Vitamin D and fertility (why you need it AND the dangers of supplementation)


It’s important for our health and fertility to make sure we get plenty of nutrients into our bodies, each vitamin and mineral is important in its own right. But vitamin D and fertility have a special connection – many studies have shown that women dealing with infertility often have low levels of this vitamin. And traditional cultures revered special foods as “fertility foods” for young couples, many of them high in vitamin D. Unfortunately we don’t get near as much in our modern culture and this has left many of us depleted.

But before you go supplementing, make sure you’re aware of the risks of taking vitamin D as well as how to take it to make sure you’re receiving the full benefits.

In this episode of the Natural Fertility and Wellness podcast/video interview, I’m talking with Lydia Shatney, a certified Nutritional Therapy Practitioner, all about Vitamin D.

Vitamin D and fertility

Lydia is a certified Nutritional Therapy Practitioner, through the Nutritional Therapy Association. For over two decades she has explored varied diets and healing modalities, ranging from raw foodism, vegetarianism to the principles founded by Weston A. Price. Her interest in health and nutrition stemmed from an innate calling she simply could not ignore and brings to life the mantra; “Healer, first heal thyself.”
She has learned that you can reverse many health maladies by simply consuming real nutrient dense foods, avoiding cheap processed foods as well as balancing your body’s biochemistry through hair tissue mineral analysis. Thus discovering the saying holds true, ‘You are what you eat (and absorb)!
In an effort to more deeply support clients on their health path she chose to offer hair tissue mineral analysis as an excellent way to get a baseline on health issues, mineral imbalances and toxic heavy metals in the body. This test allows her to create specific plans for clients based on their unique biochemistry and begin to move them out of disease states and into improved health.

Watch the video

Find Lydia here –

Read the summarized transcription and show notes below.

What is vitamin D and why is it important

The term “vitamin D” refers to a group of fat-soluble compounds that serve as pre-hormones, or hormone precursors, to the active form of vitamin D, called calcitriol – and it is responsible for regulating over 2000 genes in your body. Nearly every cell of our body has receptors for vitamin D. so… that alone tells us, it’s pretty important. BUT, as I will point out later, it’s not a stand alone nutrient.

Among the more well-known forms of vitamin D is vitamin D3 (cholecalciferol), found in fish, egg yolks, and cheese, and synthesized in the skin of humans and animals.

Another common form, vitamin D2 (ergocalciferol), is synthesized by plants, such as mushrooms, and is the form most often used to fortify foods such as commercial milk and other fortified foods that have vitamin D added.

We make vitamin D in our skin from the sun when our skin is exposed to UVB rays (ultraviolet-B radiation).

This initial form of vitamin D that we get from the sun, called 7-dehydrocholesterol, travels to the liver, where it is converted into another slightly more active form of vitamin D called 25-hydroxyvitamin D.

[This is the form of the vitamin that doctors are testing when looking for deficiency by the way.]

When vitamin D leaves the liver, it travels to the kidneys where it is converted once more into the highly metabolically active form of vitamin D called calcitriol, or 1,25 dihydroxyvitamin D.

This is no longer considered a vitamin but rather, a steroid hormone.

What are the dangers of supplementation?

Vitamin D is a nutrient that is widely misunderstood. Many people are not properly informed about this fat soluble vitamin/pro-hormone.

In my line of work I look at vitamin D through a much broader and deeper lens that helps to avoid the pitfalls of singling out any one nutrient and isolated supplementation.

Vitamin D is overdosed in so many cases and often people are taking it on their own, without testing and knowing if they really need it and in turn could be doing more harm than good.

We just don’t have solid scientific evidence about the long-term safety of high dose vitamin D supplementation.

Some researchers suggest that high levels of vitamin D supplementation may lead to kidney stones. This is occurs when the body tries to get rid of excess calcium in the body through the kidneys (this is more likely to occur when someone is taking a higer dose long-term).

If the body can’t regulate calcium levels, the mineral may deposit itself throughout the soft tissues of the body, including the arteries. And unfortunately, some studies suggest that this is a real possibility when vitamin D levels become too high. And this is what I see all the time in my practice with calcium metabolism via HTMA partnered with a full vitamin D panel.

I’ve especially seen this trend in health circles where women have issues like hypothyroidism – in fact a couple very popular thyroid websites in which there is a lot of DIY health advice being thrown around, there is a common theme that people suggest high dose vitamin D supplementation. And I’ve come to see this as a huge problem in my line of work because the majority of clients I work with have symptoms of hypothyroidism (diagnosed or not) – it’s possible to experience thyroid hormone resistance even when one’s thyroid labs show up normal when their doctor runs routine lab work.

And we know that this is important in the case of fertility as I’m sure you’ve already discussed. (You can read a bit more about vitamin D and its importance to fertility here –

But the biggest issue I see with vitamin D is the misunderstanding of how it works in the body, what co-factor nutrients are involved and if they are not considered and only vitamin D is taken to simply push a blood level to a certain level how it can have a huge affect on calcium – and cause the calcium to increase in the soft tissues causing calcifications – how this also shows up (and I see this via HTMA all the time) is in increasing calcium this way in the body it makes the cells less permeable and therefore all hormones have a harder time getting into your cells effectively.

Think about that in terms of thyroid hormone alone –  let’s say you produce perfectly adequate thyroid hormone but it can’t go where it needs to – you’ll experience symptoms of hypothyroidism – now let’s say you are someone who is already struggling to produce adequate thyroid hormone and you have excess tissue calcium on top of that – you may feel pretty poorly as well as in the case of someone who takes thyroid hormone they may not feel as good because it’s still not getting into their cells as good as it should.

Another big problem when it comes to isolated vitamin D supplementation is that the co-factor nutrients are not considered.

According to the Vitamin D Council to get the most benefit from vitamin D, you must have other co-factors in your body. Vitamin D has a number of co-factors

The fat-soluble vitamins A, D, and K work synergistically, and adequate vitamin A and K help protect against toxic effects of excess vitamin D. Sufficient levels of potassium and magnesium are also to consider in protecting against vitamin D toxicity (which honestly only occurs because of supplementation). Unfortunately, most people are deficient in these nutrients – I see it every day in my practice and unfortunately doctors are not testing assessing all these other nutrients at all or in an effective measure -for example serum magnesium isn’t really helpful – rather The RBC blood test is more sensitive to magnesium deficiencies than a standard magnesium blood test.  When the body becomes magnesium deficient, it pulls the magnesium that is stored in red blood cells out of those cells and into the serum of the blood.  A standard blood test, therefore, may show magnesium levels as normal even though the red blood cell’s stores of magnesium are depleted. Speaking of magnesium that is a key nutrient to talk about in tandem with vitamin D


So real quick, magnesium is a critical mineral in our bodies that most people do not get enough of in the diet and it’s easily lost by stress, sugar consumption, medication use and more.

Magnesium is involved in every body function, where it is required for thousands of critical enzymes everywhere in the body. Including the ability to make and use ATP, the body’s main form of energy. So, pretty darn important…

Magnesium plays an important role in proper Vitamin D activity and function and it also helps to maintain calcium balance by modulating the sensitivity of our tissues to vitamin D. The enzymes necessary to help the body use sunlight to convert into vitamin D are magnesium activated.

So, simply stated Vitamin D also needs magnesium to help it absorb calcium. Without magnesium when vitamin D is given it will raise tissue calcium which has an antagonistic effect on magnesium – thereby it can further exacerbate a magnesium deficiency, which in my opinion has more detrimental affects, such as an increased risk for heart attack or even could show up as panic attacks… I’ve seen this in a lot of women with high tissue calcium via HTMA – this is because when vitamin D drives up the calcium both potassium and magnesium can be depleted (as well as vitamin A through the liver) and both of those minerals have a balancing, stabilizing calming effect on the body.

Vitamin K2

Vitamin K allows the body to use calcium to perform its clotting function. If vitamin K is low, the body can’t use calcium in this way, and therefore, cannot clot. Vitamin K also helps to form and maintain our bones and teeth. It does this by activating osteocalcin that helps the body use calcium and deposit it where it is supposed to go.

In other words vitamin K helps the body use calcium properly. And if we’re deficient in vitamin K2 (which I am pretty sure all modern Americans are since it’s literally not in the diet), calcium levels can build up and deposit themselves in our soft tissues.

People who are low in vitamin K are more likely to suffer from atherosclerosis, or calcification of the arteries. And those with a high vitamin K intake (especially vitamin K2) seem to have less calcification of their arteries.

Simply stated: Vitamin D increases calcium levels in the body. Vitamin K helps the body use calcium.

So if one were to supplement with high-dose vitamin D in the presence of vitamin K deficiency, the long-term results could be disastrous.

Vitamin A

Excess vitamin D supplementation without adequate vitamin A supplementation will drain the bodies reserves of vitamin A.

Vitamins A, D, and K (together in the right balance) cooperate to protect our soft tissues from calcification, to nourish our bones and teeth, and to provide children with adequate growth.

Natural preformed vitamin A, consumed within a well-balanced diet, especially with vitamin D, is a strong immune system modulator and is a contributing factor to dopamine regulation, one of our main neurotransmitters. Vitamin A also regulates the female sex hormone progesterone, providing mood and fertility benefits. It acts as an antioxidant and it is important for skin cell regeneration.

Also, Zinc and Boron are important but for the sake of time I won’t go into those today.

boost fertility with vitamin d

What are “optimal” vitamin D levels and what do we do if our lab tests come back with low levels?

(Also, why do some people continue to have low levels even when supplementing higher doses).

True vitamin D deficiency — the kind that will cause bone abnormalities such as rickets and osteomalacia — occurs at levels below 25 ng/mL in blood. Many doctors today are recommending much higher levels for storage D – anywhere between 40 and even 100. The range I like to see is at least about 35 -40 ng/mL. Somewhere in that range – Chris Kresser did a great post about this and suggests a range of 35-60 ng/mL as optimal.

Why it is low even with supplementation:

  1. not getting co-factors so it can be used properly, may go into fat tissue storage.
  2. inflammation, autoimmune or chronic inflammatory diseases – because our intestinal health plays a role in vitamin D and calcium metabolism and you and I both know there is usually an issue with leaky gut in these kinds of health issues /
  3. Genetic mutations – VDR SNPs
    •  In terms of inflammation, the active form of vitamin D is what we want to pay attention to – and if people want to read up on this they can check out one of my favorite pub med articles:
    •  Binding protein transports active form of vitamin D to the vitamin d receptor in the cell nucleus. One of the VDR SNPs (a SNP is a basically a genetic mutation that some people could have but they would need to get their genetic information tested through a 23andme test and work with someone who specializes in supporting nutrition/health through this information – and I am not sure which one it is specifically – but I do know that one of them makes it hard for the storage tested form of D to ever raise very high even when vitamin D is taken regularly)

What are the best tests to check for vitamin d stores in the body?

It is a good idea to test your vitamin D status before you ever touch a single vitamin D supplement that is not food based. One reason is you are entirely guessing and not considering how it will affect calcium and other nutrients in the body (like vitamin A and potassium for instance). Also, Vitamin D brought in by supplementation has a half-life of 4 – 6 months in the body. It is very easy to over do it on the vitamin D supplementally and then your body has to store excess vitamin D in the fat.

Another issue is that many people supplement with vitamin D alone and never take co-factors or try to rebuild their body nutritionally (a great way to do this is via a Hair Tissue Mineral Analysis – HTMA). For example, magnesium activates Vitamin D, and much lower doses of Vitamin D are needed when a magnesium deficiency is corrected.

I personally recommend testing first through a Hair Tissue Analysis, and the following blood tests; RBC magnesium, Vitamin D 25-Hydroxy and Vitamin D 1,25-dihydroxy.

Only the storage form of D is usually tested routinely (that is the one most doctors test -called: 25 (OH)D or 25 hydroxy).

I like to see a robust RBC magnesium (below 6.0 is low, 6.5 and up to 7.0 is excellent) and look at the active vitamin D as well as a hair tissue mineral analysis to see what it going on with the entire mineral system.

Parathyroid hormone stimulates the active form of vitamin D -so testing parathyroid hormone is another way to help get a full picture – people who have parathyroid disorders have to avoid vitamin D. So if someone is borderline low seeing PTH can help determine is supplementation is necessary.

If you are not testing through a full spectrum approach or don’t plan to  then please don’t supplement with any significant dose of vitamin D by itself. It is so important not to supplement blindly.

If your 25(OH)D level is:

  • less than 20 ng/mL: you likely need some combination of UV exposure, cod liver oil, and a vitamin D supplement
  • 20 to 35 ng/mL: get your PTH (paarathyroid) tested. If PTH is adequately suppressed (less than 30 pg/mL), supplementing is probably unnecessary.
  • 35 to 50 ng/mL: continue your current diet and lifestyle for maintaining adequate vitamin D
  • greater than 50 ng/mL: try reducing your vitamin D supplements, and make sure you are getting adequate amounts of the other fat-soluble vitamins to protect against toxicity

supplementing vitamin D for infertility

What natural ways can we make sure we get enough vitamin d in our diet and lifestyle?

Sunshine (with optimum health and optimum sun exposure, up to 20,000 IU a day). Vitamin D brought in by sunshine has a half-life of about 4-6 weeks in the body.

Foods sources of vitamin D:  

  • Blood or blood sausage , = 4000 IU per cup
  • Standard cod liver oil, 1 Tbsp = 1200 IU
  • Herring, 3 1/2 ounces = 1100 IU
  • Duck Egg, 3 1/2 ounces = 720 IU
  • Rainbow Trout, 3 1/2 ounces = 600 IU
  • Sockeye Salmon, 3 1/2 ounces = 360 IU S
  • ardines, canned in oil, drained, 3 1/2 ounces = 270 IU
  • Chicken egg, 1 large = 41 IU
  • Cow’s Liver, cooked, 3 1/2 ounces 30 IU
  • Pastured pork lard, fat or bacon could also be a source of vitamin D but I have no idea how much

Sunshine exposure & cod liver oil  are the two best options in my opinion, but also make sure you are getting the co-factor nutrients; vitamin A, K2, magnesium, zinc, boron. Personally, I think it can be very difficult for most everyone to do this well. (I have a post about the fat soluble trio – with some food sources/suggestions for Vitamin A and K2 as well – and believe me it’s so hard to get adequate K2 from diet alone)

In northern climates I would check levels before winter so you can better determine if you need to supplement through the winter and how much – supplemental vitamin D lasts longer in the body than sunshine D so it’s something to be more careful with and test every 3 months when you are taking a supplement. I can’t believe how many people just guess on this.

If you want to supplement vitamin D:

A really good cod liver oil like Rosita’s (a good ratio of vitamin A to D – available at Beeyoutiful) and supplement like one I use called Mega Quinone K2-7 that includes K2, magnesium, zinc and boron (all key co-factors in appropriate vitamin D and calcium metabolism).

Donielle Baker

Donielle Baker

owner and editor of Natural Fertility and Wellness at Natural Fertility and Wellness
I believe women can learn how to heal their bodies & balance their hormones through natural methods. An advocate for natural health, I have a passion for nourishing/real food nutrition and natural living. My personal background includes both infertility and miscarriage and I started Natural Fertility and Wellness in 2008 in order to share all of the information I found helpful in my journey to heal from PCOS and overcome infertility.
Donielle Baker
Donielle Baker
Donielle Baker
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