Can Vitamin D Improve AMH Levels? (Episode 503)

Full Transcript: Episode 503

Lisa Hendrickson-Jack:

Today I’m sharing a brand new episode in my FAMM research series and the topic of the day is: can vitamin D improve AMH values? So without further ado, let’s go ahead and jump right in.

So today we’re going to be diving into AMH. The study we’re going to be looking at is actually a systematic review and meta-analysis of a variety of studies that were essentially measuring the impact of vitamin D on AMH. And I find this particular study to be interesting because it really sheds some light on some of the most common myths and misconceptions that I’ve heard, and that clients have heard and experienced about AMH. And I think that it really does give some hope and shed some light on just one of the factors that can have an impact on AMH levels. So I thought a good place to start is briefly touching on what AMH is and what role it plays in fertility and how it shows up for most women who are in that situation where they may be having fertility tests and they may be being provided information about their AMH levels.

And so AMH is a hormone that was actually first noted for the impact that it has on developing babies in utero. There is a stage of development where both male and female babies have similar reproductive structures, including the Müllerian ducts. And in females, those Müllerian ducts eventually develop into the female reproductive organs. So anti-Müllerian hormone actually prevents the development of these female reproductive structures in males, and so therefore it plays a crucial role in sex differentiation. But that’s not its only role.

What’s interesting about AMH is that there is a relationship between a woman’s AMH levels and her ovarian reserve — and this is where the fertility conversation comes into play. What’s interesting about AMH is it is not a direct measure of how many eggs you have left, unlike males. In men, they can do a semen sample, they can provide a sperm sample and it can be counted — in many ways it’s quite straightforward. But with females, we can’t just provide an egg sample like men can do with their sperm samples. And so in women, we are always getting an indirect measure of the potential reserve.

What’s interesting is that if you look at AMH levels in women, there is a linear relationship where they’re higher in younger women at the beginning of their reproductive life cycle, and then this value gradually decreases in line with that ovarian reserve. And so it’s often used as a proxy for how many eggs you have left. But what’s interesting about the research around AMH levels is that there is not a direct correlation — it’s not a fixed number. It always provides an estimated, indirect measure.

Really what’s happening is at the beginning of each menstrual cycle, you have a group of follicles that are developing. Out of that group of follicles, one is chosen for ovulation. When you’re younger, you typically have a larger pool of follicles developing toward the beginning of the cycle, and AMH is actually released by those developing follicles. So the amount of AMH you have is related to the size of that follicle pool developing at the beginning of your menstrual cycle. As we get older, the pool tends to decrease as our overall ovarian reserve decreases — and that’s why we see this relationship between AMH levels and overall ovarian reserve. But again, it’s not a direct measurement.

I think one of the biggest myths we’re going to tackle as we go through today’s research study is that women are often given the impression that this number is fixed, that there’s nothing they can do to change it. They’re also given the impression that AMH values directly predict their ability to conceive naturally. And although we are not today going through one of the research studies specifically looking at that relationship, I will take any opportunity to mention that when you look at research studies examining the connection between AMH and a woman’s ability to conceive naturally, what they find is that AMH can’t reliably be used that way.

The most useful and accurate way to use AMH values is as a predictor of a woman’s potential success with assisted reproductive technology. There is a good correlation between AMH values and how likely you are to have a successful egg retrieval. If your AMH levels are too low, you’re much more likely not to get a good response to ovarian stimulation. Whereas if your AMH values are too high — as we might see in a woman with PCOS — you’re more likely to overstimulate. So there’s a really good correlation between AMH values and how well you’re going to stimulate. But when you look at studies assessing how effective AMH is at predicting a woman’s ability to conceive naturally, that’s where it all breaks down — because there are studies showing that women can conceive naturally with undetectable AMH levels.

We don’t want to totally discount AMH levels — it does play a role in fertility and we should be paying attention to it. But what we should not be doing is using AMH to tell women whether or not they can conceive naturally, because that’s just not what the research tells us.

So that’s a little bit of an overview of AMH — hopefully a helpful primer for those of you who may not be as familiar. In this study, the researchers are trying to determine if there is a relationship between vitamin D supplementation or vitamin D levels and ovarian function, and how it impacts anti-Müllerian hormone specifically.

Like I mentioned, this study is a meta-analysis of a variety of studies. They looked at 18 observational studies and six interventional studies. The observational studies look at the correlation between a woman’s vitamin D levels and her AMH levels without any supplementation — just seeing how these two factors are related. Whereas the interventional studies gave women a specific dosage of vitamin D and then measured what happened.

So there are a couple of questions I want to tackle with today’s episode. One is: are AMH levels fixed? I’ve had a number of clients who’ve been told by their healthcare practitioners that AMH levels don’t change. One client told me her doctor said AMH levels were related to even her close family members — that if her AMH levels are low, it probably means her grandmother’s levels were low and her mother’s levels were low. Which is really interesting, because after reviewing numerous research studies about AMH and how it interacts with different variables, that could be a factor in a general sense, but the research does not specify that as the biggest factor by any means.

It is useful to know that although there is a relationship between AMH and overall ovarian reserve, it is not necessarily a fixed linear relationship. There are a variety of factors that can impact AMH levels, as evidenced by a range of research. For example, women with endometriosis — potentially due to inflammation and the severity of the condition — have been shown to have lower AMH levels. Women with PCOS, on the other hand, who have multiple follicles developing to an abnormal degree, show higher AMH levels. So those are examples that show it’s not always just this fixed thing we’re often told it is.

What we do know about AMH is that it is impacted by age. A woman in her early 20s and a woman in her 40s are not going to be in the same range — and there’s quite a bit of variation even within the same age group. Age is one of the most significant factors. But going back to the question: even in this particular study looking at vitamin D and its impact on AMH levels, it does call into question the idea that there’s nothing we can do and it’s just a fixed number.

So what did the researchers find? Especially with the studies looking at vitamin D supplementation, they did find significant associations. These were studies giving women a certain amount of vitamin D over a period of time and measuring what happened to their AMH levels. In many of these studies, women were given weekly doses of vitamin D — often 50,000 IUs once a week or once every other week. This is a fat-soluble vitamin that can be administered that way, and dosing it weekly rather than daily also helps standardize the research by removing the variable of daily participant adherence.

In two of the studies they examined, women’s blood levels of vitamin D increased — as you’d expect from supplementation — but also their AMH levels increased in proportion to the dosages they were taking.

Now here’s a really interesting finding I want to share. The researchers looked at studies that gave vitamin D to women who were already ovulating with normal ovulatory cycles, but they also looked at studies that gave vitamin D to women with PCOS who were not ovulating normally. Women with PCOS were often starting off with elevated AMH because — again — having multiple follicles developing is common in PCOS, so elevated AMH is typical in this population, not low AMH.

What was interesting is that vitamin D had a different effect on each group. In women with PCOS and elevated AMH, taking vitamin D decreased AMH levels, bringing them closer to what would be considered normal. In women with normal ovulatory cycles and lower AMH, vitamin D had the effect of raising AMH levels. So vitamin D was not having the same blanket effect across all women — it was normalizing AMH levels based on what was happening in that individual woman.

I’ll read a little from the study here: “In the meta-analysis of three PCOS cohorts, the serum AMH was significantly decreased following vitamin D supplementation. In contrast, in the meta-analysis of three non-PCOS cohorts, serum AMH was significantly increased following vitamin D supplementation.” The researchers go on to say: “The systematic review and meta-analysis of the interventional studies revealed that vitamin D supplementation affects serum AMH levels but has the opposite effect depending on the ovulatory status of the women. It increased serum AMH levels in ovulatory non-PCOS women while it decreased AMH levels in PCOS women.” They add: “In PCOS, in which AMH is abnormally elevated, this likely reflects the ability of vitamin D to improve folliculogenesis and is consistent with evidence from numerous clinical trials showing improved clinical manifestations following vitamin D supplementation.”

What they’re getting at is that vitamin D appears to be having a positive effect on follicular development and supporting ovulation to happen normally. And that’s something that shows up in various ways in the research. Low vitamin D is associated with lower fertility. Some of the observational studies showed a correlation between low fertility and low vitamin D levels — and that’s pretty consistent in the literature. Women with PCOS, who are characterized by having long, irregular cycles and anovulation, are also much more likely to be deficient in vitamin D.

So what does this study tell us? What can we take away? It tells us that AMH is not fixed. There are factors that impact AMH levels. If you’ve received a fertility assessment and been told your AMH is low — and your doctor has suggested there’s nothing you can do, that it’s hereditary, that it’s just what it is — know that studies like this show that’s not the only factor. If there are other factors that can play a role in AMH levels, it tells us it’s not simply fixed, and there are things you can potentially do to improve it. I’ve certainly seen that happen with many of my clients and practitioners’ clients over the years — when you’re supporting overall health, ovulatory function, and correcting nutrient deficiencies, many women see an improvement in those levels over time.

The study also tells us that vitamin D supplementation has been shown to normalize AMH levels — and I find it really compelling that it has different effects depending on a woman’s cycle status. That’s a pretty significant takeaway.

It is worth noting that this study was looking only at vitamin D. The researchers pulled studies looking at this one variable — and that’s not to say vitamin D is the only nutrient that matters or the be-all and end-all. But I do think it’s helpful to do deep dives into specific nutrients and see how they impact fertility, menstrual cycle health, ovulatory function, and follicular health, because it gives us real insight. From what I’ve seen observing the menstrual cycles of hundreds of women over the years, vitamin D is something we should be paying attention to. It’s not the only thing, but it’s important — and alongside other key nutrients for fertility, optimizing vitamin D levels is absolutely worthwhile.

If you’re looking to optimize your menstrual cycle, normalize your hormones, or improve your fertility, look at those vitamin D levels. If you’re looking for additional details about supporting your hormones and ovulation, check out The Fifth Vital Sign — head over to thefifthvitalsignbook.com for details. And definitely stay tuned for details about my next upcoming book, which goes into vitamin D and ovulatory function extensively.

I want to thank you for tuning in to today’s episode. If you found this information valuable and you know somebody who could benefit from it, make sure to share today’s episode. You’ll find the show notes over at fertilityfriday.com/503. I hope you have a wonderful week, and as always — until next time, be well and happy charting.