Antioxidant-rich diets reduce brain
damage from stroke, new preclinical study suggests
And if that's not reason enough, a new
study suggests antioxidant-rich fruits and vegetables may limit brain damage from stroke and
other neurological disorders. The study, conducted by researchers at the University of South
Florida College of Medicine, James A. Haley Veterans' Hospital and the National Institute on
Drug Abuse, is posted online in the May 2005 issue of the journal Experimental Neurology.
USF/VA neuroscientist Paula Bickford, PhD,
and colleagues found that rats fed diets preventatively enriched with blueberries, spinach
or an algae known as spirulina experienced less brain cell loss and improved recovery of
movement following a stroke.
The study builds upon previous USF/VA
research showing that diets enriched with blueberries, spinach or spirulina reversed normal
age-related declines in memory and learning in old rats.
"I was amazed at the extent of
neuroprotection these antioxidant-rich diets provided," said Dr. Bickford, a researcher
at the USF Center for Aging and Brain Repair and James A. Haley Veterans' Hospital.
"The size of the stroke was 50 to 75 percent less in rats treated with diets
supplemented with blueberries, spinach or spirulina before the stroke."
Antioxidant and anti-inflammatory
substances in these fruits and vegetables may somehow reduce the nerve cell injury and death
triggered by a stroke, the researchers suggest. "The clinical implication is that
increasing fruit and vegetable consumption may make a difference in the severity of a
stroke," Dr. Bickford said. "It could be a readily available, inexpensive and
relatively safe way to benefit stroke patients."
The researchers studied four groups of
rats, all fed equal amounts of food for one month. One group was fed rat chow supplemented
with blueberries, a second group chow with spinach, and the third chow with spirulina. The
control (untreated) group ate chow only.
After four weeks, an ischemic stroke with
reperfusion was induced in the rats. An ischemic stroke occurs when a blood clot cuts off
the oxygen supply to the brain like the kink in a hose cuts off water flow. Then, later, the
clot is released and blood flow returns, which is known as reperfusion.
The size of the stroke in the rats fed
blueberry or spinach supplements was half that seen in the brains of untreated rats. Rats
fed spirulina-enriched diets had stroke lesions 75 percent smaller than their untreated
counterparts. In addition, rats pretreated with the blueberry, spinach or spirulina diets
showed greater increases in poststroke movement than the control group.
All the supplemented diets were rich in
antioxidants, which scientists say may counteract the burst of free radicals involved in the
cascade of brain cell death triggered by an ischemic stroke. An excess of free radicals can
damage cellular lipids, proteins and DNA.
The supplemented diets also contained
anti-inflammatory substances that may help reduce inflammation-induced injury following a
stroke, Dr. Bickford said. When a stroke occurs, immune cells in the brain mount an
inflammatory response – rushing to the site of injury to clear away the dead and dying
cells. As a result, nearby healthy nerve cells may suffer collateral damage much the same
way firefighters breaking into an apartment to put out a fire in one room may inadvertently
cause damage to other rooms.
Teasing out just which beneficial chemicals
contained in the blueberries and leafy greens might be reproduced therapeutically in pill
form is difficult, Dr. Bickford said. "Whole foods contain multiple nutrients, so there
are many different ways these diets could be protecting the brain. From a scientific
perspective, it's a package deal."
Dr. Bickford's team is investigating
whether rats treated with antioxidant-rich diets following strokes will experience improved
recovery. The researchers also plan to study whether combinations of the diets might provide
even greater protection against stroke damage than one diet alone.
The study was supported by grants from the
National Institute on Drug Abuse and the Veterans Administration.
HUMAN CLINICAL STUDY SUPPORTS ANTI-ALLERGY
EFFECTS OF SPIRULINA-BASED NUTRACEUTICAL IN ALLERGIC RHINITIS PATIENTS
A recent clinical study involving 36
allergic rhinitis patients has demonstrated that ingesting only 2g of spirulina a day
provides a significant reduction in the level of Interluken-4 (IL-4) in the body. IL-4 is
produced by certain immune cells and is responsible for the production of the antibody,
Immunoglobulin E (IgE), which mediates symptoms of allergic rhinitis.
The double-blind, randomized,
placebo-controlled study was conducted by a University of California, Davis, group, led by
Dr. Eric Gershwin, Chief, Division of Rheumatology, Allergy and Clinical Immunology.
"This is the first time that a
nutraceutical has been shown to have beneficial effects on the machinery that causes human
allergies," Gershwin said. "While further studies are planned, we are pleased that
Spirulina is a material rich in anti-oxidants and containing other important nutrients ¾
has clear potential to help people with allergies".
"This study is very significant in
that it proved, in a human clinical study, what has been found in many other animal and in
vitro studies, including a previous study by the UC Davis group, about the anti-allergic and
anti-inflammatory effects of Spirulina" said Dr. Amha Belay, Sr. Vice President and
Scientific Director of Earthrise Nutritionals, LLC.
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