Effect of Dietary Intake of n-6 and n-3 Polyunsaturated Fatty Acids on Speed and Power in Humans
Dr. Kevin Cole, Hope College
While there is evidence that manipulation of dietary fats has an effect on endurance performance, there has been little research examining the effect on sprinting or muscle power. Most of the evidence for this possibility comes from studies demonstrating a strong relationship between n-6 polyunsaturated fatty acid (PUFA) content of various mammalian, reptilian and fish muscles and maximum speed. The possibility of this relationship existing in humans is enticing and warrants further study. Therefore, the purpose of this study was to compare the performance effects of ingesting a nutritional supplement containing a high percentage of n-6 PUFA to one containing a high percentage of n-3 PUFA to determine if the type of fatty acid ingested has an effect on sprinting speed, leg power, and maximal aerobic capacity in humans. Eighteen fit college-age students were recruited for the study. All subjects completed a battery of pre-test measurements to assess speed (40m dash), anaerobic power (vertical jump test and Wingate cycle test) and aerobic capacity (VO2max test). Subjects were randomly assigned to either a high n-6 PUFA supplement group or a high n-3 PUFA supplement group in a double blind manner. For three weeks subjects ingested two capsules per day containing either 1000mg flaxseed oil (high n-3) or 1000mg borage oil (high n-6) and then repeated the pre-test measurements. There were no significant differences between the two groups for Wingate test peak power or mean power, vertical jump height or 40m dash times. There was a significant interaction effect for VO2max (p<0.05) as the n-6 PUFA group improved while the n-3 PUFA group did not. These results suggest that supplementation with n-6 PUFA may improve maximal aerobic capacity but does not affect measures of anaerobic power in humans.
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