Effect of a Single High-Fat Meal and Vitamins on the Circulatory Response to Local Heat in Koreans and Caucasians

Blood flow mediated by the vascular endothelium plays an important role in removing heat from the skin. Asians who have thrifty genes have impaired endothelial function (EF) due to the westernized high fat (HF) dietary lifestyle. Hypertriglyceridemia (HTG) can produce free radicals which reduces the bioavailability of the endothelium derived relaxing factor, nitric oxide (NO). EF, as measured by the blood flow response (BFR) to heat, occlusion and the free radical concentration after a single HF meal has not been studied in Korean-Asians compared to Caucasians. The purpose of this study was to evaluate baseline and postprandial EF as related to oxidative stress from a single HF and low fat (LF) meal and the effects of vitamins on scavenging free radicals and improving EF in Korean-Asians compared to Caucasians. This was done by assessing skin BFR to vascular occlusion and local heat and analyzing malondialdehyde (MDA) levels after ingestion of a HF and LF meal before and after vitamin intake.;Ten Caucasians and ten Koreans participated in the study (mean age 25.3 +/- 3.6 years). BFR to vascular occlusion and local heat and oxidative stress was assessed after a single HF and LF meal at 2 hours compared to baseline. After administration of vitamins (1000mg vitamin C, 800IU vitamin E, and 300mg Coenzyme Q-10) for 14 days, the same measurements were repeated.;The results of this investigation showed that the skin BFR to vascular occlusion and local heat at baseline was significantly lower in Koreans than Caucasians. The skin BFR to vascular occlusion and local heat following a HF meal significantly decreased and free radicals significantly increased at 2 hours compared to baseline in Koreans (p<.001), but not in Caucasians. Also, the skin BFR to vascular occlusion (p=0.001) and local heat (p=0.003) was significantly lower and free radicals (p=0.004) were significantly higher at 2 hours after the HF meal in Koreans than Caucasians. When vitamins were given, the BFR to vascular occlusion and local heat before and after HF meal was not significantly different in both Koreans and Caucasians.;These findings suggest that Koreans may have lower EF than Caucasians which may be explained, in part, by genetic variation. Also, even a single HF meal can reduce EF through an oxidative stress mechanism but can be blocked by antioxidant vitamins in Koreans.;In conclusion, Korean-Asians are probably more susceptible to skin damage during heat application due to lower endothelial function compared to Caucasians if Koreans eat high fat foods. However, reduced endothelial function may be prevented by taking antioxidant vitamins.