Saturday, April 16, 2011

An apple a day keeps the Doctor away? Research

Apple: The health fruit? | The Why Files:

“An apple a day keeps the doctor away”? That question has been on the mind of Bahram Arjmandi, professor and chair of the department of nutrition, food and exercise sciences at Florida State University.
His answer, presented at the Experimental Biology 2011 meeting in Washington this week, is that "Apples have a profound effect on total cholesterol, and also on the “good” and “bad” types of cholesterol. They caused a major reduction in inflammatory proteins that are implicated in a number of serious diseases."
Arjmandi rounded up 100 women who had just passed menopause — a time when dropping levels of estrogen lead to unhealthy changes in cholesterol levels that allow women to catch up with the male rate of cardiovascular disease.
Randomly dividing his volunteers, Arjmandi asked one group to supplement their normal diet with dried prunes. The treatment group got one-a-day packages containing 75 grams — about 2.5 ounces — of dried apple.
Arjmandi used dry apples rather than the equivalent one or two fresh apples as a way to standardize the “dose,” but he says fresh fruit is likely to be even more healthy.
If the object of these tests was a pill, the results after one year would certainly boost the stock of the drugmaker: among the apple-eaters, total cholesterol fell by 14 percent and low-density lipoprotein (LDL, the harmful fraction of cholesterol) fell 23 percent. High levels of both total cholesterol and LDL are linked to damage to blood vessels, heart attacks and strokes.
Meanwhile, the level of a protective type of cholesterol called high-density lipoprotein (HDL) rose 3 to 4 percent.

(Anti-) inflammatory results

Moving beyond cholesterol, the level of C-reactive protein fell 32 percent. “This is significant, and not just in a statistical sense but in clinical relevance,” says Arjmandi. “CRP is associated with inflammation, and is considered a marker for cardiovascular disease, cancer and Alzheimer’s disease.”
The study was partly funded by the United States Department of Agriculture, and got no funding from the apple industry.

And the active ingredient is…

What makes apples so healthy? Although both pectin, a soluble fiber, and chemicals called polyphenols are thought to confer health benefits, Arjmandi says, “an apple is more than these compounds. I’ve been working on functional foods [which give health benefits] for 20 years, and I find it’s not good to approach whole fruit or whole vegetables like drugs. If you isolate the component chemicals and take them, you get some benefits, but you will deprive yourself of greater benefits.”

The World's Healthiest Foods tells us

The phytonutrients in apples can help you regulate your blood sugar. Recent research has shown that apple polyphenols can help prevent spikes in blood sugar through a variety of mechanisms. Flavonoids like quercetin found in apples can inhibit enzymes like alpha-amylase and alpha-glucosidase. Since these enzymes are involved in the breakdown of complex carbohydrates into simple sugars, your blood sugar has fewer simple sugars to deal with when these enzymes are inhibited. In addition, the polyphenols in apple have been shown to lessen absorption of glucose from the digestive tract; to stimulate the beta cells of the pancreas to secrete insulin; and to increase uptake of glucose from the blood via stimulation of insulin receptors. All of these mechanisms triggered by apple polyphenols can make it easier for you to regulate your blood sugar.

Scientists have recently shown that important health benefits of apples may stem from their impact on bacteria in the digestive tract. In studies on laboratory animals, intake of apples is now known to significantly alter amounts of two bacteria (Clostridiales and Bacteriodes) in the large intestine. As a result of these bacterial changes, metabolism in the large intestine is also changed, and many of these changes appear to provide health benefits. For example, due to bacterial changes in the large intestine, there appears to be more fuel available to the large intestine cells (in the form of butyric acid) after apple is consumed. 

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