Turmeric May Preserve Memory By Boosting Immunity
New Research Suggests Curry Ingredient Fights
Alzheimer’s Disease While It May Relieve Glaucoma
Alzheimer’s disease, the devastating, progressive brain-wasting disease that is approaching epidemic proportions among the elderly in the United States and other Western nations, strikes four times fewer people in rural India. The reason(s) for this remarkable differential are being vigorously investigated, but a prime suspect at this point is curry, the spice that is ubiquitous in Indian and other South Asian cooking, but which rarely makes it out of the local Indian restaurant in the US—except perhaps among people of South Asian origin. According to South Asian folklore and Indian Ayurvedic medical tradition, curry powder, among its other qualities, has the ability to preserve memory and clear thinking long into old age. New scientific research is confirming what many South Asians have known since antiquity.
The latest scientific findings to support curry’s cognition-sparing benefits include:
- A study from Singapore showing that regular curry consumption helps preserve cognitive function in mentally competent Asians aged 60 to 93 years.
- A study from UCLA School of Medicine researchers showing that an active ingredient in turmeric (the principle ingredient in curry) may boost Alzheimer’s patients’ immune system function, thus facilitating the clearance of amyloid plaques from the brain. Amyloid plaques are the primary cause of the most common brain pathology in Alzheimer’s patients.
- Finally, as bonus, new research indicating that amyloid plaques, very similar to those known to cause Alzheimer’s disease, may also be a principal factor in the loss of vision in glaucoma. Does that mean turmeric could benefit people with glaucoma, as well? It’s certainly an area ripe for investigation.
Keeping Elderly Minds Sharp
Turmeric is the bright yellow spice that gives curries their characteristic color, but the ingredient in turmeric that has scientists all over the world so excited is called curcumin, the namesake for a group of compounds in turmeric known as curcuminoids. Among its other attributes, curcumin is a potent antioxidant and anti-inflammatory agent that has shown promise in the treatment of Alzheimer’s disease, Parkinson’s disease, gastric ulcers, and even coronary heart disease.
Alzheimer’s disease results from the slow deposition among brain cells of an insoluble protein known as amyloid-ß. Amyloid-ß deposits eventually turn the brain’s complex neural microplumbing support system into a desolate landscape of plaques and tangles of useless nerves and disruptive fibers, a process known as amyloidosis. As brain cells die off, cognitive, physical, and eventually vegetative functions all evaporate. Alzheimer’s, of course, is always fatal.
A new study on curcumin comes from researchers from, not surprisingly, the South Asian National University of Singapore. Dr. Tze-Pin Ng and colleagues gathered 1,010 Asians aged 60 to 93 years with no signs or symptoms of dementia at the start of the study, and he had them take a simple mental status test—the Mini-Mental State Exam (MMSE). They also divided the people into three subgroupings, depending on how much curry they admitted to consuming over the course of their lives: 1) “Never or rarely”; 2) “Occasionally” (about once every 6 months); or 3) “Often or very often” (daily to monthly).
Taking into account such potentially confounding variables as sociodemographic factors, health, and behavioral correlates of test performance, the investigators found that those respondents who consumed the most curry—“occasionally” or “often or very often”—scored significantly better in MMSE cognitive performance those who “never or rarely” consumed it.
Although a large and growing database of experimental evidence links curry consumption and cognitive performance, these data represent the first epidemiologic confirmation supporting this link. Better cognitive performance was associated even with low and moderate levels of reported curry consumption, Dr. Ng and colleagues stated. Given turmeric’s efficacy and low toxicity (it’s virtually nontoxic, even at the highest doses used; ever hear of a curry OD?), the researchers concluded that these findings add to the growing consensus that curry/turmeric is a promising modality for the prevention and treatment of Alzheimer’s disease.
Turmeric Boosts Immune Function in Alzheimer’s Patients
While it’s becoming ever clearer that turmeric can slow or even reverse the progression of early Alzheimer’s disease, exactly how it worked its magic has remained a mystery. However, new findings from researchers at the UCLA School of Medicine suggest that the spice might be boosting immune function by stimulating macrophages—cells of the immune system that normally eat (phagocytize) pathogens and waste products in the body.
With regard to Alzheimer’s disease, in vitro (test-tube) studies show that macrophages help rid healthy brains of amyloid-ß deposits by sweeping them into cellular structures called endosomes and lysosomes, which then dispose of them. However, in people with Alzheimer’s, the macrophages seem to lose their “mojo,” opening the door to amyloidosis and destructive brain inflammation.
When macrophages from Alzheimer’s patients are treated in vitro with a substance found in turmeric, bisdemethoxycurcumin, their macrophages’ anti-amyloid-ß function increases, according to the UCLA researchers’ report. Thus, these results suggest a possible mechanism of action for turmeric’s ability to protect brain tissue against Alzheimer’s disease by correcting a defect in macrophages capacity to clear out amyloid-ß deposits.
Glaucoma and Alzheimer’s Disease: Is there a Connection?
Glaucoma, one of the leading causes of blindness in the world, is usually associated with a pathologic rise in intraocular pressure (IOP) – the pressure inside the eyeball. Chronically elevated IOP eventually leads to the irreversible destruction of retinal ganglion cells, basically crushing these vital nerve cells that transfer raw information about what the eye sees to the brain, which processes the information, integrating it into comprehensible visual images.
However, this long-accepted explanation of glaucoma is complicated by studies showing that in some patients, glaucoma progresses to blindness despite treatments that lower IOP to normal. Apparently, some other mechanism, besides high IOP, is helping destroy retinal ganglion cells. The results also suggest that an alternative treatment strategy is needed in at least some glaucoma patients.
Now, new research from a group of British, French, and Italian investigators shows that the unexplained pathology in glaucoma patients may in fact be amyloid-ß deposits, essentially the same mechanism that’s responsible for Alzheimer’s disease.
Using an established model of glaucoma in lab rats, the scientists found that amyloid-ß deposits in the eyeball were “strongly implicated” with an increased rate of apoptosis (cellular suicide, or programmed cell death) in retinal ganglion cells. Under microscopic examination, wherever they found an amyloid-ß deposit, the cells nearby were dead or dying.
Moreover, when they applied a combination of three different treatment strategies known to block amyloid-ß-induced apoptosis in three different ways, it slowed the progression of retinal ganglion cell loss by 84%, thereby preserving the animals’ vision that much longer.
Until now, glaucoma therapy—a $5 billion dollar-per-year enterprise for Big Pharma—has consisted almost entirely of drugs that reduce IOP. Now that it’s evident that glaucoma-related blindness may be due to more than just elevated IOP, the quest for effective treatments not focused on lowering IOP has become “all the rage” among glaucoma researchers.
This new European study suggests that one promising target of research should be amyloid-ß, just as it is in Alzheimer’s disease. We know that turmeric can be quite effective against Alzheimer’s due to its potent anti-amyloid-ß effects. Would it be similarly effective in people with glaucoma? Inevitably, some researchers will get around to testing turmeric in people with glaucoma; it’s not a real difficult study to do. In the meantime, though, thanks to its proven efficacy against Alzheimer’s and its remarkable record of safety, there’s no reason not to increase curry and/or turmeric consumption.* Besides, did we mention curried foods can be delicious?
- Ng TP, Chiam PC, Lee T, Chua HC, Lim L, Kua EH. Curry consumption and cognitive function in the elderly. Am J Epidemiol. 2006;164:898-906.
- Fiala M, Liu PT, Espinosa-Jeffrey A, et al. Innate immunity and transcription of MGAT-III and Toll-like receptors in Alzheimer's disease patients are improved by bisdemethoxycurcumin. Proc Natl Acad Sci U S A.2007;104:12849-12854.
- Guo L, Salt TE, Luong V, et al. Targeting amyloid-β in glaucoma treatment. PNAS. 2007:0703707104.