The ability of fish oil to suppress tumor necrosis factor alpha production by peripheral blood mononuclear cells in healthy men is associated with polymorphisms in genes that influence tumor necrosis factor alpha production.

BACKGROUND

Tumor necrosis factor alpha (TNF-alpha) mediates inflammation. High TNF-alpha production has adverse effects during disease. Polymorphisms in the TNF-alpha and lymphotoxin alpha genes influence TNF-alpha production. Fish oil suppresses TNF-alpha production and has variable antiinflammatory effects on disease.

OBJECTIVE

We examined the relation between TNF-alpha and lymphotoxin alpha genotypes and the ability of dietary fish oil to suppress TNF-alpha production by peripheral blood mononuclear cells (PBMCs) in healthy men.

DESIGN

Polymorphisms in the TNF-alpha (TNF1 and TNF2) and lymphotoxin alpha (TNFB1 and TNFB2) genes were determined in 111 healthy young men. TNF-alpha production by endotoxin-stimulated PBMCs was measured before and 12 wk after dietary supplementation with fish oil (6 g/d).

RESULTS

Homozygosity for TNFB2 was 2.5 times more frequent in the highest than in the lowest tertile of inherent TNF-alpha production. The percentage of subjects in whom fish oil suppressed TNF-alpha production was lowest (22%) in the lowest tertile and doubled with each ascending tertile. In the highest and lowest tertiles, mean TNF-alpha production decreased by 43% (P < 0.05) and increased by 160% (P < 0.05), respectively. In the lowest tertile of TNF-alpha production, only TNFB1/TNFB*2 heterozygous subjects were responsive to the suppressive effect of fish oil. In the middle tertile, this genotype was 6 times more frequent than the other lymphotoxin alpha genotypes among responsive individuals. In the highest tertile, responsiveness to fish oil appeared unrelated to lymphotoxin alpha genotype.

CONCLUSION

The ability of fish oil to decrease TNF-alpha production is influenced by inherent TNF-alpha production and by polymorphisms in the TNF-alpha and lymphotoxin alpha genes.