What is the role of omega-3 fatty acids in our health?
For Phytocea by Léa Bathily, Dietitian
We hear more and more about omega-3s and their importance in our diet. And for good reason! From heart health to brain health, omega-3s are truly all-purpose. How do they work in our bodies? How and why should we consume omega-3s? This article aims to highlight the importance of these nutrients by explaining their various ways of acting on our bodies. Omega-3s will then hold no more secrets for you!
What are omega-3s?
To understand the mechanism of omega-3 on our health, it is important to introduce certain concepts, starting by defining their structure.
Omega-3 fatty acids are molecules belonging to the lipid family. It's worth remembering that there are three classes of macronutrients: carbohydrates, lipids, and proteins. Lipids are the most energy-dense nutrients, with one gram providing 9 kcal, compared to carbohydrates and proteins, which are only worth 4 kcal. This property has long been criticized, particularly in the context of diets. Thus, lipids have often been unfairly demonized, as they are essential for the proper functioning of our bodies, especially omega-3 fatty acids.
What is the difference between omega-3 and other classes of lipids?
Omega-3s are more precisely polyunsaturated fatty acids . The term "polyunsaturated" refers to the biochemical structure of fatty acids . They consist of a specific group of atoms (carboxyl group) and a chain of varying lengths made up of different atoms (carbons and hydrogens). These atoms are linked together by what are called covalent bonds. When only one bond is formed between two carbon atoms along the entire chain of the fatty acid, it is said to be "saturated."
In contrast, some fatty acids contain carbon atoms linked together by two covalent bonds. These are called unsaturated fatty acids, or polyunsaturated fatty acids if they contain multiple unsaturates. Omega-3 fatty acids have several unsaturates. Several examples include docosahexaenoic acid (DHA) and ecosapentaenoic acid (EPA).
This structural peculiarity may seem insignificant, but it is precisely these differences that distinguish the functions of the two types of fatty acids. Today, our diet contains large quantities of saturated fatty acids in many foods. Prepared meals, processed foods, and junk food are responsible for significant intakes of saturated fatty acids. These fatty acids play an energetic and structural role at the cellular level. When consumed in excess, they accumulate in our adipose tissue and thus constitute our fat mass. They should therefore be consumed in moderation.
Polyunsaturated fatty acids, such as omega-3s, have entirely different functions. They are considered "essential" because they cannot be produced by the body. The only way to obtain them is through diet.
What are the health benefits of omega-3 fatty acids?
The benefits of omega-3 on cardiovascular health
In France, cardiovascular diseases are the leading cause of death in women and the second leading cause in men. (Public Health France)
A poor lipid intake profile can quickly become detrimental to health and can lead to a condition called dyslipidemia. There are two main types:
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Hypertriglyceridemia is characterized by an excess of triglycerides in the blood. Triglycerides are a family of lipids themselves composed of fatty acids.
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Hypercholesterolemia is characterized by an imbalance of total cholesterol, “good cholesterol” and “bad cholesterol” in the blood.
The term “bad cholesterol” actually refers to molecules called “Low Density Lipoprotein” (LDL). Their role is to transport cholesterol from the liver to other tissues. LDL is the opposite of “good cholesterol,” called “High Density Lipoprotein” (HDL), which transports cholesterol from the arteries back to the liver for elimination.
In the case of hypercholesterolemia, excess LDL has a destructive effect on the cardiovascular system because it penetrates and accumulates on the artery walls. This phenomenon triggers a series of reactions that result in the formation of an atherosclerotic plaque, which can cause partial or total obstruction of the artery. This condition is called atherosclerosis . Furthermore, excess triglycerides can also have an atherogenic effect (promoting the formation of atherosclerotic plaque).
Atherosclerosis can then lead to serious complications such as cardiovascular events, myocardial infarction, ischemic neuropathies, arterial disease in the lower limbs, or kidney failure. 80% of sudden deaths are caused by the rupture of atherosclerotic plaques.
Omega-3 fatty acids have a direct effect on LDL cholesterol, promoting its utilization and elimination by the liver. This process leads to a decrease in LDL cholesterol in the blood, thus reducing the risk of atherosclerosis and associated inflammation. Omega-3s are said to have a cholesterol-lowering effect.
In addition, it has also been shown that omega-3s have a hypotriglyceridemic effect, thus reducing the atherogenic risk associated with hypertriglyceridemia.
Finally, these polyunsaturated fatty acids also have an effect against high blood pressure. This chronic condition is characterized by abnormally high blood pressure. Its prevalence is 30.6% in France and it is a risk factor in many heart conditions (heart failure, retinopathy, kidney failure, etc.).
The role of omega-3 fatty acids in brain function
Omega-3 fatty acids play a vital role in the proper functioning of our brain. In addition to their structural role in nerve cell membranes, they are also involved in the transmission of nerve impulses by influencing neurotransmitter metabolism. Neurotransmitters are molecules stored in specific parts of neurons and act as chemical messengers. To fulfill their mediating function, they are transmitted from one nerve cell to another.
Among omega-3 fatty acids, EPA and DHA are particularly important for brain function. DHA is essential for the development of the central nervous system in newborns, as it is the only polyunsaturated fatty acid capable of integrating into cell membranes. An omega-3 deficiency can have repercussions in newborns, notably causing dysfunctions in the transmission of nerve signals. Adequate dietary intake of these omega-3s is crucial from the first days of life.
Furthermore, studies have shown that an insufficient intake of omega-3 also has a significant link with the onset of neurological diseases, such as Alzheimer's disease, depression, schizophrenia, or even childhood hyperactivity.
Omega-3 fatty acids also affect our vision!
The role of cellular structure is also found in our visual system. Omega-3 fatty acids are major components of the membranes of cells specialized in receiving light. These cells are more precisely called photoreceptors. They are present in large quantities in the specific part of the eye known as the retina. The retina is the inner membrane of the eye, and the photoreceptors there translate the received light beams into chemical signals that are transmitted to the optic nerve. Preserving the photoreceptors is therefore essential for maintaining proper vision. Omega-3 fatty acids make up more than 50% of the fatty acids in the membranes of these cells.
The retina is constantly subjected to damage induced by oxidative stress, a reaction caused by harmful molecules called reactive oxygen species (ROS). These molecules are generated by several factors, such as high-energy radiation from light, pollution, and constant contact with oxygen. Oxidative stress notably leads to the destruction of the photoreceptor membrane. DHA enables the membrane renewal of these cells.
It has been shown that a deficiency in DHA can be the cause of the onset of Age-Related Macular Degeneration (AMD).
Where can we find omega-3 in food?
Omega-3 fatty acids are found in a fairly specific range of foods. Two types of foods contain them:
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Plant-based products such as vegetable oils made from walnuts, flaxseed, soybeans or rapeseed;
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Animal products , particularly oily fish: salmon, mackerel, sardines, cod, herring
ANSES recommends consuming fish at least twice a week, including oily fish once a week, and favouring the use of oils rich in omega-3.
Note that oils rich in omega-3 fatty acids are sensitive to heat and light and degrade upon contact, which diminishes their nutritional value. To avoid this, it is necessary to avoid using this type of oil for cooking, to use it primarily for dressings, and to store it in a place protected from light.
What are the health claims about omega-3?
We have seen that omega-3 fatty acids have many functions in our bodies. To promote certain foods or dietary supplements that contain them, health claims are used. These claims are accurate under specific consumption conditions. Here are the existing health claims for omega-3 fatty acids.
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Docosahexaenoic acid (DHA) contributes to normal brain function and the maintenance of normal vision . This claim is valid for a daily intake of 250 mg of DHA.
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Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contribute to normal heart function . This claim also applies to EPA and DHA intake of 250 mg/day or more.
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Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contribute to maintaining normal blood triglyceride levels . To ensure this function, EPA and DHA consumption is significantly higher than the two previous claims and should be between 2 and 5 grams per day.
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Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contribute to the maintenance of normal blood pressure . This claim is valid for a daily intake of 3 to 5 grams of EPA and DHA.
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Alpha-linolenic acid (ALA) contributes to the maintenance of normal cholesterol levels . Alpha-linolenic acid is another type of omega-3 fatty acid. For this claim to be valid, it is necessary to consume 2 grams of this omega-3 per day.
As you've probably gathered, consuming omega-3 fatty acids is more than essential for ensuring proper brain, vision, and heart function, as these claims suggest. We've seen that these fatty acids can be obtained through diet. However, given the significant amount needed, particularly for maintaining normal triglyceride, blood cholesterol, and blood pressure levels, it's difficult to rely solely on diet alone.
The SU.VI.MAX study also revealed that the French population had a significantly insufficient intake of omega-3 fatty acids compared to recommended nutritional guidelines. Indeed, for some of the study participants, their omega-3 consumption was estimated at 0.4% of their total energy intake, whereas our needs are normally around 1% of total energy intake.
Therefore, one solution to achieve a sufficient daily intake of omega-3 is the consumption of dietary supplements.
Phytocea can help you meet your omega-3 nutritional recommendations
To help maintain brain, heart, and eye function, we have developed the Omega+ dietary supplement. This supplement is formulated with wild-caught fish oil , rich in DHA, and allows you to meet your daily omega-3 requirements with just one capsule. For optimal results, you can take 2 to 3 capsules to fully benefit from the health claims supported by the formula. Our formula is also enriched with vitamin E for its antioxidant properties . Omega+ is therefore a dietary supplement that also helps combat damage caused by oxidative stress.
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