Think fats are always bad for your fertility? Think again, because that isn’t true in the slightest. You could even BOOST your fertility if you know what you’re doing, and yes, this is backed by science!
In this third part of my Foods for Fertility series I’ll guide you on a deep-dive (yes, you’ll be an omega-3 fertility expert before you know it!).
Part 1. The Ultimate Fertility Diet: What To Eat When Trying to Conceive
Part 2. Meat, Poultry, Fish, Tofu: Which Protein is Best and Which is Worst for Fertility?
Part 3. Definitive Guide to Fats That HELP Fertility: Omega-3 and Other Fatty Acids
Part 4. Definitive Guide to Fats That HURT Fertility: Saturated Fats and Other Fats
Part 5. Sugar and Other Carbs Suck When Trying to Conceive
Part 6. Artificial Sweeteners When Trying to Conceive or Pregnant: Bad Idea?
Part 7. Two Reasons Coffee is Bad When Trying For a Baby
Part 8. Can I Drink Alcohol When Trying to get Pregnant?
Part 9. Dairy Can Help You Get Pregnant – Everything You Need to Know
Part 10. 10 Fertility Diet Tips to Implement Today
Not all fats are created equal
You might be surprised to learn that fats -or fatty acids- are an important part of a healthy “fertility” diet. Many weight loss diets focus on reducing fat intake, but there is good evidence that some fats are beneficial or even a necessity to good fertility.
Fatty acids such as fats, oils and cholesterol, can be split into different categories: saturated fats, mono-unsaturated fats, and poly-unsaturated fats. As a good rule of thumb, unsaturated fats are typically liquid at room temperature, and you would call it an oil, this is also the type of fat usually found in vegetables and fish. On the other hand, saturated fats are solid at room temperature and are more likely found in meat or dairy products such as butter.
To make it even more confusing, so-called trans fats are a type of unsaturated fat, as are Omega-3 fatty acids, but they have very different health considerations!
Fatty acids and fertility
Fatty acids play a role in fertility. For starters, fats are very important as precursors to hormones that are vital in embryo implantation and pregnancy maintenance.1 Another extremely important aspect is the influence of fats on egg quality. Yep, egg quality can be influenced by fat too! That’s because fatty acids play an important role in the metabolism and energy demands of maturing eggs, and it even plays an important role early embryo development right when they’re getting ready to settle into the endometrium).2,3
And as you probably guessed, some fats are good and other are bad. Some fats help egg quality and some hurt egg quality!
Let’s dive a little deeper into the fats that can HELP with your fertility.
Introducing Omega-3, Omega-6 and Omega-9
Let’s start with Omega-6, a polyunsaturated fat. The evidence is somewhat conflicting on if it helps or hurts your fertility, but most studies agree that Omega-6 is not beneficial. Some studies show that high Omega-6 levels lower the overall quality of eggs,4,5,6,7 and decrease the numbers of eggs retrieved in an IVF setting, while others show that Omega-6 might actually help to mature the eggs and improve the rate of becoming pregnant in obese IVF patients.8
In other words: it probably doesn’t help fertility so don’t go out of the way to consume more of it.
Not many studies have looked at Omega-9 and fertility. But one group of researchers found that the amount of oleic acid, the most prominent Omega-9 fatty acid, in the blood stream of women undergoing IVF was associated with more eggs retrieved,7 a few other studies show that Omega-9 can protect immature eggs from the bad effects of saturated fats.9,10
This suggests that Omega-9 could be beneficial to getting pregnant. But… a lot more studies are needed to actually confirm this.
Moving on the star of the night: Omega-3. It is a type of polyunsaturated fatty acid and can be divided into 4 different types:
- ALA: alpha-linolenic acid – Flaxseeds, Canola oil, Tofu, Walnuts
- EPA: eicosapentaenoic acid – Fatty fish (salmon, mackerel, sardines)
- DHA: docosahexaenoic acid – Fatty fish (salmon, mackerel, sardines)
- DPA: docosapentaenoic acid – Fatty fish (salmon, mackerel, sardines) & grass-fed beef
ALA is present in green vegetables and some vegetable oils, especially flaxseed oil. Your body can convert this type of Omega-3 into EPA, DHA, and DPA; the so-called long-chain Omega 3’s, however, this conversion is very inefficient and because of that, you should look at dietary sources that are high in EPA, DHA and DPA,11 which, is most easily found in fish and fish oil supplements.12
In the context of fertility, by far the most research into fertility and fats has focused on Omega-3 fatty acids, and for good reason: it is the most beneficial.
Omega-3: miracle fat?
Omega-3 polyunsaturated fats have a really important role in fertility, and you should eat enough of it because it’s an “essential” fat. It can’t be synthesized in your body.
The exact mechanism of how omega-3 is beneficial are complex, but omega-3 is involved in the creation of prostaglandins, a hormone like substance, and it is said to improve mitochondrial functioning, and reduce oxidative damage.13
The first evidence that omega-3 fatty acids could influence fertility came from animal studies. For example, researchers found that omega-3 supplementation minimizes preterm birth in sheep,14 increases the number of follicles in dairy cows,15 increases the frequency of ovulation in rats,16 and improves reproductive markers in cattle.17
In humans, there are 4 aspects where Omega-3 can actually help fertility:
- Improve egg quality and preserve the ovarian reserve (delay menopause)
- Luteal phase and ovulatory support
- Possibly reduce the risk of endometriosis
- Improve the odds of getting pregnant
1. Omega-3, egg quality and aging
I want to tell you a story about a really important question when it comes to fertility: in the past century or so our lifespans have become much longer, which is mostly due to improved diets. So why hasn’t women’s reproductive age much longer too? Fertility starts to drastically decline at age 35!
Well… A drop in fertility after the age of 35 is the result of a decline in both the quantity and quality of eggs.
In other words, as you age, the number of egg cells drops, your ovarian reserve decreases and the quality of your eggs does too. This happens because mechanisms within the eggs that help with cell division (the meiotic spindle apparatus) and energy production (the mitochondria) degrade.18,19 What this means in practice is an increase in chromosomal abnormalities that result in the egg not being fertilized, even if it were to meet a healthy sperm cell.
Researchers from a particularly well done study set out to investigate whether dietary omega-3 intake could lengthen the reproductive age, in essence postponing menopause.20
One group of mice were fed a diet high in the Omega-3 fatty acid and low in Omega-6, a diet mimicking high amounts of fatty fish consumption or a Mediterranean diet. And another group mice were instead fed a diet high in Omega-6 and low in Omega-3, this diet mimics the average Western diet.
The researchers found that at an “advanced maternal age” of only 10 months old, which in human years would be about 38 years of age, the mice on the Omega-3 diet were able to produce 3 litters of little baby mice each. And the mice who were fed an Omega-6 rich diet? They were not able to produce any offspring, not a single one.
That’s pretty convincing evidence by itself, older female mice could get pregnant and deliver healthy baby mice so long as they were on a high Omega-3 diet!
But the researchers didn’t stop there, they then investigated whether an acute boost in Omega-3 could improve the egg quality itself. To put it another way, mice were fed a normal diet for all of their lives until they hit middle-age. Only at that time were they switched to either a high Omega-3 diet, a high Omega-6 diet, or a regular diet for 12 weeks.
Could such short term changes in diet really improve egg quality? That would pretty much be the equivalent of us humans deciding to eat or more fish or take an Omega-3 supplement right now, and then trying to conceive in the next few months!
The findings are pretty remarkable. The mice who were fed high amounts of Omega-3 had:
- a higher percentage of fully mature eggs
- higher egg follicle counts
- a lower percentage of damaged eggs
- normal mitochondria and meiotic spindles
Mice fed diets low in Omega-3 showed mostly the opposite findings: fewer mature eggs, more cell damage, more mitochondria damage and more damage to the mechanisms important in cell-division. In other words, a short-term diet high in Omega-3 could turn back the clock and improve the overall egg quality, while a diet low in Omega-3 showed all the usual problems with aging eggs.
With this in mind, I have some good news and some and some bad news.
Let’s start with the bad news: Our Western diets are high in Omega-6 but low in Omega-3.
But the good news is that changing your diet to incorporate more Omega-3 and less Omega-6 is an easy way of improving your fertility, and as research tells us, your body might even be able to “catch up” on all the benefits of Omega-3, even if you start now!
But that’s in mice. What about humans?
Let’s move on to human IVF studies, because if you’re reading this, I’m pretty sure you’re a human who wants to know if Omega-3 can help improve your fertility.
Researchers from the Netherlands asked 235 women undergoing IVF to report their dietary fat intakes for 4 weeks prior to starting an IVF hormone stimulation cycle.21 They found that higher Omega-3 intake was associated with fewer follicles retrieved, but that the eggs that were retrieved were of higher quality. In other words, increasing dietary omega-3 resulted healthier follicles and eggs and it is exactly these high quality eggs that after fertilization with sperm will develop into high quality embryos.
2. Omega-3 and luteal phase support
In one study, reproductive hormones were compared to dietary fat intake levels.22 Researchers found a rather amazing association with omega-3 polyunsaturated fatty acid intake. The three Omega-3 sub-types found mostly in fish and fish oil, EPA, DPA and DHA were associated with higher levels of the reproductive hormone progesterone in the luteal phase of the menstrual cycle.
And this is a REALLY important finding. Let me tell you why.
The luteal phase is the phase of your menstrual cycle after ovulation, you can read all about why this phase is important if you’re trying to conceive in this post.
The luteal phase is the time where a hopefully fertilized embryo will implant in the endometrium and the hormone progesterone is crucial is making sure that the embryo can actually implant.23 Without enough progesterone, it’s not going to happen and you won’t become pregnant. So an elevated level of progesterone is SUPER important to prepare your body for embryo implantation.
Now, back to study… So the researchers found that by consuming more Omega-3 (EPA, DPA, DHA) luteal phase progesterone levels increased too. And although they did not investigate any markers of pregnancy (why would they forget to do this?!), it’s makes sense that this luteal phase support can increase fertility by preparing your body for embryo implantation.
As an added cherry on top, the researchers also found that higher DPA Omega-3 reduces the risk of being anovulatory. In other words, omega-3 can prepare your body for the incoming embryo and boost ovulation and cycle regularity. Score!
3. Omega-3 and avoiding endometriosis
Endometriosis is a condition where abnormal cell growth occurs outside of the uterus, and it is very much associated with infertility. About 40% women with endometriosis can’t get pregnant naturally.
Very little research has been done on how Omega-3 supplementation influences endometriosis so I won’t even try to overinterpret these results. But in the Nurses Health Study,24 researchers did find an association of Omega-3 intake and a reduced risk of endometriosis.25 In addition to Omega-3 possible being helpful to endometriosis patients, “bad” fats, especially trans-fats increase the risk of endometriosis (so avoid those)!
4. Omega-3 and the odds of getting pregnant
So if Omega-3 consumption or supplementation can improve egg quality, protect the ovarian egg reserve, support the luteal phase, and limit the risk of endometriosis, wouldn’t it make sense if the odds of getting pregnant go up too?
That’s exactly what researchers show in 2016 IVF study. Higher Omega-3 consumption in the 12 months preceding IVF is associated with higher pregnancy rates.26
And in 2018, Harvard researchers didn’t just ask women undergoing IVF how much Omega-3 or fish they ate, they actually blood samples and measured how much circulating omega-3 they found!1
For every 1% increase in Omega-3 found in the blood, the odds of getting pregnant through IVF increased by 8%. And narrowing it down even more, the researchers found that it was especially the long chain Omega-3 EPA, the one found in fatty fish, that was associated with better outcomes. For every 1% increase in EPA in the blood stream, a 15% increase in live birth rate was observed. That’s pretty amazing if you ask me!
So yet again, the evidence points in the direction of consuming more fish high in Omega-3 fatty acids.
The bottom line on Omega-3 and fertility
Wow. You made it until the end of this post, and I’m really happy you did! Because now you know that increasing your Omega-3 intake isn’t just an easy way to boost your fertility, it is 100% worth it.
Let’s summarize what the science says about Omega-3 and fertility:
- Omega-3 improves egg quality
- Omega-3 increases the number of mature eggs
- Omega-3 protects mitochondria and meiotic spindles
- Omega 3 supports the luteal phase important for embryo implantation
- Omega-3 reduces ovulation problems
- Omega-3 reduces the risk of endometriosis
- Omega-3 slows ovarian aging / early menopause
- Omega-3 improves the chances of getting pregnant, and
- Omega-3 improves the chances of getting pregnant when going through IVF
And all these benefits are mostly associated specifically with increasing your intake of the Omega-3 fatty acids found in fish.
But which fish is the BEST (and which should you avoid)?
Let me tell you, food labels almost never tell you whether something contains Omega-3 and they definitely don’t tell you what kind of Omega-3 it contains! And this is precisely why I created a checklist that you can download for FREE right now. It’ll tell you exactly which fish and other foods you should eat, the ones that are super high in the right kind of Omega-3 and low in toxins such as mercury.
As a bonus, I’ll also tell you which fatty foods to AVOID altogether. If you’re serious about trying to conceive, it’s really really important you get this right. Just enter your email below to download it now.
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