Healthy dietary choices in midlife may prevent dementia in later years, according a doctoral thesis published at the University of Eastern Finland. The results showed that those who ate the healthiest diet at the average age of 50 had an almost 90 per cent lower risk of dementia in a 14-year follow-up study than those whose diet was the least healthy. The study was the first in the world to investigate the relationship between a healthy diet as early as in midlife and the risk of developing dementia later on.
The researchers assessed the link between diet and dementia using a healthy diet index based on the consumption of a variety of foods. Vegetables, berries and fruits, fish and unsaturated fats from milk products and spreads were some of the healthy components, whereas sausages, eggs, sweets, sugary drinks, salty fish and saturated fats from milk products and spreads were indicated as unhealthy.
Previous studies on diet and dementia have mainly focused on the impact of single dietary components. "But nobody's diet is based on one single food, and there may be interactions between nutrients, so it makes more sense to look at the entire dietary pattern," says Ms Marjo Eskelinen, MSc, who presented the results in her doctoral thesis in the field of neurology.
Higher intake of saturated fats linked to poorer cognitive functions and increased risk of dementia
The impact of dietary fats on cognitive performance and the risk of dementia was studied separately as well. A high intake of saturated fats was linked to poorer cognitive and memory functions and to an increased risk of mild cognitive impairment in a 21-year follow-up. It was also shown that a higher saturated fat intake was associated with an increased risk of dementia among those carrying a genetic risk factor of Alzheimer's disease, the epsilon 4 variant of the apolipoprotein E (ApoE) gene. "Even those who are genetically susceptible can at least delay the onset of the disease by favouring vegetable oils, oil-based spreads and fatty fish in their diet," Ms Eskelinen says.
In addition, those consuming 3 to 5 cups of coffee daily had a smaller risk of dementia than those consuming less or more.
The doctoral thesis was based on the population-based Finnish Cardiovascular Risk Factors, Aging and Incidence of Dementia (CAIDE) study. Out of 2,000 participants, 1,449 took part in the follow-up. The participants were 39 to 64 years old at baseline and 65 to 75 years old at follow-up.
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More information: The doctoral thesis: Eskelinen, Marjo: The effects of midlife diet on late-life cognition: an epidemiological approach. Publications of the University of Eastern Finland. Dissertations in Health Sciences., no 220. epublications.uef.fi/pub/urn_isbn_978-952-61-1394-4/
Eskelinen MH, Ngandu T, Helkala E-L, Tuomilehto J, Nissinen A, Soininen H, Kivipelto M. "Fat intake at midlife and cognitive impairment later in life: a population-based CAIDE study." Int J Geriatr Psychiatry 23(7): 741-747, 2008.
Laitinen MH, Ngandu T, Rovio S, Helkala E-L, Uusitalo U, Viitanen M, Nissinen A, Tuomilehto J, Soininen H, Kivipelto M. "Fat Intake at Midlife and Risk of Dementia and Alzheimer's Disease: A Population-Based Study." Dement Geriatr Cogn Disord 22(1): 99-107, 2006.
Eskelinen MH, Ngandu T, Tuomilehto J, Soininen H, Kivipelto M. "Midlife Coffee and Tea Drinking and the Risk of Late-Life Dementia: A Population-based CAIDE Study." J Alzheimers Dis 16(1): 85-91, 2009.
Eskelinen MH, Ngandu T, Tuomilehto J, Soininen H, Kivipelto M. "Midlife Healthy Diet Index and Late-Life Dementia and Alzheimer's Disease." Dement Geriatr Cogn Disord Extra 1(1): 103-112, 2011.