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Sheila's Nutrition Digest Vol. 8 - Five Nutrition Myths Uncovered
By:  Sheila Kealey   (2005/07/29)

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Sheila's Nutrition Digest Series: In this new series, XC Ottawa member Sheila Kealey will help athletes choose the best foods for performance and overall health. Sheila has a Masters in Public Health and works in the field of nutritional epidemiology as a Research Associate with the University of California, San Diego.

If you find yourself confused with the dizzying amount of conflicting nutrition information out there, you are not alone. As an evolving science with competing interests, nutrition is prone to myths and misconceptions, leaving many individuals wondering if they're really optimizing their nutrition. Here are five common nutrition myths.


THE MYTH

Vitamins, minerals, and other supplements can make up for a poor diet.

THE FACT

If many of your meals are poor in nutrients and you rely on pills and supplements to keep you healthy, you might want to take a hard look at your diet. Although a multivitamin can fill a gap, or specific supplements are advisable for those with or at risk for deficiencies, for most individuals there is little scientific support of any benefit.

In fact, large amounts of vitamins and minerals can be a threat to good health, and recent studies have shown that supplements that were once thought to help fight disease may be harmful. For example, research shows that diets high in the antioxidant beta-carotene (found in colourful fruits and vegetables) may help prevent cancer and heart disease, but a large-scale study found that beta-carotene from supplements was actually harmful and increased cancer rates. Similarly, many physicians were recommending daily vitamin E supplements to lower heart disease risk, but results of a recent long-term study showed no benefit and possible cause for concern, since the group taking vitamin E supplements had higher risks of hospitalization for heart failure than the group taking placebo pills. Considering that most vitamins and supplements don't undergo such rigorous study (the vitamin E and beta-carotene studies were conducted with a large number of individuals over many years), you should really question what you're consuming.

In contrast to the supplement studies, an incredible amount of research supports the health benefits a diet of rich in vegetables, fruits, legumes, and whole grains. Nutrient-rich foods contain a balanced package of vitamins, minerals, and thousands of protective compounds - some that haven't even been isolated and put into pill form. These food work together to promote good health and can provide delicious meals and snacks.


THE MYTH

Caffeinated beverages will dehydrate you.

THE FACT

There is good news for those of you who don't want to forgo your morning cup of coffee on race morning. Although health experts cautioned for years that consuming caffeinated beverages could lead to dehydration, the latest review of the research challenges this advice. Early studies suggesting that caffeine increased urine output used high doses of caffeine over a short period of time, studying people who had abstained from caffeine before testing. But research looking at moderate caffeinated beverage consumption in regular caffeinated beverage drinkers found that urine output was similar to drinking the same amount of water. In addition, consumption of caffeinated beverages did not cause a fluid-electrolyte imbalance. Other research has shown that habitual caffeinated beverage consumers have increased tolerance to the diuretic effects of caffeine. So, if you're a regular cola, tea, or coffee drinker, changing your drinking habits probably isn't necessary, and you could actually negatively affect performance if you don't replace the caffeinated beverages you usually consume with other liquids.


THE MYTH

Skipping breakfast before morning exercise is a good way to burn fat.

THE FACT

Skipping breakfast does little to increase fat metabolism. Also, exercising on empty can be counterproductive to your training, especially if you're trying to do an intensity session or exercise for longer than an hour. When you wake up your liver glycogen stores are low: these stores are important to maintain your blood glucose levels. Low blood glucose can make you feel tired, lightheaded, uncoordinated, and unmotivated even when your muscle glycogen stores are topped off - not what you're looking for in a quality training session!

Foods rich in complex carbohydrates and low in protein, fat, and fiber are good pre-workout foods. You might prefer something liquid if you're eating within an hour of exercising. If you don't have time to eat at all, drink a sports drink while you're working out to provide carbohydrate that will help maintain normal blood glucose levels.


THE MYTH

Fresh fruits and vegetables are always more nutritious than frozen or canned.

THE FACT

Athletes don't need to let their busy schedules get in the way of getting the nutrients they need from fruits and vegetables. Stocking up on fresh and frozen produce means that you'll have these nutritious staples readily available when you've run out of fresh. Fortunately, you won't be sacrificing nutrition for convenience either.

Canned fruits and vegetables are picked and packed at the peak of ripeness when nutrient content is highest, cooked quickly at high temperatures, and sterilized to keep nutrients in and impurities out. For some vegetables, canning and heat processing actually enhances some nutrients: for example, the beta-carotene in canned carrots is more available to the body than from fresh carrots, and canned tomatoes have four times more of the antioxidant lycopene than the equivalent amount of fresh tomatoes.

Frozen fruits and vegetables are frozen at their peak, and their nutritional value is on par with and sometimes better than that of fresh produce, which can lose certain nutrients during storage.

While nothing beats the great flavors and textures of seasonal fresh fruits and vegetables, keeping a supply of frozen and canned produce on hand means you won't go without the important nutrients your body craves.


THE MYTH

A diet high in carbohydrates will make you fat.

THE FACT

Eating too many calories is what causes people to gain weight, not the specific ratio of carbohydrates, protein, and fat. While some blame carbohydrates for a number of health problems including obesity, diabetes, and heart disease, nutrition experts believe that for most individuals, carbohydrates should be the foundation of a nutritious diet.

If you avoid high carbohydrate foods you miss out on the important nutrients found in fruits, vegetables, and whole grains. Shunning carbohydrates can be especially detrimental to any athlete's training and performance, since carbohydrates replace depleted glycogen stores and fuel muscles for activity. If you still think carbohydrates can make athletes fat or negatively affect performance, check out the top Kenyans at the next running race you watch: their diets are reported to derive more than 70% of their calories from carbohydrates.

 
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