Effects of monounsaturated fatty acids (MUFA) and weight loss on cardiovascular (CV) risk factors in obese NIDDM

CV risk is higher in NIDDM than accounted for by standard CV risk factors. This may be due to altered LDL composition and its susceptibility to oxidation (Ox). Since diet composition modulates LDL-Ox, CV risk factors were assessed in obese NIDDM patients treated with high MUFA (70% of calories, n=9) vs high carbohydrate (CHO; 70% of calories, n=8) formula diets: 6 weeks at 5096 caloric deficit, then 4 weeks isocaloric. Fasting glucose (FBS; mM), LDL (mg/dl), triglycerides (TG; mg/dl), HDL (mg/dl) and LDL fatty acid composition (%) were measured. LDL was isolated and the delay in rapid Ox of LDL (min) after copper exposure was measured. Results: (mean±SEM; p<.05: * vs pre; # MUFA vs CHO): Weight loss in MUFA & CHO (-8±1 & -10.±1 kg) was similar. CHO: pre diet refeed MUFA: pre diet refeed FBS* 11.2±.7 8.8.± 1.4* 9.1±1.5 12.6±1.1 8.0±1.1# 8.5±1.1# LDL 98±16 92±13 99±16 119.± 15 102.± 12 96±7 * # HDL 37±3 31±2 * 31±3 37±2 36±2 37±2 TG 198.±24 171±38 185.±23 250±30 102±19 * 117.±29* # LDL-Ox 155±14 162±16 146±31 152±14 208±29 #220± 13* # The 18:1 LDL fatty acid content correlated with LDL-Ox (diet: r=.74; refeed: r=.93; both p<.001). Summary: Both diets decreased weight and FBS. LDL and TG decreased and LDL-Ox increased with the MUFA formula, while HDL was unchanged. In contrast, LDL, TG and LDL-Ox were unchanged, and HDL decreased with the CHO formula. Conclusions: Hypocaloric MUFA-enriched diets have more beneficial effects on reducing CV risk factors in obese NIDDM than low-fat, CHO-enriched hypocaloric diets. These benefits may be sustained long-term with MUFA-enriched isocaloric diets.