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Coffee influence on Alzheimer's Disease
According to research published in the Journal of Neuroscience, caffeine intake not only appears to protect against Alzheimer's but may actually help those who already have the disease.
Researchers at the Byrd Alzheimer's Institute in Florida have reported that five cups of coffee a day could protect humans in the same way that the caffeine equivalent appears to have in the study of mice.
In a controlled study experiment using Alzheimer's mice, one group of mice had caffeine added to their drinking water. The memory of mice who drank the caffeinated water was roughly similar to mice to had no Alzheimer's. Researchers also found that levels of beta-amyloid proteins reduced in mice who drank caffeine. Beta-amyloid proteins aggregate into plaques within the brain and are present in the brains of people with Alzheimer's disease.
Some interesting results were also obtained when researchers gave caffeine to aged Alzheimer's mice who already had high levels of beta-amyloid protein in their brains.
It was discovered that caffeine reduced the levels of beta-amyloid already present in the brain. This could suggest that coffee drinking is beneficial in people with Alzheimer's; for the time being this is speculation.
The therapeutic effects of caffeine over the long-term have been noted in relation to reduced risk of type 2 diabetes, Parkinson's disease, cirrhosis of the liver, cancer of the liver, colorectal cancer and suicide. Although caffeine has been suspected of causing high blood pressure the association appears stronger when caffeine is consumed via soft drinks.
Caffeine is the most widely consumed behaviourally active substance in the western world. Neuroprotective effects of caffeine in low doses, chronically administered, have been shown in different experimental models. If caffeine intake could protect against neurodegeneration in Alzheimer's disease (AD), then higher levels of caffeine consumption in normal subjects as compared with AD patients should be detectable in the presumably long period before diagnosis when insidious pathogenic changes are taking place.
A case-control study was used: cases were 54 patients with probable AD fulfilling the National Institute of Neurologic and Communicative Disorders and Stroke and the AD and Related Disorders Association criteria, in a Dementia Clinics setting. Controls were 54 accompanying persons, cognitively normal, matched for age (+/-3 years) and sex. Patients with AD had an average daily caffeine intake of 73.9 +/- 97.9 mg during the 20 years that preceded diagnosis of AD, whereas the controls had an average daily caffeine intake of 198.7 +/- 135.7 mg during the corresponding 20 years of their lifetimes (P < 0.001, Wilcoxon signed ranks test).
Using a logistic regression model, caffeine exposure during this period was found to be significantly inversely associated with AD (odds ratio=0.40, 95% confidence interval=0.25-0.67), whereas hypertension, diabetes, stroke, head trauma, smoking habits, alcohol consumption, non-steroid anti-inflammatory drugs, vitamin E, gastric disorders, heart disease, education and family history of dementia were not statistically significantly associated with AD. Caffeine intake was associated with a significantly lower risk for AD, independently of other possible confounding variables. These results, if confirmed with future prospective studies, may have a major impact on the prevention of AD.
Dementias of late life constitute a major public health challenge. Alzheimer disease (AD) is the most common form. Epidemiological studies suggest that the use of nonsteroidal anti-inflammatory drugs, wine and coffee consumption and regular physical activity may delay onset of AD or reduce rate of progression. Preclinical research in animals and epidemiological studies in humans have shown that estrogen substitution strategies and lipid lowering statins may be beneficial. Thus, despite the lack of prospective studies and, therefore, consensus, different pharmacological strategies for persons at high risk for Alzheimer's disease are discussed.
A prospective analysis of risk factors for Alzheimer's disease was a major objective of the Canadian Study of Health and Aging, a nationwide, population-based study. Of 6,434 eligible subjects aged 65 years or older in 1991, 4,615 were alive in 1996 and participated in the follow-up study. All participants were cognitively normal in 1991 when they completed a risk factor questionnaire. Their cognitive status was reassessed 5 years later by using a similar two-phase procedure, including a screening interview, followed by a clinical examination when indicated.
The analysis included 194 Alzheimer's disease cases and 3,894 cognitively normal controls. Increasing age, fewer years of education, and the apolipoprotein E epsilon4 allele were significantly associated with increased risk of Alzheimer's disease. Use of nonsteroidal anti-inflammatory drugs, wine consumption, coffee consumption, and regular physical activity were associated with a reduced risk of Alzheimer's disease. No statistically significant association was found for family history of dementia, sex, history of depression, estrogen replacement therapy, head trauma, antiperspirant or antacid use, smoking, high blood pressure, heart disease, or stroke.
The protective associations warrant further study. In particular, regular physical activity could be an important component of a preventive strategy against Alzheimer's disease and many other conditions.
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