By The Us Highbush Blueberry Council
Aside from their great taste and culinary versatility, blueberries are one of the easiest additions consumers can make to their diet to pursue a healthier lifestyle. Investigators are currently pursuing four tracks to better understand the role that blueberries may play in promoting good health — cardiovascular health, insulin response, brain health, and cancer research.
A recent study conducted at Florida State University and published in the Journal of the Academy of Nutrition and Dietetics found that daily consumption of blueberries given as freeze-dried blueberry powder resulted in a reduction of blood pressure and arterial stiffness, a measure of cardiovascular disease risk, in postmenopausal women with pre- and stage 1-hypertension.1 Conducted over an eight-week period, 40 postmenopausal women were randomly assigned to receive either 22 grams of freeze-dried highbush blueberry powder (the equivalent to 1 cup of fresh blueberries) or 22 grams of placebo powder daily. They were advised to maintain their usual diet and physical activity levels.1 The results warrant further investigation and provide some evidence for including blueberries as part of healthy dietary practices.1
In laboratory studies on rats conducted at the National Institute on Aging, researchers found a diet enriched with blueberries protected the cardiac muscle (myocardium) from damage caused by reduced blood supply during a heart attack. In addition, repair of the damaged heart muscle was more efficient in those on a blueberry-supplemented diet than those on the control diet.3 More studies are needed in this area to fully see and understand the potential effects on humans.
In a human clinical trial, 32 individuals who were already diagnosed with metabolic syndrome were given similarly tasting smoothies, either with or without blueberries twice daily for 6 weeks. The researchers found that those who consumed blueberries were more able to lower their blood glucose in response to insulin than those who were not given blueberries.4 While the study is not conclusive, it strongly suggests that more research is needed to evaluate blueberries and their potential role in improving insulin sensitivity in an insulin resistant population.
While more research is needed to understand the effects on humans, studies with animals suggest that blueberries may have an effect on the way insulin does its job. In one animal study conducted at the USDA research center at Tufts University, obese mice were given high-fat diets with or without blueberries for eight weeks. The results yielded an improved insulin response with lower blood glucose levels in response to insulin in the blueberry-fed mice than in the controls.5
In another study at the University of Michigan, researchers gave obese rats either a low or high-fat diet supplemented with 2 percent blueberries and tested the effects against the control group. After 90 days, the rats that received the blueberry-enriched diet had increased insulin sensitivity, decreased blood lipid levels and less measured abdominal fat. These results were also seen in the group that received the low-fat diet supplemented with blueberries.6
Scientists at the USDA research center at Tufts University have been studying the beneficial effects of blueberries on brain function in animal models for over a decade. In a recent study, researchers there found that object memory loss that occurs normally with age can be not only prevented but actually reversed by feeding blueberries to older rats. Moreover, the improvement persisted for at least a month after they put the animals back on a standard diet.7
In a study with nine human subjects, Robert Krikorian, professor of Clinical Psychiatry and director of the Division of Psychology, and his team at the University of Cincinnati found that older adults who were given blueberry juice scored higher on memory tests than those receiving a placebo. This study establishes a basis for human research and blueberry supplementation on cognitive aging.8 These researchers are currently conducting a similar study with older subjects who already show some signs of cognitive impairment.
According to researchers at the City of Hope National Medical Center, blueberries may have an effect on breast cancer cell growth. Three studies demonstrated that both breast tumor growth and the spread of cancer can be reduced in blueberry supplemented mice.9-11 In addition, a recent study showed that feeding rats a blueberry-supplemented diet reduced tumor growth even when feeding began after the tumors were present.12 These studies are not conclusive for humans, and more research is needed in the area of cancer and blueberry intake.
Little Changes Lead To Big Rewards
Americans know they need to make healthier food choices, but they keep tripping up when it comes to sticking with those decisions. It’s drinking an extra glass of water each day or using blueberries to sweeten your oatmeal or yogurt, these little changes will build up to a healthier lifestyle over time.
Research from ORC International shows making small changes instead of lofty resolutions makes people feel more confident and more likely to make additional positive changes. Blueberries are a great go-to snack because they’re available fresh and frozen all year-round, they add vitamin C and fiber to your diet, and they’re only 80 calories per cup.
1. J Acad Nutr Diet. 2015; 115:369-377. 2. PLoS One. 2009; 4: e5954. 3. J Nutr 2010; 140:1764-1768. 4. J Nutr 2009; 139 (8): 1510-16. 5. J Med Food. 2011; 14:1511-1518. 6. Nutrition 2011; 27:338-342. 7. J Agric Food Chem. 2010; 58:3996-4000. 8. Cancer Res. 2010;.70:3594-3605. 9. J Nutr. 2011; 141:1805-1812. 10. Nutr Cancer. 2014; 66:242-248. 11. J Ag Food Chem. 2014; 62:3963-3971.