Role Of Antioxidant Supplements On Inflammation Induced By A Low Carbohydrate, High Fat Diet

Abstract

We previously observed an increase in systemic inflammation (C-reactive protein, CRP) in overweight individuals consuming a high fat, low carbohydrate, low antioxidant (HF) diet and a decrease in those consuming a low fat (LF) weight loss diet. PURPOSE To determine whether dietary antioxidants influence the inflammatory response to HF diet. METHODS Nineteen overweight subjects, BMI 34.06 ± 7.7 (SD), were provided with all food for a HF for 7 d (16 kcals/kg, 63% fat, 6% carbohydrate, and 31% protein). Half consumed an antioxidant supplement (AS), (1g Vitamin C, 800I.U. Vit. E) while the others a placebo (P). Serum inflammatory markers (Interleukin-6, IL-6; CRP) and glucose as well as a marker of oxidative stress (urinary 8-epi-prostaglandinF2α, 8-epi) were measured at baseline and on day 8. RESULTS Both groups lost a similar amount of weight (AS −3.0kg, P −3.6kg, p < 0.001). There was a 32% non-significant decrease in CRP for AS (2.63 ± 4.08 mg/L to 1.80 ± 1.77) and 50% increase for P (2.66 ± 1.55mg/L to 3.98 ± 3.43) after 7 days (p = 0.119 for group × time interaction). IL-6 tended to decrease 15% for both groups (p = 0.17) and glucose decreased 19% over time (p<0.001). There were no significant changes in 8-epi for either group. HF resulted in increased levels of inflammation (CRP) which was prevented if a dietary antioxidant was also consumed, suggesting that the inflammation was due to an oxidative stress mechanism. However, lack of change in the oxidative stress marker suggests more research, including additional measures of other markers, is required to prove this hypothesis. CONCLUSION The inflammatory response to a HF diet was not observed when the diet was supplemented with antioxidants.