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Does Vitamin D impact fertility? What the science says

When you’re trying to conceive, or plan to in the future, it’s natural to want to do everything you can to improve your chances.

what sometimes includes considering incorporating certain dietary supplements into your daily routine.

Because of the research supporting its benefits, one such supplement that many fertility professionals have on their radars is vitamin D.

This article covers:

  • Foods that are rich in Vitamin D

  • Vitamin D and fertility

  • Vitamin D supplementation

  • Signs of Vitamin D deficiency

  • What you should know about Vitamin D and fertility treatments

Over the past few years, Vitamin D has become much more commonly discussed for its wide-ranging health benefits.

Also known as the ‘sunshine vitamin, it is produced in the skin as a response to sunlight exposure.

Although sunlight is the most common source of Vitamin D, it can also be sourced through the foods that we eat:

Foods Rich in Vitamin D

Vitamin D can be found in some foods such as:

  • Liver

  • fortified breakfast cereals

  • Margarine

  • Cheese

  • Egg yolks

Adequate levels of Vitamin D are necessary for many processes in our bodies, such as:

  • Stimulates weight loss

  • Lowers the risk of rheumatoid artherits

  • Promotes strong bones

  • Makes you happier

What you may not know, however, is that your Vitamin D status may also affect fertility.

Vitamin D is actually not a vitamin at all, it is a steroid hormone. Receptors for this hormone are found throughout the body, including the majority of reproductive organs such as the ovaries, uterus, placenta, testes, hypothalamus, and pituitary glands.

This is why levels of Vitamin D have been linked to a number of conditions affecting reproduction, including endometriosis, polycystic ovarian syndrome (PCOS) and infertility.

What you need to know

Vitamin D’s most important role in the human body is to keep bones healthy and strong by helping the body absorb calcium.

However, recent research has pointed to additional ways that Vitamin D deficiency factors into our overall health, including its role in chronic diseases such as diabetes, obesity, autoimmune disease, cardiovascular disease and cancer, as well as an association with a higher risk of both overall and cancer mortality.

How common are Vitamin D deficiencies?

If you enjoy spending time lounging in the sun, chances are, your body produces sufficient levels of the vitamin.

Although we would all love to spend time soaking up natural goodness (safely, with SPF of course!), not all of us have this luxury.

Many people, in fact, particularly those living in the Northern hemisphere, do not get enough exposure to natural sunlight in order to maintain optimal levels of Vitamin D throughout the year.

There are various other factors that may affect your levels of Vitamin D.

For instance, if you have a darker complexion, your body may not produce Vitamin D as effectively.

In fact, individuals with darker pigmented skin may requirethree to five times longer exposure to the sunthan those with lighter pigmented skin to synthesize the same amount of Vitamin D.

Vitamin D and Fertility

For women trying to conceive, sufficient Vitamin D levels appear to be linked to improved fertility, as well as a healthy pregnancy.

The active form of Vitamin D (calcitriol) has many roles in female reproduction.

Bound to its receptor, calcitriol is able to control the genes involved in making estrogen. The uterine lining produces calcitriol in response to the embryo as it enters the uterine cavity, shortly before implantation.

Calcitriol controls several genes involved in embryo implantation. Once a woman becomes pregnant, the uterus and placenta continue to make calcitriol, which helps organize immune cells in the uterus, so that infections can be fought without harming the pregnancy.

Poor Vitamin D status has been associated with certain pregnancy complications such as gestational hypertension and diabetes.

Two studies found that among populations of mostly Caucasian and non-Hispanic white women, those with a normal Vitamin D level were four times more likely to get pregnant through IVF compared to those who had a low Vitamin D level.

Although the data for Vvitamin D and fertility is not conclusive, several studies have found that Vvitamin D blood levels of 30 ng/mL or higher are associated with higher pregnancy rates.

Another study found that donor egg recipients with a normal Vitamin D level had higher pregnancy rates than those with a low vitamin D level.

Many reproductive health experts believe that maintaining a normal Vitamin D level during pregnancy is critical.

A normal Vitamin D levelduring pregnancy may improve pregnancy outcomes, and it has been linked to a reduction of pregnancy complications.

So What Does This Mean in Practice: Should You Consider Vitamin D Supplements?

The National Institutes of Health (NIH) recommends an average daily intake of 400–800 IU, or 10–20 micrograms.

While most prenatal vitamins contain 400-1,000 IU doses of Vitamin D, this dose may not enough for most women, especially if your levels are already low. 

Higher doses,2,000 to 4,000 IU of Vitamin D per day, may be more beneficial and are completely safe during pregnancy.

Few foods are naturally rich in vitamin D, so it can actually be difficult to get enough Vitamin D from your diet.

Which Supplements Should I Look For?

Unfortunately, not all fertility supplements are created equal. Vitamin D3, or cholecalciferol, is the type of Vitamin D our bodies produce after exposure to sunlight, and it’s the type that we metabolize most effectively, so it makes sense to use this type when choosing a supplement.

To maximize your body’s ability to absorb Vitamin D, take your supplement with a meal or snack containing some fat.

For example, if you take your supplement at breakfast, the fat from an egg (including the yolk), nuts, nut butter, seeds, or cheese will help your body absorb the vitamin D.

If you’re thinking of conceiving and experiencing any signs of deficiency, having a darker skin tone or do not get much sunlight in your day to day life, it may make sense for a healthcare professional to test your Vitamin D levels.

If your level is low, increasing your vitamin intake via foods or supplements may improve your chances of conceiving.

Signs of Vitamin D deficiency

Vitamin D deficiency is considered a worldwide public health problem, in particular, because in most countries, large parts of the general population do not meet the dietary Vitamin D requirements as recommended by nutritional Vitamin D guidelines.

If you’re someone who works or is frequently indoors, lives in a place that doesn’t get a lot of sunlight, you tend not to eat a balanced meal or a diet that doesn’t include food rich in Vitamin D such as fish or dairy, there is a higher chance that you may be Vitamin D deficient.

Common symptoms of a vitamin D deficiency are:

  • Alopecia (Hair Loss)

  • Getting sick often or easily

  • Depression

  • Cuts that take a while to heal

  • Feeling tired or fatigued often

  • Having stomach issues

  • Back or bone pain

  • Muscle pain

Natural sources of Vitamin D

Ideally, everyone would soak up their Vitamin D from the sun but that depends not only on where you live but what season it is.

What you should know about Vitamin D and fertility treatments

Some studies have shown that women who have lower levels of vitamin D are associated with low AMH, PCOS and uterine fibroids.

Vitamin D assists in the production of the anti-Müllerian hormone (AMH), which is the measure of a woman’s ovarian reserve.

It is thought, therefore, that increasing your Vitamin D intake can potentially improve your egg quality.

Women about to undergo in vitro fertilization (IVF) can provide valuable insight into the role of Vitamin D, since it is possible to examine each aspect of reproduction, from egg development to implantation of the embryo.

A recent study found that women with higher Vitamin D levels were significantly more likely to achieve pregnancy from IVF compared to women with lower levels of Vitamin D.

Though more research is needed, it appears that Vitamin D levels are associated with IVF success and that its most important role in reproduction may be at the uterine lining.

No studies have yet evaluated whether giving Vitamin D improves IVF outcomes. But the data that does exist at this point suggests that a role for Vitamin D supplementation may exist as a means of improving one’s natural fertility both among fertile and infertile individuals.

Remember, as always, a healthy, balanced diet is the best starting point for acquiring nutrients for fertility and pregnancy, but there can be a role for supplementation, including Vitamin D.

Before starting any dietary supplements, always check with your doctor or medical provider.

If you are looking for supplements and are not sure where to start or which brands to check out, visit our supplement page here.


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