Eating for one’s health is an ancient idea dating back to the Greek classical period. In 440 BC, Hippocrates—who’s considered the father of medicine—said, “Let food be thy medicine and thy medicine be food.” And since ancient times, berries have been prized for their health benefits.
Hippocrates called his black elderberry tree (sambucus nigra) his “medicine chest.” Chile’s Mapuche Indians, who were never defeated in battle or colonized, said the dark purple maqui berry (aristotelia chilensis) was the source of their strength. In North America, Indigenous tribes valued wild strawberry (fragaria vesca) as a blood purifier, and they knew cranberries (vaccinium macrocarpon) cured scurvy.
Now, modern science is proving that berries of all kinds have the power to help fight inflammation and ward off diseases like cardiovascular disease, dementia, diabetes and cancer.
“Berries … hit so many human therapeutic targets,” says Mary Ann Lila, director of the Plants for Human Health Institute at North Carolina State University. “You ingest a berry and the compounds will circulate in your blood to combat … diabetes, or cardiovascular disease or cancer or cognitive dysfunction.”
Lila and a group of researchers just launched a new Berry Health Tool Chest, a comprehensive online database of hundreds of reputable international studies on the benefits of berries. The goal is to help consumers discover that the berries we like on sundaes and in pies are some of the most potent foods for preventing cancer and slowing the growth and spread of cancer cells.
What’s in Berries?
Berries are mostly water, but they’re packed with an array of beneficial plant chemicals. “Berries contain multiple different compounds that reduce the risk for developing multiple diseases such as cancer, cardiovascular disease and diabetes,” says Gary Stoner, Ph.D., a professor emeritus at Ohio State University’s Department of Internal Medicine. Stoner has spent more than 30 years researching the cancer-fighting properties of berries and other foods, and is considered a pioneer in functional food research. “The most active compounds in berries are the antioxidants, particularly the phenolic compounds called anthocyanins, as well as the fiber,” he says.
Anthocyanins show up as the pigments that make berries and other foods red, blue and purple hues. Long-term exposure to X-rays, stress, cigarette smoke and toxic chemicals creates inflammation that damages normal cell functions. Over time, this cellular damage and inflammation can lead to cancer or other diseases. Eating anti-inflammatory foods like berries lessens inflammation, and protects our cells from damage and disease.
The familiar strawberry, for example, contains vitamin C, manganese, folate and potassium, as well anthocyanins and fiber which supports colon and gut health. Every berry has its own particular mix of plant compounds with potential disease-fighting power.
What Do Studies Show?
Stoner says two mechanisms go awry from cancer: Genes that drive cell growth become overactive, while the genes that stop tumors become inactive.
A 2014 study from the American Journal of Clinical Nutrition found fruit eaters were less likely to develop lung, upper gastrointestinal and colorectal cancers. Lila’s research determined that blueberries fight cancer two ways: they inhibit the development of cancer cells, and they combat the spread of tumors in lab cell cultures. “It’s a double whammy there, which is great,” she says. And they do it without the toxicity of traditional cancer drugs.
According to the Journal of Agricultural and Food Chemistry, in a 2006 lab study of human cells, extracts from strawberries, blueberries, blackberries, red raspberries, pomegranates and black raspberries all showed the ability to slow the development of cancer, kill off cancer cells or shrink tumors. Strawberries and black raspberries were the most effective.
Stoner and colleague Li-Shu Wang of the Medical College of Wisconsin have spent years studying the effects of freeze-dried black raspberries on cancer. Studies show black raspberries can work topically and on a cellular level to turn off the genes that drive cancer cell growth and turn on the genes that suppress tumor spread.
In a 2014 controlled trial in the journal Clinical Cancer Research, 40 patients with cancerous mouth lesions used a 10 percent black raspberry powder gel or a placebo for 12 weeks. Of the subjects treated with the berry gel, 76 percent saw their lesions shrink by an average of 26 percent. Lesions disappeared completely in two subjects and the remaining lesions were less severe. By contract, 95 percent of the control group saw their lesions grow by an average of 18 percent.
In a small study, Stoner and Wang tested black raspberries on 14 patients with familial adenomatous polyposis, an inherited condition that causes thousands of polyps to form in the colon. Because of the high cancer risk, patients usually have the colon removed by their 20s, and face a lifetime of surgeries to remove rectal polyps. Seven subjects drank black raspberry powder and inserted a black raspberry and wax suppository twice a day, while the other seven only used the berry suppository. Nine months later, 79 percent of subjects (11 of 14) saw a reduction in the number and size of rectal polyps, Wang says. The suppositories alone were effective on this type of cancer.
Wang and other researchers at the Medical College of Wisconsin just completed a 2020 clinical trial on the effects of black raspberries on 25 patients with minor disoprasic syndrome, a precursor to leukemia. They’re preparing to publish the results later this year.
You Are What You Eat
For Lila, the biggest takeaway is that the time to boost your berry consumption is while you’re healthy. “The way berries work best for cancer is 100 percent preventative,” says Lila. However, if someone with cancer starts eating berries and other produce, it can have benefits. Lila says a cup of berries a day is a good amount to support overall health. While berries are most often used in desserts, Lila recommends expanding your repertoire by pairing meats like duck, beef and venison with berry sauces.
Stoner suggests regularly eating berries at least three or four times a week. He believes three tablespoons of berry powder a day (about 20 grams) is enough to make a difference. With that amount, “we could expect in most people, but not all, to see some reduction in oxidative stress,” he says. Ten grams of freeze-dried berry powder is like eating 100 grams of fresh berries.
Wang agrees that an anti-inflammatory, Mediterranean-style diet that includes berries and other real, whole foods is the most effective cancer-prevention strategy. People often ask her about berry extracts, but Wang says she’s seen many faux products that don’t have any berries or anthocyanins in them.
She recommends loading up on fresh berries like strawberries, blackberries, raspberries and blueberries, especially in season. If you’re in a higher cancer risk group, with previous cancer or a hereditary history, Wang suggests eating 10 to 20 grams (1.5 to 3 tablespoons) of freeze-dried berry powder a day.
“Personally I just really like the idea of preventing disease using food in our daily life and that’s what keeps me going because I find it so interesting,” says Wang. “I practice that on myself and my family. The bottom line is that we are what we eat.”