We all hope to remain mentally alert throughout life, to be able to manage on our own, and to avoid diseases such as dementia. The diet plays a major role, and blood levels of various B vitamins, vitamin D, omega-3 fatty acids and certain other nutrients are linked directly to brain activity and cognitive functions. This was demonstrated in a new study of elderly people, which is published in the science journal Neurolmage. At the same time, other studies show that there is widespread lack of these nutrients due to poor dietary habits, the use of pharmaceutical drugs, and lack of sunshine. This may have consequences for both public health and health care expenditure, unless one installs timely prevention by providing the brain with vitamins, essential fatty acids and all the other things on which it depends.
For decades, the so-called Mediterranean diet has been associated with a lower risk of cognitive decline, fewer cardiovascular diseases, and longer lifespan. This diet typically consists of fish and seafood in great quantities, vegetables, beans, nuts, and healthy fats such as olive oil instead of red meat, dairy products and sugar. Another important factor is sunlight, which is the main source of vitamin D, and there is a lot more sunshine in the Mediterranean countries.
The new study was carried out by scientists from the University of Illinois, in the United States, and it includes 116 healthy adults aged 65-75 years. The researchers set out to investigate how diet and nutrition affect cognitive functioning in elderly, healthy adults. They specifically studied 32 important nutrients that, according to earlier studies, were associated with improved brain function in the ageing part of the population.
New methods for measuring brain performance
The scientists chose not to ask the participants about their diet habits, simply because there is always a lot of uncertainty about what and how much people eat. Instead, the scientists measured levels of different nutrients in the blood by means of various biomarkers. They also used advanced methods and scannings to study how different parts of the brain work. If the blood supply is good, and if the neural network and brain cell communication are fast, the brain works effectively, according to the scientists. The participants also conducted various cognitive tests.
Clear connection between nutrients and cognitive skills
The study revealed a clear link between high blood levels of specific nutrients and an improved ability to solve cognitive challenges. Among the included nutrients were:
- Omega-3 fatty acids (oily fish and walnuts)
- Omega-6 fatty acids (nuts, seeds, plant oils)
- Riboflavin (vitamin B2) and folic acid (coarse, green vegetables)
- Vitamin B12 (found in animal sources such as meat, fish, eggs, and dairy products)
- Vitamin D (primarily from sunlight but also found in oily fish, cod row, eggs, and dairy products)
- Carotenoids (the yellowish pigment in carrots and sweets potatoes)
- Lycopene (red pigment in tomatoes, water melon, and certain other fruits and vegetables)
Synergy effect and positive influence on the frontal lobes of the brain
The mentioned nutrients appeared to have a synergistic effect on each other. Also, it appeared that the different nutrients affected the efficiency in different parts of the brain or the neural network. For instance, the researchers observed a positive relation between elevated levels of omega-3 fatty acids frontal lobe activity. The frontal lobes constitute the control center for primary cognitive functions like language, attention, decision making and general intelligence.
The nutrients have a long-term effect
According to Professor Aron Barbey, who was one of the lead researchers, the study points to a direct link between diet, nutrients, the neural network activity of the brain, and cognitive performance. Because the scientists wanted to test the long-term effect, they invited 40 of the participants to repeat the test two years later. Here, they found a continued link between diet, nutrients and brain performance. When they measured how groups of nutrients work together, using the same blood markers, they were able to get a more precise picture of how the body utilizes these nutrients, and how they affect the brain and cognitive health in the long run.
Supplements of B vitamins and omega-3 prevent dementia and Alzheimer’s disease
Several earlier studies have demonstrated that high doses of B vitamins can slow down mild cognitive impairment, which is an early stage of dementia and Alzheimer’s disease. However, another study shows that B vitamins remain ineffective until the body is adequately supplied with the two omega-3 fatty acids EPA and DHA, which we get from oily fish or fish oil supplements.
Diet and nutritional supplements
It is always best to get all the relevant nutrients by eating a balanced diet, and the Mediterranean diet is a good place to find inspiration. Many older people may lack B vitamins because of not getting a sufficiently balanced diet, drinking too much coffee and tea, or using diuretics and antacids. Getting enough vitamin D from the diet is also difficult. The sun is our primary source, but at northern latitudes, the sun sits too low in the sky to enable us to synthesize the vitamin. It is therefore a good idea to take a vitamin D supplement during the winter period, and people should also consider doing so during the summer period if they get too little sunlight. People, who dislike fish or eat too little oily fish, may benefit from taking a high-quality fish oil supplement. Fish oil based on free fatty acids ensures the best bioavailability.
Christoffer E Zwilling et al. Nutrient biomarker patterns, cognitive function and fMRI measures of network efficiency in the aging brain. NeuroImage 2019
University of Illinois at Urbana-Champaign. Nutrients in blood linked to better brain connectivity, cognition in older adults. ScienceDaily 2018
Oulhaj et al: Omega-3 Fatty Acid Status Enhances The Prevention of Cognitive Decline by B-vitamins in Mild Cognitive Impairment. Journal of Alzheimer’s Disease. 2016
Omega-3 levels affect whether B vitamins can slow brain´s decline. University of Oxford. Health and News.2016
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