Let us pause for a moment to savor the sweet and tart black raspberry (Rubus occidentalis). It’s got amazing health benefits that you won’t get from red raspberries—or blackberries.

This rare native American fruit’s fleetingly brief season is just a few mid-summer weeks in many parts of the country. But there are ways you can still enjoy black raspberries year-round—and you’ll definitely want to.

Here’s why: Black raspberries already have a reputation for anticancer properties. A new study shows that it’s really good for your heart, too.

KEEPING BLOOD VESSELS FLEXIBLE AND HEALTHY

The new study, from South Korea, looked at men and women with metabolic syndrome, a combination of risk factors such as high blood pressure, belly fat, low HDL levels and insulin resistance that greatly increases the risk for cardiovascular disease and diabetes. Some of them took 750 mg of black raspberry extract daily for 12 weeks while the others took inactive placebo pills.

Result: Those who consumed black raspberry extract had less arterial stiffness, a key contributor to cardiovascular disease risk. The science behind the benefit: Those who took black raspberry produced more compounds that stimulate the regeneration of the cells lining the blood vessels, helping them function better.

BLACK RASPBERRY POWER

What’s so healthy about these berries? For one, they are extraordinarily rich in antioxidants, with 10 times the antioxidant power of most fruits and vegetables—a mere four berries carries the same punch as an entire three-and-a-half ounce serving of, say, spinach.

Foremost among these antioxidants are flavonoid pigments, which give the berries their dark color. These compounds have already been shown to help protect LDL cholesterol from oxidation, a key factor of heart disease. They play a key role in anticancer effects, too—in animal studies, black raspberry extract may slow or reverse the growth of breast, prostate, cervical, colon, oral and esophageal cancers and is now being studied in human clinical trials of colorectal, stomach, oral and prostate cancers as well for the management of inflammatory bowel disease (IBD).

One class of black raspberry flavonoid in particular, anthocyanins, has been shown to improve vision, lower blood pressure, enhance immunity and improve memory. Compared with red raspberries, black raspberries have seven times more anthocyanins per serving.

BLACK RASPBERRY SUPPLEMENTS

If you want to enjoy these health benefits the rest of the year, you can purchase whole freeze-dried black raspberry powder or a liquid extract. One company that makes it and supplies it to researchers in Japan and the US is BerriHealth, based in Corvallis, Oregon. The recommended serving size of its powder is one teaspoon (four grams), which is the equivalent of 20 fresh berries and has 15 calories. You can mix it in water or juice, add it as a topping to yogurt or blend it into smoothies.

How does that amount compare with what was used in the Korean study? It’s not possible to make exact comparisons, because that study used a different method to make the extract. But that teaspoon with 20 berries likely represents more than what was used in the study, which was, roughly estimated, the equivalent of seven or eight berries, according to Steve Dunfield, president of BerriHealth.

Cancer research studies have used even larger amounts—as much as 50 grams of freeze-dried black raspberry powder, the equivalent of three cups of fresh black raspberries—about 250 berries.

How much should you take? It depends on why you’re taking it. If the purpose is to treat a health condition—especially a serious condition such as cancer—you should work with your doctor to determine what’s right for you.

If you just want to enjoy the healthful properties of this berry year round, on the other hand, let food amounts be your guide. After all, that’s what the powder is—it’s just whole black raspberry, including the seeds, with nothing added. If you put a teaspoon of powder in your smoothie, that’s 20 berries. A tablespoon? That’s like putting 60 berries in your drink. All that adds are a few extra calories—specifically, 45.

One caveat: Be careful of many black raspberry capsules on the market.  Often these capsules do not contain much black raspberry, and many lack authenticity. Best to stick with either freeze-dried powders made from authentic whole black raspberries or well-prepared liquid extracts. According to Bottom Line medical contributing editor Andrew Rubman, ND, the Eclectic Institute is another reputable supplier of real black raspberry products, including freeze-dried black raspberry powder in bulk or in capsules.

GET ‘EM FRESH…WHILE YOU CAN

Fresh black raspberries are in season primarily in July, so don’t hesitate to make tracks to a grocery store or your local farmer’s market. They’re delicious eaten fresh out of hand, puréed, baked into pie (try two parts black raspberry to one-part blueberry or blackberry), blended into smoothies or preserved in jam. (How to tell the difference between blackberries and black raspberries? Easy—all raspberries have a hollow core.)

Are black raspberries superior to blackberries and red raspberries for the heart? “Neither has been tested against black raspberries for cardiovascular effects,” commented food-as-medicine expert John La Puma, MD, who wasn’t involved in the study. “But in general, the blacker the berry, the greater the antioxidant effect—and oxidation of LDL cholesterol starts cardiovascular disease.”

His advice: “Eat the berry you have, and enjoy it. All of them taste better than prescription medicine!”

To learn more, see “Beyond Blueberries: The Bottom Line Guide to the Many, Many Benefits of Berries for Better Health.