AgeLess
Mind - Increase Cognitive Function
by Kim
Schoenhals
Memory loss is unusual forgetfulness that can be caused by brain damage due to disease or injury, or it can be caused by severe emotional trauma. Normal aging may result in trouble learning new material or requiring longer time to recall learned material. However, it does not lead to dramatic memory loss unless diseases are involved. Research presented at the World Alzheimer's Congress in July 2001 suggested that high intakes of vitamin E effectively tapered memory loss and cognitive decline in a group of more than 6,000 elderly subjects whose vitamin E intake was generally between 200 to 400 IU per day.
Cognitive function includes a wide range of processes,
none of which is a generally conscious action: Thinking, calculating,
perceiving and judging occur in the mind without conscious effort. Unfortunately,
environmental toxins, vitamin deficiencies and the process of aging can
alter cognition. The aging process generally leads to difficulties with
memory, which causes many people to fear they have dementia. However,
dementia is not a normal part of aging.
Dementia, the loss of intellectual functions such as remembering and reasoning,
is itself a disease and can also be a symptom of other diseases, including
Alzheimer's, multi-infarct dementia (vascular dementia), Parkinson's and
Creutzfeldt-Jakob disease. According to the U.S. Congress Office of Technology
Assessment, 1.8 million Americans have severe dementia and another 1 million
to 5 million have mild to moderate dementia. Approximately 4 million of
these people suffer from dementia due to Alzheimer's disease, which is
expected to affect more than 6 million by the year 2040.
There is no cure for dementia or Alzheimer's, although medications can
limit the severity of the afflictions. Dietary supplements may also slow
the progression of dementia, as well as increase cognitive function impaired
as a part of the aging process. The National Institute on Aging recommends
maintaining a healthy diet and exercise regimen to preserve cognitive
function, especially for the elderly. In support of this theory, a recent
Italian study indicated cognitive function is higher in those who have
a healthy diet, as defined by the World Health Organization guidelines
for the prevention of chronic disease (Eur J Clin Nutr, 55, 12:1053-58,
2001) (http://content.naturesj.com).
Antioxidants
Many nutrients have been indicated in improving cognitive function, as
well as preventing or slowing age-related cognitive decline. Many times,
ingredients are recommended in combination with each other--vitamin B
complex, vitamin E, Coenzyme Q10 (CoQ10), Ginkgo biloba and phosphatidylserine
(PS), combined with a 15-percent fat diet, were shown to prevent memory
loss and Alzheimer's (Altern Ther Health Med, 4, 6:38-43, 1998) (www.alternative-therapies.com).
While numerous combinations are suggested for treating and preventing
cognitive decline, antioxidants are a popular part of the combination
because they combat the free radicals that have been implicated in causing
damage to brain cells. Canadian scientists tested this theory by supplementing
96 elderly subjects with trace elements and vitamins. They found that
cognitive function in the supplement group improved in comparison to the
placebo group (Nutrition, 17, 9:709-12, 2001) (www.nutrition.org).
Vitamin E, including tocopherols and tocotrienols, is one antioxidant
vitamin particularly thought to improve cognitive function and stall cognitive
decline. A suspected reason for this nutrient's success at preventing
oxidative damage in brain cells is its fat-soluble status, which makes
it well absorbed by the brain, the body's fattiest organ.
Alpha-tocopherol combined with antioxidant vitamin A (retinol) may play
a role in preventing Alzheimer's related dementia. According to French
researchers, Alzheimer's patients exhibit low plasma concentrations of
tocopherols and retinol as compared to control subjects because of high
amounts of free radicals in the brain; the researchers theorized that
much of the patients' dietary tocopherol and retinol had been utilized
to fight oxidative damage (Age and Ageing, 30:235-41, 2001) (http://ageing.oupjournals.org).
Tocotrienols are a group of antioxidants thought to reduce oxidative damage
to the brain. Preliminary research demonstrated that tocotrienols are
effective in reducing neuronal cell death in mouse hippocampal cells (J
Biol Chem, 275:13049-55, 2000) (www.jbc.org). Additional animal research
has demonstrated that palm tocotrienol complex, which contains high levels
of alpha-tocotrienol and gamma-tocotrienol, is effective in protecting
against oxidative damage to brain cells (Neuro Lett, 195:179-82, 1995).
Vitamin E in combination with a water-soluble antioxidant, vitamin C,
may protect against vascular dementia and improve cognitive function later
in life, according to the Honolulu-Asia Aging Study (Neurology, 54:1265-72,
2000) (www.neurology.org). Vitamin C also may be able to assist those
suffering from neurodegenerative diseases by improving the ability of
medications to cross the blood-brain barrier, according to a study published
in the Dec. 21, 2001, Web edition of the Journal of Medicinal Chemistry
(http://pubs.acs.org/journals/jmcmar).
CoQ10 is another antioxidant that has been studied in relation to improving
cognitive function. Specifically, oral administration of CoQ10 has been
studied in Parkinson's disease patients for increasing cognitive activity
(Biofactors, 9, 2-4:261-6, 1999) (http://www.iospress.nl). Researchers
concluded that while the antioxidant may have benefit in patients with
neurodegenerative diseases, no clinical studies have demonstrated a guaranteed
benefit. However, a study conducted at the University of California, Irvine,
noted that CoQ10 administration had no effect on improving cognitive function
in mice (Neurochem Int, 40, 2:123-30, 2002) (www.elsevier.com).
Flavonoids, polyphenolic compounds with antioxidant effects, may improve
cognitive function by reducing oxidative damage. Flavonoids are found
in a range of extracts, including blueberry, grapeseed, bilberry, hawthorn
and rosemary.
Blueberries may be helpful in aging gracefully, according to preliminary
research presented at the American Dietetic Association (www.eatright.org)
conference in October 2000. The symposium, "Fruits and Vegetables'
Effects on Brain Aging," was presented by James Joseph, Ph.D., chief
of the Neuroscience Laboratory at the U.S. Department of Agriculture (USDA)
Human Nutrition Research Center on Aging at Tufts University. Joseph reported
that blueberries may improve motor skills and reverse short-term memory
loss associated with aging, and USDA trials showed improved navigational
skills in animals fed a diet supplemented with blueberry extract for two
months. Additionally, a study focusing on the cognitive effects of blueberries,
spinach and strawberries singled out blueberries as the most effective
(J Neuroscience, 19, 18:8114-21, 1999) (www.jneurosci.org).
Grapeseed extract contains oligomeric proanthocyanidins (OPCs), a class
of flavonoid known for antioxidant activity. When compared to the antioxidant
activity of vitamins C, E and beta-carotene, researchers at Creighton
University in Omaha, Neb., stated that grape seed proanthocyanidin extract
is highly bioavailable and provides greater protection against free radical
damage (Toxicology, 148, 2-3:187-97, 2000) (www.elsevier.com).
Bilberry, Vaccinium myrtillus L., also contains OPCs, which may explain
why it is thought to positively affect cognitive function through free
radical scavenging. Bilberry has strong free radical scavenging properties,
and its active constituents may inhibit lipid peroxidation (Phytother
Res, 12, S1:S104-S106, 1998) (www.interscience.wiley.com).
Hawthorn's antioxidant activity lies within its large makeup of flavonoids,
including OPCs (Z Naturforsch, 56, 9-10:739-44, 2001). Another herb, rosemary,
Rosmarinus officinalis, contains rosmarinic acid, which has been shown
to inhibit cancer formation in animal studies and acts as an antioxidant.
While numerous antioxidant ingredients appear to improve cognitive function
and stave off oxidative damage, vitamin deficiencies may exacerbate cognitive
decline. It has been suggested that dementia may occur in those with deficiencies
of vitamin B12, as well as deficiencies of the other B vitamins. Research
gathered from the NHANES III study in December 2001 indicated that elderly
people with high homocysteine levels, as a result of low B vitamin intake,
could be affected in terms of memory loss and cognition. Further, according
to researchers in Stockholm, vitamin B12 and folic acid deficiencies may
be involved in the development of Alzheimer's disease (Neurology, 56:1188-94,
2001).
Brain
Food
Compounds derived from the brain may also be able to assist
cognitive function in supplement form. Phosphatidylserine (PS) is a phospholipid
that has been studied for its ability to slow cognitive decline because it is
responsible for assisting in brain function and helping the brain process energy.
PS can be derived from both plant and bovine sources, although there has been
concern in recent years with the latter because of "mad cow" disease.
Both plant- and bovine-derived PS have been shown in clinical trials
to positively affect cognitive function. According to a study conducted in Israel
at the Tel Aviv University Sackler School of Medicine, plant- and bovine-sourced
PS act similarly in vivo (Isr J Psychiatry Relat Sci, 37, 4:302-7, 2000) (http://www.niwi.knaw.nl).
In addition, PS has been shown in clinical trials to improve memory, learning,
concentration, word recall and mood in middle-aged and elderly subjects with dementia
or age-related cognitive decline (Alt Med Rev (4, 3:144-61, 1999) (www.thorne.com/altmedrev).
Phosphatidylcholine (PC), another phospholipid nutrient, may also play
a part in cognitive function. According to an animal study conducted in France,
levels of PC (as well as PS) are lower in the brains of aged mice than younger
mice (Prostaglandins Leukot Essent Fatty Acids, 64, 3:189-95, 2001). In an earlier
human trial, researchers from the University of Guelph in Ontario discovered that
patients with Alzheimer's disease, other dementias or general cognitive impairment
had lower plasma phospholipid and PC concentrations (Lipids, 35, 12:1305-12, 2000)
(www.aocs.org).
Acetyl-l-carnitine (ALC) is another compound found in
the human body that may be relevant to cognitive function. ALC is an ester of
the trimethylated amino acid, L-carnitine, which is synthesized in the human brain,
liver and kidney. "[ALC] benefits mitochondrial efficiency and functions
as an antioxidant within the mitochondria, helping neurons maintain optimal energy
levels," wrote Robert Crayhon, Ph.D., in the May/June 2000 issue of International
Journal of Integrative Medicine. The consumption of alcoholic beverages is contraindicated
with ALC, and epileptics should avoid the supplement, Crayhon noted.
In an animal study conducted at the Tokyo Metropolitan Institute of Gerontology,
ALC-treated rats had a superior learning capacity when compared to the control
group (J Neurosci Res, 66, 2:266-71, 2001) (www.amedeo.com). Another study conducted
at the University of California, San Diego, concluded that early-onset Alzheimer's
patients may benefit more than late-onset Alzheimer's patients from ALC supplementation
(Neurology, 47, 3:705-11, 2001). However, the same researchers conducted another
double blind, placebo-controlled, randomized trial and ended up with different
findings: ALC supplementation failed to slow cognitive decline in early-onset
Alzheimer's patients (Neurology, 55, 6:805-10, 2000).
Herbs
and Botanicals
Herbal products have also been extensively studied
for their ability to improve cognitive function. Huperzine A, prepared from the
moss Huperzia serrata, is a Chinese herb said to benefit cognitive health. According
to a Chinese study, huperzine A shows promise for treating mental decline (Xhongguo
Yao Li Xue Bao, 16, 5:391-5, 1995). In more recent research, scientists at the
Chinese Academy of Sciences in Shanghai discovered that huperzine A treatment
on transient global ischemia in gerbils resulted in lessened memory deficits and
neuronal damage. Scientists concluded that huperzine A may have benefit in cerebrovascular
type dementia (Neurosci Lett, 313, 3:137-40, 2001).
Lion's mane (Hericium
erinaceus) is a mushroom thought to possess the ability to improve cognitive function.
The correlation is suggested because the mushroom seems to be able to stimulate
nerve growth factor (NGF), which may help inhibit cognitive decline. According
to an early study, Lion's mane contains six compounds that were found to induce
the synthesis of NGF, which is believed to be associated with Alzheimer's disease.
The authors concluded that the mushroom may have potential in slowing progression
of Alzheimer's (Tetrahedron Letters, 30, 3:373-76, 1990).
Vinpocetine
is derived from vincamine, an alkaloid found in the periwinkle plant, and is recommended
for cognitive function improvement--specifically memory and improving blood circulation
to the brain. "Experiments with vinpocetine indicate that it can dilate blood
vessels, enhance circulation in the brain, improve oxygen utilization, make red
blood cells more pliable and inhibit aggregation of platelets," wrote Ray
Sahelian, M.D., in his book Mind Boosters (St. Martins Griffin, 2000). Sahelian
cited three clinical trials in which vinpocetine improved cognitive function and
one trial that failed to demonstrate an effect. "The long-term effects of
vinpocetine are not known," Sahelian warned. "It does have blood-thinning
potential, hence those taking warfarin or high doses of aspirin or other blood
thinners need to inform their physician before use."
Sahelian also
reviewed Ginkgo biloba, stating "the primary indications for Ginkgo use are
age-related cognitive decline and Alzheimer's disease ... A well-publicized study
in the Journal of the American Medical Association indicated that 120 mg of Ginkgo
extract per day for one year was able to slightly improve cognitive performance
in patients with Alzheimer's disease (Le Bars 1997)."
While it
has been suggested that Ginkgo extract improves cognitive function more effectively
in patients with dementia (Public Health Nutr, 3, 4A:495-9, 2000), a trial conducted
in The Netherlands did not find any effect on people with mild to moderate dementia
or age-related memory impairment (J Am Geriatr Soc, 48, 10:1183-94, 2000) (www.lww.com/AGS).
Another herb that may have application in cognitive health is ashwagandha,
otherwise known as Withania somnifera. According to Indian researchers at M.L.
Sukhadia University in Udaipur, ashwagandha demonstrates anti-stress and neuroprotective
effects when applied to the hippocampal region of stressed rats (Phytother Res,
15, 6:544-8, 2001).
Bad Press
While the numerous
ingredients being studied for improving cognitive function are proving themselves
in scientific research, additional research and media coverage sometimes casts
a negative light on the supplement industry. The U.S. Senate Special Committee
convened on Sept. 10, 2001, for a hearing titled, "Swindlers, Hucksters and
Snake Oil Salesmen: The Hype and Hope of Marketing Anti-Aging Products to Seniors"
(www.senate.gov/~aging/hr73.htm). The committee focused on companies that mislead
consumers in regard to dietary supplements.
"As with any industry,
the vast majority of manufacturers and marketers of supplements are reputable
and law abiding," said Sen. John Breaux (D-La.), chairman of the committee.
"It is the bad actors that we are concerned with." He added that the
hearing was focused only on those marketing misleading or ineffective products
and not the science of complementary therapies.
Industry organizations
attempted to pre-empt and respond to the negative press coverage. The Dietary
Supplement Education Alliance and the Council for Responsible Nutrition issued
releases the day of the hearing discussing positive news about dietary supplements
and the elderly. Both discussed ongoing studies on supplements and aging conducted
by the National Institutes of Health, as well as recently published clinical studies
on the benefits of dietary supplements for the elderly.
Ginkgo biloba
has been especially persecuted this year in the media. In the July 11 Journal
of the American Medical Association (286:208-16, 2001) (www.jama.com), researchers
found that certain herbs, including Ginkgo biloba, may interfere with a patient's
recovery time after surgery. Research indicated that complications could occur
during post-op recovery because of the anti-clotting attributes of Ginkgo.
Another negative review of Ginkgo was printed in the September issue of Chemical
Research in Toxicology (14, 9:1254-8, 2001) (http://pubs.acs.org), with researchers
reporting they found colchicine--a substance that might cause birth malformations--in
Ginkgo biloba supplements. The researchers, led by Howard Petty, Ph.D., from Wayne
State University, concluded that Ginkgo may create fetal malformations and that
"the potential detrimental roles of natural plant products in reproductive
health merit further analysis." (More on this story can be found at http://www.naturalproductsinsider.com/articles/191news1.html.)
All in all, the research on dietary supplements is positive, demonstrating
the supportive benefits they lend to cognitive function. As the numerous industry
organizations continue to promote the clinical evidence behind dietary supplements,
and the supplement manufacturers continue to sponsor peer-reviewed clinical trials,
this industry will have additional support to combat negative media.
Cognitive Function Factoids
To the Detriment
· Age-related cognitive incline can slightly impair memory and mood.
· Dementia is not a symptom of old age.
· Dementia is a disease
characterized by serious changes in memory, personality and behavior.
·
1.8 million Americans suffer from severe dementia.
· 1 million to
5 million Americans have mild to moderate dementia.
· 4 million dementia
cases are because of Alzheimer's disease.
· Alzheimer's disease is
expected to affect more than 6 million by the year 2040.
· The prevalence
of Alzheimer's disease doubles every five years after age 65.
· Nearly
half of all people age 85 and older are thought to have some form of dementia.
To the Benefit
· Fat-soluble vitamin E
fights free radical damage in the body's fattiest organ--the brain.
·
Antioxidant CoQ10 increases brain activity in Parkinson's patients.
·
Flavonoids combat free radical damage and may improve cognitive function.
· Phosphatidylserine assists brain function and helps the brain process
energy.
· Low phosphatidylcholine concentrations are common in dementia
patients.
· Acetyl-l-carnitine helps neurons maintain optimal energy
levels.
· Huperzine A may improve memory, cognitive and behavioral
function.
· Lion's mane stimulates nerve growth factor, which may
inhibit cognitive decline.
· Vinpocetine improves blood circulation
to the brain.
· Ginkgo biloba may improve cognitive performance in
Alzheimer's patients.
· Ashwagandha has shown neuroprotective effects
in animal studies.