Can Low Vitamin D Affect Fertility?

Vitamin D is a nutrient that everyone needs in order to stay healthy. Plus, it’s a vitamin that influences steroid hormone production, metabolism and hormone receptor function (influencing major bodily processes, including the reproductive system). We have receptors for Vitamin D in almost every tissue in our bodies, including the testes, ovaries and uterus—so, yes, being deficient in Vitamin D does affect your fertility. Unfortunately, in North America, many of us are low in the sunshine vitamin, so getting the right forms at the right levels is crucial, not only for your fertility, but also your overall health. 

Read on to learn how Vitamin D can benefit fertility, what forms to look for and the right amount to take when you’re trying to conceive.

What benefits does Vitamin D have?

When Vitamin D attaches to its receptors, it can turn different genes on and off, affecting many essential activities in the body, including: 

1. Bone health: Vitamin D regulates Calcium and is necessary for building bone tissue.
2. Immune regulation: Vitamin D has antimicrobial actions and modifies the release of immune-signalling molecules, helping to prevent both infections and autoimmune reactions.
3. Brain function: Vitamin D acts as an anti-inflammatory in the brain and protects its function.
4. Metabolism: Vitamin D enhances insulin sensitivity.
5. Cardiovascular health: Vitamin D has antioxidant and anti-inflammatory effects in blood vessels and heart muscle cells.

What are the symptoms of Vitamin D deficiency?

Having low levels of Vitamin D can cause problems both big and small, depending on the severity of the deficiency. In your every day, it can be associated with fatigue, achiness, hair loss, loss of appetite and getting sick more easily. It even affects your mental health, with deficiency being linked to sadness and depression. If left untreated, it can contribute to major health problems like infections, osteoporosis, type 2 diabetes, kidney disease, depression, attention-deficit disorders and infertility.

Does Vitamin D affect fertility?

Vitamin D has a huge influence over many major body systems, so it’s no surprise that it can affect both male and female fertility. A 2018 study even showed that pregnancy rates tend to go up and down when there’s more or less sunshine (thus, Vitamin D), respectively.

How does Vitamin D affect female fertility?

When it comes to female fertility, Vitamin D is primarily associated with the proper function of your ovaries and uterus: egg development, ovulation, and supporting implantation. 

Supplementing with Vitamin D has a direct impact on anti-Mullerian hormone (AMH) production (a marker of ovarian reserve). In one study, which included infertile participants with Vitamin D deficiency, supplementing with Vitamin D improved AMH levels and antral follicle count (AFC) after two months.

Vitamin D can also help get your uterine lining in tip-top shape to support implantation. And its immune-regulating actions can influence the development of abnormal uterine cells. For example, low Vitamin D levels are linked to the development of uterine fibroids, and supplementing can help decrease the size of fibroid lesions, leading to less interference with embryo implantation. 

There's also evidence that Vitamin-D deficiency is associated with a higher risk of miscarriage, compared to those who were not deficient.

For people with polycystic ovarian syndrome (PCOS), where Vitamin D deficiency is common, supplementing with Vitamin D to healthy levels can improve ovulation rates, egg development, and pregnancy rates.

How does Vitamin D affect male fertility?

Vitamin D receptors are found in multiple areas of sperm cells and the male reproductive tract in general, making the nutrient important in sperm development and maturation and sperm motility. Conversely, being deficient in Vitamin D has been linked to lower sperm counts in infertile males and higher miscarriage rates.

Can Men Take Prenatal Vitamins? →

How much Vitamin D do you need?

How much Vitamin D you should take is very individual and depends on your baseline Vitamin D status. Typical doses can range from 1,000 IU to 4,000 IU or higher if you're severely deficient. The recommended daily intake of Vitamin D for most adults is 600 IU, though there are some challenges to getting Vitamin D (more on that below), and it’s common for many to need a daily dose of 1,000 to 2,500 IU year-round. You’re considered deficient in the nutrient with levels less than 50 nmol/L (for Canadians) or 20 ng/mL (for Americans).

All of Bird&Be’s supplements contain 1,000 IU of vegan Vitamin D3, covering your daily recommended dose. For those who could use a little extra, adding on Bird&Be Calcium + Magnesium + Vitamin D Boost (which contains an extra 1,000 IU) ensures that you’re covered throughout your fertility journey and even beyond it.

What form of Vitamin D should you take?

Vitamin D exists in two forms: ergocalciferol (D2) and the hormonally active form, cholecalciferol (D3). The vitamin D that is produced from sunlight exposure is in the form of D3, while D2 is made by yeast and fungi. Both types are available in supplement form, with D2 being known as vegan-friendly since historically most D3 supplements have been sourced from sheep lanolin, a waxy oil found on sheep’s wool. But, when researchers compare D2 and D3 supplements, many have found that the D3 form is superior in raising blood levels of Vitamin D. In one comparison of 14 different studies, all but three reported that the D3 form was better at raising blood levels of Vitamin D when given high doses. More recently it was found that lichen (a form of algae) can also produce D3, thus introducing a new vegan source for D3 supplementation.

Where do you get Vitamin D?

Although we can get Vitamin D from sunlight, it’s actually a challenge for a lot of people, thanks to location. Those living in Northern latitudes (including all of Canada and regions north of San Francisco in the U.S.) have the hardest time getting the vitamin, especially in the colder months. In summer, barrier sunscreens (those with minerals such as zinc oxide) act as a shield against the rays that provide the skin with Vitamin D (though we don’t recommend skipping your sunscreen). Cloud cover and smog will also block out those rays. 

There are also genetic variations that decrease the ability of an individual to convert the sun’s rays into Vitamin D. Bottom line? It’s not always easy to get the recommended daily dose, often because of factors you can’t control. It’s why opting for a supplement can be especially beneficial when it comes to Vitamin D.

What foods are high in Vitamin D?

There aren’t many natural dietary sources of Vitamin D. The highest amounts can be found in fatty fish such as trout, salmon, mackerel, and in cod liver oil. Even with these sources, it’s not always easy to eat enough in a day to cover the doctor-recommended amount (to reach the minimum recommended daily intake of 600 IU, you would need to eat three to four ounces of these fish daily).

How much Vitamin D is in a prenatal vitamin?

Because we know Vitamin D deficiency is linked to poor fertility outcomes, look for a preconception supplement with 1,000 to 2,500 IU, or consider additional supplementation if your prenatal is a little low (most contain about 400 to 1,200 IU). And the benefits don’t stop after you conceive: both you and a growing babe can make good use of the vitamin. Vitamin D is important for proper fetal development of the skeletal, immune and respiratory systems and can help with major pregnancy complications like gestational diabetes and pre-eclampsia. Read more about Vitamin D in pregnancy here.