Even before we open our eyes, DHA is already accumulating in two tissues that will accompany us throughout our lives: the brain and the retina.
Later, the retina will capture light and transform it into a signal. The brain will receive these messages and give them form, a face, depth, and sometimes even a memory.
And at the heart of the membranes of the cells that make all this possible, we find a remarkable amount of the same molecule: DHA.
Its role is discreet but fundamental: it helps these highly specialised membranes retain the flexibility they need to function and communicate.
So, how can an omega-3 play such an intimate role in the way we perceive the world?
DHA: a particularly flexible omega-3
DHA stands for docosahexaenoic acid. Behind this name lies one of the major omega-3s in our body, alongside ALA and EPA.
Its uniqueness lies largely in its shape: DHA is an extremely flexible molecule. Its long chain forms many small bends that help it integrate into our cell membranes without making them too rigid.
Imagine not a brick wall, but a living surface, capable of moving and adapting. That is the beauty of DHA: its shape becomes a function.
This flexibility is particularly important in tissues that must constantly receive and transmit information, such as the brain and the retina.
Our body can make a little DHA from the ALA present in certain plants, but this conversion remains low, or even negligible, and highly variable.
To understand what distinguishes ALA, EPA, and DHA, discover our article ALA, EPA, DHA: what are the differences between these omega-3s?
In the brain, DHA helps neurons communicate
Our brain is made up of billions of neurons that continuously exchange information.
For these exchanges to take place under optimal conditions, their membranes must remain flexible and mobile. This is precisely where DHA finds its place.
It integrates in large quantities into the membranes of neurons and synapses (the areas where nerve cells communicate with each other) and contributes to their flexibility. We can almost imagine it as a material that prevents this living membrane from becoming rigid.
DHA thus helps create an environment conducive to communication between nerve cells.
It should therefore not be imagined as a stimulant that would suddenly give you more memory or concentration. Its role is played out over the long term: helping the brain retain the structures it depends on to function normally.
Experimental data show that a marked deficiency in DHA can alter certain properties and functions of these membranes. DHA therefore tells less a story of performance than of preservation, flexibility, and balance.
In our eyes, DHA accompanies the transition from light to vision
The retina is the other major territory of DHA.
At the back of our eye are the photoreceptors, cells that capture light and transform it into an initial signal that the brain can then interpret. Their membranes are among the richest in DHA in our body.
These cells must constantly react to changes in light. DHA helps keep their membranes flexible and suited to this precision work.
Similarly, a marked deficiency in DHA has been associated with changes in the functioning of these membranes. It is therefore not DHA that "gives" sight: it participates in the proper functioning of the cells that make it possible.
The retina receives light that is still devoid of meaning. A few moments later, the brain will turn it into a colour, a movement, a face, or a landscape.
From light to image, DHA accompanies two of the tissues that allow us to see the world.
During pregnancy, DHA helps build what will serve a lifetime
This story begins long before our first image of the world.
The foetus's brain rapidly accumulates DHA, with a particularly significant acceleration during the third trimester of pregnancy. This accumulation then continues during the first years of life, as the brain grows and its connections multiply.
At that time, DHA does not arrive in a brain that is already finished. It arrives while it is being built.
The cells develop, their membranes form, and the retina also continues its development. DHA is one of the lipids used to build these highly specialised membranes.
This is why the mother's intake matters during pregnancy and breastfeeding. The benchmark associated with the normal brain and eye development of the foetus and breastfed infants is an additional 200 mg of DHA per day, in addition to 250 mg daily of EPA + DHA.
Its benefit is both simple and profound: to provide the developing brain and eyes with one of the raw materials they naturally use, and thus help prepare the structures with which the baby will soon discover the world that awaits.
A face to recognise. A voice to associate. A light to follow. Then, little by little, an entire world to observe, learn, and interpret.
How much DHA do we need?
For the brain and vision, 250 mg of DHA per day corresponds to the amount associated with recognised effects on their normal functioning.
DHA can be provided directly by certain fatty fish (sardines, mackerel, herring, or salmon), but also by oils derived from certain aquatic microorganisms.
To discover how these oils are obtained, check out our article How are omega-3s from fish and microalgae produced?
Plant-based ALA remains interesting, but our body converts very little of it into DHA. To provide DHA directly, you must therefore choose a source that already contains it.
For those who want a direct intake of DHA without fish oil, discover Thaléïs Omega 3 - DHA, our algal DHA.
A discreet molecule behind two extraordinary functions
An aquatic microorganism. A neuron membrane. A retina cell. A baby's brain developing even before birth.
At first glance, nothing really connects these images. And yet, the same molecule is found in all of them.
DHA is not fascinating because it promises a spectacular effect in a few days. It is fascinating because its particularly flexible structure allows it to find its place in some of the most specialised tissues in our body.
Before a thought becomes a memory and before light becomes an image, there are first cells capable of receiving, transmitting, and transforming information.
Perhaps that is ultimately the most beautiful role of this omega-3: to participate, very discreetly, in the functioning of the cells through which we can perceive the world, and then little by little give it meaning.