Healthy pensioners who eat two or more servings of fish a week could reduce their risk of developing vascular brain disease, according to French researchers.
A study by researchers at the University of Bordeaux, France, found a diet rich in fish had the greatest protective effect on people under the age of 75.
Study author Dr Cecilia Samieri said: “Our results are exciting because they show something as simple as eating two or more servings of fish each week is associated with fewer brain lesions and other markers of vascular brain damage, long before obvious signs of dementia appear.
“However, eating that much fish did not have a protective effect in people 75 years of age and older.”
The research, published yesterday in Neurology, followed 1,623 people aged 65 and over, none of whom had dementia, stroke or a history of cardiovascular disease. Their average age was 72.
They all underwent brain scans, which looked for three markers of vascular disease that are strong predictors of cognitive decline and dementia: white matter hyperintensities; covert infarcts; and enlarged perivascular spaces.
The researchers combined these three markers to calculate a single measure of underlying vascular brain disease and participants completed questionnaires about their diets, which included a question about how frequently they ate fish.
On average, the cohort ate fish twice a week, but 11% said they ate it less than once a week, 37% said they ate fish about once a week, while 47% said they ate it two-three times a week. Only 6% said they consumed fish four or more times a week.
The researchers found 8% of participants had covert infarcts and 6% had severe dilated perivascular spaces. Of overall white matter volume, 2% was from hyperintensities.
Researchers found that of those who ate no fish, 31% had markers of severe underlying vascular brain disease, compared to 23% of those who ate three servings a week, and 18% of those who ate four or more servings of fish per week.
When they looked at age, there were stronger associations for younger people, but no association for people 75 and older.
Neurology also publishes a new US study that found women with higher cumulative oestrogen exposure over their lifetime had greater brain volumes and fewer indicators of brain disease on their brain scans in midlife.
The study by researchers at Weill Cornell Medicine in New York monitored 99 women between the ages of 40 and 65 who did not have dementia but had risk factors for late-onset Alzheimer’s.
The women were compared to 29 men, matched for age, with similar risk factors, and the research team looked at the association of reproductive history with the volume of grey matter, which is an indicator of brain health, and scores on thinking and memory tests.
They found several events that indicate longer oestrogen exposure, such as more than 39 reproductive years, a higher number of children and pregnancies, and use of hormone replacement therapy and/or hormone contraceptives, were associated with greater grey matter volume.
This appeared mainly in the temporal cortex, frontal cortex, and precuneus, and the results were the same after adjusting for factors such as high blood pressure and smoking.
When researchers looked at people’s scores on tests of thinking and memory, no association was found with reproductive history indicators, but grey matter volume in the temporal regions of the brain was associated with better scores.
Author Dr Lisa Mosconi said: “Previous research has shown that the midlife decline in oestrogen that comes with menopause is a driver of brain ageing and Alzheimer’s risk in women.
“Our results confirm that, but there’s also good news. Other factors related to women’s reproductive history, such as a longer reproductive span and use of hormonal therapy, appear to offset the effects of menopause.
“While the age at which menopause starts is determined partly by a person’s genetics, lifestyle and environmental factors like smoking, obesity and exercise also play a role, and may modify a woman’s risk of brain ageing.”
Neurology 3 November 2021
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