A healthy diet earlier in life can help keep you mentally sharp into your 70s, and even stave off dementia, according to research that followed thousands of Britons for seven decades.
While most studies on diet and cognitive ability have focused on people already in their prime, the new review was the first to track people throughout their lives – from the age of four to 70 – and suggests that the links can start to be recognized much earlier than before.
The research adds to a growing body of evidence that a healthy diet can reduce the risk of Alzheimer’s disease and age-related cognitive decline. The findings were presented at the annual meeting of the American Society for Nutrition.
“These initial findings generally support current public health guidance that it is important to establish healthy dietary patterns early in life to support and maintain health throughout life,” said Kelly Cara, of Tufts University in Massachusetts.
“Our findings also provide new evidence suggesting that improvements in dietary patterns up to midlife can affect cognitive performance and help mitigate or reduce cognitive decline in later years.”
Cognitive performance can still improve well into middle age, but typically begins to decline after age 65, the researchers said. More serious conditions such as dementia can also develop along with age-related decline.
For the new research, scientists studied 3,059 adults from the UK who were enrolled as children in a study called the National Survey of Health and Development. Members of the cohort, called the 1946 British Birth Cohort, provided data on dietary intake, cognitive outcomes and other factors over more than 75 years via questionnaires and tests.
Researchers analyzed participants’ diet at five time points in relation to their cognitive ability at seven time points. Diet quality was closely linked to trends in cognitive ability, they found.
For example, only 8% of people with low-quality diets maintained high cognitive ability and only 7% of those with high-quality diets maintained low cognitive ability over time compared to their peers.
Cognitive ability can have a significant impact on quality of life and independence as people age, the researchers said. For example, by age 70, participants in the highest cognitive group showed much higher retention of working memory, processing speed, and general cognitive performance compared to those in the lowest cognitive group.
In addition, nearly a quarter of the participants in the lowest cognitive group showed signs of dementia at that time, while none of those in the highest cognitive group showed signs of dementia.
While most people saw steady improvements in their diet through adulthood, the researchers noted that small differences in diet quality in childhood appeared to set the tone for dietary patterns in later life, for better or worse.
“This suggests that dietary intakes in early life can influence our dietary decisions later in life, and the cumulative effects of diet over time are linked to the progression of our global cognitive abilities,” Cara said.
Study participants who maintained the highest cognitive abilities over time relative to their peers tended to eat more recommended foods such as vegetables, fruits, legumes, and whole grains, and less sodium, added sugars, and refined grains.
“Dietary patterns high in whole or less processed plant food groups, including leafy green vegetables, beans, whole grains and whole grains, may be most protective,” Cara said.
“Adjusting one’s dietary intake at any age to include more of these foods and to more closely match current dietary recommendations is likely to improve our health in many ways, including our cognitive health.”
