Omega 3: what is it for, benefits and harms, do you lose weight?


What is omega 3?

Omega 3 is an essential fatty acid very important for the functioning of the body. Since it is not produced naturally by the body, it must be consumed in the form of fats.

There are, in general, 3 types of omega 3: DHA, EPA and ALA. DHA and EPA can be found, mainly, in cold and deep water fish that feed on marine animals. ALA, in turn, is found in legumes, oilseeds and other foods.

There are several benefits of omega 3 for the body. It is an ally during pregnancy, helps to prevent cardiovascular disease, treat the symptoms of rheumatoid arthritis , prevent diabetes and can be an ally in the treatment of depression and other psychiatric disorders.

The real effectiveness of this substance in the treatment of psychiatric disorders is not yet known, although some researchers defend its use for the treatment of such problems.

Probably, omega 3 is one of the most studied substances in recent years, with almost 30 thousand scientific articles about it. All of its benefits and harms have not yet been discovered, as research is recent, and it has been strengthened since the 1990s.

The consumption of omega 3 in Western societies is very low when compared to that of ancestral populations. Therefore, there is a great concern to increase the levels of consumption of this substance.

Still, it is necessary to pay attention to the consumption of omega 3, as the excessive use of this substance can bring a series of problems, especially for patients with hemophilia and people allergic to fish.

In Brazil, there are not many natural sources of omega 3. Fish produced in the national territory are usually raised in captivity and do not have the proper diet to become reservoirs of this substance. Therefore, it is recommended that supplementation be done through capsules.

However, Brazilian capsules can often contain high amounts of mercury, which is toxic to the body and can have severe consequences and even lead to death.

Therefore, before using this substance, talk to your doctor and nutritionist to evaluate the possibilities, risks and benefits that omega 3 can bring you.

Check out more information in the text below, and good reading.

What is a fatty acid?

Fatty acids are a type of fat present in several types of food. They can be classified as Saturated, Monounsaturated and Polyunsaturated.

Saturated fatty acids are present in meat and dairy products. Excessive consumption can lead to circulation problems, such as increased cholesterol in the blood. Monounsaturated fatty acids, on the other hand, are found mainly in vegetables and can bring some benefits, such as reducing the risks of high blood pressure.

Polyunsaturated fatty acids, on the other hand, are called essential, as they cannot be produced directly by the body, and must be obtained from external sources, that is, from food.

Essential fatty acids

Essential fatty acids are very important for the body, as they can be used as energy by the cells of our body. In addition, they act as coagulating agents and, since they have antioxidant action, they help to maintain the skin’s elasticity and combat its premature aging.

They can be modified within the body to produce substances that control inflammatory processes, mood and to compose adipose tissue. In addition, they influence cell signaling and have a direct action on DNA, activating or inhibiting the transcription of certain factors.

It is seen, then, that essential fatty acids do not receive this name by chance.

Types of omega 3

In general, there are 3 types of omega 3: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

EPA and DHA are found more commonly in fish and seafood and, according to studies, have more health benefits than ALA, which is more commonly found in plant-based foods such as flaxseeds, nuts and soy oil. Understand the difference:


EPA has an anti-inflammatory action, as it helps the enzymatic reactions responsible for the production of substances essential to fight inflammation that neutralize pro-inflammatory activity.

One of the main benefits of this type of omega 3 is in helping the health of the heart and blood circulation, as it helps to prevent the formation of thrombi (clots) in the blood, thus decreasing the risk of thrombosis and stroke (stroke) ).

People who suffer from cellulite , obesity , lupus and rheumatoid arthritis, for example, can benefit greatly from consuming EPA.


In addition to having antioxidant action, DHA is essential for the development of the fetus. It helps in the formation of the retina (part of the eyes responsible for transforming the light stimulus into a nervous stimulus).

It is the type of fatty acid most beneficial for brain health, as it favors cognition and connections between neurons, benefiting memory, attention, reasoning, imagination, judgment and several other aspects related to the human mind.

Studies indicate that DHA supplementation during adulthood can support the memory of healthy people aged 55 and over. Other research also links the intake of DHA to increased production of anti-inflammatory and neuroprotective substances that prevent the formation of harmful substances in the brain.

This is a strong indication that DHA can be a great ally in the prevention of neurodegenerative diseases, such as Alzheimer’s disease.


Of vegetable origin, ALA can be converted to DHA or EPA after ingestion. The human body is able to produce enzymes that make this transformation, however, their activity is reduced by factors such as smoking , alcohol consumption, diabetes, stress , high intake of trans fats and, mainly, by aging.

Therefore, it is essential not only to be careful with the fats ingested, but also with life habits such as the practice of sports, stress management, quality of life and balanced diet.

ALA can be easily found in the following foods:

  • Share;
  • Linseed;
  • Pumpkin seeds;
  • Nuts;
  • Spinach;
  • Cabbage.

Omega 3 and 6: what is the difference and what is the correct ratio?

Omega 6 is another essential fatty acid for maintaining health. They are considered antagonists of omega 3, so their excessive consumption can prevent the body from enjoying the benefits of omega 3.

It is present mainly in vegetable oils, such as sunflower oil, corn and sesame. If ingested in the right proportions, it helps fight stress, control blood pressure and protect the heart and skin.

However, when in excess, omega 6 can end up exerting an inflammatory action, something that no one wants for himself. Therefore, it is important to maintain a balance between the intake of omega 3 and 6.

Recent research shows that Western diets have a ratio of omega 6 to omega 3 equivalent to 15: 1, which is far from ideal, which would be about 4g of omega 6 per 1g of omega 3 per day.

However, experts’ opinions differ as to the ideal proportion. This makes it most recommended to seek an individual consumption recommendation for each of these fatty acids. If you want to know your ideal proportion, consult a specialist.

Foods rich in omega 3

As stated earlier, there are 3 types of omega 3. Each of them can be found in different dietary sources, with EPA and DHA being more easily found in fish and seafood.

However, it is not just these foods that contain significant amounts of omega 3. Check out:


The richest foods in EPA and DHA come from the sea. So fish, algae and crustaceans are the biggest sources of this food. That is why omega 3 supplements are usually made with fish oil, which should be avoided by people allergic to these animals.

We can mention some foods rich in these substances, such as:

  • Sardine;
  • Cod oil;
  • Herring;
  • Salmon;
  • Mackerel;
  • Tuna fish;
  • Tuna;
  • Seaweed oil.


As mentioned earlier, ALA, unlike DHA and EPA, does not have so many health benefits, but it can, however, be transformed into these substances through the action of natural enzymes in the human body.

As it does not come from animals, it is the recommended diet for vegans, vegetarians and people with a seafood allergy . Some of the ALA-rich foods are:

  • Linseed;
  • Nuts;
  • Chia seeds;
  • Hemp seeds;
  • Chickpea;
  • Peas;
  • Lentils;
  • Bean;
  • Cereals.

Proven benefits of omega 3

Assists in development during pregnancy

One of the main and best known benefits of omega 3 is in pregnancy. When the pregnant woman makes use of this substance, the chances of a better development of her baby improve.

In addition, consumption of omega 3 reduces the chances of premature birth and can make babies stronger. A study at the University of Kansas Medical Center in the United States revealed that omega 3 has these beneficial effects for babies.

To reach this conclusion, the study followed 300 future mothers, chosen at random. Half received omega 3 supplementation in late pregnancy while the other half received a placebo.

During the observations, it was discovered that the mothers who received the supplementation had a longer gestation, above 34 weeks, resulting in a lower incidence of premature births. In addition, newborns who received supplementation were born stronger and heavier when compared to those who received placebo.

Although no contraindications have been found, the researchers stress that more studies should be done before conclusive results are released.

Other known benefits of omega 3 during pregnancy are the regulation of physiological activities, such as the production of essential substances during pregnancy that regulate the functioning of organs such as the kidneys and help with other physiological phenomena, such as blood clotting.

Because of its anti-inflammatory action, the consumption of omega 3 during pregnancy can help pregnant women to avoid a series of diseases, especially those related to inflammation. Its antioxidant action is also very important to ensure a healthy pregnancy.

In addition, omega 3 has also been linked in several studies to the good neurological and optical development of the baby. Especially the fatty acids EPA and DHA help in the healthy development of the cognitive and visual system, helping in the formation of the brain and the retina.


During breastfeeding, various nutrients pass from the mother to the child. So if the mother has a diet rich in omega 3, she will pass these benefits on to her child.

As stated earlier, omega 3 is closely related to an improvement in the development of visual functions. When the child is still a baby, visual functions will develop in a more complex way. So, it is not a bad idea to use supplements during this period.

However, never use omega 3 without first consulting your doctor . Despite its benefits, excessive consumption of this substance can compromise some functions and even hinder the baby’s development.

Helps prevent cardiovascular disease

The countless studies done on omega 3 have made the substance known to be effective for the benefit of heart health, that is, it is a cardioprotective substance.

It is considered so because, mainly EPA, it regulates the activity of blood platelets, preventing blood clots, which can lead to a stroke or a heart attack . It also lowers triglyceride levels and DHA helps prevent cardiac arrhythmias by stabilizing the heart’s activity.

This is scientifically based. A study carried out in Denmark, for example, at the Staten Serum Institut in Copenhagen , and published in the American Heart Association, showed that the risk of women of reproductive age having cardiovascular disorders is much lower in those who consume fish with high concentrations of omega 3.

Another survey by the Physician’s Health Study , in the United States, showed that men with higher levels of omega 3 in their blood were less likely to have heart attacks, decreasing the risk of sudden death.

In addition, omega 3 is responsible for lowering cholesterol, as it causes an increase in HDL (“good” cholesterol) levels and decreases the concentration of LDL (“bad” cholesterol). This helps to regulate blood pressure and prevent the formation of fatty plaques on the artery wall.

Therefore, people who have high triglyceride levels, that is, above 500mg / dL, can supplement omega 3 daily, ingesting around 2 to 4g per day. It is worth remembering that, in these cases, he has a supporting role in the task of lowering the indexes. And remember: before starting to use, always  consult a doctor or nutritionist.

Improves symptoms of rheumatoid arthritis

The consumption of omega 3 contributed to the relief of the symptoms of rheumatoid arthritis. This happens because of its anti-inflammatory action, making it function as a blocker of enzymes that produce inflammatory processes.

It is worth mentioning that the use of the compound will not cure the disease, but only help to relieve its symptoms, especially when it is used in conjunction with other medications for the treatment of the disease.

Helps fight diabetes

There is a correlation between the consumption of omega 3 and the prevention of diabetes.

A study done at the University of Minnesota, in the United States, reveals that the levels of omega 3 in the blood are related to a lower incidence of diabetes. Research has shown that there is an increase in insulin sensitivity by the body when the levels of omega 3 are high.

In addition, people with diabetes are more susceptible to inflammatory processes. As omega 3 has an anti-inflammatory action, it can be an ally to treat these complications.

It is worth mentioning that these anti-inflammatory properties will only be effective if the consumption of omega 3 is in the correct proportions with that of omega 6 (see more in the topic “Omega 3 and 6: what is the difference and what is the correct proportion?”).

Improves symptoms of depression

The relationship between omega 3 and depression is still poorly understood. Many researchers have been looking into the matter to try to discover the real correlation between the substance and the psychiatric disorder.

What is actually known so far is that populations that consume more fish from deep, cold waters and that are not raised in captivity have a lower rate of depression in general, which makes some researchers believe that consumption of this substance is related to the prevention of the onset of the disease.

A 2003 study published in the American Journal of Psychiatry  evaluated the effects of omega 3 on psychiatric disorder in 36 depressed patients. Half of the patients were offered capsules with doses of DHA, while for the other half, they were offered a placebo.

The improvement in the effects of depression occurred in approximately 25% of patients in both groups, showing that both placebo and treatment with DHA have similar results. The conclusion is that there is no significant correlation between DHA consumption and positive effects on the symptoms of depression .

A review of articles also published in the American Journal of Psychiatry  found a significant relationship between the consumption of EPA and DHA with depression. According to the data collected, the substances have a positive effect on the symptoms of the disorder, but the article concludes that further studies should be done taking into account individual factors that could not be measured in the review.

Because of this, we can conclude that the relationship between the consumption of omega 3 and depression is not yet fully understood by science (read more in the topic “Is omega 3 effective in the treatment of psychiatric disorders?”).

This does not mean that you should not use omega 3, but the reminder is valid, since many promoters say with full certainty that it is effective in treatment when the effectiveness of the substances is not exactly known.

If you suffer from depression, consult a psychiatrist before taking any action. He is the appropriate and recommended professional to treat the symptoms of the disease.

Helps decrease seizures in patients with refractory epilepsy

Omega 3 can also be a great ally in helping patients with epilepsy to decrease the frequency of their seizures.

A survey of patients with refractory epilepsy, a variation of the disease that does not respond well to medication use, showed that individuals who took 3g of omega 3 a day had a 34% reduction in the frequency of their epileptic seizures.

It can improve sports performance

Due to its antioxidant role, the consumption of omega 3 can bring benefits to the sportsman and even improve the performance as a whole.

This is because the body produces high amounts of free radicals during exercise and compounds with antioxidant functions are able to neutralize free radicals, preventing their action in the body.

Under normal conditions, free radicals are important for the functioning of the body, however, when in excess, they can cause problems and even lead to cell death.

For this reason, it is recommended that people who do intense sports practice do some dietary supplementation with antioxidants.

How to consume

The Ministry of Health of Brazil recommends the consumption of 1000mg to 3000mg of omega per day. To obtain these results, there are, basically, two possible ways: through supplementation or through diet.

In the diet, it is enough to consume foods known to be rich in the substance, such as cold water fish, some types of crustaceans, oilseeds, such as peanuts and nuts, and some types of vegetables (see chapter “Foods rich in omega 3”).

However, for Brazilians, consuming foods rich in omega 3, especially those with a high concentration of DHA and EPA, such as fish, can be a difficult task, as animals sold in the Brazilian market are usually raised in captivity and feed on ration.

For a fish to have high levels of omega 3 in its body, it is necessary that it consumes smaller animals rich in this molecule, such as krill  and some species of algae. This, unfortunately, does not happen with animals raised in captivity, which makes obtaining natural omega 3 a difficult task for Brazilians.

There is, however, an alternative: supplement capsules. Made with fish oil, these supplements can serve as an alternative for those who cannot acquire the amounts of fatty acid naturally.

However, it is necessary to keep an eye on the quality of the product, as many of the supplements sold in Brazil may contain a high amount of mercury and other components that can be harmful to health.

To find out if omega 3 is free of these components, it’s easy. Quality supplements print this information on the packaging label, prominently, to be easy to identify.

Another very valuable tip when choosing your supplement is to pay attention to the product label, as the concentration of DHA and EPA varies depending on the source.

There are several compositions of omega 3. The most found is 18/12, with 18% EPA and 12% DHA, but in addition to this, it is also possible to find products with other dosages, such as 33/22, 40/20, among others.

The larger the compositions, the more expensive the product will be. However, as the price goes up, so do the health benefits.

Consumption of vitamin E

It is very conducive and beneficial for health and for a better use of the benefits of omega 3, combining its consumption with vitamin E supplements , a true ally of fatty acids.

This is because fatty acids oxidize very easily within the body, which causes their beneficial properties to be lost quickly. Vitamin E, being a potent antioxidant, can guarantee greater durability to fatty acids and enhance their beneficial effects within the body!

Where to buy?

As stated earlier, omega 3 is found in a variety of foods, so you don’t necessarily need to supplement. If your diet is well balanced and controlled, it is possible to obtain significant amounts of omega 3 naturally.

Thus, paying attention to foods rich in this fatty acid is one of the alternatives. So markets, vegetable and seafood stores can be a good option, as long as, in the case of buying fish, you make sure that the animal was not raised in captivity.

As this task can be very difficult for most people, as it requires a good amount of time, the use of supplements should not be ignored.

These supplements can be found in markets, supplement stores or any pharmacy, physical or online .


Especially if consumed in excess, omega 3 can cause some health problems. Not only because, as previously mentioned, heavy metal infections can happen, but also because it can favor hemorrhagic processes, raise cholesterol and even increase the chances of getting prostate cancer . Understand:


Omega 3 has anticoagulant properties that can result in bleeding episodes. Therefore, as you will see later, in the topic “Contraindications”, patients with hemophilia, especially, should avoid consuming the product.

High cholesterol

Although it has the potential to increase levels of “good” cholesterol (HDL) and reduce levels of triglycerides in the body, excess omega 3 in the blood can cause an increase in cholesterol levels.

A study carried out in Campinas, São Paulo, carried out on rabbits, shows an increase in cholesterol in these animals.


Because it has anti-inflammatory properties, some people believe that omega 3 can be an ally in fighting cancer . The problem is that this hypothesis still has no strong scientific support and assuming that the product has anti-cancer properties can be very dangerous.

For example, a few years ago, folic acid deficiency was found to increase the chances of cancer. However, recent studies have shown that supplementation of this substance can generate tumors even more aggressive than those caused by the deficiency.

It may be that the same thing happens with omega 3. What causes the confusion is that some studies have pointed out that omega 3 could help make tumors more sensitive to therapies used to fight cancer, that is, omega 3 would improve the effectiveness of drugs used to treat tumors.

However, it is not yet possible to have a clear conclusion on the subject, since there are several types of cancer and each one manifests itself in a different way.

Just to give you an example: a recent study published in the Journal of the National Cancer Institute , shows that excess omega 3 in the blood can lead to a higher incidence of prostate cancer.

Although this relationship is not yet fully understood and further studies are needed to prove its veracity, this is already a sign for us not to jump to conclusions.

In order to discover a scientific truth, patience, insistence and persistence are necessary. There are years of research and tests and repetitions until a result is reached.

Other side effects

In addition to these consequences, there are other effects that excess omega 3 can cause in the body. Check out:

  • Gases;
  • Heartburn and acid reflux;
  • Loose stools;
  • Abdominal cramps;
  • Hypotension;
  • Allergic reactions.


Because it is extracted mainly from fish, omega 3 is contraindicated for people allergic  to this animal. However, there are still other rich sources of the substance that can serve as an alternative, such as certain seeds and legumes.

Although these alternatives do not have EPA and DHA, the most beneficial types of omega 3, they do have ALA, a variation that can still bring several benefits and increase the quality of life.

Fatty acid is still contraindicated for people with clotting problems , such as hemophilia, as there is a risk of bleeding as its consumption may end up causing the blood to become more fluid.

People with cardiac prostheses  should also avoid the consumption of omega 3. Pregnant women should be aware of the appropriate doses recommended by the doctor, as the excess of this substance in the body can cause problems for the development of the fetus during pregnancy.

In the case of supplementation through capsules, it is necessary to keep an eye on the type of omega 3 you are consuming. What happens, and a lot, is that, in Brazil, many of the capsules sold on the market have high concentrations of mercury, which can be quite harmful to health.

Problems with mercury intake

Ingestion of mercury can bring serious health problems, as this substance causes intoxication and can affect several organs of the body, which can cause damage to the brain, kidneys and lungs, for example.

The consumption of fish and seafood is by far the biggest cause of mercury poisoning. Fish that eat other fish, such as tuna, are more likely to have high levels of mercury in their bodies because they are in the upper layers of the food chain.

However, even small plants and animals can cause mercury poisoning, especially if they have been exposed and contaminated by the metal.

Problems related to ingesting mercury can be serious and even lead to death. In pregnant women, intoxication can cause problems to the fetus and even terminate the pregnancy. The main symptoms of mercury poisoning include:

  • Changes in mood;
  • Insomnia;
  • Headache;
  • Abnormal sensations;
  • Muscle contractions;
  • Tremors;
  • Weakness;
  • Muscle atrophy;
  • Reduction of cognitive functions (memory, perception, learning, etc.).

Fish with higher levels of mercury that should be avoided by pregnant and lactating women are:

  • Mackerel;
  • Marlin or sailfish;
  • Clockfish;
  • Shark;
  • Swordfish;
  • Pyre;
  • Tuna fish;
  • Bluefish;
  • Grouper;
  • Achigã.

Myths and truths about omega 3

Omega 3 lose weight?

By itself, the consumption of omega 3 does not lose weight . What studies have shown is that, when combined with physical exercise  and a regular diet, omega 3 can help fight inflammatory processes and improve blood circulation, heart health and, consequently, the performance of physical exercise.

What has been identified by research around the world is that consumption of omega 3 helps to maintain weight , and not necessarily decrease measurements.

So, we can conclude that, as omega 3 helps to improve cardiac and circulatory aspects, it improves the quality of life and exercises, enabling greater profitability of sports practices and ensuring greater energy expenditure.

So far, it is in this way and only in this way that it can be said that omega 3 helps in weight loss. So don’t think that just consuming omega 3 will help you lose weight. It is very important to maintain a healthy lifestyle, with exercise and a balanced diet.

Talk to your doctor and nutritionist to find out more about the risks and benefits of consuming omega 3. If appropriate, combine consumption with a healthy lifestyle. Then the results will be satisfactory!

Is Omega 3 effective in the treatment of psychiatric disorders?

Although research indicates that yes, the real effectiveness of omega 3  for the treatment of psychiatric disorders is not yet known .

Some studies suggest that omega 3 is effective in preventing the appearance of disorders such as depression, bipolar disorder and anxiety , however, there is no proven effect that this substance has a significant action in the treatment of these diseases. The results, unfortunately, are still mostly inconclusive.

If you have any of these psychiatric disorders, seek assistance from a specialist in the field. Never self-medicate or fail to follow medical recommendations. Psychiatric problems are serious and deserve extra attention from your patients.

Still, this does not mean that you should avoid the consumption of omega 3. It has several proven benefits, such as improved cardiovascular conditions and anti-inflammatory action, in addition to being an ally of diet and exercises for weight reduction .

Therefore, by using omega 3 to improve exercise and nutrition, you will also be improving your quality of life, which, in fact, can be a great ally in the treatment of psychiatric illnesses.

We can conclude, then, that omega 3 alone does not necessarily treat depression and other psychiatric disorders, but that its use combined with improving the quality of life can have positive effects in the treatment of these diseases.

Who already eats a lot of fish needs to supplement with omega 3?

In the case of people who live in Brazil, yes, it is necessary to supplement omega 3 . This is because the Brazilian fauna of crustacean fish is very different from the Nordic fauna, for example.

While in these countries animals are reservoirs of this substance, in Brazil the case is different. This happens because of the type of feeding of Brazilian fish, which is not conducive for the animal to naturally become an omega 3 reservoir.

In addition, despite being a coastal country, most of the fish consumed in our country is raised in captivity, that is, it is fed with feed, which also does not allow the animal to become a good source of omega 3.

Omega 3 improves brain function?

Some say that omega 3 works by improving the brain, since it can be used by the body in the composition of neurons. However, although there is a wide variety of clinical case reports showing the consumption of omega 3 improves cognitive functions, there are still not enough studies to support this statement with a relative degree of certainty.

This is because the characteristics of people who volunteer to participate in these surveys vary widely, making obtaining reliable results more difficult.

It will still take a few years of research before we have effective answers to this question and, in the meantime, both the general population and the researchers themselves yearn for a definitive answer.

Omega 3 is a substance that has several health benefits. Excessive consumption, however, can cause some health problems. In addition, allergic people and hemophiliacs should avoid their consumption. Consult a doctor and calculate with him the risks and benefits of consuming this product!

Doubts? Suggestions? Put them in the comments! We will be happy to answer them!