Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2004
Publication Date: March 7, 2005
Citation: Lukaski, H.C., Johnson, P.E. 2005. Dietary copper (Cu) at the recommended intake decreases muscle cytochrome c oxidase (CCO) activity and alters metabolic responses during exercise in men [abstract]. The Federation of American Societies for Experimental Biology Journal. 19(5):A982. Technical Abstract: Emphasis by public health organizations to increase physical activity and consume balanced diets to promote health and well-being raise the question of adequacy of nutrient recommendations to support increased energy output. Analyses of usual diets indicate that Cu intake is less than dietary reference intake recommendations for a significant percentage of US adults. If dietary Cu is limiting, then Cu status and activities of Cu containing enzymes including CCO, a key regulator of mitochondrial energy production, would be decreased with impaired physiological function. This study tested the hypothesis that marginal compared to supplemental Cu intake decreases CCO activity in muscle and adversely affects metabolic responses during exercise. Nine men (27-38 y) resided on a metabolic unit and consumed whole food diets that contained adequate (1.5 mg/2500 kcal/d) then marginal Cu (0.7 mg/2500 kcal/d) for 7 wks each. Marginal Cu increased (p<0.05) heart rate (144 vs 138 bpm), ventilation (62 vs 56 L/min), oxygen uptake (1.99 vs 1.69 L/min), energy cost (135 vs 120 kcal), anaerobic metabolism (53 vs 39%), and plasma lactate (5.8 vs 3.4 mmol/L) during exercise (50% peak VO2 for 15 min). Muscle CCO activity (5.2 vs 7.4 µmol/min/g), plasma Cu (12 vs 15 µmol/L), ceruloplasmin activity (38 vs 30 mg/dL), and muscle Cu (1140 vs 910 ng/g) decreased (p<0.05) with marginal Cu. Hemoglobin was unaffected by dietary Cu. These findings indicate that marginal dietary Cu decreases muscle CCO activity and impairs cardiorespiratory function during submaximal exercise.