Low zinc levels increase fatigue during workouts, study says

• Active people who get too little zinc in their diets may run out of juice sooner than they should, new research suggests.
• The study found that when 14 active young men followed a 9-week diet low in zinc, their cardiovascular fitness dipped in comparison to their performance during 9 weeks on a zinc-fortified diet.
• The reason appears to be related to an enzyme in the body called carbonic anhydrase, which relies on zinc for proper functioning.
• The carbonic anhydrase enzymes in red blood cells help the body expel carbon dioxide, with the demand rising substantially during exercise.
• When men in the new study followed a low-zinc diet, these enzymes were less active.
• The result was that, during exercise, their bodies were less efficient at "getting rid of carbon dioxide," explained study author Henry C. Lukaski, a researcher with the U.S. Department of Agriculture's Human Nutrition Research Center in Grand Forks, North Dakota.
• He reports the findings in the American Journal of Clinical Nutrition.
• The new findings point to the importance of adequate zinc intake in a person's capacity for exercise, according to Lukaski.
• The best way to get enough zinc is through food, Lukaski told Reuters Health.
• Red meat and oysters are rich in the nutrient, while chicken and pork have lesser amounts.
• People who shun red meat, Lukaski said, should be careful to get enough zinc from sources such as fortified cereals and beans.
• The recommended zinc intake is 11 milligrams (mg) per day for men and 8 mg for women; because high levels of the mineral can be toxic, experts advise that adults take no more than 40 mg per day.
• The low-zinc diet provided 3.5 mg of the mineral per day through food, while the high-zinc diet comprised the same foods, but with a daily 15-mg zinc supplement.