Fitness Q & A

Can omega-3 fatty acids reduce the risk of heart disease?

A variety of health benefits have been attributed to the consumption of omega-3 fatty acids, including a reduced risk of coronary heart disease. But research that has looked at omega-3 fatty acids offers conflicting results. While some studies have found that consuming omega-3 fatty acids can decrease the risk of heart disease, other studies have found no benefit. These contradictory findings might be best summed up by the U.S. Food and Drug Administration (FDA), which notes that there's "supportive but not conclusive research" that omega-3 fatty acids "may reduce the risk of coronary heart disease."

Good sources of omega-3 fatty acids are fatty fish such as salmon and tuna. When taken in reasonable quantities, there doesn't appear to be any dangers from consuming omega-3 fatty acids. The FDA has determined that intakes of up to 3 grams per day of omega-3 fatty acids are "generally recognized as safe."

The bottom line is that more consistent evidence must be shown to prove that there's a link between omega-3 fatty acids and a decreased risk of heart disease.

When performing crunches on a stability ball, does the position of the ball affect abdominal activity?

One of the most popular exercises to perform on a stability ball is the abdominal crunch. In one study, 41 subjects performed a crunch on a stability ball in two different positions: one in which the ball was placed high, near the bottom part of their shoulders, and the other in which the ball was placed low, near their lumbar area. At each of the two positions, the subjects performed one set of eight to 10 repetitions using the same speed (three seconds per repetition) and range of motion.

Researchers found that performing the crunch with the stability ball positioned low, near the lumbar area, produced significantly greater electromyographic (EMG) activity in the abdominal muscles (the upper rectus abdominis, lower rectus abdominis and external oblique) than when it was placed high, near the shoulders. In fact, the values were nearly twice as much. So, correct placement of the stability ball appears to be crucial.

Incidentally, the study also found that performing a crunch while positioned low on a stability ball had significantly more EMG activity in the abdominal muscles than performing a traditional crunch on the floor. Performing a crunch while positioned high on a stability ball had significantly less EMG activity in the abdominal muscles than performing a traditional crunch on the floor.

Does vitamin C prevent or treat the common cold?

For many decades, it has been thought that vitamin C can aid in the prevention and treatment of the common cold. Interest in vitamin C was spurred by the work of Linus Pauling, who won Nobel prizes in chemistry and peace.

In an exhaustive review of the literature, researchers pooled the data from studies in which subjects were given at least 0.2 grams of vitamin C per day, and compared the treatment to a placebo. In 33 studies that involved 11,350 subjects, vitamin C didn't reduce the risk of developing a cold; in 30 studies that involved 9,676 subjects, vitamin C reduced the duration of colds slightly; in seven studies that involved 3,294 subjects, vitamin C wasn't significantly better than a placebo after the onset of symptoms; and in four studies that involved 2,753 subjects, vitamin C wasn't significantly better than a placebo in reducing cold severity.

The review did find evidence that taking vitamin C was beneficial by those who were exposed to brief periods of severe exercise or cold environments (such as marathon runners and skiers). Vitamin C appears to be safe in dosages of up to several grams per day.

Researchers concluded that "there seems [to be] no justification for routine vitamin C supplementation in the normal population."

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