EFFECTS OF INCREASING DIETARY PALMITOLEIC ACID COMPARED WITH PALMITICAND OLEIC ACIDS ON PLASMA-LIPIDS OF HYPERCHOLESTEROLEMIC MEN

Palmitoleic acid is a minor monounsaturated fatty acid in the human di et and in blood plasma. Because macadamia oil is at least one potentia lly large source of palmitoleic acid, we tested its effect on plasma l ipid levels against two other dietary fatty acids, oleic acid and palm itic acid. The dietary adjustments, through the use of supplements, pr ovided comparisons of the three test fatty acids in which palmitoleic could be judged as behaving either like a saturated or a monounsaturat ed acid. Thirty-four hypercholesterolemic men ate the three test diets in random order in 3-week periods. Plasma total cholesterol and low d ensity lipoprotein (LDL) cholesterol concentrations were similar with palmitic and palmitoleic acids and significantly higher than with olei c acid. High density lipoprotein (HDL) cholesterol was significantly l ower with palmitoleic than with palmitic acid. The study confirms that , at least in hypercholesterolemic men, a modest increase in palmitic acid (+4% en) raises LDL cholesterol relative to oleic acid (+3% en), even when dietary cholesterol is low (< 165 mg/day). Palmitoleic acid( +4% en) behaves like a saturated and not a monounsaturated fatty acid in its effect on LDL cholesterol.