32.5% [12 of 38] vs 17.4% [8 of 46]). Similarly, more patients in the intervention group had a saturated fatty acid intake of 10% or less of total energy intake at the end of the study (35.0% [13 of 38] vs 8.7% [4 of 46]). The mean dietary cholesterol intake was within recommendations in both groups at the end of the study. The relative percentage of linoleic acid of serum lipids increased significantly and the relative percentage of palmitic acid of serum triglycerides, phospholipids, and cholesterol esters decreased in the intervention group. These changes indicate that intensified dietary therapy improved the quality of fat in the diet of patients with NIDDM.

Traditional risk-factor profile fails to explain striking geographical differences in IHD mortality among middle-aged men. The project "myocardial infarction in mid-Sweden".

An east-west gradient in cardiovascular mortality has been reported from the region of mid-Sweden. Postal questionnaire studies found that the risk factor distributions among middle-aged men were similar in areas with striking differences in cardiovascular mortality. In this study, 120 randomly selected 50-year-old men in two high mortality communities in the west and 120 men from two low mortality communities in the east were invited to a health survey in which serum lipids and other risk factors were analysed. Total serum cholesterol, LDL-cholesterol, HDL-cholesterol, and triglyceride levels were similar. Among fatty acids, stearic acid was high and arachidonic acid was low in the high mortality area. The levels of other traditional risk factors were the same. After taking these differences into account, the mortality differences remain large.

Rapeseed oil and sunflower oil diets enhance platelet in vitro aggregation and thromboxane production in healthy men when compared with milk fat or habitual diets.

In this highly controlled trial, 26 normolipidemic men (average age 28 years, range 18 to 60) were fed a baseline diet high in milk fat (MF) (fat 36% of energy, saturates 19%, monounsaturates 11%, polyunsaturates 4%), followed by a diet high in sunflower oil (SO) (fat 38% of energy, saturates 13%, monounsaturates 10%, polyunsaturates 13%) and another diet high in low erucic-acid rapeseed oil (RO) (fat 38% of energy, saturates 12%, monounsaturates 16%, polyunsaturates 8%). All diets were mixed natural diets with the same cholesterol contents. The baseline milk fat diet was given for 14 days and the oil diets for 24 days in a blind cross-over design. The platelet in vitro aggregation (slope %/min) induced by 1, 2 and 3 microM ADP and collagen (25 micrograms/ml PRP) was highly significantly (p less than 0.001) increased after both oil diets when compared with the results from the milk fat diet. The aggregation pattern determined by threshold collagen concentration confirmed increased collagen sensitivity of the platelets after the rapeseed oil diet (p less than 0.001). The enhancement of platelet aggregation was associated with increased in vitro platelet thromboxane production after the oil diets vs. the milk fat diet (p less than 0.05 after the sunflower oil diet and p less than 0.001 after the rapeseed oil diet).

The hypercholesterolaemic factor in boiled coffee is retained by a paper filter.

In order to study the effects of filtering on the serum cholesterol-elevating effect of boiled coffee, 20 healthy volunteers consumed, in random order, 6-10 dl d-1 of strong boiled coffee (BC) and similarly boiled coffee that had been passed through a conventional paper filter (BFC), for periods of 4 weeks in a crossover design. During periods of BC consumption serum total cholesterol and LDL-cholesterol levels (P less than 0.05), as well as serum triglyceride and apoprotein B concentrations and the LDL/HDL ratio (P less than 0.01), were significantly higher than during BFC periods. Serum HDL-cholesterol and apoprotein A-I levels remained unchanged. Filtering removed more than 80% of the lipid-soluble substance that was present in boiled coffee. The results indicate that the hypercholesterolaemic factor in boiled coffee, which is presumably lipid-soluble, is retained by the paper filter. They also suggest that boiling is not essential for the previously observed difference between the effects on serum lipoproteins of boiled coffee and filtered coffee.

Fatty acid composition of serum cholesterol esters in different degrees of glucose intolerance: a population-based study.

The fatty acid composition of serum cholesterol esters was investigated in 325 subjects with normal glucose tolerance, 97 subjects with impaired glucose tolerance (IGT), and 98 subjects with non-insulin-dependent diabetes mellitus (NIDDM) identified by population-based screening. The proportions of palmitic acid (16:0) and palmitoleic acid (16:1) in serum cholesterol esters increased from the normal glucose tolerance group to the IGT and diabetic groups. On the other hand, the proportion of linoleic acid (18:2) was lower in diabetic subjects than in the subjects with IGT or normal glucose tolerance. The proportions of gamma-linolenic (18:3), dihomo-gamma-linoleic (20:3), and arachidonic (20:4) acids were highest in diabetic subjects and lowest in subjects with normal glucose tolerance. Our findings suggest that subjects with NIDDM or IGT have had higher dietary intake of saturated fatty acids. Both serum insulin and blood glucose concentrations probably have an effect on the elongation and desaturation of fatty acids, but the metabolism of linoleic acid to prostaglandin precursors seems to be different in different types of diabetes, NIDDM patients showing no abnormalities. The possibility that the fatty acid composition of plasma and membrane lipids has a role in insulin resistance and blood glucose regulation deserves further investigation.

Evening primose oil and fish oil are ineffective as supplementary treatment of bronchial asthma.

The effect of daily dietary supplementation with 15 to 20 mL of evening primrose seed oil or fish oil was assessed by comparison with olive oil as placebo in a cross-over study in 29 asthmatics. During 10 weeks of each regimen, the patients kept record of symptoms, peak expiratory flow rates and medication. Plasma and urine TxB2, PGE2, PGF2 alpha and 6 keto-PGF1 alpha and plasma fatty acid composition of plasma cholesterol esters were measured at the end of each treatment period. There were no differences between regimes with regard to peak flow rates, symptoms, or drug consumption. Plasma PGE2 levels increased during the fish oil treatment but there were no changes in other prostanoids in plasma or urine. The fatty acid pattern of plasma cholesterol esters showed significant differences between the supplementation periods. We conclude that moderate doses of evening primrose oil or fish oil are ineffective as a supplementary treatment of bronchial asthma.