The arachidonic acid content of the Australian diet is lower than previously estimated

Linoleic acid [18:2(n-6)] is the most abundant polyunsaturated fatty acid in the Western diet and is considered to be the primary source of tissue arachidonic acid [20:4(n-6)]. Dietary 20:4(n-6) may also contribute to tissue 20:4(n-6) levels in humans, but the extent of this contribution is unclear. We believe that literature estimates of 20:4(n-6) intake of 200-1000 mg/d are too high, possibly because of incorrect values in food composition tables where high amounts of 20:4(n-6) are recorded in margarines, some vegetable products and animal fat. We assessed the 20:4(n-6) content of common Australian foods and found that the 20:4(n-6) levels (on a 100-g edible basis), were 891 mg and 390 mg, respectively, for duck and chicken egg yolks, 294 mg for liver, 153 mg for kidney, 75 mg for skinless turkey, 56 mg for lean pork, 49 mg for lean lamb, 31 mg for chicken breast, 56 mg for chicken legs and 35 mg for lean beef. Eicosapentaenoic acid [20:5(n-3)] levels were < 10 mg/100 g in chicken meat, turkey meat, emu meat and chicken eggs, whereas the values for 20:5(n-3) for beef, lamb, liver, kidney and duck egg yolk ranged from 11 to 138 mg/100 g food. Applying our current 20:4(n-6) measurements to previously determined food intakes of Australian adults determined in an Australiawide survey in 1983, we estimated the mean 20:4(n-6) intake for Australian adult males to be 130 mg/d and females 96 mg/d. Whether such intakes of dietary 20:4(n-6) make an important contribution to tissue 20:4(n-6) levels is uncertain.