Increased intake of fish may reduce the risk of dementia by about 20 per cent, according to a new study spanning three continents.
Data from 14,960 people in seven countries indicated that the more fish consumed, the more beneficial the effects, researchers report in the American Journal of Clinical Nutrition.
“We showed for the first time that a statistically significant trend toward a lower prevalence of dementia among those with higher dietary fish intake in large population-based samples of older people living in 5 countries in Latin America, China, and India,” wrote the researchers led by Emiliano Albanese from King’s College London.
“Our results extend findings on the associations of fish and meat consumption with dementia risk to populations in low- and middle-income countries and are consistent with mechanistic data on the neuroprotective actions of omega-3 long-chain polyunsaturated fatty acids commonly found in fish,” they added.
Two earlier studies published in April 2007 in the American Journal of Clinical Nutrition reported that regular consumption of omega-3-rich food could prevent age-related cognitive decline.
The studies, from the Dutch National Institute for Public Health and the Environment, and the University of North Carolina, stated that only a limited number of studies have looked at the decline in cognitive function that precedes these diseases.
The majority of science for the health benefits of fish and omega-3 consumption has focused on cardiovascular health, but the science for cognitive benefits is growing and almost as compelling as the heart health data.
Albanese and his co-workers examined the links between dementia and fish and meat intake in low- and middle-income countries, including China, India, Cuba, the Dominican Republic, Venezuela, Mexico, and Peru.
“To our knowledge, this is the largest population-based study on this topic to date from either developing or developed country samples,” they said.
Almost 15,000 people aged 65 or over were surveyed. After adjusting for various confounders and pooling the data from all the sites, the researchers report that they observed a dose-dependent inverse association between dementia and fish consumption.
On the other hand, meat consumption was found to increase dementia risk.
“More substantive evidence will come from the incidence phase of our project, in which we will be able to compare the incidence of dementia according to dietary exposure at baseline, and from randomized controlled trials of the effectiveness of n-3 long-chain polyunsaturated fatty acids supplementation for the prevention of cognitive decline,” said the researchers.
Alzheimer's disease is the most common form of dementia and currently affects over 13 million people worldwide. The direct and indirect cost of Alzheimer care is over $100 bn (€81 bn) in the US alone. The direct cost of Alzheimer care in the UK was estimated at £15 bn (€22 bn).
Source: American Journal of Clinical Nutrition
Published online ahead of print, 24 June 2009, doi:10.3945/ajcn.2009.2758
“Dietary fish and meat intake and dementia in Latin America, China, and India: a 10/66 Dementia Research Group population-based study”
Authors: E. Albanese, A.D. Dangour, R. Uauy, D. Acosta, M. Guerra, S.S. Gallardo Guerra, Y. Huang, K.S. Jacob, J. Llibre de Rodriguez, L. Hernandex Noriega, A. Salas, A.L. Sosa, R.M. Sousa, J. Williams, C.P. Ferri, M.J. Prince