Researchers from the University of Hertfordshire observed the effects of Montmorency tart cherry consumption on the cardio-metabolic markers of eleven participants that had metabolic syndrome, a set of conditions (including waist circumference above 35 inches and high fasting triglycerides levels) that are precursors to type 2 diabetes or cardiovascular diseases.
They found that participants experienced lowered systolic blood pressure and reduced serum insulin after consuming Montmorency tart cherry either in juice or capsule form compared to a placebo.
“Montmorency tart cherry juice is an effective, low-risk intervention for reducing [systolic blood pressure] in various populations and should be considered for individuals with isolated systolic hypertension,” they wrote in their paper, published recently in the Journal of Functional Foods.
Additionally, “this study demonstrated for the first time that Montmorency tart cherry capsules could reduce insulin concentrations in humans,” they added.
"The unique composition of tart cherries, including the synergistic influence of anthocyanins, other polyphenols, and fiber may be a factor,” said lead author Terun Desai about the results in a press release issued by the Cherry Marketing Institute (which, according to the paper as well as a trade group spokesperson, did not fund the study. Funding came from Heart UK, a cholesterol charity).
"Global rates of metabolic syndrome are on the rise and the results of the present study suggest Montmorency tart cherries, in juice or capsule form, could exert beneficial effects for adults with this condition when incorporated into an overall healthy diet," Desai added.
Eleven individuals, men and women between the ages of 37 and 61, completed the randomized, placebo-controlled crossover trial that lasted six weeks.
Participants had to have at least three of the five criteria for metabolic syndrome, which includes waist circumference above 35 inches for women and above 40 inches for men, high triglyceride levels, low levels of HDL, high blood pressure, and high fasting blood sugar.
Only the Montmorency tart cherry juice was placebo controlled. Participants consumed either either Montmorency tart cherry juice (30 ml of juice concentrate mixed with 100 ml of water), Montmorency tart cherry capsules (10 capsules to match the anthocyanin content of the juice with 130 ml water) or a placebo drink (30 ml of a fruit-flavored syrup mixed with 100 ml of water).
The tart cherry supplements, both concentrate and capsule, came from CherryActive by Active Edge Nutrition, while the placebo syrup was Cherries and Berries from Morrisons.
The supplement juice contained the equivalent of about 90 to 110 whole tart cherries and the capsules were made from about 100 whole tart cherries.
The six weeks were divided into three testing sessions where participants received one of the three different supplements provided each time. The testing sessions lasted six hours, and a 14-day ‘washout period’ was scheduled in between each.
Each testing day started at 7:00 AM and ended at 10:00 AM, with participants instructed to fast overnight for at least 10 hours.
The researchers measured height, weight, waist circumference and markers of heart and metabolic health (including arterial stiffness, blood pressure, heart rate, cardiac output, stroke volume, mean arterial pressure, total peripheral resistance, resting metabolic rate, glucose and insulin levels, insulin resistance/sensitivity and blood lipids) at the beginning of the study.
Other than height, weight and waist circumference, these tests were repeated at regular intervals over 5 hours after the drink or capsules were consumed.
Source: Journal of Functional Foods
Published online ahead of print, doi: 10.1016/j.jff.2019.04.005
“Effects of Montmorency tart cherry supplementation on cardio-metabolic markers in metabolic syndrome participants: A pilot study”
Authors: Terun Desai, et al.