Omegas

source: Le Figaro.fr santé

author: Juliette Camuzard

translation: doxa-louise

WHY THE BRAIN SHOULD NOT BE DEPRIVED OF FATS

The brain not only runs on glucose. It also needs fats and, in particular, those infamous polyunsaturated 

fatty acids.

The brain is the most energy-hungry organ; it represents a mere 2% of total weight ( for a 60 kg person), 

yet its basal metabolism consumes some 20% of the calories we consume. For the most part glucose, 

but other nutritional elements are essential, and particularly fats.

The latter serve as an energy substratum in situations where sugar reserves are lacking,‘fatty acids are 

then transformed into compounds that nerve cells can use for energy’, explains Sophie Layé, research 

director for l’Institut national de la recherche agronomique (Inra) and director for NutriNeuro labs, at 

Bordeaux. But their primary function in the brain, is to first serve as the building blocks for the cells which 

form the brain: 60% of its dry matter is made up of fat. ‘The membranes of neurons and glial cells, 

which play a role of support and protection of nervous tissue, are made up of fats. As is myelin, this sheath 

which isolates nervous fibers, and enables the passage of the nervous message’, adds the specialist.

A balance of omegas

Certain fats are more important than others for brain functionning. This is true for the omega-3s and 

the omega-6s. These polyunsatured fatty acids account for approximately 30% of brain fats and are 

concentrated in the nerve endings. The organism cannot itself produce these, so the brain finds them 

in the foods ingested: colza oil, nuts or fatty fish for omega-3, sunflower, corn oil and animal products 

for the omega-6. ‘These fatty acids and their derivatives are part of a number of processes such as 

neurotransmission, cell survival, neuroinflammation and, as a consequence, affect mood and cognition’, 

elaborates Sophie Layé. They add flexibility to neuron membranes, which means a better transmission 

of the nervous impulse. The omega-6, particularly important in the make-up of the cell membrane, have 

in turn anti-inflammatory properties.

But one shoud not neglect the omega-3/omega-6 proportion, which should respect a one to four ratio. I

f not, excessive omega-6 becomes a lack of omega-3. This situation is rather frequent, in fact: ‘In France, 

the proportion is more like one for twenty’, laments the specialist.

Olive oil and avocados

Could a lack  or unbalance in one of these acids affect the brain. It is a hypotheses for many researchers. 

‘Many studies have shown, that there exists a very strong link in man between an insufficient intake of 

omega-3s and the incidence of neurological illnesses with an inflammatory aspect, such as Alzheimer’s, 

Parkinson’s, or again certain types of depression. Indeed, animals deprived of omega-3s will develop 

anxious behaviours, depression, memory difficulties, etc.’, adds Sophie Layé.

What to eat to nourish the brain

Other than essential fatty acids, the brain also needs omega-9s, known as oleic acid. One finds these 

in prominently in olive oil and avocados. Their direct effects on neurons are not as well known, but are 

starting to be understood, notably the protective role of olive oil to combat cognitive decline. Finally, the 

brain needs cholesterol, this major component of cellular membranes.

This we know, fats play a role of messenger between brain cells and are useful to the absorption of 

certain vitamins. Given bad press because of their nefarious role in the development of cardiovascular 

diseases, they should never be dismissed out of hand; for essential needs, an adult male should be 

getting every day 2,7 grams of omega-3 and 9 grams of omega-6. An adequate intake is absolutely 

essential for the optimal operation of the brain and the maintenance of brain function with age. Inversely, 

deficits in polyinsaturated fatty acids weaken the neurobiological processes involved in memory and mood.