ABSTRACT
We investigated the effects of habitual exercise and diet restriction on the hepatic fat accumulation in Zucker fatty rats. Male 6-week-old Zucker fatty rats were divided into obese (Ob), diet restriction (DR), and diet restriction + exercise (DR + Ex) groups. Male Zucker lean rats (L) were used as a control group. The rats in the L and Ob groups were maintained on ad libitum diets. The rats in the DR and DR + Ex groups were fed a 30% restricted diet. The rats in the DR + Ex group exercised voluntarily on a wheel ergometer. After 6 weeks of intervention, the serum free fatty acid and leptin levels in the Ob group were significantly higher than those in the L group. In the Ob group, the hepatic triglyceride content was higher than that in the L group and hepatocyte fat infiltration was observed on haematoxylin and eosin staining. These changes were suppressed by DR + Ex, but not by the DR intervention. These results suggest that habitual exercise inhibits fat accumulation in the liver of Zucker fatty rats.
ABSTRACT
The objective of this study was to examine whether the combination of n-3 polyunsaturated fatty acids PUFA) supplementation and physical exercise training would decrease oxidative stress in comparison with n-3 PUFA supplementation only in humans. Eighteen women college students were divided into a perilla oil supplemented control group or a perilla oil supplemented physical exercise trained group throughout the experimental period of 4 weeks. After the intervention in both groups, plasma triglyceride levels were decreased. Serum thiobarbituric acid reactive substances (TBARS) level in the control group was increased by n-3 PUFA supplementation. In the trained group, however, TBARS level was unchanged. Plasma vitamin C level in the trained group was significantly decreased by n-3 PUFA supplementation. These results suggest that the combination of n-3 PUFA supplementation and physical exercise training might result in attenuated tissue damage induced by reactive oxygen species, if appropriate daily antioxidants, especially vitamin C, were provided.
ABSTRACT
N-3 polyunsaturated fatty acid supplementation has been recognized to affect the peripheral oxygen delivery system with increasing blood rheology. The purpose of the present study was to investigate whether n-3 polyunsaturated fatty acid supplementation, using purified perilla oil rich in α-linoleic acid, improves aerobic capacity in young women. Eighteen young, sedentary female college students were divided into an n-3 polyunsaturated fatty acid supplemented control group (PUFA-C, n=10) and an n-3 polyunsaturated fatty acid supplemented trained group (PUFA-T, n=8). All subjects took 20g of perilla oil (11g of n-3 polyunsaturated fatty acid) in addition to the usual diet throughout the experimental period of 4 weeks. PUFA-T subjects exercised for 30 min on a bicycle ergometer (intensity, 60% of VO<sub>2</sub>max) 4 times a week for 4 weeks. Maximal oxygen uptake (VO<sub>2</sub>max) and oxygen uptake at the ventilatory anaerobic threshold level (VT) significantly (p<0.05) increased after treatment in both groups. However, the endurance time in the exhaustive exercise test significantly (p<0.05) increased in the PUFA-T group only. Increasing rates of VO<sub>2</sub>max and VT with treatment for the PUFA-C group were lower than those for the PUFA-T group (VO<sub>2</sub>max, 12.6% vs 14.4%, VT, 9.7% vs 16.9%). After treatment, these values returned to baseline levels within 2 months of the recovery period without n-3 polyunsaturated fatty acid supplementation in both groups. Only for the PUFA-T group, VO<sub>2</sub>max and VT at 2 months after the treatment period were significantly (p<0.05) higher compared with baseline levels. These results suggest that n-3 polyunsaturated fatty acid supplementation might have a beneficial effect on improving aerobic capacity with increasing peripheral oxygen delivery. However, n-3 polyunsaturated fatty acid supplementation was less effective than aerobic training.