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Alex Hutchinson draws on the latest research to answer your fitness and workout questions in this biweekly column on the science of sport.

Last summer, researchers at the Salk Institute for Biological Studies in California made a splash by announcing an exercise pill that allowed mice to gain the benefits of vigorous exercise - all without setting a paw on their exercise wheels. That era hasn't yet arrived for humans, but strolling down the aisle of any drugstore makes it clear that we're very interested in pills whose claims include faster, higher and stronger.

With a few exceptions, if you're eating a healthy, balanced diet, there's very little evidence that any (legal) pill you pop will make you a better athlete. But there's hope: New research is constantly emerging, as the links between nutrition and physical activity become clearer. In the first part of a two-part series, we look at the hard data behind some currently popular supplements.

OMEGA-3 FATTY ACIDS

Used for: Endurance

The Claim:

Omega-3 fatty acids are found in fish such as salmon and tuna and (in a less usable form) in plants such as flax and canola. Because they have well-established effects on the cardiovascular system, researchers have hypothesized that they should improve endurance.

The Evidence:

The most recent look at this idea comes in a forthcoming issue of the Journal of Science and Medicine in Sport. Researchers from the University of South Australia studied a team of Aussie Rules football players who were given six grams of either an omega-3-rich fish oil or a sunflower oil placebo. After five weeks, as expected, the fish oil group lowered a host of cardiovascular markers. They also lowered their heart rate during a run to exhaustion on a treadmill - but they didn't actually improve their performance.

The Verdict: FALSE.

The amount of omega-3 fatty acid we get in a typical Western diet - equivalent to a fish meal about every 10 days - isn't sufficient. Eat more fatty fish or take fish oil (rather than plant oil) supplements. But don't count on a performance boost.

CREATINE

Used for: Strength

The Claim:

Creatine is a compound that occurs naturally in meat, and is well-known to those hoping to pack on muscle in the weight room. Its effects are quickly apparent - though the kilogram or so of lean mass that people typically put on in the first week

is mainly intracellular water.

The Evidence:

A long list of studies have found that creatine enhances strength and mass gains when coupled with resistance training. But most of these studies didn't ensure that the control group was getting optimal protein and carbohydrate intake immediately after training. Mark Tarnopolsky and his colleagues at McMaster University Medical Centre were able to compare creatine use with protein and carbs. Their results: identical gains in strength, but greater gains in size for the creatine group.

The Verdict: TRUE.

If you want to get big and strong like a football lineman, you might consider creatine. But if you want to be strong as well as agile and fast, like a running back or a basketball player, skip it.

Dr. Tarnopolsky's group also found that adults 65 and over trying to maintain muscle mass through resistance training could benefit from a teaspoon of creatine with breakfast.

ANTIOXIDANTS

Used for: Endurance, Recovery

The Claim:

The logic seems sound: Endurance exercise requires large amounts of oxygen, which results in high levels of oxidative stress - those nasty free radicals that damage muscles and tire you out. So taking antioxidants such as vitamin A or C should slow that process down.

The Evidence:

Despite years of trying, no one has been able to make it work. Most recently, 63 runners in a 160-kilometre race in California received either an antioxidant

or a placebo. There were no differences in either race performance or blood tests for oxidative damage after the race. Even studies looking for accelerated recovery from exercise have been equivocal, unless the subjects were already suffering from a dietary deficiency.

The Verdict: FALSE.

The theory that free radicals cause aging, which has prevailed for decades, is currently in flux. Exercise scientists, too, are rethinking their understanding of the role of antioxidants. For now, getting plenty of fruit and vegetables remains as important as ever, but mega-dosing on A and C is out.

Alex Hutchinson blogs about research on exercise and athletic performance at http://www.SweatScience.com.

jockology@globeandmail.com

Science v. supplements