Foods that protect the brain
“Certain information is circulating to the effect that dried fruits and cereals, dairy products, fruits and vegetables, fish and vegetable oils as well as organ meats improve memory. This list of foods seems quite general to me, which might no longer mean much,” writes Hélène. The Rumor Detector dug into the matter.
Diet and brain-health
Our lifestyle, our diet, certain diseases and pollution are all factors that can contribute to what is called oxidative stress, an inevitable consequence of our interaction with oxygen. But as we age, the brain becomes more vulnerable to it. This vulnerability, along with chronic inflammation, vascular problems or exposure to toxic substances can lead to the loss of neurons and synapses. This is what can cause problems with perception, attention, memory, decision-making and language comprehension.
In 2018, in the journal Lancet Neurology, Greek scientists, summarizing recent literature, wrote that diet throughout life does appear to have an impact on brain function. In an article published in the British Medical Journal In 2020, British and Canadian researchers were seeing more and more data showing that certain foods could delay the deterioration of cognitive functions. But they themselves recognized the difficulty in distinguishing food from other factors.
What foods exactly? Here are a few that seem to optimize brain function and slow cognitive decline, according to these experts.
Fruits and vegetables
According to Greek scientists, a high consumption of fruits and vegetables slows cognitive decline and the risk of dementia, especially berries and leafy green vegetables.
According to Italian researchers earlier this year, the protective action of berries is due to their content of flavonoids, a type of polyphenol with antioxidant and anti-inflammatory properties. In addition, according to the authors of a meta-analysis also published this year, flavonoids delay cognitive aging, reduce neuronal inflammation, improve vascular function and influence interactions between the microbiome and the neurotransmitter system.
A 2021 post from Harvard University School of Medicine added that eating two or more servings of strawberries and blueberries each week would slow memory decline in women. The benefits of blueberries were also confirmed by the 2022 meta-analysis.
However, this is not the case with all foods that contain flavonoids. For example, the Italian researchers cited above analyzed 12 studies on the link between berries and cognitive functions. They did not note consistent effects in healthy people. It is possible that, depending on the food, flavonoids do not always have the same ability to be assimilated by the body.
As for leafy green vegetables, they contain folate and beta-carotene, among other things. According to a review of the literature published in 2020 by South Korean researchers, there is a link between the consumption of B vitamins such as folate, vitamin B6 or vitamin B12, and an improvement in cognitive functions in general and episodic memory in particular. In addition, according to Greek scientists, high concentrations of carotene in the blood have been associated with a lower incidence of Alzheimer's disease.
< strong>Fatty Fish
According to the 2020 British Medical Journal article, high fish consumption is associated with better cognitive health in the elderly. In 2017, French researchers analyzed the results of several studies carried out on a total of 23,688 people over the age of 65. They concluded that there was a link between higher fish consumption and less rapid memory decline.
It must be said that fish are an excellent source of omega-3 fatty acids and that high concentrations of omega-3 in the blood are associated with a lower risk of dementia or Alzheimer's disease, especially in old people. In addition, autopsies performed on Alzheimer's patients have revealed that their levels of ADH, a type of omega-3, are 30-50% lower in the area of their brain called the hippocampus, than in a healthy person.
Fish is also a source of vitamin B12 and vitamin D. Several studies have observed a protective association between blood levels of vitamin D and the risk of dementia or Alzheimer's disease, the Greek researchers point out.
The text from the Harvard University School of Medicine already cited also recalls that nuts are a source of protein and good fats such as omega-3 alpha linoleic acid. They also contain fiber, B vitamins and antioxidants. According to some studies, the consumption of nuts improves scores on cognitive tests. However, a literature review published in 2021 by Australian researchers could not show conclusive results on the effect of all types of nuts on cognitive performance in the general population, but these researchers point out that the positive effects seem more marked with people at high risk of dementia.
Moreover, according to this same study, the benefits of nuts could be greater in the context of the Mediterranean diet.
Coffee and tea
Many claim that higher caffeine consumption is associated with better scores in tests measuring mental functions. Caffeine would also help to better anchor new memories. According to the 2020 review of several studies by European researchers, consuming moderate amounts of caffeine through coffee and green tea even reduces the risk of dementia and cognitive decline in women. In addition, according to Greek scientists, coffee and tea also contain polyphenols, appreciated for their antioxidant and anti-inflammatory properties.
The virtues of a varied diet
Whatever the virtues attributed to a particular food, the Greek researchers point out, however, that it is preferable to have a global approach to food rather than focusing on a single food group. For example, Mediterranean-style diets have been well-studied and are believed to be associated with slowing cognitive decline. Beneficial effects have been observed to reduce the risk of dementia, cognitive impairment or Alzheimer's disease.
The World Health Organization also recommends a whole food approach to prevent cognitive decline . The best strategy is to adopt a healthy eating routine that includes fruits and vegetables, legumes, whole grains, vegetable proteins, fish, and olive or canola oil.
Certain foods appear to be able to slow cognitive decline. However, there is no miracle food and experts suggest instead to promote good eating habits in general.