Knocked Up Podcast - The Vitamin D and AMH connection
This episode of "Knocked Up" explores the connection between AMH (Anti-Müllerian Hormone) and Vitamin D in fertility.
Ever wondered why your fertility specialist tests both AMH and vitamin D? In this episode of "Knocked Up," Dr. Raelia Lew explains the relationship between these two crucial markers and why it matters for your fertility journey.
Plus, find out how vitamin D impacts male fertility too, and why this "low-hanging fruit" could be a game-changer for couples trying to conceive.
TRANSCRIPT
JORDI: Hello and welcome to Knocked Up, the podcast about fertility and women's health. You are joined as always by me, Jordi Morrison, and Dr. Raelia Lew, CREI Fertility Specialist. Welcome, Raelia.
DR. RAELIA LEW: Hi, Jordi.
JORDI MORRISON: Raelia, today it was a request actually from one of the team members at Women's Health Melbourne. She wanted to know more about the connection between AMH and vitamin D. I want to start at the beginning. I feel like we talk about AMH a lot but just very quickly, what is AMH, and then I'm going to ask you what is vitamin D?
DR. RAELIA LEW: Yeah, sure. Well, look, AMH is a peptide hormone that's made in the ovary and we use it in fertility as a biomarker of ovarian reserve. So the amount of AMH that the ovary makes is broadly speaking proportional to the size of the ovary and the density of ovarian follicles, which are the structures that contain eggs in our ovary. So if you have a high AMH it means you have a high egg count, and if you have a low AMH it means you have a low egg count, and if you have a moderate AMH it means you have a normal egg count.
JORDI MORRISON: And vitamin D? We hear about this a lot, vitamin D.
DR. RAELIA LEW: It's not just a fertility thing.
JORDI MORRISON: No.
DR. RAELIA LEW: Vitamin D is a really important vitamin. It's one of the fat soluble vitamins and it's naturally present in a few foods like fish and oily fish. And it is to a degree produced endogenously in the body when UV light is exposed to our skin — it triggers vitamin D synthesis — but we tend to get a little bit less vitamin D than previous generations because we're a little bit more careful about sun exposure, so a lot of people in our population are vitamin D deficient. And it is a very important co-factor in the body. It has roles like reducing inflammation and modulation of cellular processes, affecting cell growth, neuromuscular development, glucose metabolism, and it's important to ensure that we have adequate serum calcium and phosphate concentrations, and that's why vitamin D is associated with keeping our bone density normal, so it's important for the bones and the strength of your bones.
JORDI MORRISON: Which is why it's important in perimenopause and menopause as well.
DR. RAELIA LEW: Absolutely, and many people will be familiar with a condition called rickets that children can be born with or can develop in early childhood. That happens generally when a mother is vitamin D deficient during pregnancy, or when she's breastfeeding, because that's when vitamin D is really sourced from the baby via the mother. So you'll often see people are on vitamin D supplements these days.
The supplement that we take still requires activation in the body. It actually has to be what we call hydroxylated, which means using enzymes to add a little side chain to the vitamin D. And so it undergoes two hydroxylation processes, actually one in the liver and one in the kidney. And because we're all a little bit different and the efficiency of our enzymes in our body can vary person to person, as can our liver and kidney function, some people are better at making vitamin D than others or activating vitamin D than others.
JORDI MORRISON: Okay, so we might be having vitamin D but we're not necessarily absorbing it so well.
DR. RAELIA LEW: Yeah, some people don't absorb it so well. Some people don't convert it so well. Often in countries where people are very covered up for cultural reasons, like countries in the Middle East where women are veiled, they often have real problems with vitamin D deficiency, very severe vitamin D deficiency. And actually, moving on to a topic relevant to your initial question, we see actually that women who are vitamin D deficient in the longer term have a higher risk of premature ovarian failure and going through early menopause.
JORDI MORRISON: Right, so that's really interesting. And you test for vitamin D and AMH at the start of every fertility patient's journey with you?
DR. RAELIA LEW: Yeah, look, we do a whole heap of blood tests for our patients who are having trouble getting pregnant because we're really looking to find out all of the potential underlying causes that might be contributing to infertility, and also when we're trying to help someone overcome infertility we want to optimize normal processes as much as possible because every little bit helps. So vitamin D is a really key investigation and I kind of consider it low-hanging fruit so to speak, because we can always top it up with some supplementation. If it's low — and it does have a very important role in female reproduction on many levels — ensuring that people have vitamin D replete is a bit of a no-brainer.
JORDI MORRISON: So the connection between AMH and vitamin D, what do we need to know?
DR. RAELIA LEW: Look, it's complicated, and a recent review looking at the association between AMH and vitamin D in summary really pointed to the fact that in different people the effects are a bit different. But the overall feeling is that AMH is more normal when vitamin D is replete. So when people have polycystic ovaries that's uncontrolled and they have polycystic ovarian syndrome and a very high AMH, if they're vitamin D deficient their PCOS is worse, and if you correct their vitamin D, then their AMH from being abnormally high actually comes down to a slightly more normal level. Whereas when people have normal ovarian function and they are vitamin D deficient, it actually affects in the opposite direction, that their AMH level is lower and it improves if you make them vitamin D replete. So basically the vitamin D normality makes the AMH hormone revert more to the mean. So it's important to point out, as we always mention in fertility care, that every person is different and every context is unique. The problems we face in infertility really are contextual to our physiology and that of our partner. But one thing that we can say for sure is that having a normal vitamin D level has potential benefit to female reproduction in general.
JORDI MORRISON: So if someone's blood test has come back with low vitamin D, what are the options for supplementation? I'm guessing we can take a tablet?
DR. RAELIA LEW: Yes. So the normal route of supplementation is oral. And that really points to the fact that we have to absorb vitamin D in our gut and then hydroxylate it in our liver through first pass metabolism to activate it. And then the secondary activation happens in the... We generally supplement with oral vitamin D. A standard dose is about a thousand units per day and some people do take higher doses like seven thousand units. It's one of those things that for fertility really it's complicated to say that there's one perfect dose, and probably taking a thousand units per day orally and just keeping it by your toothbrush and taking it when you take your prenatal supplement is pretty much ideal for most people. Vitamin D comes generally in little capsules or capulets. They're quite easy to swallow and they don't really cause side effects that are complained about by many people. There's really no downside to taking a vitamin D supplement.
The other thing to say is that not all sun exposure is bad and getting a little bit of sunlight in a way that's not going to be dangerous for you is a good thing. Obviously, we all know that wearing sunscreen and protecting ourselves from skin cancer, particularly in the Australian context where we have a very strong Australian sun, is important as well. So I would say getting a little bit of sunshine, especially in winter, and taking a vitamin D supplement can't cause harm and it might be very helpful for reproduction.
JORDI MORRISON: And you're also talking about a few minutes in the sun, not a day in the sun.
DR. RAELIA LEW: Yeah, exactly. And also it's... to mention that vitamin D is also important in male reproduction.
JORDI MORRISON: Before we move on to male reproduction, can I ask — if we're like low in iron or low in B12, there are ways we might be feeling, like we might be feeling a bit tired or sluggish. But if we're low in vitamin D, would we feel it?
DR. RAELIA LEW: It's a good question. We don't generally diagnose vitamin D deficiency when patients present with symptoms. It's generally more of an incidental finding on a blood test. We know in the literature that there are potentially symptoms of vitamin D deficiency, but they are often subtle and not necessarily noticeable, or at least not attributed to that deficiency. But what's been described is that some individuals might experience some muscle weakness and fatigue, so that's pretty non-specific.
JORDI MORRISON: Yeah.
DR. RAELIA LEW: Whereas in children, prolonged or severe deficiencies can lead to increased risk of bone fractures and rickets, and in women particularly after menopause, a long-term and severe vitamin D deficiency can not only be associated with risk of bone fractures, but also osteoporosis. It's important for women in longitudinal health promotion to ensure that we are vitamin D replete so that our bones are protected, especially as we age and as our hormone levels fall.
JORDI MORRISON: You mentioned male reproduction and vitamin D. How does vitamin D impact sperm?
DR. RAELIA LEW: Well, we know, interestingly, that men who have low vitamin D levels — there's been a studied association with poorer sperm quality and potentially reduced fertility. So no causal link has been identified yet, but it makes sense that particularly in infertile men with vitamin D deficiency that we supplement vitamin D in men, and we could potentially expect improved or a positive impact on human male fertility.
So in summary, vitamin D is an important fat soluble vitamin. We see a lot of vitamin D deficiency in our general and infertile population. Ensuring we have vitamin D replete can help optimise our general health and fertility for both males and females.
JORDI MORRISON: Great. Thank you, Raelia. To support Knocked Up, leave us a review or recommend to a friend. Join us on Instagram @knockeduppodcast and join Raelia @drraelialew. And email us your questions to podcast at womenshealthmelbourne.com.au.
Hosted by Dr Raelia Lew and Jordi Morrison
Dr Raelia Lew is a RANZCOG Board Certified CREI Fertility specialist, Gynaecologist and the Director of Women’s Health Melbourne.
Find us on Instagram - @knockeduppodcast
Have a question about women's health? Is there a specific topic you'd like us to cover? Email podcast@womenshealthmelbourne.com.au. We keep all requests anonymous.