Macadamia or olive oil enriched diets induce changes in heart structure and function similar to regular exercise in rats.

Harrison, G.; Somerset, S.

Background - Previously, we found that the hearts of rats fed olive oil as a sole fat source developed non-pathological hypertrophy, characterised by larger left ventricular volumes, increased cardiac outputs, and a greater resistance to ischaemic stress. These changes are similar to those observed in 6-week exercise trained rats on a standard rat chow (SRC) diet. Objectives - to determine if dietary macadamia and olive oil (oleic acid rich), generate similar adaptations in heart physiology, and to test if such changes translate into an endurance advantage. Design - Rats were divided into 3 groups of 12 rats. Each group received one of three diets differing only in oil source. One group received a control diet (SRC), one group received a diet containing extra virgin olive oil, and one group received a diet containing macadamia oil. Each diet group of rats was further divided into two subgroups of 6 rats, one subgroup being run-trained for 30min/day run at 0.8km/h for 5 days on a treadmill. The other subgroup was left untrained. All rats were run challenged to exhaustion on the 6th day and rested on the 7th. After 7 weeks of diet with or without exercise training, rats underwent in vivo echocardiography to calculate cardiac function. Hearts were then isolated and perfused to examine tolerance to 20 min of ischemia followed by 30 min of reperfusion. Outcomes - Improved cardiac structure, endurance performance in vivo and recovery after ischaemia in animals fed macadamia or olive oil, compared to the control diet. Exercise did not appear additive to diet although macadamia fed animals had the highest exercise endurance times. Conclusions - These findings suggest macadamia oil confers similar beneficial effects on the cardiovascular system to those seen with olive oil. These favourable events resemble (but are not amplified by) those evoked by regular exercise in rats.

MACADAMIA; EDIBLE fats & oils; OLIVE oil; CARDIOVASCULAR system; EXERCISE; LABORATORY rats

Asia Pacific Journal of Clinical Nutrition, 2004, Vol 13, pS48

0964-7058

Academic Journal