So, what do omega-3s do in the body?
Most of us have heard that they’re “good for the heart” or “important for the brain” — but what’s really happening on a biological level?
The answer lies in the way omega-3s are built into the very structure of our cells. These essential fats aren’t just passive nutrients; they become part of cell membranes, influence how cells communicate, and help regulate key processes in two of the body’s most complex systems — the cardiovascular system and the central nervous system.
In this article, we take a closer look at how omega-3 fatty acids support the heart and the brain, offering insight into their shared need for fluidity, balance, and precise signalling.
A Quick Recap: What Are Omega-3 Fatty Acids?
Omega-3s are essential fats, meaning we must get them through our diet because the body can’t produce them on its own. The most relevant forms for heart and brain health are EPA and DHA, which are found in oily fish and marine algae. These long-chain fatty acids are built into cell membranes, where they help shape how cells function and communicate — particularly in tissues with high energy demands like the heart and brain.
Omega-3 and the Heart: A System in Motion
The cardiovascular system includes the heart, blood vessels, and circulating blood — all of which are in constant motion. Omega-3s support several important aspects of this system.
Blood Vessel Function
Omega-3s, particularly EPA and DHA, help support the flexibility and responsiveness of the endothelium — the inner lining of blood vessels. They influence the production of nitric oxide , a molecule that helps blood vessels relax and widen when needed. This supports smooth blood flow and allows the cardiovascular system to respond to changing demands.
Triglyceride Balance
Triglycerides are a type of fat found in the blood, produced and regulated by the liver. Omega-3s help reduce the overproduction of triglycerides and influence how fats are packaged and moved around the body. This contributes to a healthier internal environment for the heart and blood vessels.
Electrical Stability and Heart Rhythm
The heart beats because of electrical signals that pass through its muscle cells. These signals depend on ions moving across cell membranes — and those membranes are partly made of fat. Omega-3s help maintain membrane fluidity, which in turn supports the stable flow of electrical signals that keep the heart beating rhythmically.
Blood Flow and Platelet Activity
EPA and DHA influence the behaviour of platelets, the cells that control clotting. They help reduce excessive stickiness, supporting smoother, more balanced blood flow. This contributes to the overall ease with which blood circulates through the body.
Inflammation and Immune Balance
Chronic low-grade inflammation can affect the cardiovascular system silently over time. Omega-3s help produce compounds called resolvins and protectins, which are involved in the natural resolution of inflammation .
Omega-3 and the Brain: Structure, Signalling, and Support
While the heart is always moving, the brain is always processing. It governs everything from memory and movement to mood and coordination — and omega-3s are deeply involved in how it functions.
Cell Membrane Fluidity and Neural Communication
The brain is rich in fat — particularly DHA, which is highly concentrated in the membranes of neurons (nerve cells). These membranes are responsible for how signals are passed from one brain cell to the next. The presence of DHA helps keep these membranes fluid and responsive , which supports quick and efficient communication between neurons.
Neurotransmitter Pathways
More and more research shows that the way our brain cells communicate with each other (known as neurotransmission) relies heavily on having the right balance of omega-3 and omega-6 fats, especially in the brain. DHA in particular is found in high amounts in the parts of brain cells where messages are passed along. This makes DHA essential for healthy brain chemicals – like serotonin, dopamine, glutamate and GABA.
Brain Inflammation and Immune Modulation
As in the cardiovascular system, neuroinflammation — or inflammation within the brain — can disrupt balance and function. EPA and DHA are precursors to specliased pro-resolving mediators (SPMs) called resolvins and protectins which help maintain stability in the face of physical or emotional demands.
Cognitive Demands and Ageing
The brain’s remarkable ability to adapt—known as neuroplasticity—relies on a supportive structural and biochemical environment, which is influenced by nutrient availability, including omega-3 fatty acids. While omega-3s do not guarantee sharp memory or prevent cognitive decline outright, substantial evidence shows they play a key role in maintaining cognitive function , especially as we age.
Nourishing the Body’s Command Centres
Omega 3’s form part of the structure of our cells and help those cells send and receive messages. They also support the body’s ability to stay balanced — whether that’s between activity and rest or movement and stillness. From the steady rhythm of the heart to the constant activity of the brain, omega-3s are quietly involved in keeping these vital systems running smoothly, every moment of the day.
*The advice in this article is for information only and should not replace medical care. As with any nutritional supplement please consult your qualified healthcare professional before use, especially if pregnant, breastfeeding, if you have a known medical condition or are taking medication. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
