Lapses of memory and other signs of declining mental sharpness are a common, sometimes disturbing sign of aging. People may experience such episodes from age thirty on, and a majority have some by age sixty. Researchers call it age-related cognitive decline (ARCD). Clinicians distinguish this "normal" mental decline from Alzheimer’s disease or other abnormal dementias.
Researchers and clinicians don’t always agree as to what the norms are for ARCD and how many persons experience above-average memory decline. Over the past twenty years, though, Thomas Crook, Ph.D. developed a useful set of tests for short-term memory that can measure ARCD. Poorer than average performance on name-face matching, grocery list recall, telephone dialing, and object location can indicate that cognitive decline is accelerated for an individual.
With or without such testing, though, one does not have to become the victim of an aging brain. As medical researchers have achieved a greater understanding of what causes brain aging, nutritional researchers have kept apace by discovering how various nutrients can help reverse cognitive decline.
In general, cognitive decline occurs as the brain loses a significant number of brain cells (neurons) and inter-cell connections because of various chemical assaults. Research suggests that neurons can be damaged by free oxygen radicals generated by normal metabolism and by cigarette smoke, pollutants, alcohol, and stress. Free radicals damage cell membranes crucial to cell function.
The chronic stress so many experience in our fast-paced society causes an excess of cortisol (a hormone produced by the adrenal glands) to be produced. Such constant cortisol release is believed to generate free radicals and to prevent sufficient oxygen and glucose from getting to the brain. Also, a lack of adequate blood circulation to the brain (caused by arteriosclerosis, diabetes, or other disease) reduces available glucose and oxygen, which causes neuronal decline and death.
Impaired brain function has also been linked to a loss of adequate acetylcholine, the neurotransmitter that plays the greatest role in memory processing. A lack of choline—a key B-vitamin-type nutrient—can lead nerve cells to cannibalize their own cell membranes for the choline needed to produce acetylcholine.
The cell membranes of the brain’s neurons are primarily composed of fatty acid molecules called phospholipids. Lecithin, a food supplement that is derived from soybeans, is packed with such phospholipids. Phosphatidyl Choline (PC) is the phospholipid that is most prevalent (23%) in lecithin, although phosphatidyl ethanolamine (21%) and phosphatidyl inositol (19%) are also abundant. Phosphatidyl serine, a remarkable anti-brain-aging nutrient, is present in trace amounts in lecithin. The cell membranes of nerves contain all of these phospholipids. Getting adequate lecithin in one’s diet, or through supplementation, is important for two reasons. PC and the other phospholipids in lecithin help nerve cells rebuild cell membranes, and the choline is essential for both the manufacture of acetylcholine and the cell membranes.
Human studies suggest that lecithin can benefit memory. In one study, a group of 61 healthy adults (50 to 80 years of age) were given 2 Tbsps. of lecithin for five weeks. Memory tests given at the close of the study indicated that the lecithin group had significant memory improvement, with almost 50 percent fewer memory lapses, in comparison to the control group.
A new form of choline, called CDP-choline (cytidine 5-diphosphocholine), has been used successfully to treat learning and memory impairment. It has also proven valuable in the treatment of stroke and head trauma victims in restoring motor abilities, and shows some promise in slowing the progress of Alzheimer’s disease. I recommend taking 2 Tbsps. (15 grams) of lecithin, which provides about 3.5 grams of PC and 500 mgs. of choline. One should take care to buy it from a source that can guarantee freshness, to avoid rancid (oxidized) lecithin. Or, you can use capsules of PC. These usually contain about 180 mgs of PC, so about 10 capsules would need to be taken in order to get the PC equivalent of 1 Tbsp. of lecithin granules.
People used to get a lot more phosphatidylcholine in their diets before low fat diets became the norm, since eggs and meats have by far the most, with nuts, seeds, soybeans, and dairy also having considerable amounts. Americans used to get about 6 grams; today many people get less than one-half of this. The much maligned egg contains a whopping 3.4 grams of PC, while a Tbsp. of granular de-fatted lecithin contains 1.7 grams of PC and about 250 mg. of choline.
The best nutritional strategy is to provide both additional lecithin (or PC caps) to one’s diet and additional choline, most often available in the form of choline bitartrate. Although ample amounts of supplemental choline fuels the production of membranes and acetylcholine, some people can experience a fishy odor with high intake due to a breakdown product. I would recommend trying 500 to 1,000 mgs. of choline, taken along with lecithin. Note: Too much choline can cause diarrhea, whereas gas and bloating can sometimes be a problem with high lecithin intake. Each person needs to find the dose and schedule that works without even these benign side effects. All of these supplements are best taken with meals.
Acetyl-L-Carnitine (ALC) is a form of the amino acid carnitine. The body naturally produces this amino acid, which is also found in small amounts in certain foods. ALC has long been recognized for its ability to increase cellular energy production, including in the brain, which uses 20% of the body’s energy. The acetyl group of ALC also increases the production of acetylcholine, not only by providing its acetyl group to brain cells but also by stimulating their uptake of choline. As discussed above, the production of sufficient acetylcholine is important to memory and learning functions of brain cells.
ALC provides other important benefits to brain cells. Foremost of these, perhaps, is its ability to protect neurons that are important in guarding the brain against excessive cortisol, the hormone released during chronic stress. Neurons in the area of the brain called the hippocampus shut down excessive cortisol by signaling the pituitary and adrenal glands to stop production. With aging and long-term stress, the number of these neurons in the hippocampus seriously declines. ALC has been shown, in animal studies, to help preserve these neurons. And in human clinical trials, ALC has restored the ability of the nervous system to control cortisol production during stress and physical exertion. ALC has also been shown to preserve nerve receptors that transmit a substance called nerve growth factor, which stimulates nerve repair and the rebuilding of nerve interconnections. There is also evidence that ALC stimulates nerve survival and repair itself.
In clinical trials, ALC has improved memory and cognition in persons with age-related cognitive decline (ARCD), and has even helped people with Alzheimer’s delay progress of the disease and improve in some cognitive functions. It has also been useful in alleviating depression and in improving the functioning of Parkinson’s patients.
Aceyl-L-Carnitine is usually taken at doses of 1,000-2,000 mg. per day with meals, and has no side effects reported other than occasional skin rash or increased appetite. Taking ALC as part of a regimen that also includes sources of choline (lecithin, PC, or choline bitartrate) has added benefits in that choline has been shown to conserve carnitine by inhibiting its loss in the urine.
Phosphatidyl serine (PS), a phospholipid that occurs in trace amounts in lecithin, occurs in all cell membranes but is most highly concentrated in those of the brain. Up until recently, the PS used was derived from cow brains; the development of a soy-derived product has allowed for its greater availability and safety. PS is believed to be especially important in supporting, at the cell membrane level, the functions of various proteins that help control brain cell function. Like Acetyl-L-carnitine, PS helps reduce high levels of the stress hormone cortisol.
Numerous clinical trials show that PS can significantly improve memory and brain performance for those experiencing ARCD. In one trial, PS was given to a group of subjects ages 50 to 75 at 300 mg per day for 12 weeks; it was found to benefit all subjects. Name-face recognition tests for subjects who were 64 years old, with accelerated ARCD, was improved by 12 years—that is, their memory performed as if they were 52 years old. PS has also been clinically tested on persons with Alzheimer’s and other dementias; these trials have determined that PS can significantly improve cognitive skills and quality of life for such patients.
Clinical trials of PS have been ongoing for more than twenty years, and they have confirmed both the safety and effectiveness of PS for all conditions that result in memory and cognitive impairment, from ARCD to Alzheimer’s or stroke. Clinical doses have ranged from 200 to 800 mg per day, although 300 mg taken in divided doses with meals has been the norm. The only contraindication for PS is for persons with soy allergy.
Vitamin E is an important fat-soluble antioxidant, and as such it provides special protection against free radical damage to the phospholipid structures of cell membranes. Doses of 400-800 IUs are beneficial for persons with ARCD. Clinical trials have suggested that larger doses (2,000 mg) can be of benefit to persons with Alzheimer’s or other dementias.
DMAE is believed to be an efficient precursor of acetylcholine in that, unlike choline bitartrate, it readily crosses the blood-brain barrier (vascular membranes that protect the brain from potentially toxic substances). Early studies suggested that alertness and cognition was improved at doses of 400 mg per day, but later studies using large doses (1800 mg per day) with Alzheimer’s patients demonstrated improvement in behavior but not in memory. I would suggest that, in conjunction with the use of lecithin, phosphatidyl choline, and choline, DMAE could be used in relatively small doses (100 mg in the morning) to improve alertness and mood if not cognition. It is presently being so used by various physicians as part of a natural treatment for hyperactivity in children. The use of DMAE may also have, as a side effect, recall of lucid dreams.
No review of supplements that can benefit cognitive function should neglect to mention Ginkgo. At doses of 40 to 80 mg taken three times daily, Ginkgo biloba extract has been shown to improve memory and other cognitive functions in persons with ARCD. (Trials in healthy persons under 40 snow no measurable improvement, but it should have a preventive effect against ARCD—more research is needed.) Not only does it improve circulation to the brain (and to extremities) and thus provide needed oxygen and glucose, but also some of its bioflavonoids protect cell membranes from free radical damage. Look for products guaranteed to contain 6% terpenes and 24% ginkgosides—the minimum standard used in successful clinical trials.