Fabulous fungus

Supplements from a Chinese fungus may help older and out-of-shape people feel more energized.

Supplements made from a Chinese fungus may help older and out-of-shape people feel a bit more energized, corporate researchers said on Monday.

They said people who took the supplements increased their ability to use oxygen as they exercised -- one way doctors measure fitness -- and were able to walk a mile slightly more quickly than those who took a placebo.

Jia-Shi Zhu and Dr. James Rippe of Pharmanex LLC and the Rippe Lifestyle Institute in Shrewsbury, Massachusetts, said their tests on 131 sedentary people aged 40 to 70 showed modest but clear effects.

After 12 weeks of taking Pharmanex's branded supplement, called Cordymax, peak oxygen consumption rose 5.5 percent when middle-aged people who had been sedentary used a treadmill or exercise bike, Zhu said. It rose 2.2 percent in the group that took dummy pills.

The supplement-takers also were able to walk a mile (1.6 km) 29 seconds more quickly and the placebo group took 19 seconds longer, on average, after the three months.

This suggests the product can help people get fitter, Zhu told a meeting of the American Physiological Society, part of a larger conference called Experimental Biology 2004.

Other studies have also shown the product can help regulate fat and sugar metabolism, he said.

But it does little for people in peak physical shape. "If you have normal glucose levels, you don't see any difference after taking this product," Zhu said in an interview.

The fungus, scientifically known as Cordyceps sinensis, is used in traditional Chinese medicine as an aphrodisiac and anti-aging agent. Some Chinese athletes use it in a bid to boost performance.

Zhu said the fungus infects a burrowing caterpillar, eating the creature until it dies. In the spring, a grasslike fungus sprouts from the underground corpse.

Zhu said he does not know what the active ingredient in the fungus is. He is also unsure just how it boosts performance, although he speculated it may affect adenosine triphosphate, or ATP, the power source of cells.

In the study of 131 people, Zhu said those allergic to mushrooms experienced a mild rash, and others found the large capsules uncomfortable to swallow, but otherwise side-effects were minimal.

Pharmanex is a subsidiary of Nu Skin Enterprises.