Omega-3 Fatty Acids and Blood Pressure

Whether Omega-3 fatty acids can directly lower blood pressure is controversial. However, positive effects of Omega-3 fatty acids have been demonstrated in people with early-stage heart disease. In a "Rote-Hand-Brief," the Federal Institute for Drugs and Medical Devices (BfArM) warned in November 2023 that depending on the dosage of Omega-3 supplements taken, there was an increased occurrence of atrial fibrillation in certain individuals.

What are Omega-3 Fatty Acids?

Omega-3 fatty acids are polyunsaturated fatty acids.

Unsaturated fatty acids are important for the immune system, blood clotting, and the formation of nerve cells. They are components of cell membranes, precursors of signaling molecules, hormones, and inflammatory mediators. They are essential, meaning vital, and cannot be produced by the body, so they must be obtained through diet.

Effects of Omega-3

Particularly important and well-studied are the Omega-3 fatty acids EPA and DHA (found in fatty cold-water fish such as carp, eel, salmon, mackerel, and the like; plant-based: microalgae oil) as well as alpha-linolenic acid (found exclusively in plants, for example in rapeseed, hemp, walnut, or flaxseed oil).

The effects of DHA have been studied by two research teams. They discovered that DHA can dock at specific sites on muscle cells and open potassium channels, allowing potassium to flow out of the cell. As a result, the muscle cell relaxes. The hypothesis that this leads to the dilation of blood vessels and a decrease in blood pressure has been demonstrated in experiments with anesthetized mice.

A study published on June 1, 2022, was able to demonstrate a blood pressure-lowering effect of Omega-3 fatty acids in humans. The effect was greater the higher the baseline blood pressure was. The highest reduction was shown with a daily dose of 3 g of Omega-3 fatty acids. According to the study, these can be obtained through supplements or through diet.

In the summer of 2023, the Swiss Medical Forum and Medical Tribune questioned the results of many studies, as most studies on Omega-3 supplements were not blinded. Additionally, the control group was sometimes given a placebo, which could negatively affect the expected effect. It is therefore possible that the positive effects found for the Omega-3 fatty acids under investigation are less due to the beneficial effect of the product in the experimental group and more due to the adverse effect of the placebo in the control group.
They also point out that Omega-3 fatty acids are only present in small amounts in fish. To meet the demand for fish oil capsules, an excessive amount of fish must be caught and processed, contributing to overfishing and disrupting the ecological balance in the seas. Traces of PCB and dioxins are also detectable in the finished fish oil capsules. These do not have an effect when taken in small amounts but can have adverse effects on humans at high intake doses. Therefore, be sure to pay attention to high quality when purchasing fish oil capsules.

Positive Effects of Omega-3

Furthermore, Omega-3 fatty acids are attributed the following positive effects:

Protection against arrhythmias
Stabilization of atherosclerotic deposits and thus prevention of the rupture of deposits, which can lead to heart attacks or strokes
Prevention or slowing of the progression of coronary heart disease (CHD)
Inhibition of platelet aggregation - thus improving the flow properties of blood and promoting circulation
Positive effects on certain inflammatory mediators
Reduction of triglyceride levels
Indications that the risk of dementia or depression is reduced

Side Effects of Omega-3

However, side effects are also known.

Side Effects of Omega-3 Medications

There are also medications with ethyl esters of Omega-3 fatty acids, Icosapent ethyl is mentioned as an ingredient, which can be prescribed to people with elevated blood lipid levels. Here, the side effects are named more specifically. In addition to nausea, abdominal pain, inflammation of the mucous membranes in the gastrointestinal tract, and disturbances in taste perception, dizziness is also listed. For a medication that is currently unavailable in Germany due to a price dispute, bleeding, edema, atrial fibrillation, constipation, muscle and bone pain, gout, and skin rashes were known as undesirable but possible side effects. The Federal Institute for Drugs and Medical Devices (BfArM) warned in a so-called "Rote-Hand-Brief" in November 2023 that there was an increased occurrence of atrial fibrillation in individuals with cardiovascular diseases or cardiovascular risk factors. This was dependent on the dosage of Omega-3 fatty acids that the participants took in the respective studies. It was shown that the risk of developing atrial fibrillation was highest with a daily dose of 4 g.

Side Effects of Omega-3 Supplements

For Omega-3 preparations available as dietary supplements, reports often mention fishy burps and bad breath, and less frequently discomfort and problems with the stomach or intestines.

As mentioned above, there was an increased occurrence of atrial fibrillation with medications containing Omega-3 fatty acids. In the corresponding communication, the BfR explicitly writes about dietary supplements:

Dietary supplements containing Omega-3 fatty acids are offered, for example, in the form of fish oil capsules and contain similar high dosages as medications. Unlike medications, dietary supplements are freely available in stores and can also be taken over longer periods without medical supervision. Possible undesirable health effects can thus be more easily overlooked.

The Federal Institute for Risk Assessment (BfR) therefore particularly recommends that consumers with heart diseases or corresponding risk factors take Omega-3 fatty acid-containing preparations, such as dietary supplements, only in consultation with a doctor, especially over a longer period.

The Omega-3 Index

The so-called Omega-3 index refers to the proportion of Omega-3 fatty acids to total fatty acids in the membranes of red blood cells. If this is below 4 percent, the risk of sudden cardiac death is ten times higher compared to an index of over 8 percent.

For comparison: In Germany, the Omega-3 index averages 4 percent - for every 100,000 people, there are 148 cases of sudden cardiac death. In Japan, the Omega-3 index averages 11 percent - sudden cardiac death occurs in only 7.8 out of 100,000 people.

The Ratio of Omega-3 to Omega-6 Fatty Acids

However, it is not only the amount of Omega-3 fatty acids consumed that is important. Through our diet, we generally consume a relatively large amount of Omega-6 fatty acids, which are known to counteract Omega-3 fatty acids. The breakdown of linoleic acid, which belongs to the Omega-6 fatty acids, to arachidonic acid requires the same enzyme system as the breakdown of alpha-linolenic acid, which belongs to the Omega-3 fatty acids, to EPA. If there is an oversupply of linoleic acid, as is common in Western diets, less alpha-linolenic acid can be converted.

Therefore, it is important to pay attention to a balanced ratio of Omega-6 to Omega-3 fatty acids. The German Society for Nutrition (DGE) recommends a ratio of a maximum of 5:1. This means consuming no more than five times as much Omega-6 as Omega-3 fatty acids. Currently, the ratio is usually about 8:1.

To obtain a sufficient amount of beneficial Omega-3 fatty acids, the German Society for Nutrition recommends two fish meals per week or an intake of EPA and DHA of 250 mg/day. However, the effectiveness of intake through capsules is often questioned.

Those who adjust their diet accordingly, eat fish, and prefer valuable plant oils (such as flaxseed, microalgae, chia, camelina, or hemp oil for cold dishes and rapeseed oil for both warm and cold cooking) over unhealthy saturated animal fats benefit in multiple ways. On the one hand, they consume the Omega-3 fatty acids in this form, which are likely more useful, and on the other hand, they eliminate a meal of less favorable red meat in favor of the healthier fish meal.

Fish	Omega-3 Fatty Acid Content
Atlantic Salmon, farmed, cooked, smoked	1.8%
Anchovies Europe, preserved in oil or salt	1.7%
Sardine Pacific Ocean, preserved in tomato sauce or salt, with bones	1.4%
Atlantic Herring, pickled in vinegar	1.2%
Mackerel Atlantic, cooked, smoked	1%
White Tuna preserved in water or salt	0.7%

As a plant-based alternative to fish, flaxseed oil is of greatest importance, as it contains alpha-linolenic acid in its most concentrated form. The body can convert this (in limited amounts) into Omega-3 fatty acids. Of course, the content is also high in whole flaxseeds and can be well absorbed from the ground version with adequate fluid intake. Hemp oil and walnuts or walnut oil also provide a good plant-based source of alpha-linolenic acid. Other, but currently still rather exotic sources include chia, perilla, sacha inchi, and camelina oil. The latter should not be confused with flaxseed oil; it is a different plant.

Plant Oil	Omega-3 Fatty Acid Content
Flaxseed Oil	56-71%
Chia Oil	up to approx. 64%
Perilla Oil	approx. 60%
Sacha Inchi Oil	approx. 48%
Camelina Oil	approx. 38%
Hemp Oil	approx. 17%
Walnut Oil	approx. 13%
Rapeseed Oil	approx. 9%
Soybean Oil	approx. 8%

Omega-6 Fatty Acids

In connection with the benefits of Omega-3 fatty acids, Omega-6 fatty acids are often mentioned. And that one should pay attention to a balanced ratio of the two fatty acids. The recommendation is 5:1. This means that one should consume no more than five times as many Omega-6 fatty acids as Omega-3 fatty acids. This is difficult if one does not know what they are and in which foods the fatty acids are contained.

Omega-6 fatty acids are also polyunsaturated fatty acids. Some of them are essential, meaning they must be supplied because the body cannot produce them itself.

The most important Omega-6 fatty acids are linoleic acid, gamma-linolenic acid, and arachidonic acid. Of these, linoleic acid is the essential Omega-6 fatty acid that must be supplied. The other two and other fatty acids can be formed from it by the body.

Functions of Omega-6 Fatty Acids

Omega-6 fatty acids are components of cell membranes. They also serve as precursors for various substances. They are involved in growth and repair processes and lower bad LDL cholesterol, but unfortunately also good HDL cholesterol.

The arachidonic and gamma-linolenic acids formed from linoleic acid have more specific functions. Arachidonic acid is not only a component of the cell membrane - it also serves as a basis for building tissue hormones (eicosanoids). These produce free radicals that are necessary to defend against harmful substances. However, they also promote inflammatory processes in the body and have a vasoconstrictive effect. Gamma-linolenic acid, on the other hand, has anti-inflammatory effects.

Occurrence of Omega-6 Fatty Acids

Omega-6 fatty acids are found in many foods. Therefore, one does not have to worry much about adequate intake.

Linoleic acid is found in large amounts, for example, in thistle and sunflower oil. However, it is also present in meat and meat products from conventional farming, as farmed animals often receive linoleic acid-rich feed.

Arachidonic acid is particularly found in animal fats, muscle meat, and offal, eggs (especially in the yolk), and milk fat.

Gamma-linolenic acid is found in pomegranate seeds and hemp oil.

Omega-6 fatty acids are therefore also important for the body. However, an excess is rather harmful.

Sources

By Sabine Croci. This article is medically reviewed. Last updated (03/2024).
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