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Fatty acids (FA) can impair glucose metabolism to a varying degree depending on time of exposure and also of type of FA. Here we tested for acute effects of marine n-3 FA on insulin sensitivity, insulin secretion, energy metabolism, and oxidative stress. This was a randomized, double-blind, crossover study in 11 subjects with type 2 diabetes mellitus. A 4-hour lipid infusion (Intralipid [Fresenius Kabi, Halden, Norway], total of 384 mL) was compared with a similar lipid infusion partly replaced by Omegaven (Fresenius Kabi) that contributed a median of 0.1 g fish oil per kilogram body weight, amounting to 0.04 g/kg of marine n-3 FA. Insulin sensitivity was assessed by isoglycemic hyperinsulinemic clamps; insulin secretion (measured after the clamps), by C-peptide glucagon tests; and energy metabolism, by indirect calorimetry. Infusion of Omegaven increased the proportion of n-3 FA in plasma nonesterified fatty acids (NEFA) compared with Intralipid alone (20:5n-3: median, 1.5% [interquartile range, 0.6%] vs -0.2% [0.2%], P = .001; 22:6n-3: 0.8% [0.4%] vs -0.7% [0.2%], P = .001). However, glucose utilization was not affected; neither was insulin secretion or total energy production (P = .966, .210, and .423, respectively, for the differences between the lipid clamps). Omegaven tended to lower oxidation of fat (P = .062) compared with Intralipid only, correlating with the rise in individual n-3 NEFA (r = 0.627, P = .039). The effects of clamping on phospholipid FA composition, leptin, adiponectin, or F(2)-isoprostane concentrations were not affected by Omegaven. Enrichment of NEFA with n-3 FA during a 4-hour infusion of Intralipid failed to affect insulin sensitivity, insulin secretion, or markers of oxidative stress in subjects with type 2 diabetes mellitus.

Background Android fat distribution (abdominal obesity) is associated with insulin resistance, hepatic steatosis, and greater secretion of large very low‐density lipoprotein ( VLDL ) particles in men. Since abdominal obesity is becoming increasingly prevalent in women, we aimed to investigate the relationship between android fat and hepatic lipid metabolism in pre‐ and postmenopausal women. Methods and Results We used a combination of stable isotope tracer techniques to investigate intrahepatic fatty acid synthesis and partitioning in 29 lean and 29 abdominally obese women (android fat/total fat 0.065 [0.02 to 0.08] and 0.095 [0.08 to 0.11], respectively). Thirty women were premenopausal aged 35 to 45 and they were matched for abdominal obesity with 28 postmenopausal women aged 55 to 65. As anticipated, abdominal obese women were more insulin resistant with enhanced hepatic secretion of large (404±30 versus 268±26 mg/kg lean mass, P VLDL (160±11 versus 142±13). However, postmenopausal status had a pronounced effect on the characteristics of small VLDL particles, which were considerably triglyceride‐enriched (production ratio of VLDL 2 ‐ triglyceride:apolipoprotein B 30±5.3 versus 19±1.6, P r s =−0.49, P =0.006), de novo lipogenesis ( r s =0.55, P =0.003), and desaturation ( r s =0.48, P =0.012) were closely correlated with abdominal obesity‐driven large VLDL ‐triglyceride secretion rate. Conclusions In women, abdominal obesity is a major driver of hepatic large VLDL particle secretion, whereas postmenopausal status was characterized by increased small VLDL particle size. These data provide a mechanistic basis for the hyperlipidemia observed in postmenopausal obesity.

Background Effects of fish oil supplements on metabolic variables are insufficiently clarified in type 2 diabetes. Objective We aimed to investigate short-term (1 wk) and longer-term (9 wk) effects of n-3 fatty acids. Design Twenty-six subjects with type 2 diabetes without hypertriacylglycerolemia participated in a double-blind controlled study. Median intake in the intervention group was 17.6 mL fish oil/d (1.8 g 20:5n-3, 3.0 g 22:6n-3, and 5.9 g total n-3 fatty acids). The control group received 17.8 mL corn oil/d (8.5 g 18:2n-6). Results Plasma phospholipid 20:5n-3 and 22:6n-3 increased, whereas 18:2n-6 decreased, in the fish oil group compared with the corn oil group after 1 wk. The two n-3 fatty acids also increased in adipose tissue biopsy samples taken after 9 wk in the fish oil group. Glucose concentrations (home-monitored) were approximately 1 mmol/L higher in the fish oil group than in the corn oil group at the end of the intervention (P = 0.035). Glucose utilization measured by using an isoglycemic clamp was lowered in the fish oil group compared with that in the corn oil group at the end of the intervention (P = 0.049), whereas glucagon-stimulated C-peptide tended to increase (P = 0.078). The fish oil group utilized less fat for oxidation after 1 wk, with a change to more fat and less carbohydrate oxidation after 9 wk (P = 0.040), than did the corn oil group. Conclusion A high intake of fish oil moderately increases blood glucose and decreases insulin sensitivity in persons with type 2 diabetes without hypertriacylglycerolemia and alters carbohydrate and fat utilization in a time-dependent manner.

All-population and area-based investigations of diet in central obesity are scarce. We used cross-sectional data from 50 339 individuals who responded to the HUNT3 survey of 2006–2008, which recruited from all county-residing adults 20 years and older, to investigate whether those with central obesity eat and drink differently than others. Answers to dietary questions were recoded and analyzed with multiple linear regression, using waist/hip ratio (WHR), age, and sex as explanatory variables. Frequencies of consumption or amounts of food, beverages, and meals were compared among WHR quartiles. Central obesity was present in the quartile with the highest WHR, WHR4 (WHR ≥ 0.917 for women and 0.981 for men) but not in the quartile with the lowest WHR, WHR1 (WHR < 0.817 for women and 0.895 for men). Dietary variables differed markedly by age and sex. After adjustment for these factors and for multiple testing, we found significant differences between WHR4 and WHR1 for 19 of 30 dietary variables. Central obesity was associated with a lower intake of any bread, and of whole-grain bread in particular. Intake of fruits and berries, vegetables, and pasta and rice was less, and intake of sausages and hamburgers and boiled potatoes was more frequent. Intake of alcohol, tea, and fruit juice was lower in those with central obesity, whereas intake of sugar-free soft drinks and coffee was higher. The frequency of breakfast and lunch was lower and of nightly meals was higher in those with central obesity. In conclusion, in this large area-based population, central obesity was associated with differences in dietary habits, some of which (such as decreased consumption of whole-grain bread and increased intake of sugar-free drinks) are of possible clinical significance.

To measure effects of fish oil supplements on lipoprotein subclasses by nuclear magnetic resonance (NMR) in subjects with type II diabetes and relate them to insulin sensitivity.Two-armed, parallel, placebo-controlled, randomized.Normotriglyceridemic subjects with type II diabetes without insulin treatment were given either fish oil (n=12, median intake 5.9 g/day total n-3 fatty acids (FA) (1.8 g 20:5n-3, 3.0 g 22:6n-3)) or corn oil (n=14, 8.5 g/day 18:2n-6 FA).Size and concentration of lipoproteins subclasses were measured by NMR, insulin sensitivity by hyperinsulinemic, isoglycemic clamps.After 9 weeks, there were differences between those treated with fish and corn oil with respect to very low-density lipoprotein (VLDL) size (median -15 vs +0.6%, P=0.001), particle concentrations of large VLDL (-99 vs -4.1%, P=0.041) and small high-density lipoprotein (HDL) (-12 vs +10%, P=0.051). Compared with corn oil fish oil tended to increase HDL size and small low-density lipoprotein (LDL) concentration (P=0.063 and 0.068, respectively, for differences between groups). There was no effect on oxidized LDL. Insulin sensitivity (glucose utilization) decreased in the fish oil group compared with the corn oil group (P=0.049). The decrease in insulin sensitivity did not correlate with the effects on lipoprotein subclasses.A high intake of n-3 FA exerts effects on several lipoprotein subclasses without obvious influence from changes in insulin sensitivity.

Alpha-linolenic acid deficiency is described in four adults fed by gastric tube. In plasmaand erythrocytes,total lipid 20:3n-9 was slightly increased but total n-6 fatty acids, arachidonic acid, and dihomo-gammalinolenic acid were normal. Total n-3 fatty acids, l8:3n-3, 20:5n-3, 22:5n-3, and 22:6n-3 were decreased in both plasma and erythrocytes. Patients had a slight but definite scaly dermatitis, which disappearedwith essential fatty acids supplementation.Simultaneously, levelsof 18:3n-3, 20:5n-3, 22:5n-3, 22:6n-3, 20:3n-9, and total n-3 fatty acids became normal while l8:2n-6, 20:3n-6, 20:4n-6, and total n-6 acidswere unchangedor slightly lowered.Estimated minimal daily requirement of linolenic acid and of long-chain unsaturated n-3 acidsin adults is �0.2-0.3% and 0.1-0.2%, respectively,of total energyintake. Resultssuggestthat conversionof linolenic acid to 22:6n-3 is increasedin linolenic acid deficiency. Am I Clin Nuir l987;45:66-77.