Omega-3 for Fertility: A Dietitian's Guide for Women and Men
Sophie Mumby, Registered Dietitian (HCPC)
If you're trying to conceive, you may have come across a lot of advice about omega-3.
Should you be taking a supplement? Can omega-3 improve egg quality? What about sperm health? Do you need to eat oily fish every week? And does your partner need to think about omega-3 too?
There is a huge amount of fertility nutrition information online, and it can be difficult to work out what is actually supported by evidence.
The good news is that omega-3 doesn't need to be complicated. It is an important part of a balanced diet for both women and men, including during the pre-conception period.
In this guide, I'll explain what omega-3 is, why it matters for fertility, where to get it from and what we know about supplements.
What are omega-3 fatty acids?
Omega-3 fatty acids are a type of polyunsaturated fatty acid. There are three main types:
EPA (eicosapentaenoic acid)
DHA (docosahexaenoic acid)
ALA (alpha-linolenic acid)
ALA is an essential fatty acid, meaning our bodies cannot make it and we need to obtain it from our diet.
We can convert small amounts of ALA into EPA and DHA in the body, but this conversion is limited. This is one reason why dietary sources of EPA and DHA are useful.
EPA and DHA are particularly concentrated in oily fish, while ALA is found in plant foods such as flaxseed, chia seeds and walnuts.
Why might omega-3 matter for fertility?
Omega-3 fatty acids have important roles throughout the body. They are incorporated into cell membranes and are involved in processes including inflammation, cardiovascular function and cell signalling.
These functions are relevant to reproductive health because eggs, sperm and reproductive tissues are all made up of cells whose membranes contain fatty acids.
There is growing research into the role of omega-3 in fertility, including ovarian function, egg quality, embryo development and sperm health.
However, it is important to be realistic about what the evidence tells us.
Omega-3 isn't a fertility treatment, and taking more isn't necessarily better.
Rather, getting enough omega-3 as part of an overall nutritious diet is one piece of the bigger picture when preparing for pregnancy.
And importantly, this applies to both partners.
Omega-3 and women's fertility
Research has suggested that omega-3 may have a role in several aspects of female reproductive health.
Studies have investigated associations between omega-3 intake and:
ovarian function
ovulation
oocyte (egg) quality
embryo development
implantation
reproductive ageing
There is also interest in the role of omega-3 in the inflammatory and vascular processes involved in reproduction.
Some studies have found associations between higher omega-3 intake and fertility-related outcomes, but the evidence is not consistent enough to say that omega-3 supplementation will improve fertility for every woman.
So rather than thinking about omega-3 as a treatment for infertility, I prefer to think about it as part of a healthy pre-conception diet.
What about men?
This is an area that is often overlooked when we talk about fertility nutrition.
Fertility isn't just a woman's issue.
Around half of couples experiencing difficulty conceiving have a male factor contributing to the problem, either alone or alongside female factors.
Sperm are particularly rich in polyunsaturated fatty acids, including DHA, which plays an important role in sperm cell membranes.
Research has therefore looked at whether omega-3 intake or supplementation could influence male fertility.
Studies have investigated outcomes including:
sperm concentration
sperm motility
sperm morphology
sperm membrane composition
sperm quality
Some studies suggest that omega-3 supplementation may improve certain measures of sperm quality, particularly sperm concentration and motility, but the evidence is mixed and trials have differed considerably in their doses and populations.
Importantly, improvements in sperm parameters do not necessarily mean a higher chance of pregnancy or live birth.
So again, omega-3 should not be viewed as a magic supplement for male fertility.
Instead, men who are trying to conceive should pay attention to their overall diet and lifestyle too.
That means your partner's nutrition matters just as much as yours.
Where do omega-3s come from?
Oily fish
EPA and DHA are found in particularly high amounts in oily fish.
Examples include:
Salmon
Sardines
Mackerel
Herring
Pilchards
Some shellfish, including crab and oysters, also provide EPA and DHA, although generally in smaller amounts than oily fish.
Plant foods such as flaxseed, chia seeds and walnuts provide ALA.
These are excellent foods to include as part of a healthy diet, but because conversion of ALA into EPA and DHA is limited, they aren't equivalent to oily fish as a source of long-chain omega-3.
How much omega-3 do you need when trying to conceive?
There isn't a specific UK government recommendation for a daily amount of EPA and DHA specifically for people trying to conceive.
UK healthy eating guidance recommends eating at least two portions of fish per week, including one portion of oily fish.
One portion is around 140g.
This is a practical way for both partners to include EPA and DHA in their diets while also getting other important nutrients.
The European Food Safety Authority (EFSA) has established an Adequate Intake of 250mg of EPA + DHA per day for adults.
This applies to both women and men.
It's worth remembering that this is an Adequate Intake for the general adult population rather than a specific fertility target.
You therefore don't need to calculate your omega-3 intake every day or try to reach a particular number specifically because you're trying to conceive.
Not all fish contain the same amount of omega-3
The McCance and Widdowson's Composition of Foods Integrated Dataset (CoFID) gives us an idea of how much EPA and DHA different fish contain.
Approximate EPA + DHA content per 140g portion of uncooked fish:
Fish | EPA + DHA |
Mackerel | 3,570mg |
Farmed salmon | 3,038mg |
Wild salmon | 2,338mg |
Herring | 1,680mg |
Sardines | 1,554mg |
Alaskan pollock | 182mg |
Cod | 98mg |
This shows why oily fish are such useful sources of EPA and DHA.
A portion of salmon, sardines, herring or mackerel provides substantially more EPA and DHA than the same amount of white fish.
The exact amount varies depending on the species, where the fish comes from, what it has been fed and how it has been prepared, so these figures are estimates rather than precise amounts.
What if you don't eat fish?
You can absolutely follow a healthy fertility-focused diet without eating fish.
People may avoid fish because they are vegetarian or vegan, have an allergy, don't like the taste, have ethical concerns or simply don't eat it regularly.
Eggs
Eggs contain small amounts of DHA.
Some omega-3-enriched eggs contain considerably more DHA because the hens are fed omega-3-rich feed such as flaxseed.
Eggs can therefore contribute to your overall omega-3 intake, although they aren't equivalent to oily fish as a source of EPA and DHA.
Plant sources
If you don't eat fish, include foods rich in ALA regularly, such as:
Ground flaxseed
Chia seeds
Walnuts
Rapeseed oil
Soya and soya products
These are nutritious foods that can form part of a healthy pre-conception diet.
However, remember that conversion of ALA to EPA and DHA is limited.
What about omega-3 supplements?
This is where fertility advice online can become particularly confusing.
You will find supplements marketed specifically for:
"egg quality"
"ovarian health"
"sperm health"
"implantation"
"IVF success"
"hormone balance"
The evidence does not currently support the idea that everyone trying to conceive needs a high-dose omega-3 supplement.
If you regularly eat oily fish, you may already be getting substantial amounts of EPA and DHA from your diet.
For people who don't eat fish, an omega-3 supplement can be a useful way of obtaining DHA and/or EPA.
If you are vegetarian or vegan, an algae-derived supplement can provide DHA and some products also provide EPA.
If you are undergoing fertility treatment, have a diagnosed fertility problem or are considering supplements specifically to improve egg or sperm quality, it's worth discussing this with your fertility team or a dietitian rather than assuming that a higher dose will necessarily be beneficial.
Omega-3 and sperm health: should men take a supplement?
There is some promising research here, but it is important to keep the evidence in perspective.
Some clinical trials have found improvements in sperm parameters following omega-3 supplementation, including sperm concentration and motility.
However, studies have used different doses and formulations, and the overall evidence is not strong enough to recommend high-dose omega-3 supplements routinely to every man trying to conceive.
For men, I would therefore start with the basics:
Eat oily fish regularly.
Include plant sources of ALA.
Eat a varied, nutrient-rich diet.
Don't smoke.
Keep alcohol intake within recommended limits.
Maintain a healthy weight where possible.
Avoid excessive heat exposure to the testes.
Get any fertility concerns assessed rather than relying on supplements alone.
And remember that sperm production takes around three months, so changes to diet and lifestyle aren't expected to have an immediate effect.
Omega-3 and egg quality: can it improve your eggs?
This is one of the most common questions I hear.
Unfortunately, there isn't a food or supplement that can guarantee improved egg quality.
Egg quality is strongly influenced by age and many other biological factors.
There is research investigating whether omega-3 may support aspects of ovarian function and oocyte quality, but the evidence isn't strong enough to say that taking an omega-3 supplement will improve egg quality or increase your chances of conceiving.
That doesn't mean omega-3 isn't worth including.
It means we should keep it in perspective.
Rather than looking for one "fertility superfood", think about your overall dietary pattern.
A varied diet containing plenty of fruit and vegetables, wholegrains, pulses, nuts and seeds, sources of protein, healthy fats and oily fish where appropriate is much more meaningful than any individual supplement.
What about grass-fed beef?
You may have seen claims on social media that grass-fed beef is a particularly good source of omega-3.
Grass contains ALA, which contributes to the omega-3 content of the animal's diet. As a result, grass-fed beef does contain some omega-3 and generally contains more than grain-fed beef.
However, the amounts are very small compared with oily fish.
A 2022 review estimated that grass-fed beef provided around 17.5mg of EPA + DHA per 100g, compared with around 10.5mg in grain-fed beef.
Compare this with oily fish, which can provide thousands of milligrams per 140g portion.
So while grass-fed beef can contribute some omega-3, it shouldn't be considered a major source of EPA and DHA when preparing for pregnancy.
A 2026 update: what's happening with tinned mackerel?
You may have noticed that some tins labelled as mackerel in UK supermarkets are now using jack mackerel.
Some supermarkets, including Sainsbury's, Tesco and Lidl, have changed some products because of concerns around the sustainability of Atlantic mackerel fisheries.
Jack mackerel is a different species from the Atlantic mackerel traditionally used in many UK products.
Different fish species can have substantially different fatty-acid profiles. At present, there isn't a reliable UK CoFID value that allows us to say exactly how much EPA and DHA is in the Chilean jack mackerel now appearing in some UK products.
So if you're specifically choosing tinned mackerel as an omega-3 source while trying to conceive, check the species listed on the label rather than assuming every tin labelled "mackerel" has the same nutritional profile.
Omega-3 when trying to conceive: the simple version
You don't need to make fertility nutrition complicated.
For both women and men, a sensible approach is:
Aim for at least two portions of fish each week, including one portion of oily fish.
Include a range of unsaturated fats from foods such as nuts, seeds, olive and rapeseed oils and avocado.
Include plant sources of ALA such as ground flaxseed, chia seeds and walnuts.
Eggs can contribute small amounts of DHA, particularly omega-3-enriched eggs.
If you don't eat fish, consider whether an algae-derived or fish-oil supplement could help you obtain EPA and/or DHA.
Remember that your partner's diet matters too — male fertility is part of the picture.
And most importantly, don't feel that you need to find the "perfect" fertility supplement.
Omega-3 is one small part of a much bigger picture.
A final thought
When you're trying to conceive, it can be very easy to become overwhelmed by lists of foods you "should" eat and supplements you "need" to take.
You don't need a perfect diet to conceive.
For both women and men, regularly eating a varied, balanced diet that includes sources of omega-3 is a sensible part of preparing for pregnancy.
For women, omega-3 also becomes particularly relevant during pregnancy because DHA contributes to the development of the baby's brain and eyes.
For men, omega-3 is relevant because sperm cell membranes contain high levels of polyunsaturated fatty acids, including DHA, and research is continuing to investigate its role in sperm quality.
So rather than thinking about omega-3 as a magic fertility supplement, think of it as one part of looking after your nutritional health before pregnancy — for both partners.
If you're struggling to conceive, have been diagnosed with a fertility problem or are undergoing fertility treatment, nutrition can form part of your overall care, but supplements shouldn't replace appropriate medical assessment and treatment.
This article is intended for general education and does not replace individual dietetic assessment, medical advice or mental-health care.
References
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal. 2010;8(3):1461. doi:10.2903/j.efsa.2010.1461.
NHS. Fish and shellfish. NHS website.
NHS. Healthy eating in pregnancy. NHS website.
Nogoy KMC, Sun B, Shin S, Lee Y, Zi Li X, Choi SH, Park S. Fatty Acid Composition of Grain- and Grass-Fed Beef and Their Nutritional Value and Health Implication. Food Sci Anim Resour. 2022;42(1):18–33. doi:10.5851/kosfa.2021.e73.
Office for Health Improvement and Disparities. McCance and Widdowson's Composition of Foods Integrated Dataset (CoFID). 2021.
Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. Omega-3 fatty acid addition during pregnancy. Cochrane Database of Systematic Reviews. 2018;11:CD003402. doi:10.1002/14651858.CD003402.pub3.
National Institutes of Health, Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals.
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