Resveratrol: the real and the putative health benefits

How come French people, despite eating diets high in saturated fats, have a significantly lower rate of coronary heart disease than people from United States? In the early nineties, the CBS television show ’60 minutes’ started and investigation to solve this mystery. The reporters came to the conclusion that it is the high red wine consumption that is responsible for the great cardiovascular health of France inhabitants. Further scientific research has shown that it is particularly resveratrol, a substance found in grape skins and many other plants, which consumption has heart protective effects (among many other health benefits).

Because of its extra thick skins and numerous seeds, muscadine grapes are considered the best source of resveratrol. The substance is highly soluble in alcohol, so wine is especially abundant in it. Apart from grapes, the substance can be found in pomegranates, berries, peanuts, cocoa, dark chocolate, tea and giant knotweed.

The list of resveratrol’s health benefits is quite long. As an antioxidant, it is claimed to prolong organism’s lifespan by reducing free radical damage to cell DNA and cell membranes. It is also claimed to prevent skin ageing. It inhibits spread of cancer (especially prostate cancer), lowers blood pressure, normalizes your anti-inflammatory response, keeps your heart healthy and improves the elasticity of your blood vessels. Contrary to other antioxidants, resveratrol is able to cross blood-brain barrier and protect the nervous system, which is considered as preventive from Alzheimer’s disease. It also makes a very healthy way to lose weight, as it boosts metabolism and reduces carbohydrate utilization. By preventing insulin resistance, a condition where the organism is less sensitive to this blood-sugar lowering hormone, resveratrol protects the organism from diabetes. According to some researchers, resveratrol activates a special gene that is responsible for protecting organism from harmful effects of obesity and ageing.

Unfortunately, there are couple flies in the ointment. First of all, many of the headlines concerning the salutary properties of resveratrol come from laboratory or animal studies and have no support in evidence from trials involving humans. Scientists permanently argue with each other whether resveratrol really has the effects it is claimed to have.

Second, to get the potential benefits, much higher doses are required than that from eating berries or drinking wine. The market is full of resveratrol based supplements. Manufacturers claim that their products contain effective doses of the substance. However, one should be careful when choosing the supplement, since these made of low-purity trans-resveratrol contain large amounts of a harmful substance – emodin – which may act like a laxative and cause a gastrointestinal distress, stomach cramps, gas and diarrhea. You should always choose high purity resveratrol (>99%), which contains insignificant amounts of emodin.

Another important thing concerning resveratrol is the question whether is it helpful to everyone. Studies have shown that resveratrol does not change much in the condition of healthy people, whether it regard body fat, resting metabolic rate, the level of fat in the blood, or markers of inflammation. Furthermore, there are some empirical data suggesting that resveratrol might actually counteract heart healthy benefits of physical exercise, particularly those concerning the level of oxygen in the body, lowering blood pressure and decreasing the level of bad cholesterol in older men.

If you nonetheless decide to use resveratrol supplements, you should make sure the dosage is adequate and there is no interference with other drugs you take. Resveratrol might interact with blood thinners such as warfarin and non-steroidal anti-inflammatory medicines like aspirin or ibuprofen. Another resveratrol related controversy regards its dosage. Critics often point out that the recommended dosages of most resveratrol supplements are usually far lower than the amounts proven to be beneficial in scientific studies. Insofar as most supplements contain 250 to 500 mg of the substance, one would have to consume at least 2000 mg to reach the dose used in animal trials.

Are the resveratrol supplements worth buying? Perhaps it’s better to profit from its natural sources and postpone the purchase of a supplement until more convincing study will be published.

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