October 4th, 2010
By: David Gutierrez
Researchers from Johns Hopkins University believe they have discovered a biochemical pathway by which a chemical naturally found in dark chocolate can help protect the body from strokes.
Previous research has shown that a flavanol known as epicatechin appears to protect the body against cardiovascular disease and stroke. In the current study, researchers induced strokes in mice and then dosed them with epicatechin to observe how the chemical acted in their bodies.
“We gave different doses of epicatechin in mice 90 minutes before a stroke and found that it reduced infarct [stroke damage] size,” lead researcher Sylvain Dore said. “When we gave epicatechin after a stroke, it had a protective effect up to 3.5 hours later, but not after six hours.”
The researchers found that epicatechin activated two chemical pathways known to protect brain cells from damage, the Nrf2 pathway and the heme oxygenase pathway. When the researchers later induced stroke in mice genetically modified to lack both pathways, epicatechin had no protective effect.
The researchers suggested that epicatechin may one day form the basis for a drug to protect the brain from damage in those who have suffered strokes. The three-hour duration of the protective benefit is particularly encouraging, as modern pharmaceuticals are protective for a much shorter period. But Dore warned that it will be years, if ever, before such a treatment can be developed.
In the meantime, researchers caution consumers against gorging on chocolate as a way to protect their hearts, as the high sugar content can produce other health problems.
“Chocolate comes with a lot of calories,” said flavanol researcher and doctoral candidate Martin Lajous of Harvard University. “I would talk about small amounts of dark chocolate rather than chocolate in general.”
“I prefer to focus on cocoa,” Dore said. “Cocoa is not like chocolate, which is high in saturated fat and calories. Cocoa can be part of a healthy diet, combined with fruits and vegetables.”
December 2, 2009
By David Gutierrez
Evidence continues to mount that the family of plant compounds known as flavonoids can help slow or even halt the progression of Alzheimer’s disease and other forms of dementia.
Flavonoids are a family of chemicals that have been widely studied for a variety of health benefits. They are powerful antioxidants and occur in high concentrations in a variety of fruits and vegetables, particularly citrus fruits, berries, grapes, onions, parsley and legumes. Other good sources include tea (especially green and white), red wine, dark chocolate, ginkgo biloba and seabuckthorn.
Researchers warn that much dark chocolate found in stores is actually relatively low in flavonoids, as the compounds tend to impart a bitter flavor and are often removed during processing.
For a long time, scientists believed that the powerful antioxidant properties of flavonoids – allowing them to scour damaging free radicals from the body – were behind their health effects. Alzheimer’s-related flavonoid research fell out of favor, however, when studies demonstrated that most flavonoids break down rapidly in the body and cannot cross the blood-brain barrier, and when tests with other antioxidants such as Vitamin E showed no benefit in dementia patients.
New research suggests that flavonoids may operate by a different mechanism entirely to provide benefit to patients with Alzheimer’s disease and other forms of dementia, however.
“There have been some intriguing epidemiological studies that the consumption of flavonoid-rich vegetables, fruit juices and red wine delays the onset of the disease,” said Robert Williams of Kings College London.
In a presentation to the summer meeting of the British Pharmacological Society in Edinburgh, Williams reported findings that the chemical epicatechin, in the catechin family of flavonoids, can reduce the symptoms of Alzheimer’s disease when taken orally.
“We have found that epicatechin protects brain cells from damage but through a mechanism unrelated to its antioxidant activity and shown in laboratory tests that it can also reduce some aspects of Alzheimer’s disease pathology,” Williams said. “This is interesting because epicatechin and its breakdown products are measurable in the bloodstream of humans for a number of hours after ingestion and it is one of the relatively few flavonoids known to access the brain suggesting it has the potential to be bioactive in humans.”
“Our findings support the general concept that dietary intake of flavonoid-rich foods or supplements could impact the development and progression of dementia,” Williams said, calling for more research.