Scientific studies have shown that diets that include wine can improve cardiovascular health. Now, a review of several large studies has found strong evidence of a link between keeping trim and the polyphenolic compounds found in wine and some fruits and vegetables.
The review, published January in the British Medical Journal, looked at three cohort studies—the Health Professionals Follow-Up Study, Nurses' Health Study and the Nurses' Health Study 2—involving more than 124,000 male and female participants. The analysis conducted by researchers from the Harvard T.H. Chan School of Public Health studied the eating patterns of the participants to determine whether foods rich in flavonoids had any effects on managing body weight. Flavonoids are naturally occurring compounds that are found in specific fruits and vegetables, including grapes, blueberries, apples, pears and prunes.
What was unique about this study is that previous weight-loss research had targeted one small subset of flavonoids, flavan-3-ol, which is found in high concentrations in green tea. This megastudy focused on several subclasses of flavonoids and found that most had a positive effect on participants' long-term health.
The Harvard study centered on seven specific subclasses of flavonoids. Wine, especially red wine, is high in dietary flavonoids. The principal flavonoids consumed by the participants were anthocyanins, which were derived from blueberries and strawberries, flavan-3-ols, acquired from beer, tea and apples, and flavones from oranges, onions, teas, beer and wine.
The researchers observed a significant correlation between a diet that is heavy in fruits, vegetables and flavonoid-heavy drinks, and participants who were healthier overall and less overweight. Most positive dietary changes correlated with flavonoid consumption were small and incremental. But, according to the researchers, "A single serving per day of many fruits can often increase the effect of weight loss. For example, one half-cup of blueberries provides about 121 mg of anthocyanins."
And losing even small amounts of weight can improve health: "Losing just 11 to 22 pounds is associated with a decrease in blood pressure, and reducing body mass index by 1-3 kg/m2 is associated with a 2 to 13 percent lower risk of cardiovascular disease events. Similarly, preventing even small amounts of weight gain could have an important public-health impact: Gaining 10 pounds or more between the ages of 40 and 60 increased the risk of developing diabetes by 40 to 70 percent and a meta-analysis of 221 studies found a 24 to 59 percent increased risk of several cancers."
As with many dietary studies, what the researchers observed was not so much a cause and effect of flavonoid consumption but a correlation between a flavonoid-heavy diet and healthier participants. In order to truly prove how a specific flavonoid can affect an individual's health, more concentrated research needs to be done.