Herbs for Alzheimer’s

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Lemon balm has been found to have some effect on the enzyme thought to play a part in the development of Alzheimer's.

It starts with a seemingly natural forgetfulness–short-term memory lapses that are barely noticeable, even to friends and family. As it progresses, the memory fades away completely, like a ship heading out to sea, becoming engulfed by fog. A childlike mentality takes over, and a loss of control over functions such as talking and walking begins. Depression, delusions, and hallucinations may become part of the new life of a once happy, mentally astute human being.

So it goes with Alzheimer’s disease, a degeneration of brain cells that leads to deteriorating mental abilities. Named for Alois Alzheimer, the German neurologist who identified it in 1907, the disease tends to strike people older than age sixty-five, although it can occur in people much younger. According to the National Institute on Aging, about four million Americans have the disease, and about half of all people who live beyond age eighty-five will be afflicted.

Alzheimer’s is not an inevitable part of aging, but its cause has not been conclusively determined. Many believe that it is linked to the destruction of acetylcholine, a chemical that helps transmit nerve impulses in the brain. Other possible causes include genetic factors, exposure to toxins, abnormal protein production, viruses, and abnormalities in the barrier between the blood and the brain.

One method used to treat Alzheimer’s patients is to try to increase their levels of acetylcholine to stave off progression of the disease and slow memory loss. This method focuses on an enzyme known as anticholinesterase, which prevents another enzyme, cholinesterase, from destroying acetylcholine. In the United States, the drug tacrine is approved for this use. However, tacrine can have serious side effects, including liver damage.

Recent preliminary research shows that some herbs–including many members of the mint family, such as sage, rosemary, and balm–also hold potential for keeping Alzheimer’s at bay. This research is new, as the word preliminary implies, but points to promising inroads into treatments for this devastating disease.

Alzheimer’s Defined

Alzheimer’s is progressive degenerative disease of cells in the brain, where it may show up as “senile” plaques or lesions. It is the most common cause of dementia, widespread cerebral damage that manifests in a variety of symptoms, including memory loss, disorientation, restlessness, impaired judgment, and irritability.

Alzheimer’s can result in a vegetative state and death. Onset may occur at any age, but most commonly strikes those older than sixty-five. Women are afflicted twice as often as men.

The cause of the disease may be related to a loss of acetylcholine, a chemical messenger in the brain. Other possible causes currently being researched include genetic factors, estrogen loss in females, excessive protein production, and exposure to toxics such as aluminum.

Sage, Balm, and Memory

Legend has it that the Chinese would trade three chests of their best tea for one chest of sage. Perhaps this custom was linked to sage’s reputation for improving heart conditions, including circulation through the coronary arteries.

Today, laboratory research from England shows that common sage (Salvia officinalis) and Spanish sage (S. lavandulifolia), both members of the mint family of plants (Lamiaceae), may help restore brain function and memory in Alzheimer’s patients.

The British researchers investigated fifteen plants with reputations for enhancing memory and alleviating mental disorders, applying crude extracts of the herbs to human brain tissue to see whether any could inhibit cholinesterase. “Sage oil was the most promising,” the researchers reported, effectively blocking the destructive enzyme from going to work in the part of the brain responsible for memory.

In the same study, researchers found that the essential oil of another member of the mint family, lemon balm (Melissa officinalis), fought off the enzyme and indeed was a more potent weapon than either sage species. However, the researchers noted that lemon balm oil in Great Britain is often adulterated with the essential oils of lemongrass (Cymbopogon citratus) and lime (Citrus aurantifolia). Study results showed that lemongrass had no effect against the culprit enzyme, but that lime was strongly inhibitory. The study didn’t include an investigation of pure, authenticated lemon balm oil.

And Rosemary For Remembrance

In ancient Greece, it was believed that rosemary could strengthen the memory, and students wore sprigs of the herb in their hair while they studied. Since that time, rosemary has been known as the “herb of remembrance.”

Today, it is known that rosemary, which is recommended by aromatherapists to treat Alzheimer’s, contains carvacrol and other compounds that protect acetylcholine. James A. Duke, Ph.D., points out that rosemary also contains an abundant supply of antioxidants. Antioxidants are important because Alzheimer’s may be linked to oxidation, or destruction, of brain cells.

Marshall Folstein, M.D., Psychiatrist-in-Chief at the department of psychiatry at the New England Medical Center in Boston, writes that antioxidants as well as other nutritional supports may be an effective treatment for Alzheimer’s. Given the evidence, he suggests a treatment combination of a cholinesterase inhibitor to raise levels of acetylcholine, nonsteroidal anti-inflammatory drugs (NSAIDs), and vitamin E and other antioxidants.

Perhaps when you think of herbs for memory, ginkgo is the first that comes to mind. Research from 1997 published by the Journal of the American Medical Association led to an increased amount of press for this substance. The study indicated that extracts of ginkgo (Ginkgo biloba) can stabilize and in some cases improve the cognitive function and social behavior of demented patients for six months to one year, and with side effects no different than those associated with a placebo.

Their conclusions were based on their study of 202 outpatients with mild to severe dementia as a result of Alzheimer’s and/or stroke. Every day for one year, they received either a placebo or 120 mg of a ginkgo extract called EGb 761. At the end of the year, the researchers reported, not only did the extract appear to stabilize the patients, but it also improved daily living and social behavior for 37 percent of those taking ginkgo, compared with 23 percent taking the placebo. In the ginkgo group, cognitive performance improved for twice as many patients as in the placebo group, and social functioning worsened in half as many patients as in the placebo group.

According to researchers, ginkgo may provide a six-month delay in the progression of the disease for some patients. How ginkgo does this is not well understood, but researchers suggest that compounds in ginkgo act as antioxidants, neutralizing free radicals believed to be associated with the cell damage observed in Alzheimer’s patients.

Ginkgo is a widely used phytomedicine in Europe, and it is approved in Germany for treating dementia, tinnitus (ringing in the ear), and other conditions.

A Formula From Japan

One human study shows that an herbal formula from traditional Japanese medicine, or kampo medicine, can help treat vascular dementia. In a study at the Toyama Medical and Pharmaceutical University in Toyama, Japan, researchers gave participants a placebo or 7.5 g of an extract of the formula, known as Chotosan, three times daily for twelve weeks. A total of 139 patients, including fifty men and eighty-nine women with an average age of 76.6, participated.

The researchers concluded that the kampo extract is “statistically superior” to a placebo in diminishing psychiatric symptoms and improving daily life, including decreasing such disturbances as lack of facial expression, decline in simple mathematical calculations and overall intellectual ability, and inability to perform routine tasks such as putting on and removing clothing.

Chotosan is a formulation of eleven herbs, with the Chinese herb gou-teng or gambir plant (derived from the dried stems of various Asian cat’s claw species including Uncaria rhynchophylla, U. macrophylla, U. hirsuta, U. sinensis, or U. sessilifructus) recognized as the most important ingredient. The formula also contains roots of ginseng (Panax ginseng), licorice (Glycyrrhiza spp.), and the rhizomes of ginger (Zingiber officinale).

Additional reading

• Cohen, B. et al. “Decreased brain choline uptake in older adults.” Journal of the American Medical Association 1995, 274(11):902-907.
• Folstein, Marshall. “Nutrition and Alzheimer’s disease.” Nutrition Reviews 1997, 55(1):23-25.
• Foster, Steven. “Memory Power.” Herbs for Health 1996, Spring/Summer: 30-32.
• Miyazawa, M., H. Watanabe, and H. Kameoka. “Inhibition of acetylcholinesterase activity by monoterpenoids with a p-methane skeleton.” Journal of Agricultural Food Chemistry 1997, 45(3): 677-679.
• Perry, Nicolette, et al. “European herbs with cholinergic activities: Potential in dementia therapy.” International Journal of Geriatric Psychiatry 1996, 11(23): 1063-1069.
• Terasawa, K., et al. “Choto-san in the treatment of vascular dementia: A double-blind, placebo-controlled study.” Phytomedicine 1997, 4(1): 15-22.

Adapted with permission from Herbs for Health January/February 1998 and edited by Steven Foster for use in The Herb Companion.

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