People give omega-3 fatty acids a lot of attention due to their health benefits. Fatty fish, nuts, and seeds are rich in omega-3s.
Omega-3s are important parts of the body's cell membranes, and they help with the functioning of the heart, lungs, immune system, and hormone system.
There are three types of omega-3 fatty acid:
- docosahexaenoic acid (DHA)
- eicosapentaenoic acid (EPA)
- alpha-linolenic acid (ALA)
DHA levels are especially high in the eye, brain, and sperm cells. EPA may have certain benefits for reducing inflammation. The body breaks down ALA into EPA and DHA, but the conversion rate is low. For this reason, people should include all three omega-3s in their diet.
Fatty fish are high in DHA and EPA. Plant sources are high in ALA. If a person does not get enough of each type of omega-3 from their diet, they might consider taking a supplement.
This article will explore the recommended intake of omega-3s for different people to achieve optimal health.
What are the daily guidelines for omega-3?
Daily guidelines for omega-3 intake vary depending on factors such as age.
Several national organizations have released guidelines for omega-3 intake, but they vary considerably.
As such, there is no absolute rule about how much omega-3 a person needs.
Research does suggest, however, that different groups of people need different amounts, and higher intakes of omega-3 can be helpful for certain health conditions. We discuss the dietary needs below.
Adult males and females
According to the National Institutes of Health (NIH), there are not enough data available to work out a recommended daily allowance of omega-3 for healthy adults. There are also no specific recommendations for EPA and DHA separately.
Other sources have estimated an adequate intake (AI) for omega-3s. AI is the amount a person needs to ensure nutritional adequacy.
One report from 2008 suggests that adult males and females should get around 0.25 grams (g) of EPA plus DHA per day for their AI.
For an AI of ALA, the NIH recommend 1.6 g for males and 1.1 g for females.
Pregnancy, breastfeeding, and children
People should add more omega-3 to their diet when pregnant and lactating, as follows:
- 0.3 g of EPA plus DHA, of which at least 0.2 g should be DHA
- 1.4 g of ALA while pregnant
- 1.3 g of ALA while lactating
The Food and Drug Administration (FDA) have advised that women who might become pregnant, those who are breastfeeding, and young children should include more fish in their diets every week. They recommend that women who are pregnant or breastfeeding eat 8–12 ounces of low-mercury fish every week to benefit fetal growth and development.
Male and female infants up to the age of 1 should consume 0.5 g as total omega-3s. Human milk contains ALA, DHA, and EPA for breastfed infants.
Omega-3 for heart health
A 2002 study published in the journal Circulation recommended that people with cardiovascular disease consume around 1 g of EPA plus DHA per day, preferably from oily fish. However, they can speak to their doctor about taking supplements. That said, updated guidelines are needed.
Researchers have conducted many studies to evaluate the effects of taking omega-3 supplements on heart disease.
One review found that there was a modest decrease in mortality in people with established coronary heart disease, as well as those with heart failure. However, the results are mixed with those of another large study, which concluded that DHA and EPA supplements may have little effect, while ALA might have a small effect. Further research is needed.
Omega-3 for depression
Some studies have suggested that taking omega-3 supplements may help with symptoms of depression.
One small-scale study of young adults with depressive symptoms reported that a group receiving 1.4 g of DHA plus EPA every day had a significantly lower depression status compared with a placebo group after 21 days.
Omega-3 for Alzheimer's disease
Omega-3 may help treat Alzheimer's disease.
Omega-3 supplements may also have potential as a future treatment for Alzheimer's disease.
A 2018 review found that omega-3s may be beneficial in early Alzheimer's disease, when there is only a slight impairment in brain function.
However, there are not enough data to support using omega-3 supplements in more advanced cases of Alzheimer's disease.
Omega-3 for cancer
Many studies have examined the positive effects of omega-3 supplementation on certain cancer types.
How much is too much?
There is no established upper limit of omega-3 intake. According to the NIH, the FDA have suggested that people should take no more than 3 g per day of DHA and EPA combined.
Over long periods, scientists say that omega-3 can reduce immune system function because it lowers the body's inflammatory responses.
High doses of omega-3 may also increase bleeding time. Therefore, people who take blood-thinning drugs should take caution and talk to their doctor before starting to take an omega-3 supplement.
What happens if you have an omega-3 deficiency?
There are few known symptoms of omega-3 deficiencies. Doctors have found links between deficiency of essential fatty acids, including omega-3 and omega-6, and symptoms of dermatitis and rough, scaly skin.
Researchers do not know whether there is a certain threshold of DHA and EPA in the body that could raise the risk of neurological or immune dysfunction.
In the United States, omega-3 deficiency is very rare.
About omega-3 supplements
Flaxseed is a source of omega-3 that is suitable for vegetarians and vegans.
If a person cannot get enough omega-3 in their diet, they might consider taking a supplement. Speak to a doctor before taking any new dietary supplements.
The ingredients of omega-3 supplements vary widely. People may wish to examine the product label to see what exactly their supplement contains.
The amount of each ingredient can vary between batches of the same product because the FDA do not regulate the quality of omega-3 supplements.
A typical omega-3 supplement will provide around 1 g of fish oil and varying doses of EPA and DHA.
Long-chain omega-3s EPA and DHA, which have the most well-researched health benefits, are present in fish oil, krill oil, and cod-liver oil supplements.
Plant-based algal oil provides around 0.1 g–0.3 g of DHA, and some also contain EPA. Other plant-based supplements, such as flaxseed capsules, only provide ALA fatty acids.
While seafood can contain heavy metals, scientists have not found these in omega-3 supplements since the manufacturers remove them during processing and purification.
People can find omega-3 supplements in health stores or choose from a range of brands in online stores:
- shop for fish oil supplements
- shop for krill oil supplements
- shop for flaxseed supplements
- shop for algal supplements
The amount of omega-3 a person needs depends on their age, sex, and health status. People should eat oily fish twice per week to get adequate EPA and DHA, and they should include plant-based sources of ALA in their diet.
Health sources recommend that people should not exceed 3 g of omega-3 in a day, unless otherwise directed by a medical professional.
If a person does not eat fish, taking an omega-3 supplement might be a good idea. Be sure to read a supplement's label carefully and talk to a doctor before taking any new supplements. References