Sweet, tart treats pack a preventive health punch powerfully out of proportion to their size
by Craig Weatherby
Some 50 million Americans—about one in three adults—have a cluster of health-status markers linked to increased risk of developing cardiovascular disease, stroke, and type II diabetes.
This common condition is called "metabolic syndrome" or "syndrome X", and it constitutes perhaps the greatest under-recognized threat to Americans' health.
Metabolic syndrome—MetS for short—is usually defined as having three or more of these half-dozen risk factors:
- Abdominal obesity (excessive fat tissue in and around the abdomen).
- High blood triglycerides, low HDL cholesterol and high LDL cholesterol: a state that fosters plaque buildups in artery walls.
- Elevated blood pressure.
- Insulin resistance or glucose intolerance (the body can’t properly use insulin or blood sugar).
- Pro-thrombotic state that promotes dangerous clots (e.g., high fibrinogen or plasminogen activator inhibitor–1 in the blood).
- Pro-inflammatory state (e.g., elevated C-reactive protein in the blood).
The keys to preventing these contributors to metabolic syndrome are ample aerobic exercise and calorie-conscious eating.
No single food or nutrient can stop MetS, but marine omega-3s rank high among the dietary factors that can discourage these six dangerous trends (See “Omega-3s Seen to Fight Metabolic Syndrome”).
Now, findings in animals suggest that tart cherries can join the list of MetS-deterring nutritional allies.
The anthocyanin pigments in tart cherries inhibit the body's COX-1 and COX-2 enzymes, which play key roles in the body's production of messenger chemicals that mediate inflammation.
(These messenger chemicals are called prostaglandins, and they are made from the omega-3 and omega-6 fatty acids in human and animal cell membranes. Omega-3s are the basis for anti-inflammatory prostaglandins, while omega-6s yield pro-inflammatory ones.)
Like cherry anthocyanins, aspirin and other nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, dampen inflammation by blocking COX enzymes... but these drugs have side effects unknown with cherries.
This similarity explains why tart cherries are ancient traditional remedies for arthritis and gout.
And as well as being a main feature of arthritis, inflammation is a key promoter of the factors that make up MetS.
Tart cherries suppress metabolic syndrome
As with our accompanying story on tea and arthritis, the results summarized here come from the University of Michigan Health System and were presented at last month’s Experimental Biology 2007 conference in Washington, D.C.
Lead researcher E. Mitchell Seymour told attendees that these especially antioxidant-rich cherries produced major improvements in health measures relevant to preventing metabolic syndrome.
Better yet, the fruits did their good work at intake levels easy to attain via one’s diet, without need of concentrated tart-cherry extracts.
The research was conducted in 48 six-week old male rats bred to be genetically susceptible to high blood pressure, high cholesterol and impaired glucose (blood sugar) tolerance.
The scientists divided the rats into two groups, and fed them one of three diets for three months:
- Carbohydrate-enriched diet
- Carbohydrate-enriched diet that was one percent cherries by weight
- Carbohydrate-enriched diet that was 10 percent cherries by weight
Tart cherries are very high in anthocyanin-type antioxidant pigments, so both cherry-supplemented groups had higher blood antioxidant levels and significantly lower blood levels of oxidation byproducts.
More importantly, both cherry diet groups had significantly lower blood levels of total cholesterol, triglycerides, glucose, and insulin than did the rats that ate no cherries.
Naturally, no toxic effects were seen in either of the cherry diet groups.
According to Dr. Seymour, “Rats fed tart cherries as one per cent of their total diet had reduced markers of metabolic syndrome. Previous research by other groups studied pure anthocyanin compounds rather than anthocyanin-containing whole foods, and they used concentrations of anthocyanins that would be very difficult if not impossible to obtain in the diet.”
The Michigan team said they were now conducting research in animals prone to both obesity and diabetes, while some University of Michigan colleagues are starting a small clinical trial to see if people can accrue similar anti-MetS benefits.
The study was supported financially by a cherry marketing trade association, but the findings fit with many studies on anthocyanins.
For example, the authors of a previous study in athletes found that daily consumption of 45 Bing sweet cherries reduced blood levels of inflammatory markers, and might lessen the damage response to exercise.
That’s a lot of fresh, whole Bing cherries, but tart cherries are substantially higher in the same antioxidant anthocyanins, and dried tart cherries like ours are quite tiny… the 25 or so dried tart cherries that would offer an antioxidant capacity comparable to 45 whole Bing cherries would only be a handful or two.
- Seymour EM, Singer AAM, Bennink MR, Bolling SF. Oral presentation 225.8 Cherry-enriched diets reduce metabolic syndrome and oxidative stress in lean Dahl-SS rats. Session Title - Across Societies: Experimental Biology (Nutrition) Experimental Biology 2007, Washington, D.C. Friday, April 27, 2007. Accessed online May 10, 2007 at http://www.eb2007.org/
- Kelley DS, Rasooly R, Jacob RA, Kader AA, Mackey BE. Consumption of Bing sweet cherries lowers circulating concentrations of inflammation markers in healthy men and women. J Nutr. 2006 Apr;136(4):981-6.
- Jacob RA, Spinozzi GM, Simon VA, Kelley DS, Prior RL, Hess-Pierce B, Kader AA. Consumption of cherries lowers plasma urate in healthy women. J Nutr. 2003 Jun;133(6):1826-9.