Berries & Polyphenols for Heart Disease, Brain Health & More

12/17/2021 | 5 min. read

Dr. Stephen Sinatra

Dr. Stephen Sinatra

Did you know that raspberries, blackberries, and strawberries are not actual berries, but bananas, tomatoes, and watermelons are? Botanists classify blueberries and cranberries as true berries but other small fruits we call berries as “aggregate fruits.” 

Still, a berry by any other name would taste as sweet—and have as many health benefits. 

Many Reasons to Love Berries 

Some foods with exceptional health benefits have a reputation for not being particularly tasty. Kale, for instance, is an acquired taste for many. But everybody loves berries, and taste is just one of their many attributes:

  • Calories: Berries are low in calories, averaging 60–80 per cup. 
  • Glycemic index: They have a low glycemic index, meaning they won’t cause a spike in blood sugar and are safe for people with diabetes.
  • Fiber: Most berries contain decent amounts of fiber. Raspberries and blackberries have 8 g of fiber per cup, and blueberries and strawberries have 4 g and 3 g, respectively. 
  • Vitamins: They are a good source of vitamins. A cup of sliced strawberries, for example, has nearly 100 mg of vitamin C. 
  • Prebiotics: Berries contain prebiotics, which are indigestible carbohydrates that nurture healthy gut bacteria. A robust, diversified gut microbiome supports all aspects of health.
  • Polyphenols: Perhaps most importantly, berries are nature’s richest source of polyphenols.

Richest Source of Polyphenols

Phytochemicals are natural compounds produced by plants that protect them against insects, microbes, weather extremes, and other environmental stressors. The benefits we get from eating healthy plant foods are due not only to vitamins, fiber, etc., but also to certain phytochemicals. 

Of the more than 25,000 phytochemicals identified so far, polyphenols are among the best studied for their effects on human health. Polyphenols are abundant in herbs and spices, onions, extra-virgin olive oil, flaxseed, dark chocolate, coffee, tea, red wine, and other foods known for their health benefits. But the richest source per serving is berries.

French researchers analyzed hundreds of different foods to determine their polyphenol content. They found that eight of the top 12 dietary sources of polyphenols are various types of berries, including blueberries, strawberries, blackberries, raspberries, black currants, and elderberries. (Artichokes, coffee, sweet cherries, and plums also made the top 12.) 

Polyphenols Reduce Oxidative Stress & Inflammation 

Anthocyanins, flavonoids, tannins, phenolic acids, and other polyphenols in berries have one thing in common. By virtue of their chemical structure, they can stabilize free radicals and reduce oxidative stress. These powerful antioxidants also help curb low-grade inflammation, which is triggered by free radical damage to healthy cells.  

This combination of oxidative stress and systemic inflammation sets off a vicious cycle of tissue damage and degeneration that, over time, can lead to heart disease, diabetes, arthritis, obesity, neurodegeneration, and other chronic diseases. That’s why I emphasize the importance of antioxidants and natural anti-inflammatories—and why polyphenol-rich foods and extracts protect against these and other common diseases.

Berries, Polyphenols & Heart Disease

Polyphenol-rich berries are one of my top dietary recommendations for heart health. In addition to reducing the oxidation of LDL cholesterol, which is involved in the buildup of plaque in the artery walls, polyphenols promote the production of nitric oxide (NO) in the endothelial lining of the blood vessels. 

NO keeps the arteries healthy and flexible, ensuring optimal circulation and blood pressure. A study published in The American Journal of Clinical Nutrition concluded that a higher intake of anthocyanins, mostly from berries, was linked with an 8–10% lower risk of hypertension. Protection was even greater in individuals younger than age 60. 

Eating berries may also reduce your risk of heart attack. Researchers from the Harvard School of Public Health followed more than 93,000 women for 18 years to determine the effects of polyphenols on heart health. They discovered that women who ate blueberries or strawberries at least three times a week had a 32% reduction in their risk of heart attack, compared to those who ate berries once a month or less. 

Berry extracts are also protective, as demonstrated in a 2019 study involving men and women with metabolic syndrome—a cluster of conditions such as abdominal obesity and elevated blood sugar and blood pressure that increases the risk of heart disease and diabesity. The study participants who took a freeze-dried powder with standardized levels of anthocyanins and other polyphenols (equivalent to one cup of blueberries) daily for six months had a 12–15% lower risk of heart disease.

Berries Also Protect Against Chronic Diseases

Polyphenol-rich berries have proven benefits for other common chronic diseases:

  • Brain: Polyphenols help reduce inflammation and oxidative stress in the brain. A hearty consumption of blueberries, which have been referred to as “brainfood,” is associated with a lower risk of memory loss and neurodegenerative diseases.  
  • Weight: A study spanning more than two decades linked a higher intake of berries and other foods abundant in polyphenols with less weight gain.
  • Immunity: Polyphenols support overall immune health. Studies suggest they also protect against cancer of the colon, prostate, endometrium, and breast by interfering with tumor cell growth. 
  • Diabetes: Anthocyanins and other polyphenols protect the insulin-producing beta cells in the pancreas and help improve glucose transport and blood sugar control. 
  • Gut microbiome: A growing body of research reveals that berry polyphenols are prebiotics that support the growth of beneficial gut bacteria, reduce inflammation, protect against intestinal diseases, and enhance overall health. 
  • Aging: It’s premature to say that berries increase longevity. Yet, given the plethora of polyphenols’ protective effects against chronic diseases, they do support healthy aging. 

Eat More Berries!

My advice? Eat more berries! Be aware that conventionally grown berries, especially strawberries but also blueberries and raspberries, are notorious for containing high levels of pesticide residues, so purchase organic berries whenever possible. Aim for a cup of berries, fresh or frozen, at least three times a week.

To make sure you’re getting enough polyphenols, I also recommend freeze-dried powders and extracts. In fact, some high-quality multivitamins contain extracts of berries or other polyphenol-rich plants.

Look for a supplement that contains extracts of commonly eaten berries and/or more exotic polyphenol-rich berries such as acai, jaboticaba, and maqui, which are dark-colored berries native to South America; amla, or Indian gooseberry, a standard in Ayurvedic medicine; goji, a reddish-orange berry native to China; and acerola, which is also one of the most concentrated sources of vitamin C. 

Whether you grab a handful of berries as a snack, eat them in salads or cereal, serve them as a healthy dessert, add them to your smoothies—or take them in the form of powders or supplements—berries benefit your health in more ways than you might imagine. In fact, I believe in the research so much that I make it a habit to eat mixed organic berries with a gluten-free cereal and almond milk at least three to four times a week.

Dr. Stephen Sinatra

Meet Dr. Stephen Sinatra

Dr. Stephen Sinatra is a highly respected and sought-after cardiologist and nutritionist with more than 30 years of clinical practice, research, and study. His integrative approach to heart health focuses on reducing inflammation in the body and maximizing the heart's ability to produce and use energy.

More About Dr. Stephen Sinatra