X-Message-Number: 25101
Date: Thu, 18 Nov 2004 20:32:07 -0800 (PST)
From: Doug Skrecky <>
Subject: apples, spinach, spirulina versus Alzheimer's?

Antioxidant-Rich Diets Improve Age-Related Declines In Mental Function Of Rats
Tampa, FL (July 15, 2002) - Popeye was right - eat your spinach. In fact,
add some fresh-cut apples to that spinach salad.

Two new animal studies by researchers at the University of South Florida
Center for Aging and Brain Repair and James A. Haley Veterans Hospital
bolster a growing body of evidence that certain fruits and vegetables may
protect the brain against the ravages of age. The complementary research
papers appear in today's issue of the Journal of Neuroscience.

"If these pre-clinical findings translate to humans, it suggests that
eating a diet high in antioxidant-rich fruits and vegetables may help
reverse declines in learning and memory as you get older," Paula
Bickford, PhD, lead author of both studies and a professor at the USF
Center for Aging and Brain Repair.

In the first study, co-authored by USF's M. Claire Cartford, PhD, older
rats fed a diet rich in spinach for six weeks showed a reversal in the
normal loss of learning that occurs with age. The rats that ate rat chow
containing 2 percent freeze-dried spinach learned to associate the sound
of a bell  tone with a subsequent puff of air faster than those fed
regular rat chow, the study found.

The test measured how quickly the rats learned to blink, after hearing
the tone, in anticipation of the oncoming puff of air - a conditioned
response shown to slow with age in rodents and humans.

Spinach is rich in antioxidants, which scientists say can counteract free
radicals generated in the body during normal metabolism and exposure to
environmental insults such as pollution, ultraviolet light and radiation.
An excess of free radicals can damage cellular lipids, protein and DNA.
Studies suggest that a lifelong accumulation of free radicals can slow
mental processes in old age and may be a factor in Alzheimer's and
Parkinson's diseases, Dr. Bickford said.

The second study, co-authored by Carmelina Gemma, PhD, of USF and James
A. Haley VA Hospital, found that the benefit of a diet high in fruits and
vegetables depends on the levels of antioxidant nutrients in the fruits
and vegetables. Furthermore, the researchers suggest, the protective
effect of antioxidants may be linked to their ability to reverse
age-related accumulations of potentially harmful inflammatory substances
in the brain.

The USF researchers compared three groups of older rats. One group ate a
diet supplemented by spirulina, a blue-green algae high in antioxidant
activity. The second group was fed a daily ration of apple, a food
moderate in antioxidant activity, with their rat chow. The third group
ate a cucumber-enriched diet, low in antioxidant activity.

Aged rats fed either spirulina-or apple-enriched diets for two weeks
demonstrated improved neuron function, a suppression of inflammatory
substances in the brain, and a decrease in malondialdehyde (MDA), a
marker for oxidative damage. In fact, spirulina reversed the impairment
in adrenergic neural function normally associated with aging. There was no
improvement in rats fed a diet supplemented with cucumber.

"Not all foods are cr eated equal," Dr. Bickford said. "Cucumbers taste
good and have lots of fiber. But unlike spirulina and apples, they are
not rich in phytochemicals that have antioxidant or anti-inflammatory
effects in the brain."

The research has hopeful implications for the prevention of
neurodegenerative disorders in an increasingly aging population, but
still must be tested in humans, Dr. Bickford said.

Until then, the USF neuroscientist recommends that daily diets include a
variety of richly colored fruits and vegetables - the most colorful ones
tend to pack the greatest antioxidant punch. She favors spinach salads
for lunch and routinely snacks on blueberries and strawberries.

"Studies like these are lending scientific credibility to what
nutritionists, and our mothers, have been telling us for years," Dr.
Bickford said. "Eat your fruits and vegetables. They're good for you!"

Researchers at the University of Colorado Health Sciences Center and
Denver Veterans Affairs Medical Center contributed to the study on diets
enriched with spirulina, apples and cucumbers.

J Neurosci. 2002 Jul 15;22(14):5813-6
Eighteen-month-old Fischer 344 rats fed a spinach-enriched diet show
improved delay classical eyeblink conditioning and reduced expression of
tumor necrosis factor alpha (TNFalpha ) and TNFbeta in the cerebellum.
  Diets high in antioxidant properties are known to reverse some deficits
in neuronal and cognitive function that occur in aging animals.
Antioxidants are also known to reduce levels of proinflammatory factors
in the CNS. We report here that 6 weeks of a spinach-enriched diet
ameliorates deficits in cerebellar-dependent delay classical eyeblink
learning and reduces the proinflammatory cytokines tumor necrosis factor
alpha (TNFalpha) and TNFbeta in the cerebelli of eyeblink-trained
animals. Eighteen-month-old Fischer 344 rats were given spinach-enriched
lab chow or regular lab chow for 6 weeks. The rats were then given 6 d of
30 trials per day training using a 3 kHz tone conditioned stimulus and
airpuff unconditioned stimulus. Rats were killed 3 weeks after eyeblink
training. Cytokine expression was measured using RNase protection assay
analysis in the eyeblink-trained animals and in a group of young control
animals given regular lab chow diet. Old animals on the spinach-enriched
lab chow diet learned delay eyeblink conditioning significantly faster
than old animals on the regular diet. Cerebelli fr om older animals on
the spinach-enriched diet had significantly less TNFalpha and
TNFbeta than cerebelli from older animals on the control diet.

J Neurosci. 2002 Jul 15;22(14):6114-20
Diets enriched in foods with high antioxidant activity reverse
age-induced decreases in cerebellar beta-adrenergic  function and
increases in proinflammatory cytokines.
  Antioxidants and diets supplemented with foods high in oxygen radical
absorbance capacity (ORAC) reverse age-related decreases in cerebellar
beta-adrenergic receptor function. We examined whether this effect was
related to the antioxidant capacity of the food supplement and whether an
antioxidant-rich diet reduced the levels of proinflammatory cytokines in
the cerebellum. Aged male Fischer 344 rats were given apple (5 mg dry
weight), spirulina (5 mg), or cucumber (5 mg) either in 0.5 ml water by
oral gavage or supplied in the rat chow daily for 14 d. Electrophysiologic
techniques revealed a significant decrease in beta-adrenergic receptor
function in aged control rats. Spirulina reversed this effect. Apple (a
food with intermediate ORAC) had an intermediate effect on cerebellar
beta-adrenergic receptor physiology, and cucumber (low ORAC) had no
effect, indicating that the reversal of beta-adrenergic receptor function
decreases might be related to the ORAC dose. The mRNA of the
proinflammatory cytokines tumor necrosis factor-alpha (TNFalpha) and
TNFbeta was also examined. RNase protection assays revealed increased
levels of these cytokines in the aged cerebellum.  Spirulina and apple
significantly downregulated this age-related increase in proinflammatory
cytokines, whereas cucumber had no effect, suggesting that one mechanism
by which these diets work is by modulation of an age-related increase in
inflammatory responses. Malondialdehyde (MDA) was measured as
a marker of oxidative damage. Apple and spirulina b ut not cucumber
decreased MDA levels in the aged rats. In summary, the improved
beta-adrenergic receptor function in aged rats induced by diets rich in
antioxidants is related to the ORAC dose, and these diets reduce
proinflammatory cytokine levels.

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