Fatty acid composition of serum phospholipids in an elderly institutionalized Japanese population.

The fatty acid composition of serum phospholipids of 277 persons, aged 63-97 y (average 78 y), was measured. Subjects had been living independently in a facility with full food service for 1 y or more. Eleven saturated and unsaturated fatty acids were detected in all the subjects. Stearic acid (18:0) was positively (p = 0.028) and dihomo-gamma-linolenic acid (20:3 n-6) was negatively (p = 0.012) related to age. Arachidonic acid (20:4 n-6) tended to decline with age (p = 0.063). In addition, the oleic acid (18:1 n-9)/18:0 ratio decreased significantly with age (p = 0.024). 18:0 and total saturated fatty acids were lower, and linoleic acid (18:2 n-6) and 20:4 n-6 and n-6 fatty acids were higher in males than in females. These results suggest deficits in n-6 essential fatty acids as age advances, particularly in females.