A healthy diet from a young age can help you stay mentally sharp into your 70s and even prevent dementia, according to research that followed thousands of Britons for 70 years.
While most studies of diet and cognitive ability have focused on people who were already old or in their early teens, the new review is the first to follow people across their entire lives — from ages 4 to 70 — and suggests the links may begin much earlier than previously thought.
The research adds to a growing body of evidence that a healthy diet can reduce the risk of Alzheimer’s disease and slow age-related cognitive decline. The findings were presented at the annual meeting of the American Nutrition Association.
“These initial findings generally support current public health guidelines that it is important to develop 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 middle age may influence cognitive performance and help mitigate or reduce cognitive decline in later years.”
Cognitive performance can continue to 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 alongside age-related decline.
For the new study, scientists studied 3,059 adults in the United Kingdom who participated as children in a study called the National Survey of Health and Development. Members of the cohort, called the 1946 British Birth Cohort, have provided data on dietary intake, cognitive outcomes and other factors through questionnaires and tests for more than 75 years.
Researchers analyzed participants’ diets 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 on a low-quality diet maintained high cognitive ability, while only 7% of people on a high-quality diet maintained low cognitive ability in the long term, 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, participants in the highest cognitive group showed much higher working memory retention, processing speed and overall cognitive performance at age 70 compared to those in the lowest cognitive group.
Furthermore, nearly a quarter of participants in the lowest cognitive group showed signs of dementia at the time, while none of the participants in the highest cognitive group showed signs of dementia.
While most people saw steady improvements in their diets throughout their adult lives, the researchers noted that small differences in diet quality in childhood appeared to set the tone for eating patterns later in life, for better or worse.
“This suggests that dietary intake in early childhood may influence our dietary decisions later in life, and that the cumulative effects of nutrition over time are related to the development of our general cognitive abilities,” Cara said.
Study participants who maintained the highest cognitive skills compared to their peers were more likely to eat 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 greens, beans, whole fruits, and whole grains, may be most protective,” Cara says.
“Adjusting dietary intake at each age to include more of these foods and to more closely align with current dietary recommendations will improve our health in many ways, including our cognitive health.”