Showing posts with label exercise. Show all posts
Showing posts with label exercise. Show all posts

Saturday, January 30, 2010


Your mother told you to eat your vegetables. You probably remind your children to do the same. The American Heart Association recommends eating eight or more servings of fruits and vegetables daily. The health benefits from fruits and vegetables range from reducing the risk of developing certain cancers to fighting heart disease. Some fruits, vegetables, and herbs can aid in the digestive process.

Grapefruit contains high amounts of vitamin C and smaller amounts of vitamins A, B complex, E, and K. This fruit contains large amounts of calcium, folic acid, phosphorus, and potassium. Though it contains citric acid, after digestion, grapefruit juice undergoes an alkaline reaction which has a positive effect in the treatment of acidity in the digestive system. Grapefruit juice increases the flow of gastric juices. In turn, it promotes digestion. High in fiber, grapefruit aids in maintaining bowel regularity. Grapefruit and grapefruit juice can cause potentially serious interactions with certain antidepressant and immunosuppressant medications, calcium channel blockers which are used to treat high blood pressure, and statins which are used to treat elevated cholesterol levels. People who are taking prescription medications should consult with their physicians regarding drug interactions.

Papaya is rich in antioxidants, vitamin B complex, potassium, and magnesium. It contains a digestive enzyme, papain, which is valuable for aiding the digestion of proteins. Papaya is a good source of fiber and is associated with reducing the risk of colon cancer, lowering elevated cholesterol levels, and preventing constipation.

Pineapple is high in antioxidants, vitamins A, C, and K, magnesium, and bromelain, which is an enzyme that breaks down and absorbs protein in foods. This fruit aids in digestion and helps prevent constipation.

Broccoli is high in fiber, antioxidants, and magnesium which facilitates proper digestion.

Ginger root and ginger oil are often used to treat indigestion and to improve digestion. In India, fennel seeds are chewed after meals to facilitate digestion.

Yogurt is a good source of easily digestible proteins.

It contains Lactobacillus, a bacteria which ferments milk and yogurt and aids in digestion. Yogurt is a rich source of calcium, potassium, and magnesium, as well as vitamins B2 and B12, D, and E. It is a nutritious supplement for individuals who are lactose intolerant.



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Wednesday, December 30, 2009

How do antioxidants affect my workout?


Sales of orange juice are soaring as people seek flu protection from vitamin C, The Globe and Mail reported last month.

Old habits die hard, and our faith in the power of antioxidants is deeply entrenched. Over the past few years, a vast series of studies involving hundreds of thousands of subjects have failed to find any health benefits from antioxidant supplements.

Now, a handful of studies suggest that popping these pills may even block some of the benefits of exercise, and even slow down post-workout muscle recovery.

It would be premature to pronounce the end of the vitamin era on the basis of a few studies – as premature as it was to leap on the bandwagon in the first place – but some skepticism is due.

“For something like vitamin C, it's important to have enough,” says Stephen Cheung, a physiologist at Brock University. “But that doesn't mean more is better.”

Antioxidants – vitamins C and E as well as molecules ranging from beta-carotene to the currently fashionable resveratrol – attack and neutralize the “free radicals” associated with aging and disease. Exercise stimulates the production of free radicals, which is why athletes are often advised to take antioxidant supplements.

But exercise is itself an antioxidant, since the body gradually learns to produce more and more of its own antioxidants in response to the spike of free radicals generated by exercise. One theory now gaining support is that taking extra antioxidants means the body never gets the opportunity to adapt on its own.

In May, Michael Ristow and colleagues at the University of Jena in Germany published a study in the Proceedings of the National Academy of Sciences examining how a four-week exercise program affected insulin sensitivity – one of the most significant health benefits conferred by physical activity. Half of the 40 volunteers were given a placebo, and saw significant improvements in insulin sensitivity; the other half took 1,000 milligrams of vitamin C and 400 IU of vitamin E each day, and saw no change despite the exercise regime.

To Dr. Ristow, this suggests that antioxidants are unequivocally bad, even though the research in favour of eating fruits and vegetables is unimpeachable.

It implies that fruits and vegetables are healthy despite their antioxidant content, not because of it, and that “other compounds in fruit and vegetables are responsible for their health-promoting effects,” he explained in an e-mail exchange.

The idea that antioxidants can stave off some muscle damage and soreness caused by free radicals after heavy exercise has also taken a hit.

In a study published in the September issue of Medicine & Science in Sports & Exercise, Portuguese researchers studying the national kayak team found hints that a cocktail of antioxidants actually delayed muscle recovery after training when compared with a placebo.

Victor Hugo Teixeira of the University of Porto, the study's lead author, speculates that free radicals may serve as a natural brake to prevent excessive exertion, while antioxidants override that signal and allow the muscles to work a little harder and sustain greater damage.

If that's true, athletes might benefit from taking antioxidants right before a competition, but would impede their recovery from training by taking them on a regular basis.

Even if antioxidants do ruin your workout, many people would gladly take that risk if it helped them avoid the flu. It is well established that they can help boost immune function in people who have undergone extreme physical exertion, such as ultramarathoners, Dr. Cheung says. But it's less clear that the same benefits accrue in everyday life.

In a study published last year, Dr. Cheung had volunteers cycle at moderate intensity for two hours – hardly slacking – and tested whether their immune function was helped by 1,500 milligrams of vitamin C a day for two weeks afterward.

The results were equivocal: If there was any effect, it was weak.

Dr. Cheung's advice is to ensure you are getting enough vitamin C from your diet, and if not, to change your diet before resorting to supplementation.

In a field where the science is still hotly contested, this seems like wise counsel. Some day, perhaps, we'll know exactly which molecules make fruit and vegetables so good for us – but until then, as long as you're eating lots of them, you don't have to worry about which ones.



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