by Craig Weatherby
A large, unprecedented study among people in developing countries—the so-called Third World—supports seafood’s ancient reputation as “brain food”.
The majority of evidence concerning the benefits of fish and their unique, long-chain omega-3 fatty acids has to do with cardiovascular health.
But the evidence indicating robust mood and cognitive benefits is growing fast.
The evidence that fishy diets may reduce dementia risk is currently limited to “observational” studies from America and Western Europe, in which scientists match people’s dietary habits to their health status to look for associations.
Most such studies link higher-than-average fish consumption to better brain performance even in younger adults, and to reduced risk of dementia in middle age and beyond.
A lack of data from the developing world—where lifestyles and people’s genetics may differ considerably from those in America and Western Europe—prompted researchers from King’s College London to conduct the new study.
In addition to being conducted in novel places, this is the largest population study on this topic to date... from anywhere.
They collected diet interview and mental test data from almost 15,000 people in seven countries: China, India, Cuba, the Dominican Republic, Venezuela, Mexico, and Peru.
The results show that the people who reported eating more fish than average were about 20 percent less likely to have any form of dementia including Alzheimer’s disease.
No fish-related risk reduction was found among the 1,998 Indians in the study... but the Indians also had the lowest overall fish intake, and the results across all seven countries were positive.
As they noted, positive findings from their research, and from other observational studies, are made plausible by the large body of animal and test tube evidence showing that omega-3s possess brain-protective powers:
“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 neuro-protective actions of omega-3 long-chain polyunsaturated fatty acids commonly found in fish” (Albanese E et al. 2009).
First-ever “Third World” study of fish and dementia
Emiliano Albanese led the King’s College team that examined links between dementia and fish or meat intake in parts of China, India, Cuba, the Dominican Republic, Venezuela, Mexico, and Peru.
Researchers surveyed 14,960 people aged 65 or over in the seven countries.
They conducted face-to-face interviews to record people’s dietary habits, and administered a “cross-culturally validated” dementia test to avoid being misled by cultural, ethnic, and income- or education-related differences in normal behavior or expression.
After adjusting for various dietary, hereditary, and lifestyle factors that affect dementia risk, and pooling the data from all the countries, the researchers found a dose-dependent “inverse association” between dementia and fish consumption: that is, the more fish people ate, the less likely they were to have dementia.
Those who ate the most fish were 19 percent less likely to show dementia signs.
In contrast, higher-than-average meat consumption was linked to a 19 percent increase in dementia risk (Albanese E et al. 2009).
Evidence that higher intake of saturated fat and cholesterol correlates with higher dementia rates is mixed… but prior studies do not show a strong, consistent link between higher meat intake and greater dementia risk.
We take this new research as further evidence that it's smart to eat more fish than most Americans do... and/or to take omega-3 fish oil.
- Albanese E, Dangour AD, Uauy R, Acosta D, Guerra M, Guerra SS, Huang Y, Jacob K, Llibre de Rodriguez J, Noriega LH, Salas A, Sosa AL, Sousa RM, Williams J, Ferri CP, Prince MJ. Dietary fish and meat intake and dementia in Latin America, China, and India: a 10/66 Dementia Research Group population-based study. Am J Clin Nutr. 2009 Jun 24. [Epub ahead of print] Accessed at http://www.nutrition.org/media/publications/ajcnAug709.pdf
- Llibre Rodriguez JJ, Ferri CP, Acosta D, Guerra M, Huang Y, Jacob KS, Krishnamoorthy ES, Salas A, Sosa AL, Acosta I, Dewey ME, Gaona C, Jotheeswaran AT, Li S, Rodriguez D, Rodriguez G, Kumar PS, Valhuerdi A, Prince M; 10/66 Dementia Research Group. Prevalence of dementia in Latin America, India, and China: a population-based cross-sectional survey. Lancet. 2008 Aug 9;372(9637):464-74. Epub 2008 Jul 25.