Effects of a hypoenergetic diet rich in α-linolenic acid on fatty acid composition of serum phospholipids in overweight and obese patients with metabolic syndrome.

OBJECTIVE

Plant-derived α-linolenic acid (ALA) may exert cardioprotective effects. Dietary ALA can undergo desaturation and elongation to form long-chain ω-3 polyunsaturated fatty acids, but the extent to which this occurs in humans is unclear. The aim of the study was to examine the effects of an energy-restricted diet enriched with ALA on fatty acid composition of serum phospholipids in patients with metabolic syndrome.

METHODS

The present analysis compared the effects of a hypoenergetic diet high in ALA (3.4 g/d) with a control diet low in ALA (0.9 g/d) on fatty acid composition of serum phospholipids in 81 overweight or obese patients with features of metabolic syndrome.

RESULTS

After a 26-wk intervention, concentration of ALA in serum phospholipids remained constant in both diet groups. The control group had a significant decrease in serum phospholipid eicosapentaenoic acid concentration, although no significant intergroup difference was observed. Serum phospholipid docosahexaenoic acid concentration significantly decreased to a similar extent with both interventions. Additionally, both interventions significantly decreased serum phospholipid concentrations of palmitic acid, stearic acid, total saturated fatty acids, linoleic acid, total ω-6 and ω-3 polyunsaturated fatty acids, with no effect of diet group on these changes. Compared with the ALA diet, the control diet led to a significant increase in serum phospholipid oleic acid concentration.

CONCLUSIONS

Daily intake of 3.4 g of ALA during a 26-wk energy-restricted diet did not lead to an enrichment of serum phospholipids with ALA and did not increase eicosapentaenoic acid due to conversion. Additionally, dietary ALA was unable to compensate for a decrease in serum phospholipid docosahexaenoic acid.