Effects of diets high in Peanuts-Peanut Butter (P/PB) and Peanut Oil (PO) on the susceptibility of LDL to oxidative modification

Oxidation of LDL is thought to be a causative factor in the development of CHD. Some studies show LDL enriched in PUFA to be more susceptible to oxidation than LDL enriched in MUFA, but studies using P/PB or PO as a PUFA source have not yet been performed. Since recent studies suggest a protective effect of frequent nut consumption against CHD, we used a randomized, double-blind, five-period crossover design (n=22) to study the effects of the following diets on LDL-ox: average American (35% fat, 15% SFA), low-fat (25% fat, 7% SFA), P/PB (35% fat, 7% SFA), PO (35% fat, 7% SFA), and olive oil (35% fat, 6% SFA). LDL-ox was measured spectrophotometrically by the formation of conjugated dienes at a wavelength of 234 nm. There was no difference in lag time or maximum diene production among diet groups. The lower rate of oxidation (nmol dienes/min/mg LDL protein) for the olive oil (OO) diet (20.5 ± 1.3; lsmean ± SE) versus the PO diet (24.7 ± 1.2; p<0.08) and the P/PB diet (24.7 ± 1.2; p<0.09) was likely due to a lower LDL PUFA content. Further studies are needed to determine whether P/PB and PO have unique antioxidants that protect against the initiation of LDL oxidation (i.e., lag time).