Increasing intake of antioxidant-rich cherries may help lower the risk of metabolic syndrome and cardiovascular disease, suggests a new study.
Researchers say the animal study is encouraging and will lead to further clinical studies in humans.
"Metabolic syndrome is a cluster of traits that can greatly increase your risk of heart disease, stroke and Type 2 diabetes, so it's a serious condition that significantly affects public health," said study co-author Dr. Steven F. Bolling, a cardiac surgeon at the University of Michigan Cardiovascular Center who also heads the U-M Cardioprotection Research Laboratory, where the study was performed. "Lifestyle changes have been shown to lower the odds of developing metabolic syndrome, and there is tremendous interest in studying the impact of particular foods that are rich in antioxidants, such as cherries."
Metabolic syndrome (also called insulin resistance syndrome) has become increasingly common in the United States, especially among adults in their mid-30s.
The American Heart Association estimates that 50 million American adults have it, and many of them don't even know it. That's why metabolic syndrome is frequently called a "silent epidemic."
The study, presented by University of Michigan researchers, used cherry powder derived from tart cherries - the variety frequently sold as dried, frozen or juice. These cherries contain a compound known as anthocyanins, which provide the deep rich red color and have been shown to have anti-inflammatory properties and other health benefits.
In the new study, whole tart cherry powder was fed to two groups of rats as either 1 percent or 10 percent of their diet for 90 days. Other rats received diets with no cherry powder, but with an equal amount of carbohydrates and calories to those that received cherry powder.
Results showed that the cherry-enriched diets significantly lowered total cholesterol levels, triglycerides, insulin and fasting glucose levels after 90 days. All of these measures are factors that are linked to metabolic syndrome. The study also showed the cherry-fed groups had lower levels of a plasma marker of oxidative damage and increased blood antioxidant capacity - not surprising since cherries are one of the richest sources of antioxidants.
Additionally, the cherry-enriched diets reduced "fatty liver" or the accumulation of triglycerides and cholesterol in the liver.
The amount of cherries used in the study is estimated to be about 1 ¼ to 1 ½ cups of whole frozen cherries or a little more than ½ cup of dried cherries.
People with metabolic syndrome - characterized by abdominal obesity (or belly fat), high triglycerides, low HDL cholesterol levels, high blood pressure and high blood sugar levels - are at greater risk for cardiovascular disease, which remains the nation's top killer.
Previous studies have shown that the compounds in cherries may offer protection against heart disease due to enhancements in blood vessel health. Other studies suggest that cherries have anti-inflammatory benefits that may help ease the pain of arthritis and gout.