Involvement of dietary Fatty acids in multiple biological and psychological functions, in morbidly obese subjects.

BACKGROUND: Fatty acid (FA) profile is often altered, in morbidly obese subjects, both before and after bariatric surgery. We measured FA plasma levels before and 6 months after Roux-en-Y gastric bypass (RYGB), in order to evaluate their relationship with different biological and psychological parameters and the impact of RYGB on the FA plasma levels.
METHODS: Thirty eight morbidly obese patients were investigated before RYGB, and 28 of them were reexamined 6 months postoperatively. Anxiety, depression, and quality of life were evaluated by validated questionnaires. Plasma FA (saturated, monounsaturated, polyunsaturated ω-6 and ω-3), vitamins A and E, fasting insulinemia, and high-sensitive C-reactive protein (hs-CRP) were measured.
RESULTS: Before surgery, ω-3 polyunsaturated FA and vit A showed significant negative relationship with fasting insulinemia (γ-linolenic p = 0.03, eicosapentaenoic, vit A p = 0.01) and hs-CRP (eicosapentaenoic p = 0.03, vit A p = 0.02) and a positive link with HDL cholesterol (γ-linolenic p = 0.03, vit A p = 0.02). Depression score was significantly and negatively linked with palmitoleic (p = 0.03), γ-linolenic (p = 0.006), dihomo-γ-linolenic (p = 0.02), and α-linolenic (p = 0.03) acids. After surgery, FA and both vit A and E were significantly reduced. Vit A levels were below 2.4 μmol/l in 63 % of the patients, preoperatively, and in 79 % after surgery. Preoperative levels of linoleic acid were significantly related with the postoperative weight reduction (p = 0.0006).
CONCLUSIONS: FA are involved in several biological and psychological functions. The RYGB-induced reduction of FA could have deleterious consequences on vitamin absorption, metabolism, and depression. Thus, the surveillance of FA levels is of primary importance both before and after RYGB.