This invention aims at providing compositions and foods for improving lipid metabolism which improve the metabolism of lipids and thus are expected to contribute to the prevention and amelioration of hyperlipemia, obesity, atherosclerosis and the like. The invention provides compositions for improving lipid metabolism, compositions for preventing or treating hyperlipemia, compositions for preventing or treating obesity and foods for preventing or ameliorating hyperlipemia and obesity, which contain valine as an active ingredient.


> Non-human transgenic mammals expressing an n-3 desaturase gene

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