Blueberries are a treat of the summer. The month of May’s high temperatures may have damaged North Carolina’s crop, but California and New Jersey are set for plentiful harvests. As well as being delicious, they are frequently cited as being a “superfood.” They promote healthy digestion, bone health, skin’s appearance, lower blood sugar and so much more. They are rich in antioxidants, fiber and vitamins. Research has shown that they protect the body from LDL cholesterol. A new study, published this month, has strengthened our understanding of just how good blueberries are for heart health. Research from the UK, published in the American Journal of Clinical Nutrition, saw that eating 150 grams (one cup) of blueberries a day reduced the risk of cardiovascular disease by up to 15 percent.

Researchers examining Metabolic Syndrome wanted to see if blueberries had an impact. If a person has Metabolic Syndrome, which one-third of adults in the western world do, it means they have at least three risk factors for heart disease. Excess belly fat, high blood pressure, low levels of “good” cholesterol, high levels of triglycerides and high blood sugar are all potential components of Metabolic Syndrome. With a group of 138 people with Metabolic Syndrome who were between 50 and 75 years of age, researchers performed the study. Some people ate one cup of freeze-dried berries, others ate half a cup and a third group ate a placebo that tasted and appeared to be freeze-dried berries.

“We found that eating one cup of blueberries per day resulted in sustained improvements in vascular function and arterial stiffness — making enough of a difference to reduce the risk of cardiovascular disease by between 12 and 15 percent,” said Dr. Peter Curtis, one of the co-lead research, from the Univ. of East Anglia. “Unexpectedly, we found no benefit of a smaller 75 gram (half cup) daily intake of blueberries in this at-risk group. It is possible that higher daily intakes may be needed for heart health benefits in obese, at-risk populations, compared with the general population.”

“Blueberries contain powerful bioactive compounds called anthocyanins, which are part of the flavonoid family,” lead researcher Prof. Aedin Cassidy said. “In lab and animal experiments we know that anthocyanins, the ingredient that imparts the brilliant red-blue colors in fruits and other plant foods, can reduce inflammation, keep arteries healthy, improve blood flow and reduce cholesterol levels.” People eating the highest amount of blueberries in the study had increased levels of anthocyanin and increased levels of cyclic guanosine monophosphate, which relaxes smooth muscle cells and improves blood flow.

Eating a cup of blueberries in a sitting isn’t a hard goal to achieve. Sadly, doing so every day can be daunting. But that shouldn’t turn you off the idea altogether. The people in this study were already at high risk for heart problems. The researchers say that for people at lower risks, smaller intakes may work well. “We have great population-based data from large cohorts showing that the habitual intake of just three servings a week reduces the risk of having a heart attack,” Prof. Cassidy said. “The next step in research is a clinical trial in healthier people.”