Junk food ‘linked with increased risk of dementia’

People who eat ultra-processed food and drinks high in sugar, fat and salt may have a higher risk of developing dementia than those who have lower amounts in their diets, a study has indicated.

The study found that replacing these meals, snacks and drinks with unprocessed or minimally processed foods was associated with a lower risk.

Eating more unprocessed or minimally processed food by the equivalent of half an apple a day, while decreasing ultra-processed foods by the equivalent of a chocolate bar a day, is associated with a 3 per cent lower risk of dementia, researchers found.

Ultra-processed foods include soft drinks, salty and sugary snacks, ice cream, sausage, deep-fried chicken, canned baked beans, ketchup and flavoured cereals.

The researchers highlighted that their findings do not prove that ultra-processed foods cause dementia, only that they show an association.

“Ultra-processed foods are meant to be convenient and tasty, but they diminish the quality of a person’s diet," said study author Huiping Li, of Tianjin Medical University in China.

“These foods may also contain food additives or molecules from packaging or produced during heating, all of which have been shown in other studies to have negative effects on thinking and memory skills.

“Our research not only found that ultra-processed foods are associated with an increased risk of dementia, it found replacing them with healthy options may decrease dementia risk.”

The study suggests that for every 10 per cent increase in daily intake of ultra-processed foods, people had a 25 per cent higher risk of dementia.

The research also found that substituting just 10 per cent of ultra-processed foods with unprocessed or minimally processed foods, such as fresh fruit, vegetables, legumes, milk and meat, was associated with a 19 per cent lower risk of dementia.

Researchers studied the health information of 72,083 people from the UK Biobank study, a large database containing the health information of 500,000 people.

They were aged 55 and older and did not have dementia at the start of the study.

After being followed for an average of 10 years, 518 had dementia diagnosed.

Researchers determined how much ultra-processed food people ate by calculating the grams each day and comparing it with daily grams of other food to create a percentage of their daily diet.

The participants were divided into four equal groups, from lowest percentage consumption of ultra-processed foods to highest.

Researchers found that on average, ultra-processed foods made up 9 per cent of the daily diet of people in the lowest group, an average of 225 grams a day, compared with 28 per cent for people in the highest group, or an average of 814 grams a day.

They say the main food group contributing to high ultra-processed food intake was drinks, followed by sugary products and ultra-processed dairy.

In the lowest group, 105 of the 18,021 people developed dementia, compared with 150 of the 18,021 people in the highest group.

“Our results also show increasing unprocessed or minimally processed foods by only 50 grams a day, which is equivalent to half an apple, a serving of corn, or a bowl of bran cereal, and simultaneously decreasing ultra-processed foods by 50 grams a day, equivalent to a chocolate bar or a serving of fish sticks, is associated with 3 per cent decreased risk of dementia," Ms Huiping said.

“It’s encouraging to know that small and manageable changes in diet may make a difference in a person’s risk of dementia.”

The findings are published in the Neurology journal.

Another study suggests that activities such as household chores, exercise and visiting family and friends may help to lower the risk of dementia.

Carrying out household chores is associated with a 21 per cent reduced risk, the study found.

People who have frequent exercise and daily visits of family and friends had 35 per cent and 15 per cent lower risk respectively, compared with people who were the least engaged.

Researchers found that the associations were present even in people at genetic risk for dementia, suggesting the activities may be effective interventions in preventing dementia.

“Our study found that exercise, household chores and social visits were linked to a reduced risk of various types of dementia,” said study author Huan Song, of Sichuan University in China.

The study looked at the effects of these activities, as well as mental activities and use of electronic devices, in people with and without higher genetic risk for dementia.

It involved 501,376 people from a UK database without dementia, with an average age of 56.

They filled out questionnaires at the start of the study, including one on physical activities, and were asked how often they took part in activities such as climbing a flight of stairs, walking and strenuous sports.

They were also asked about household chores, job-related activities and what kind of transport they used, including walking or riding a bike to work.

Another questionnaire asked people about their mental activities, their education level, whether they attend adult education classes, how often they visit friends and family, visit pubs, social clubs or religious groups, and how often they use electronic devices such as computer games, TV and phones.

They reported if immediate family members had dementia, helping researchers to determine the genetic risk for Alzheimer’s disease.

Study participants were followed for an average of 11 years and at the end of the study, 5,185 had developed dementia.

The researchers found that most physical and mental activities studied showed links to the risk of dementia.

“Our brains are incredibly complex, responsible for our memory, as well as what we think, feel and do," said Dr Sara Imarisio, of Alzheimer’s Research UK.

“Keeping our brains healthy as we age can help stave off diseases like Alzheimer’s, which physically attack brain cells, tearing away at the very essence of who we are.

“We know that being physically and socially active can help us feel happier, healthier and more positive in general.

“Lifting weights and running marathons aren’t for everyone, but there are many ways that we can stay physically active in our lives.

“This self-reported study adds to evidence that finding something you can stick to that keeps you physically and socially active is likely to have the greatest benefit to your health, rather than the activity itself.

“The researchers found that even people with a high genetic risk for Alzheimer’s, the most common cause of dementia, could benefit from keeping physically active.”

The findings are also published in the Neurology journal.