If you give women 3 g of fish oil daily in capsule form, the fat around their middle shrinks. Researchers at Inserm in France discovered this when they did a two-month-long experiment with thirty women who had diabetes-2.
Fatty acids derived from fish delay the growth of fat cells. If you take fish oil capsules – or eat fish often – while dieting, your weight loss will progress more quickly. Weight loss through exercise also goes faster if you increase the amount of fish oil you take. The effect occurs because fish fatty acids enhance fat burning in the muscles.
Many of the positive results obtained with fish fatty acids by other researchers were the result of high doses, however. The French researchers decided to see whether a more modest amount of supplement – around 3 g of fish oil per day – would have an effect. This amounts to three large capsules per day. In the experiment, the three capsules that the test subjects took provided a daily dose of 1.8 g of n 3-fatty acids. [1.1 g EPA en 0.7 g DHA.]
Half of the women were given fish oil capsules. The other half got a placebo. The effects of the pills are shown below. NS = not statistically significant. Where figures appear in the table the effect was significant.
The fish oil capsule users lost an average of one kilogram; the placebo group remained the same weight. The effect was not statistically significant. But the total fat mass of the fish-oil users decreased, and that effect was statistically significant.
The decrease in fat is especially noticeable in the trunk.
The researchers were particularly interested in sensitivity to insulin. That did not change, but taking fish oil supplements seems to reduce the risk of a heart attack. Taking a supplement halved the amount of the ‘heart attack protein’ PAI-1 in the blood. The higher the level of PAI-1 in your blood, the greater the chance of your having a heart attack. In the placebo group the concentration of PAI-1 increased from 16.9 to 19.2 IE per milliliter, whereas in the fish oil group the concentration decreased from 18.9 to 9.5 IE per milliliter.
The supplement reduced the activity of inflammatory genes in the women’s fat cells, the researchers discovered. According to the French, this molecular effect is the cause of the health effects that were observed.
Treatment for 2 mo with n 3 polyunsaturated fatty acids reduces adiposity and some atherogenic factors but does not improve insulin sensitivity in women with type 2 diabetes: a randomized controlled study.
Abstract
BACKGROUND:
Information is lacking on the potential effect of n-3 polyunsaturated fatty acids (PUFAs) on the adipose tissue of patients with type 2 diabetes.
OBJECTIVE:
We evaluated whether n-3 PUFAs have additional effects on adiposity, insulin sensitivity, adipose tissue function (production of adipokines and inflammatory and atherogenic factors), and gene expression in type 2 diabetes.
DESIGN:
Twenty-seven women with type 2 diabetes without hypertriglyceridemia were randomly allocated in a double-blind parallel design to 2 mo of 3 g/d of either fish oil (1.8 g n-3 PUFAs) or placebo (paraffin oil).
RESULTS:
Although body weight and energy intake measured by use of a food diary were unchanged, total fat mass (P < 0.019) and subcutaneous adipocyte diameter (P < 0.0018) were lower in the fish oil group than in the placebo group. Insulin sensitivity was not significantly different between the 2 groups (measured by homeostasis model assessment in all patients and by euglycemic-hyperinsulinemic clamp in a subgroup of 5 patients per group). By contrast, atherogenic risk factors, including plasma triacylglycerol (P < 0.03), the ratio of triacylglycerol to HDL cholesterol (atherogenic index, P < 0.03), and plasma plasminogen activator inhibitor-1 (P < 0.01), were lower in the fish oil group than in the placebo group. In addition, a subset of inflammation-related genes was reduced in subcutaneous adipose tissue after the fish oil, but not the placebo, treatment.
CONCLUSIONS:
A moderate dose of n-3 PUFAs for 2 mo reduced adiposity and atherogenic markers without deterioration of insulin sensitivity in subjects with type 2 diabetes. Some adipose tissue inflammation-related genes were also reduced. These beneficial effects could be linked to morphologic and inflammatory changes in adipose tissue. This trial was registered at clinicaltrials.gov as NCT0037.
PMID: 18065585 [PubMed - indexed for MEDLINE]
Sources: http://www.ncbi.nlm.nih.gov/pubmed/18065585
