June 2013 Issue

Latest Scoop on Berries — Harvard Study Shows Heart Health Benefits for Young Women

By Juliann Schaeffer

Today’s Dietitian

Vol. 15 No. 6 P. 16

Berries are known for their myriad health benefits, most of which are said to come from their deep, rich color, indicative of their flavonoid content. But unlike previous studies, which largely have focused on the older population, a recent study from the Harvard School of Public Health and the University of East Anglia shows berries offer heart health benefits for the younger population as well.

“We showed for the first time that a regular sustained intake of anthocyanins [a class of flavonoids] from berries can reduce the risk of a heart attack by 32% in young and middle-aged women,” explains lead study author Aedin Cassidy, PhD, MSc, BSc, a professor in the nutrition department at Norwich Medical School at the University of East Anglia in the United Kingdom.

“To date, most studies have focused on older women or men, but apart from oral contraceptive use and smoking, we know little about risk factors for having a heart attack in younger/middle-aged women. The impact of diet is largely unknown,” Cassidy explains.

Beginning in 1991, Harvard researchers tracked 93,600 women aged 25 to 42 and surveyed them about their diets every four years for 18 years. During the study, 405 heart attacks occurred. The study showed heart health benefits in participants who consumed at least three servings of blueberries and strawberries per week. Yet Cassidy says that doesn’t mean women shouldn’t eat other types of berries as well for similar benefits.

“Blueberries and strawberries are the most frequently consumed sources of these flavonoid compounds in the US diet. But [anthocyanins] also are present in high levels in black currants, blackberries, aubergines [eggplants], cranberries, grapes, red wine, fruit juices, and jams, so there are benefits to be had from other berries as well,” she says.

These flavonoids are found in all red, blue, and purple fruits and vegetables, so people also can reap the benefits from nonberry foods, says Angela Lemond, RDN, CSP, LD, a spokesperson for the Academy of Nutrition and Dietetics. “That includes berries of all kinds as well as eggplant, cherries, red currants, and even black beans,” she says. “There’s a little-known relative of the blueberry family called a bilberry [or huckleberry] that contains even more anthocyanins than its counterparts.”

Cassidy says researchers believe these anythocyanins are behind the berries’ heart health benefits, and she and her colleagues are now conducting a clinical trial on this for confirmation. “Even when we added total fruit and vegetable intake to our statistical model, there was still a reduction in risk with higher anthocyanin intake, suggesting that the benefits are specific to anthocyanin-rich foods and not just those eating a diet high in fruits and vegetables.

“The berry connection wasn’t simply due to healthier people tending to eat better because the findings held even after we controlled for other factors linked to high heart attack risk, including family history, body mass index, physical activity, medication use, and multiple other dietary factors,” she adds.

Benefits Beyond Heart Health

In past studies, research has shown that the healthful properties of berries go beyond a healthier heart. “Previous population-based studies have shown that berries can reduce the risk of diabetes and cognitive decline, and higher intakes also have been associated with a reduction in risk of Parkinson’s disease,” Cassidy says.

According to Anne VanBeber, PhD, a professor and the chair of the department of nutritional sciences at Texas Christian University, fiber is behind berries’ blood sugar benefits. “Fiber is in high concentrations in the skin of berries, and you eat a lot of skin when you eat berries. This helps regulate blood sugar and keeps it more level, avoiding spikes and dips,” she explains. “Put another way, berries have a lower glycemic index than many other fruits do. The glycemic index of strawberries is 40, while the glycemic index of blueberries is 53.” (Low-glycemic foods generally are defined as those with a glycemic index of less than 55.)

“In addition to heart health benefits, studies have shown that berries have anticancer effects by inhibiting tumor growth and decreasing inflammation in the body,” says Lauren Graf, MS, RD, a dietitian with the Montefiore-Einstein Cardiac Wellness Program at Montefiore Medical Center in New York City. “Some studies also show that berries are a brain food and improve both motor coordination and memory.”

Incorporating Berries Into the Everyday

According to the Harvard study, participants who ate at least three servings of berries per week saw the most benefits. Most people incorporate berries into their breakfast, using them as a topping for oatmeal, waffles, pancakes, or low-fat yogurt, but there are several other ways to fit berries into meals.

Lemond suggests making a quick smoothie when on-the-go sustenance is in order. “Mix some frozen berries with some milk and low-fat yogurt,” she says, adding that “most berries can be washed ahead of time and placed in single-serving baggies to be eaten in the car with some mixed nuts.”

One of the most popular lunch options RDs recommended was a salad with added berries. Lemond likes berries mixed with field greens, chopped walnuts, and tuna, while Nieca Goldberg, MD, medical director of The Joan H. Tisch Center for Women’s Health at New York University’s Langone Medical Center, prefers a strawberry salad with romaine lettuce, nuts, and a lemon dressing.

But berries also can be incorporated into warm meals, too. Graf suggests stirring some berries into a light couscous or quinoa lunch meal. Or for a heartier dinner option, Lemond recommends clients make their own berry sauce.

“Make your own mojito sauce or berry glaze to top your favorite extra lean meat, chicken, or fish by blending one or more berries along with some wine, spices, and your other favorite pairings,” she says.

Looking to imbibe with berries? Mary Grace Webb, MA, RD, CDN, CDE, assistant director of clinical nutrition at New York Hospital Queens, has an idea for swapping out high-calorie beverages with berries instead. “Drink water infused with berries or add blueberry juice to seltzer,” she says.

And, of course, frozen or fresh wild blueberries can be the perfect complement to a hot summer’s day, either relaxing on the grass or working at your desk. (Webb’s favorite combination is a bit of dark chocolate with a handful of blueberries.)

For fresh dessert ideas, Lemond suggests a mixed berry salad that she says is perfect for potluck affairs. “Our salad is always the first dessert gone,” she says. “They’re so beautiful and can be topped with a nice dollop of low-fat yogurt or whipped cream.”

For another idea, see VanBeber’s blueberry compote recipe below, which she says is great when mixed with plain Greek yogurt. “I suggest something like this for a dessert instead of eating a cookie or pastry,” she says.

Take-Home Message

Based on findings from the Harvard study and previous research, Cassidy says adding berries to a weekly grocery shopping list can only improve health “as the available population-based evidence suggests they have benefits not only for keeping your heart healthy but also in relation to other health conditions, including diabetes, Parkinson’s, and cognitive decline.” Long-term clinical studies are currently under way to further understand anthocyanins’ impact on heart health.

“Berries provide so much more than a sweet source of energy for our bodies,” Webb says. “While fruits in general should be a regular part of a healthful diet, berries are so special that they should be enjoyed frequently. Fresh, in season is best, but frozen and dried berries (as well as juice) also can be [enjoyed].”

— Juliann Schaeffer is a freelance writer and editor based in Allentown, Pennsylvania, and a frequent contributor to Today’s Dietitian.

Blueberry Compote

Serves 8 (yields 2 cups)

Ingredients

1 1/2 cups blueberries, frozen

1/2 cup water

1 1/2 T agave syrup

1/2 tsp vanilla extract

1 pinch salt

1/2 tsp lemon juice

1 tsp cornstarch

2 tsp cold water

Directions

1. Combine blueberries, water, agave syrup, vanilla, and salt in a small saucepan. Bring to a low simmer. Cook 5 minutes or until the water takes on a rich purple color and the blueberries are warmed through. Stir in lemon juice.

2. In a small bowl, combine cornstarch and cold water to make a slurry. Stir into the blueberries.

3. Bring mixture to a low simmer; cook for 1 minute to thicken. If sauce is too thin, add a little more cornstarch mixed with cold water.

Nutrient Analysis per 1/4 cup serving

Calories: 29; Total fat: 0 g; Sat fat: 0 g; Trans fat: 0 g; Cholesterol: 0 mg; Sodium: 0 mg; Total carbohydrate: 7 g; Dietary fiber: 1 g; Sugars: 6 g; Protein: 0 g

— Recipe courtesy of Anne VanBeber, PhD