Be careful, eating too much of this kind of food will make you stupid! Check if you are eating it every day.

Generally speaking, people are more concerned about the impact of food on personal body shape, health and other issues. However, some new studies have found that some foods can affect our nervous system and cognitive ability - in short, some foods are likely to make a person more stupid .

01

Surprising findings

At the end of 2022, the JAMA Neurology, a subsidiary of the authoritative journal JAMA, published a new study. The research paper, titled "The Association between Ultra-Processed Food Consumption and Cognitive Decline", explored the relationship between "ultra-processed foods" and cognitive decline. The researchers screened 10,775 people who met the requirements from tens of thousands of Brazilian civil servants - excluding those with extremely high or extremely low calorie intake (less than 600 kcal per day or more than 6,000 kcal per day). In addition, participants who took medications that may have a negative impact on cognitive ability were also excluded. The researchers then followed up on more than 10,000 subjects for 6-10 years to analyze the association between the intake of ultra-processed foods and the rate of cognitive decline [1].

The overall conclusion of the study is that when the intake of ultra-processed foods exceeds 19.9% ​​of total daily energy, the rate of overall cognitive decline will increase by 28%, and the rate of executive function decline will increase by 25%. The "overall cognitive ability" mentioned here includes executive function, language fluency, and memory, while "executive ability" refers to the ability to plan and execute goals. Although, as we age, everyone will have a certain degree of cognitive decline. But those who have eaten too much ultra-processed food may experience cognitive decline earlier and faster. In other words, eating too much ultra-processed food will make people dumber .

02

Young people are more susceptible

An important finding of the study is that the effect is more pronounced among younger people .

The study found that high intake of ultra-processed foods more strongly accelerated overall cognitive and executive function decline in people under 60, especially in those aged 35-59, while this effect was barely observed in people aged 60 and over.

Take this study as a starting point, and consider your own age - if you want to slow cognitive decline, maybe you should limit your intake of ultra-processed foods .

03

What are ultra-processed foods?

So the question is, what exactly are ultra-processed foods?

The study used the NOVA classification, a system for classifying foods based on their degree of processing. It divides foods into four categories:

Categories 1 and 2: Unprocessed or minimally processed foods, and condiments.

Includes minimally processed fruits, vegetables, grains, beans, nuts, meat, fish, milk, etc., as well as natural condiments and spices.

Category 3: Generally processed foods (low degree of processing).

Including canned fruit, canned fish, cheese, bacon, etc.

Category 4: Ultra-processed foods.

These are foods that have undergone complex processing, with added flavors, colors, sweeteners, emulsifiers or other food additives.

For example: puff pastry, cakes, biscuits, various sauces, chocolate, candy, smoked sausages, sausages, hamburgers, hot dogs, pizza, ham, fried snacks, puffed snacks, ice cream, popsicles, pudding/mousse, processed juice, artificial beverages, distilled spirits, etc.

Therefore, eating too much Category 4 ultra-processed food was associated with accelerated cognitive decline .

04

The problem with ultra-processed foods

What exactly went wrong?

In fact, the harm of ultra-processed foods does not come from the processing itself, but they usually have the following characteristics:

1. Lack of vitamins, dietary fiber, minerals and phytochemicals, but rich in sugar and fat.

2. High in calories and easy to fill up , if you consume too much of this food, it will lead to malnutrition and inflammation, which will affect the brain and the health of the whole body. A large intake of ultra-processed foods is associated with cognitive decline, cardiovascular disease, metabolic syndrome and obesity risk.

It should be noted that some processed foods are processed to make them more nutritious to meet the special nutritional needs of certain groups of people, such as infant formula. These foods naturally do not have the above-mentioned adverse effects .

05

What can you eat to slow cognitive decline?

Excessive consumption of ultra-processed foods can lead to a rapid decline in cognitive ability. So, what foods can help slow cognitive decline? Some studies have shown that appropriate intake of certain food components can help slow down age-related cognitive decline.

1. Omega-3 fatty acids

Omega-3 fatty acids are one of the most studied ingredients. Some clinical trial data show that supplementation with omega-3 fatty acids can improve cognitive status, maintain normal cognitive function, and prevent age-related cognitive deficits in young and middle-aged adults . Improvement effects have also been observed in people who already suffer from mild cognitive deficits [4-6].

However, not everyone will benefit from omega-3 fatty acid supplementation, and some studies have shown that omega-3 fatty acid supplementation does not improve cognitive ability in healthy older adults, nor does it help in people who already have Alzheimer’s disease [4].

2. Fish

Among various foods, fish is one of the foods rich in Omega-3 fatty acids . It is recommended to give priority to mackerel, salmon, sardines, herring, flounder, anchovies, tuna, etc., because these fish have relatively low mercury accumulation and are rich in Omega-3 fatty acids. In addition, seafood such as mussels and shrimps can also supplement Omega-3 fatty acids.

3. Are walnuts useful?

Many people believe that walnuts can nourish the brain, mainly based on the similarity of shape, but this is obviously unreliable. However, the fat content in walnuts is as high as 58.8%, of which 10% is Omega-3 fatty acids, which is a very prominent proportion among various nuts. But compared with edible fish, walnuts have no advantage .

4. Antioxidants in Plants

Some plant foods are rich in antioxidants, such as vitamin E, folic acid, flavonoids, and carotenoids, which have been found to help slow brain aging .[7] These ingredients are mainly found in foods such as leafy vegetables, nuts, fruits, and whole grains.

Studies have found that green leafy vegetables, especially the green parts of vegetables, have the most significant effect, while some berries, such as strawberries, blackberries, raspberries, blueberries, etc., also have very significant antioxidant effects[8].

References:

[1] Gomes Gonçalves N, Vidal Ferreira N, Khandpur N, Martinez Steele E, Bertazzi Levy R, Andrade Lotufo P, Bensenor IM, Caramelli P, Alvim de Matos SM, Marchioni DM, Suemoto CK. Association Between Consumption of Ultraprocessed Foods and Cognitive Decline. JAMA Neurol. 2022 Dec 5. doi: 10.1001/jamaneurol.2022.4397. Epub ahead of print. PMID: 36469335.

[2] Schnabel L, Kesse-Guyot E, Allès B, Touvier M, Srour B, Hercberg S, Buscail C, Julia C. Association Between Ultraprocessed Food Consumption and Risk of Mortality Among Middle-aged Adults in France. JAMA Intern Med. 2019 Apr 1;179(4):490-498. doi: 10.1001/jamainternmed.2018.7289. PMID: 30742202; PMCID: PMC6450295.

[3] Du S, Kim H, Crews DC, White K, Rebholz CM. Association Between Ultraprocessed Food Consumption and Risk of Incident CKD: A Prospective Cohort Study. Am J Kidney Dis. 2022 Nov;80(5):589-598.e1. doi: 10.1053/j.ajkd.2022.03.016. Epub 2022 Jun 6. PMID: 35679994; PMCID: PMC9613500.

[4] Beilharz, JE; Maniam, J.; Morris, MJ Diet-Induced Cognitive Deficits: The Role of Fat and Sugar, Potential Mechanisms and Nutritional Interventions. Nutrients 2015, 7, 6719-6738.

[5] Cederholm, T.; Salem, N., Jr.; Palmblad, J. Omega-3 fatty acids in the prevention of cognitive decline in humans. Adv. Nutr. (Bethesda) 2013, 4, 672–676.

[6] Fontani, G.; Corradeschi, F.; Felici, A.; Alfatti, F.; Migliorini, S.; Lodi, L. Cognitive and physiological effects of omega-3 polyunsaturated fatty acid supplementation in healthy subjects. Eur. J. Clin. Invest. 2005, 35, 691–699.

[7] Martha Clare Morris, Christy C. Tangney, Yamin Wang, Frank M. Sacks, Lisa L. Barnes, David A. Bennett, Neelum T. Aggarwal, MIND diet slows cognitive decline with aging, Alzheimer's &Dementia, Volume 11, Issue 9, 2015, Pages 1015-1022

[8] Devore EE, Kang JH, Breteler MM, Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol 2012;72:135–143.

Author: Gu Zhongyi Reviewer: Gao Chao Associate Researcher, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention