Concentrations of n-3 and n-6 fatty acids in Dutch bovine milk fat and their contribution to human dietary intake

Abstract

Weekly samples representative of Dutch milk were analyzed for concentrations of n-3 and n-6 fatty acids (FA). Concentrations of the n-3 FA α-linolenic acid (ALA), eicosatetraenoic acid, eicosapentaenoic acid, and docosapentaenoic acid were 0.495±0.027, 0.041±0.004, 0.067±0.005, and 0.086±0.008g per 100g of fat, respectively, whereas docosahexaenoic acid was absent or present in concentrations lower than 0.020g per 100g of fat. Concentrations of the n-6 FA linoleic acid (LeA), γ-linoleic acid, dihomo-γ-linoleic acid, and arachidonic acid were 1.428±0.068, 0.070±0.007, 0.066±0.004, and 0.089±0.004g per 100g of fat, respectively; adrenic acid was present in concentrations lower than 0.020g per 100g of fat, whereas docosapentaenoic acid was absent in all samples. The concentrations of ALA and LeA were significantly higher in spring and summer, compared with autumn and winter. The concentrations of all other ALA- and LeA-derived n-3 and n-6 FA were not significantly different between seasons. The contribution of milk fat to the daily intake of eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid was calculated for human consumption levels in different countries. Milk fat contributed between 10.7 and 14.1% to the daily intake of eicosapentaenoic acid and between 23.5 and 34.2% to the intake of docosapentaenoic acid; whereas docosahexaenoic acid contribution was marginal. Arachidonic acid from milk fat contributed between 10.5 and 18.8% to the human intake of n-6 FA.