Omega-3 Fatty Acids
The omega-3 fatty acids belong to the group of polyunsaturated fatty acids. Omega-3 fatty acids are essential nutrients that must be obtained through diet. They are primarily needed as components of the brain (nervous system), retina, and cell membranes 1.
The three most well-known and important omega-3 fatty acids are:
- Alpha-linolenic acid (ALA)
- Eicosapentaenoic acid (EPA)
- Docosahexaenoic acid (DHA)
Eicosapentaenoic acid and docosahexaenoic acid are derived from alpha-linolenic acid.
Omega-3 fatty acids have multiple double bonds between carbon atoms in their chemical structure, which is a carbon-hydrogen chain with oxygen and hydrogen atoms. The first double bond, starting from the methyl end (also known as the omega end), is between the third and fourth carbon atoms.
Alpha-linolenic acid (18:3n-3; 18 carbon atoms and 3 double bonds in the carbon-hydrogen chain) is a long-chain essential fatty acid. It cannot be synthesized by the body and therefore must be obtained through diet. It primarily serves as a precursor for the synthesis of eicosapentaenoic acid and docosahexaenoic acid.
Eicosapentaenoic acid (20:5n–3; 20 carbon atoms and 5 double bonds) is a long-chain fatty acid and is required as a precursor for health-promoting eicosanoids (series-3). Eicosanoids derived from EPA have anti-inflammatory effects, which contribute to the prevention of cardiovascular diseases, hypertension, autoimmune diseases, arthritis, and various types of cancer 2.
A vegan diet is low in eicosapentaenoic acid since this fatty acid is found in very few plant-based foods such as algae and seaweed 3. The oil from the brown seaweed kelp also contains some eicosapentaenoic acid 4.
According to a Finnish study from 2016, vegans had higher levels of eicosapentaenoic acid compared to other fatty acids, as expected. 5.
Docosahexaenoic acid (22:6n–3, 22 carbon atoms and 6 double bonds) is also a fatty acid that is needed for metabolism and as a component of the brain, nerve cells, retina, and cell membranes. 6 7. They provide cell membranes with flexible and permeable properties, among others. 8.
Docosahexaenoic acid is found in microalgae and microalgae oil. 9 10. When consuming microalgae oil, it should be noted that it can lead to an increase in the less desirable LDL cholesterol in the body. 11. Nonetheless, cholesterol levels are generally low in vegans, so the consumption of such foods should not have a significant impact.
Conversion of ALA to EPA and DHA
Alpha-linolenic acid (ALA) is not biologically active in the body and therefore needs to be converted. Alpha-linolenic acid is initially converted to eicosapentaenoic acid (EPA) through stearidonic acid and eicosatetraenoic acid 12. Eicosapentaenoic acid is then further converted to docosahexaenoic acid (DHA) through docosapentaenoic acid.
According to study results, vegans have very low levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) 13. This is due to the extremely low levels of EPA and DHA found in plant-based foods, as well as the low conversion rates of ALA to EPA (around 5%) and ALA (via EPA) to DHA (below 0.5%) 14. Other scientists estimate conversion rates of 5 to 10% for EPA and 2 to 5% for DHA 15.
This is also supported by a study on supplementation with simultaneous administration of ALA and gamma-linolenic acid (an omega-6 fatty acid) 16. The result was only a very slight increase in eicosapentaenoic acid levels.
In women, conversion rates are higher, presumably due to the regulatory effect of estrogen 17 18 19. Women after menopause were able to increase their plasma ALA levels by 138% and EPA levels by 39% with the help of 25 g of ground chia seeds per day (no increase in DHA was observed) 20.
No adverse health effects due to lower EPA and DHA status in vegans have been reported so far 21.
Vitamins and minerals are required for the formation of EPA and DHA
The body also needs to be supplied with adequate amounts of vitamins B3, B6, and C, as well as the minerals iron, calcium, copper, magnesium, and zinc in order to form eicosapentaenoic acid and docosahexaenoic acid. (Source: vitamins, minerals, iron, calcium, magnesium, and zinc). According to scientists, dietary factors associated with reduced conversion include trans-fatty acids, excessive alcohol and caffeine consumption. (Sources: 22 23).
Reduced conversion of ALA due to excessive Omega-6 and chronic diseases
Excessive omega-6 fatty acids can reduce the conversion rates of ALA to EPA and DHA because omega-6 and omega-3 compete for the same enzyme systems for conversion (Δ-6-desaturase and Δ-5-desaturase). 24. With an omega-6-rich diet, the conversion is reduced by 40 to 50%. 25. Through another four-week study, by reducing the daily intake of linolenic acid from 4.6 to 2% while maintaining the intake of omega-3, the proportion of omega-3 plasma lipids was significantly increased from 5.53 to 6.22%. 26.
People with diabetes may not be able to convert ALA to EPA and DHA 27. The conversion may also be limited in other chronic diseases such as obesity, atherosclerosis, metabolic syndrome, hypertension, and hyperlipidemia 28.
Therefore, for individuals who potentially experience impaired conversion, a dietary supplement of 200 to 300 mg/day of DHA and EPA is recommended 29. DHA and EPA are also available from plant-based sources such as microalgae. Studies have shown that small amounts of preformed DHA (200 mg) lead to a significant increase in DHA levels in the blood of vegans (from 23 ± 12 mg/L to 33 ± 12 mg/L) 30 31. EPA can be formed in the body through retroconversion of DHA 32. Nonetheless, dietary supplements should always be taken with caution and in consultation with a physician.
In addition, cigarette smoke during pregnancy negatively affects the synthesis of omega-3 in breast gland cells, resulting in lower levels of omega-3 fatty acids in breast milk 33.
Omega-3 Functions and Effects in the Body
Multiple studies have shown that omega-3 fatty acids inhibit natural bodily inflammation and support crucial functions of the immune system 34 3536. Additionally, they assist in the hormone regulation of insulin 37. Among other things, they have a positive influence on lipid metabolism.
Scientific studies also suggest that omega-3 fatty acids positively influence prenatal (pre-birth) development of the nervous system 38 39. Additionally, researchers have found evidence that omega-3 protects against neurodegeneration and may potentially reduce the risk of cognitive impairments in older age. However, scientists conducting a recent study on this issue were unable to observe significantly positive effects on cognitive improvement or prevention of cognitive decline in older individuals after administering low doses of omega-3 fatty acids (EPA and DHA) for 6 months 40.
Omega-3 fatty acids are important building blocks of cell membranes. They exert a function-preserving effect and are indirectly involved in cellular metabolism. Without omega-3 fatty acids, cell membranes become less flexible, significantly impairing their functionality.
Consuming omega-3 fatty acids also reduces the number of triglycerides in the blood. 41 42. Higher triglyceride levels can lead to thrombosis and arterial calcification. Omega-3 fatty acids are also associated with a cholesterol-lowering effect. 43. Since a vegan diet is already free of cholesterol, vegans need not worry much about high cholesterol levels.
Omega-3 for Health and Well-being
Studies on Omega-3, specifically EPA and DHA, have shown that these fatty acids can reduce the body's own inflammation and protect against arthritis 44 45. A study summary from 2015 confirms the anti-inflammatory effects of Omega-3 fatty acids 46. According to this, Omega-3 fatty acids are known as substrates required for the synthesis of novel lipid mediators (such as resolvins, protectins, and maresins) with strong anti-inflammatory and inflammation-resolving properties.
In 2014, researchers from the University of Oxford found that higher levels of DHA omega-3 are associated with improved sleep quality 49.
According to studies from 2015, omega-3, along with vitamin D, is involved in serotonin production 50. Serotonin, the neurotransmitter known as the "feel-good hormone," is responsible for maintaining a positive mood. Conversely, a serotonin deficiency can lead to depression. The evidence is growing that omega-3 fatty acids can alleviate depression and contribute to an improvement in mood 51 52 5354 55.
In addition, omega-3 fatty acids are also believed to reduce the progression of psychotic disorders (psychosis) 56. According to scientists, omega-3 could be a safe and effective strategy for preventing subthreshold psychotic states in adolescents.
Do Omega-3 Fatty Acids Protect Against Heart Diseases?
Results regarding a reduced risk of cardiovascular diseases, morbidity, and mortality due to Omega-3 are not yet clear enough to form a conclusive judgment. 57 5859. Further study results indicate that supplementation with Omega-3 fatty acids cannot be associated with a lower risk of overall mortality, cardiac death, sudden death, myocardial infarction, or stroke 60 61. However, some scientists believe in the cardioprotective effect of omega-3 fatty acids 62. According to a 2011 study, high intake of omega-3 has significant cardioprotective effects in women 63.
According to a large 2016 study that summarizes 19 studies from 16 countries involving 45,000 participants, having higher levels of circulating omega-3 fatty acids in the blood is associated with an average nearly 10% lower risk of fatal coronary heart diseases such as heart attacks. 64 Participants with the highest omega-3 levels had a 25% lower risk of fatal heart attacks.
Omega-3 fatty acids reduce the risk of cancer
Omega-3 fatty acids are associated with a reduced risk of colorectal cancer in men 65. There is also evidence that omega-3 can protect against skin cancer 66. Additionally, it is believed that higher levels of omega-3 are associated with a reduced risk of breast cancer 676869 70. This is justified, among other things, by the inflammation-resolving properties of EPA and DHA on oncogenic proteins (cancer genes responsible for tumor initiation) 71.
Omega-3 for Fitness
In a smaller study involving 16 older adults, Omega-3 fatty acids were found to stimulate muscle protein synthesis 78. Additionally, they could be beneficial for the prevention and treatment of sarcopenia (age-related loss of muscle mass).
Omega-3 has an additional positive effect on alleviating muscle soreness after intense training. 79.
For beneficial effects in combating exercise-induced inflammation and for the overall health of athletes, an intake of approximately 1-2 grams of EPA and DHA per day is suggested (with an EPA to DHA ratio of 2:1). 80. However, it should be noted that the data is not yet conclusive. Further studies are needed to determine whether it leads to a reduction in inflammatory and immunomodulatory response as well as an improvement in training performance.
Mitochondria, which are particularly present in cells with high energy consumption (such as muscle cells), are also influenced by Omega-3. It has been shown that Omega-3 supplementation increased the content of mitochondria 81. These intracellular powerhouses generate adenosine triphosphate (ATP), which is the universal and readily available energy carrier in every cell. Therefore, ATP is the building block that enables cells to perform their functions. The greater the number of mitochondria present, the higher the cellular performance.
In 2014, scientists found that higher Omega-3 consumption is associated with improved insulin sensitivity 82. This also benefits athletes as insulin sensitivity is closely linked to muscle building. Improved insulin sensitivity promotes the breakdown of blood sugar (energy release), reducing the storage of carbohydrates as fat in the tissues.
Omega-3 Fatty Acid Requirements
For health reasons, it is extremely important for vegans to incorporate plants with high amounts of omega-3 fatty acids into their diet. Omega-3 fatty acids can only be stored in limited amounts in adipose tissue. 83. According to Harvard University, it is recommended to consume at least one omega-3-rich food per day. 84.
The requirements depend on age and gender. The following requirements (AI) of α-linolenic acid (ALA) are recommended for vegetarians, which vegans can also follow. 85:
|Gender and Age Group||Amount in g|
|18 years and older||2.6|
|18 years and older||1.6|
|0 to 12 months||0.5|
|1 to 3 years||1|
|4 to 8 years||1.6|
|Boys 9 to 13 years||2|
|Boys 14 to 18 years||2.4|
|Girls 9 to 13 years||1.6|
|Girls 14 to 18 years||1.6|
As mentioned before, the values provided are for vegetarians (currently no list available for vegans). Due to a lack of plant-based foods containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), vegans rely on consuming higher amounts of alpha-linolenic acid (ALA) regularly to produce sufficient EPA and DHA on their own. This is attributed to lower conversion rates of ALA to EPA and DHA. Therefore, for vegans, 2 to 4 g of alpha-linolenic acid daily is considered appropriate 86.
During and after pregnancy, (expectant) vegan mothers should consider incorporating higher intake levels of omega-3 fatty acids into their diet. Recommended amounts are ≥ 650 mg EPA and 300 mg DHA per day. 87. The European Food Safety Authority (EFSA) recommends 100 to 200 mg DHA per day. 88.
ALA or EPA dietary supplements have little impact on the DHA levels in blood or breast milk, whereas consumption of preformed DHA contributed to an increase in blood DHA levels during the study 89. A study conducted with lactating mothers found that daily supplementation of 10.7 grams of flaxseed oil (which contains a high amount of alpha-linolenic acid at 53.4 grams) over a period of 4 weeks did not significantly increase DHA concentrations in breast milk 90. However, the concentrations of ALA and EPA did increase.
In general, the mother's DHA levels have an influence on the DHA content in breast milk 91. Vegan dietary supplements can be considered in consultation with a physician. Parents should also ensure adequate supply of essential omega-3 fatty acids for their children.
Among vegans, there can be a rapid deficiency in the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid, as they are scarce or nonexistent in plant-based foods, and the conversion rates of alpha-linolenic acid to eicosapentaenoic acid and docosahexaenoic acid are very low. 92. As a result, vegans usually have low but stable plasma concentrations of endogenous (within the body) EPA and DHA. 93 94. The cause often lies in inadequate intake of omega-3-rich foods.
An omega-3 deficiency can lead to a higher risk of cardiovascular diseases 95. Symptoms may include dry skin, muscle weakness, difficulty concentrating, sleep disorders, migraines, and depression 96 97. Additionally, a deficiency in DHA has been associated with several neurological disorders and behavioral disorders such as schizophrenia, Alzheimer's, dementia, and attention deficit syndrome 98 99.
If fetuses and infants lack EPA and DHA (found in breast milk), it can lead to reduced visual acuity and impaired brain and nervous system development. 100 101102 103 104. However, it should be noted that DHA supplementation does not lead to additional improvement in cognition, language, and executive functions. 105 106.
Possibly, omega-3 deficiency can increase the risk of osteoporosis 107. However, the study findings on this topic are not conclusive, so a definitive assessment is not possible.
A deficiency can be determined through a plasma test conducted by a doctor. If DHA levels are reduced, a deficiency is present 108. Treatment usually involves the administration of omega-3 supplements, unless there is a deficit in patients with reduced fat absorption 109.
Excess of Omega-3
High levels of omega-3 fatty acids, which can arise, for example, from faulty dietary supplementation, can suppress the production of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) 110. TNF-α and interleukins are important messenger molecules needed for immune and inflammatory reactions. Furthermore, it should be noted that high levels of omega-3 can lead to immune suppression and prolong bleeding time 111.
Omega-3 fatty acids oxidize upon contact with oxygen and high temperatures
According to scientific research, omega-3 fatty acids oxidize more quickly at high temperatures, causing the fatty acids to spoil, become toxic, and rancid 112.
Alpha-linolenic acid is particularly sensitive to destruction by light, oxygen, and heat 113. It is destroyed 5 times faster than the essential omega-6 fatty acid linoleic acid. Cold-pressed fats should therefore not be used for cooking or frying, as they can also form harmful trans fats. Store the corresponding products and food in a cool and dark place, if possible.
When in contact with oxygen, free radicals are formed in the body cells, especially affecting polyunsaturated fatty acids, which can damage health and even cause cancer. In the body, vitamin E can prevent oxidation as an antioxidant 114. Consequently, the vitamin E requirement also increases according to scientific studies. Scientists recommend consuming at least 0.6 mg of vitamin E (vitamin E foods) per gram of omega-3 115.
What should vegans consider?
In addition to a higher intake of Omega-3, vegans should pay attention to the fatty acid ratio of Omega-6. A vegan diet is usually rich in Omega-6 fatty acids and relatively low in Omega-3. This imbalance can have negative effects on health (including cardiovascular diseases and increased occurrence of inflammation). Therefore, the focus should be on an Omega-3-rich diet.
For pregnant and breastfeeding women, supplementation with 100 to 300 mg of DHA per day is recommended to avoid jeopardizing the child's development. A study from Poland indicates that a vegan diet does not contain EPA and DHA 116.