Several interesting reports relating to alcohol consumption and its effects on older people were published towards the end of 2005.Ganguli M, Bilt JV et al looked at alcohol consumption and cognitive function in late life. The researchers examined the association between alcohol use and cognitive decline in a longitudinal study of a dementia free elderly community (average 74 years old). Cognitive functions and self-reported drinking habits were assessed at 2-year intervals over an average of 7 years of follow-up. Few heavy drinkers were identified in this elderly cohort, but compared to non-drinking, both minimal and moderate drinking groups were associated with lesser cognitive decline. The associations were more pronounced when comparing current drinkers to former drinkers rather than to lifelong abstainers
A study by Järvenpää T, Rinne JO et al examining binge drinking in midlife and dementia risk found conflicting results. The researchers goal was to determine whether drinking patterns, in addition to total alcohol consumption, would provide new insights about the relationship of alcohol use with dementia risk. 554 Finnish twins, who provided data on alcohol consumption in questionnaires in 1975 and 1981, were followed for 25 years. Subjects were age 65 years or older at the time of dementia assessment in 19992001. By the end of follow up, 103 participants had developed dementia. Binge drinking (i.e., 5 bottles of beer or a bottle of wine on 1 occasion at least monthly), as reported in 1975, was associated with a relative risk of 3.2 (95%confidence interval = 1.2 8.6) for dementia. Passing out at least twice as a result of excessive alcohol use during the previous year, as reported in 1981, was associated with a relative risk of 10.5 (2.4 46) for dementia in drinkers. This long-term follow up of men and women in Finland showed that those who reported binge drinking and, especially, those who reported ever passing out from excessive alcohol intake, were at markedly increased risk of meeting criteria for dementia or less severe cognitive decline illustrating the long term risks of binge drinking in middle age.
Deng J, Zhou DHD, et al published results of alcohol consumption and the risk of dementia in an elderly Chinese population. Their results indicated that light-to-moderate drinking (no more than 168 g of alcohol per week for men and 112g for women) was associated with a significantly lower risk of dementia compared with non-drinking, with particularly positive results for wine and spirit drinkers. Excessive drinking was related to a higher risk of dementia. The effect of light-to-moderate drinking seemed most effective for vascular dementia; odds ratios were 0.63 (0.550.72) for Alzheimer’s disease, 0.31 (0.190.51) for vascular dementia, and 0.45 (0.121.69) for other dementia.
Lindeman RD, Wayne SJ et al analysed cognitive function in drinkers compared to abstainers. The purpose of this study was to compare nine measures of cognitive function in drinkers compared to abstainers. 883 randomly selected Hispanic and non-Hispanic white men and women, age > 65 years of age were surveyed. Results showed that participants who consumed alcohol had significantly better mean scores on 7 of 9 cognitive function tests and less frequently had scores below selected “cut points” compared to those who abstained from all alcohol intake. The cross-sectional analysis is important as it measured a large number of parameters related to cognitive function, was in older people (average age 74 years), and because it contained a high percentage of Hispanics. With appropriate control for potential confounders, their analyses support a number of previous studies showing better cognitive functioning, and lower risk of poor cognitive functioning, among moderate drinkers. While potential mechanisms for such an effect are not known, the authors suggest that improvements in HDL-cholesterol, lowered risk of diabetes and insulin resistance, and less obesity, all seen among the drinkers, may have contributed to both a reduced risk of cardiovascular disease and poor cognitive functioning.
A study published in the Journal of Biological Chemistry sheds potential light as to why the Chinese study found enhanced results for wine. According to Marambaud et al, resveratrol lowers the levels of the amyloid-beta peptides which cause the telltale senile plaques of Alzheimer’s disease.
One of the characteristic features of Alzheimer’s disease is the deposition of amyloid-beta peptides in the brain.
Philippe Marambaud of the Litwin-Zucker Research Center for the Study of Alzheimer’s Disease and Memory Disorders in Manhasset, New York, administered resveratrol to cells which produce human amyloid-beta and tested the compound’s effectiveness by monitoring amyloid-beta levels inside and outside the cells. They found that levels of amyloid-beta in the treated cells were much lower than those in untreated cells. The researchers believe the compound acts by stimulating the degradation of amyloid-beta peptides by the proteasome, a barrel-shaped multi-protein complex that can specifically digest proteins into short polypeptides and amino acids. “It is difficult to know whether the anti-amyloidogenic effect of resveratrol observed in cell culture systems can support the beneficial effect of specific diets such as eating grapes,” cautions Marambaud. “Resveratrol in grapes may never reach the concentrations required to obtain the effect observed in our studies. Grapes and wine however contain more than 600 different components, including well-characterized antioxidant molecules. Therefore, we cannot exclude the possibility that several compounds work in synergy with small amounts of resveratrol to slow down the progression of the neurodegenerative process in humans.”
Resveratrol may also be effective in fighting other human amyloid-related diseases such as Huntington’s, Parkinson’s and prion diseases. Studies by a group at the Institut National de la Santé et de la Recherche Médicale in Paris, France headed by Christian Néri have recently shown that resveratrol may protect neurons against amyloid-like polyglutamines, a hallmark of Huntington’s disease.
Sources: Ganguli M, Bilt JV et al Alcohol consumption and cognitive function in late life: a longitudinal community study Neurology 2005;65:1210-1217).
Jarvenpaa, Tarja et al Binge Drinking in Midlife and Dementia Risk. Epidemiology. 16(6):766-771, November 2005.
Deng J, Zhou DHD, eA 2-year follow-up study of alcohol consumption and risk of dementia Clin Neurol Neurosurg 2005 August
Lindeman RD, Wayne SJ et al Cognitive Function in Drinkers Compared to Abstainers in The New Mexico Elder Health Survey J Gerontology 2005;60A:1065-1070.
Philippe Marambaud, Haitian Zhao, and Peter Davies Resveratrol Promotes Clearance of Alzheimer’s Disease Amyloid- Peptides* J. Biol. Chem., Vol. 280, Issue 45, 37377-37382, November 11, 2005