Fatty acid composition of French butters, with special emphasis on conjugated linoleic acid (CLA) isomers

Conjugated linoleic acids (CLA) are fatty acids primarily found in dairy products. These fatty acids may have potential biological properties interesting for human health. Update of French food composition data banks was needed to determine CLA levels in French dairy products and to evaluate CLA intake by the French population. As part of this investigation, we analyzed 54 butters from local producers at different times of the year. The average CLA levels in butter were 0.45 g CLA/100 g butter in winter, 0.58 in spring, and 0.80 in summer. Regional variations of CLA levels in butters were observed from different producing areas in France. Butters from hill and mountain regions, and butters from Normandy, a prairie land, showed the highest annual average CLA levels and the largest magnitudes of variations from winter to summer. During the study, we also analyzed the total fatty acid composition of the butters, including the seasonal and regional variations. Butters produced from summer milks contained more unsaturated long chain fatty acids and less saturated middle chain fatty acids than the winter butters. Butters from mountain areas and from Normandy (prairie) showed larger differences from winter to summer than those from other prairie lands. These differences may be due to the polyunsaturated fatty acid levels, and especially to the linoleic acid levels, in the cow diets.