April 4, 2016 -- You already know berries are good for you. But researchers are finding more and more reasons to eat these nutritious powerhouses.
Here’s one of the latest juicy details: Berries may lower the risk of erectile dysfunction. Other recent studies show they may play a potential role in the fight against Alzheimer’s disease and help with weight loss.
“Berries do warrant the hype that they get,” says Barbara Shukitt-Hale, PhD, a USDA staff scientist with the Human Nutrition Research Center on Aging at Tufts University. “And where we are now in terms of research is leaps and bounds ahead of where we were 10 years ago.”
But the link to erectile dysfunction is new. In a study of more than 25,000 men, those who ate the greatest amount of blueberries and citrus fruits were reported to have a nearly 20% lower risk of ED, compared to those who ate the smallest amounts. Researchers can’t prove that eating berries caused the drop in risk, and they say more study is needed.
So what makes berries so beneficial? They have several different compounds that are good for you. Some of the most important:
- Antioxidants. These chemicals, which include vitamins A, C and E, protect cells from damage and possibly from disease. Berries are loaded with them.
- Resveratrol. This is found in grapes and some other berries, as well as in red wine and dark chocolate. It may help lower inflammation, prevent clogged arteries, and offer cancer protection. A recent study suggests it may be good for people with Alzheimer’s. "In our lab we have found that they have direct effects on the brain,” Shukitt-Hale says.
- Flavonoids. These nutrients give berries their brilliant colors and may help protect against cancer, inflammation, and heart disease.
Alzheimer’s Disease and Resveratrol
Berries boost a process called neurogenesis, or making new neurons, Shukitt-Hale explains. That may aid our memories and our ability to learn. They’re also involved in the brain’s "housecleaning" activities. They help clear out toxic proteins that build up in the brain, such as tau and amyloid beta. Excessive amounts of those proteins are linked to Alzheimer's disease.
High doses of resveratrol found in berries may impact the advance of Alzheimer's. It stabilized the buildup of brain plaques tied to the disease in people with mild to moderate Alzheimer’s, according to a study published late last year. But it’s still unclear why resveratrol had this effect, and it’s too soon to tell whether it would provide any relief from symptoms of the disease. More research is needed.
The resveratrol used in the study was much more concentrated than what’s available in supplement. Study participants took much higher doses than you could realistically eat or drink if you were getting it from its natural sources. The lead researcher estimated that you'd need to drink 1,000 bottles of red wine a day to get a similar dose.
Still, experts say the study is an important one. “To me, it’s a hopeful way that we may be able to use the compounds found in these fruits,” says nutrition expert Frances Largeman-Roth, RD, author of Eating in Color. “Resveratrol is definitely a compound to look at, and for Alzheimer’s, we really don’t have anything yet in terms of treatment.”
New research released earlier this month at a meeting of the American Chemical Society suggests blueberries, in particular, may be a weapon in the fight against Alzheimer’s. In one study, people 68 and older who were already having thinking problems seemed sharper after eating freeze-dried blueberry powder, equivalent to a cup of berries, daily for 16 weeks.
“The blueberry group demonstrated improved memory and improved access to words and concepts,” says research team leader Robert Krikorian, PhD, in a statement. They also showed increased brain activity on MRI scans.
Berries and the Body
Flavonoids have also been linked to health perks in recent studies. In one, eating strawberries, cherries, blueberries, and other colorful fruits and vegetables rich in these nutrients appeared to contribute to a small amount of weight loss.
Arpita Basu, PhD, an associate professor of nutritional sciences at Oklahoma State University, has done research that shows a link between eating several daily servings of strawberries and lower cholesterol, potentially protecting against heart disease and diabetes. A daily serving of dried cranberries, she also said, may help people with type 2 diabetes manage their blood sugar levels. Cranberries, she suggests, may help prevent blood sugar spikes and dips.
The Whole Berry
Research into extracts like resveratrol is only one part of the picture. Scientists are focusing more attention on whole berries rather than their individual parts.
Studying those parts “has not proved to be the right approach,” says Zhaoping Li, MD, PhD, chief of the division of clinical nutrition at UCLA. “When you take something as a single compound, it’s not the same as taking it in its natural form.”
Largeman-Roth agrees. “We really need to focus on the whole berry, not just an extract or powder, because that’s how people eat them.”
Basu says that berries in general have higher nutritional value than other fruits, and agrees that you have to eat the whole fruit. They have fiber, flavonoids, complex carbohydrates, vitamins and some minerals, and other important compounds.
Keep in mind that no single berry offers the full range of health benefits, Li says.
“Berries all have different colors, which means they have different nutrients, so the best approach is to eat different varieties to get those different nutrients,” she says. “Don’t eat just blueberries.”
And, Basu says, while berries offer many benefits, the key to good nutrition is to eat a wide range of fruits and vegetables. Flavonoid-rich foods and drinks also include apples, pears and tea, among others.
“We have to educate the public that flavonoids, as these recent studies show, come from many dietary sources,” Basu says. “It’s not only berries.”