MT. PLEASANT, Mich. — Michigan's tart cherries could unlock a key to improving brain function and reducing symptoms of diseases such as Alzheimer's and Huntington's, according to studies by a neuroscientist at Central Michigan University.
Earlier studies have suggested antioxidants found in tart cherries can be useful in treating inflammation-related ailments such as arthritis, and new studies of their effects on degenerative brain diseases such as Alzheimer's are breaking new ground.
Michigan is a world leader in the production of tart cherries, producing up to 75% of the U.S. crop, with orchards concentrated in the Traverse City area.
Gary Dunbar, director of CMU's neuroscience program, said the compound built around extracts from tart cherries improved brain function in mice with Alzheimer's symptoms and reduced symptoms of Huntington's disease in other lab animals. He published the results of some of his research in the Journal of Medicinal Food in 2012.
Still, such studies are controversial because cherries are natural products unregulated by the U.S. Food and Drug Administration and can be consumed without the rigorous testing required of pharmaceuticals. Some medical experts say nearly all such dietary supplements are shown to be ineffective when subjected to placebo-controlled testing on humans.
Dunbar conducted the studies at the urging of Traverse City cherry entrepreneur Ray Pleva.
Pleva, who grew up on his father's cherry orchard in Cedar, near Traverse City, developed the natural supplement used for the studies and supplied the compound at no charge.
"Was it a startling response? Did it cure them? No," said Dunbar, who conducts a wide range of stem cell and other research related to neurodegenerative diseases and spinal cord injuries. "Did it slow down the disease process? Yes. Is that important? Well, if I had Huntington's disease and it gave me — I don't care if it was one more day of symptom-free living — thank goodness."
Dunbar, who has a doctorate in psychobiology from Clark University in Massachusetts, is frank about the limitations of the studies he conducted with Pleva's dietary supplement, marketed under the name Cerise.
But the results are a big deal for Pleva, who has scores of testimonials to the therapeutic benefits of Michigan cherries and appeared on Oprah Winfrey's show in 1995.
Dunbar's Alzheimer's study with lab animals was paid for by the Field Neurosciences Institute in Saginaw and by a CMU endowment.
Pleva, founder and chairman of Pleva International, said he believes Dunbar's student-based research with rats and mice, though preliminary, is an important step in supporting through science what he has heard anecdotally for years.
He said his supplements, which contain a concentrated powder from tart cherries, Nordic fish oil and emu oil, have strong anti-inflammatory properties and have helped people with arthritis, high cholesterol, headaches and Crohn's disease, among other ailments.
An animal study conducted by a colleague of Dunbar found Cerise — which is not regulated by the FDA — helpful in relieving symptoms in rodent models of Parkinson's disease. None of the studies showed any harmful side effects, Dunbar said.
Skepticism and hope
Dr. Sidney Wolfe, founder and senior adviser to Public Citizen's Health Research Group — a branch of the consumer advocacy group founded by Ralph Nader — said Dunbar's results should be viewed with skepticism.
"Publicizing something like this, you can give false hopes ... to people who start slugging down cherry juice," Wolfe said.
Josh Bloom, director of pharmaceutical and chemical science at the American Council on Science and Health, also was skeptical. He noted the models for diseases such as Alzheimer's implanted in lab animals do not fully replicate the diseases found in humans.
Dunbar agrees that there is a big jump from his findings to effective therapies in human clinical trials, but he maintains the results at least suggest this may be an avenue worthy of further exploration.
Other than the fact they all relate to problems with the brain, Alzheimer's, Huntington's and Parkinson's disease don't appear to have much in common, based on their symptoms.
Alzheimer's features memory loss. Huntington's sufferers can't control their body movements, which can be extreme. Those with Parkinson's typically show tremors, rigidity and slowness of movement.
But Dunbar, who studies all three diseases, said they are related in important ways. Evidence shows all three diseases are linked to problems with mitochondria — the parts of brain cells and other cells that produce energy. All three diseases also feature a buildup of a kind of plaque inside brain cells that exacerbates problems if not cleared away, as it is inside healthy brains.
Antioxidants such as those found in tart cherries appear to help mitochondrial function, Dunbar said.
Mice with genes that mimic Alzheimer's who were treated with Cerise in Dunbar's study performed better in two memory-related tests than mice with Alzheimer's genes that did not receive the supplement.
One test involved repeatedly putting the mice into a closed area containing two objects and then replacing one of the objects with a new object. The impaired mice continued to spend about half of their time with each object. The treated mice spent more time with the new object.
Another test featured a water maze. The treated mice did better at remembering where the escape hatch was, Dunbar said.
In the Huntington's study, the treated mice did better on a motor skills test that involved timing how long they could stay on a rotating rod without falling off.
An idea that grew
Pleva credits his daughter with the original idea, which led to a long line of specialty meat products, skin lotions and dietary supplements.
Cindy Pleva-Weber was Michigan Cherry Queen in 1987, and part of her role was marketing.
"We didn't think we could sell any more cherry pies in the world," Pleva-Weber, now CEO of Pleva International, said in a recent interview.
She asked her dad, who worked as a butcher in another family business: "Is there any way you could just throw some in your meat and see if we could sell more that way ... never realizing that this would become something bigger, and on a national scale."
That led to Pleva's first meat-cherry product — a cherry pecan pork sausage — which was followed by a line of Plevalean products. Pleva found the taste of the cherries couldn't be detected, but their addition enhanced the juiciness of the leanest meat.
Pleva said he started to hear from people with health problems who said they could digest his meat better than regular meats and credited the cherry product with other health benefits.
Dunbar said his research work involving Cerise is more open to criticism than the stem cell and other research he performs related to neurodegenerative diseases, but he's OK with that.
Because it's a compound, it's impossible to pinpoint which specific ingredient had the beneficial effect or whether it was the ingredients in combination. For that reason, it is difficult — if not impossible — to obtain research grants to study the compound further.
But Dunbar noted many people benefited from the effects of aspirin in preventing heart attacks before the mechanism behind it was fully understood.
"If I have Huntington's and this gives me a year or two more, who cares?" Dunbar said.