A natural way to lower cholesterol could be as close as the produce section of your favorite market: A new study in the journal Nutrients suggests that grapes may not only improve this heart-health marker but also boost the diversity of your beneficial gut bacteria, too.
Researchers asked 19 healthy adults to eat a diet low in fiber and polyphenols—the compound in fruits and vegetables that reduces inflammation and helps to regulate blood pressure—for a month, in order to see how grape powder would affect them afterward. They continued to eat the same diet but added 46 grams of the powder, the equivalent of two servings of fresh grapes, which comes in at two cups.
After four weeks of the daily grape powder, participants all saw increases in gut bacteria diversity, especially a type associated with glucose regulation and breakdown of fatty acids. They also had an almost 8% decrease in "bad" cholesterol levels, as well as a 40 percent drop in steroid acids—a substance that plays a role in how cholesterol works in the body. At high amounts, these acids can lead to blocked blood vessels, increasing the risk of heart attack and stroke.
This effect is likely because grapes are such a rich source of fiber and polyphenols, which both provide benefits to the gut and cardiovascular system, according to study co-author Jieping Yang, PhD, at the Center for Human Nutrition, David Geffen School of Medicine at University of California, Los Angeles.
Although this was considered a pilot study due to its small number of participants, Yang says it adds to ample, previous research showing that compounds in grapes have a range of benefits, including antibacterial and antiviral properties.
The main finding in the recent study was the boosted gut health, but Yang says the cholesterol effect is also promising. That's especially the case since participants had to refrain from eating fruits and vegetables for a month, which means that even those who rarely eat these foods could see benefits after only a few weeks of including them in their diet.
"Dietary intervention is the primary approach to cholesterol management," she says. "In this study, the equivalent of two servings of grapes provided enough dietary fiber to have a small but significant impact."
More research will need to be done, Yang adds, but in the meantime, this adds to other research that suggests grapes definitely have a heart-healthy—and gut boosting —place in your fruit bowl.
For more, check out the Secret Effects of Eating Grapes, Says Science.