Disturbances in essential fatty acid metabolism in patients receiving long-term home parenteral nutrition

Patients receiving home total parenteral nutrition (HTPN) are at risk for the development of essential fatty acid deficiency (EFAD). This study examined the essential fatty acid status of patients on long-term HTPN for gut failure. Serum phospholipid and triglyceride fatty acids were measured in 11 patients and 10 healthy volunteers. Patients had similar levels of linoleic acid (18:2w6) in serum triglyceride fatty acids but significantly lower levels of 18:2w6 in serum phospholipids compared to controls. Although there was accumulation of Mead acid (20:3w9) in both fatty acid fractions, the ratio of 20:3w9 to arachidonic acid (20:4w6) remained less than 0.2, reflecting an adequate essential fatty acid status in these patients. There were, however, substantial increases in 20:4w6 content in both triglyceride and phospholipid fractions in serum despite the lower levels of 18:2w6 in serum phospholipids, suggesting that an accelerated hepatic conversion of 18:2w6 to 20:4w6 occurs in HTPN patients, as well as the 20-carbon members of w3 (20:3w3) and w9 (20:3w9) families. The determination of optimal parenteral fat intakes should be investigated further as important priority in patients receiving long term HTPN.