It seems that the lifestyle one leads is a major factor determining the probability that a person will suffer from Alzheimer’s Disease in their twilight years. In recent months, various studies have provided evidence that apple juice, a Mediterranean diet, cabernet sauvignon and curry can either reduce the likelehood of developing Alzheminer’s or reverse the cognitive impairment which is symptomatic of the disease. To that list we can now add omega-3 oils. And marijuana.
Yvonne Freund-Levi and her colleagues at the Karolinska Institute in Sweden report that a diet supplemented with omega-3 oils may slow the cognitive decline associated with Alzheimer’s Disease.
Omega-3 oils are polyunsaturated fatty acids found in abundance in oily fish such as salmon, mackeral and herring. They are classified as essential because they cannot be synthesized by the body but instead have to be obtained from food.
In a year-long randomized doule-blind study, 204 Alzheimer’s patients were given either 1.7 g of docosahexaenoic acid (DHA) and 0.6 g of eicosapentaenoic acid (EPA) on a daily basis for 6 months a placebo. All the patients were already being treated with acetylcholinesterase inhibitors.
At the end of the 6-month period, the levels of cognitive impairment in all the patients was then tested using the Mini Mental State Examination (MMSE). Omega-3 oils were seen to have a significant effect on the performance of one sub-group of 32 patients with very mild cognitive dysfunction, in which cognitive decline was delayed. The effect was not observed in patients with more advanced Alzheimer’s symptoms.
“To our knowledge, this…is the first to be published on the effects of omega-3 fatty acid supplementation…for Alzheimers disease,” writes Freund-Levi in the Annals of Neurology paper in which the study is described. “Our study indicated that the omega-3 fatty acid preparation conferred a slower decline of cognition in those with the mildest impairment compared with placebo control subjects with a similar degree of cognitive dysfunction at the start of the study.”
It is unclear how omega-3 oils may act to prevent the advance of Alzeimer’s, but Freund-Levi speculates that it may have something to do with their anti-inflammatory properties. Furthermore, as Freund-Levi points out, the improved performance of the patients with mild cognitive impairments may have been due to practice rather than the effects of omega-3 oils.
At the Scripps Institute, researchers have shown that delta-9 tetrahydracannabinol (THC), the psychoactive ingredient in marijuana, inhibits acetylcholinesterase (AChE) more effectively than several approved drugs which are being prescribed to Alzheimer’s patients.
The neurodegeneration that occurs in Alzheimer’s severely damages cholinergic pathways (ones that use the neurotransmitter actylcholine) in the brain. Hence, drugs such as propidium and donepezil, which block the actions of AChE, the enzyme that breaks down acetylcholine once it has been released from nerve terminals, are prescribed to Alzheimer’s patients. By preventing the degradation of the transmitter, its actions are prolonged, and the consequences of the degeneration alleviated somewhat.
AChE acts as a molecular chaperone during the deposition of misfolded amyloid-beta, which causes the formation of plaques that are characterisitic of Alzheimer’s. While carrying out biochemical assays, the Scripps Institute researchers observed that THC was more effective than other AChE inhibitors in preventing the AChE-induced aggregation of plaques. THC binds to a different site on the enzyme, and the inhibition required far lower concentrations of THC than of the approved AChE inhibitors.
“In a test against propidium, one of the most effective inhibitors reported to date, THC blocked AChE-induced aggregation completely, while the propidium did not,” says Kim Janda, the chemistry professor who led the study. “Although our study is far from final, it does show that there is a previously unrecognized molecular mechanism through which THC may directly affect the progression of Alzheimer’s disease.”
The findings, which are published in the journal Molecular Pharmaceutics, may eventually lead to an effective treatment for Alzheimer’s. Although marijuana is prescribed for medicinal purposes in a small number of cases, it is illegal in the U.S. and the U.K., and Janda emphasises that he does not advocate its use.
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