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 a cid 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 contri bute to tissue 20:4(n-6) levels in humans, but the extent of this cont ribution 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 v alues in food composition tables where high amounts of 20: 4(n-6) are recorded in margarines, some vegetable products and animal fat. We ass essed 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 f or 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 m g/100 g in chicken meat, turkey meat, emu meat and chicken eggs, where as 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 a dults 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 fe males 96 mg/d. Whether such intakes of dietary 20:4(n-6) make an impor tant contribution to tissue 20:4(n-6) levels is uncertain.