They might seem unavoidable, as most of our grocery stores are filled with them. But they’re not unavoidable, and they should be avoided. Ultra-processed food is often the easiest and most convenient option, but perhaps we should be trying a little harder, as evidence of the negative health effects of ultra-processed food is starting to pile up.

A new study suggests that eating ultra-processed foods such as chips, cookies, and snacks could have a negative impact on cognitive performance in older adults. The researchers also found that, unsurprisingly, replacing these choices with unprocessed or minimally processed food was associated with a much lower risk of dementia.

Ultra-processed foods go through several industrial processes that can’t be reproduced at home — they’re not just processed, they’re ultra processed. They usually have little to no whole foods and contain things like colorings, flavorings and emulsifiers, among other additives. They also tend to be high in added fats and salt and sugar while simultaneously low in fiber and protein.

There’s been a growing number of studies linking consumption of ultra-processed foods with adverse health outcomes such as cardiovascular disease, depression, and all-cause mortality. However, whether these foods were associated with dementia hadn’t been proven until now, with earlier research suggesting this could be the case.

“Ultra-processed foods are meant to be convenient and tasty, but they diminish the quality of a person’s diet,” study author Huiping Li said in a statement. “These foods may also contain food additives or molecules from packaging or produced during heating, all of which have been shown to have negative effects on memory skills.”

The consequences of ultra-processed food

The researchers identified a group of about 72,000 people from the UK Biobank, a database with health information of over half a million people. The chosen participants were aged 55 and older and didn’t have dementia at the start of the study. They were followed for 10 years and in the end, 518 people were diagnosed with dementia.

During the study, the participants completed at least two questionnaires about what they drank and ate the previous day. The researchers then estimated how much of that was ultra-processed. Based on this, they divided the participants into four groups, from the lowest percentage of consumption of ultra-processed foods to the highest.

They found that ultra-processed foods accounted for up to 9% of the daily diet of people in the lowest group (225 grams per day), compared to 28% for people in the highest group (814 grams per day). The main food group that contributed to a high ultra-processed food intake was beverages, followed by sugary products and dairy.

In the lowest group, 105 people developed dementia, compared to 150 in the highest group – both of a total of 18,000 people in each group. The researchers found that for every 10% increase in daily intake of ultra-processed foods, people had a 25% extra higher risk of dementia. Meanwhile, substituting 10% of ultra-processed food led to a 19% lower risk.

“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% decreased risk of dementia,” said Li.

The incidence of dementia worldwide is expected to triple by 2050, reaching over 152 million people worldwide, with most cases concentrated in North Africa, sub-Saharan Africa, and the Middle East. High body mass and high blood sugar will be two of the leading causes of the rise, which means changing our diet can still make a big difference.

The study was published in the journal Neurology.