Vitamin D Benefits For Fertility, Pregnancy & Overall Health

Unless you live in the tropics year-round or take supplements proactively, chances are you aren’t getting enough vitamin D. And despite widespread educational campaigns to raise awareness, vitamin D deficiency has persisted to the point that most forward-thinking doctors recommend testing your levels annually.

And for nearly everyone over 30, supplementation is indicated. However, as a functional medicine doctor (and a busy mother of three), I recommend my patients get their vitamin D levels checked more frequently and as early in their adult lives as possible. Why? Because optimal vitamin D levels are crucial to nearly every single bodily function, including successful conception―for men and women―and maintaining a healthy pregnancy. Plus, optimizing your vitamin D levels sooner rather than later can prevent a slew of modern chronic ailments from manifesting later in life.

Here is everything you need to know about vitamin D for health, conception, pregnancy, disease prevention, and beyond.

What is vitamin D?

While its name is slightly misleading, vitamin D is both a vitamin and a hormone essential for healthy bodily function. Often nicknamed "the sunshine vitamin," vitamin D mostly enters our bodies via the sun, which is absorbed by our skin and converted to a usable form by cholesterol. You can get some vitamin D from specific foods, but the majority comes from good old-fashioned sunshine.

While all nutrients play a crucial, symbiotic role in maintaining health, vitamin D is especially important as it is essential for nearly every single bodily system and function including the musculoskeletal, gastrointestinal, renal, endocrine, and cardiovascular systems.

It’s even essential for healthy genetics and gene expression. Vitamin D has been shown to be responsible for up to 3 percent of what’s known as "gene transcription," the process in which your inherited genes are expressed or activated. In other words, vitamin D plays one of the most essential roles in nourishing your body, protecting your genes, preventing acute and chronic disease, and maintaining your overall health.

How vitamin D supercharges your health and prevents disease.

Vitamin D and fertility.

While the research on vitamin D, fertility, and conception is up-and-coming, the studies that have been done are promising. For example, it’s been shown that vitamin D supplementation can increase a couple's chances of conceiving when using IVF, and new research suggests vitamin D supplementation may increase fertility and sperm count in men.

Plus, given what we now know about how vitamin D levels affect your immunity, inflammatory levels, and overall health, I wager we’ll be seeing many more exciting studies published in the coming years. For now, it seems prudent for future fathers (that’s you, guys) to get serious about their vitamin D levels to enhance their chances of a speedy conception.

Vitamin D and pregnancy.                        

Now that we’ve got dads on board with vitamin D optimization, it’s time to move on to the moms. While vitamin D optimization will benefit women at any time in their life, it’s absolutely essential you keep on top of your levels before getting pregnant (ideally) and definitely during and after pregnancy.

Significant evidence shows that vitamin D deficiency during pregnancy increases your risk of anemia, gestational diabetes, pre-eclampsia, bacterial vaginosis, and unplanned caesarean birth. For baby, a variety of studies have shown suboptimal vitamin D levels can negatively affect an unborn child’s health in a number of ways including lower birth weight, tooth enamel defects, lowered cognitive function, and increased risk of obesity.

If that isn’t enough to turn your head, studies show you can reduce your baby's risk of asthma by 40 percent by increasing your intake of vitamin D. Vitamin D also plays a key role in the nutritional quality of your breast milk. Therefore, if you’re supplementing for two, I tend to recommend a higher-dose supplementation for breastfeeding mothers, often 5,000 IUs daily and up. Talk to your doctor or health care practitioner about what’s best for you.

Vitamin D and hormone and thyroid health.

The thyroid is one of the most powerful glands in your body, regulating everything from metabolism and body temperature to hormonal balance and sleep patterns. It’s also a key player in fertility, pregnancy, and postpartum recovery. Therefore, if you want to increase your chances of a healthy conception, pregnancy, and postpartum period, protecting your thyroid is key.

Beyond pregnancy, caring for your thyroid will help you maintain a healthy weight, mood, sleep cycle, immunity, and energy levels and keep your hair, skin, and nails youthful and strong. Vitamin D plays a crucial role in thyroid health as it regulates the production of thyroid hormones, which help protect you from thyroid diseases.

Further studies have shown low levels of vitamin D levels are associated with chronic thyroid conditions like autoimmune thyroid disease such as Hashimoto’s thyroiditis and Grave's disease. I mention this in the context of pregnancy, birth, and postpartum health because many of the patients I see with thyroid insufficiencies are mothers.

The reason is pregnancy, birth, and caring for a new baby require an increased amount of stress hormones, sleep deprivation, and stamina. This puts a huge strain on the body’s hormonal balance and nutrient reserves, which often results in a compromised thyroid and adrenals. Ladies, if I could give you one piece of preventive advice for a healthy postpartum recovery it would be to take care of your thyroid before, during, and after your pregnancy―and getting enough vitamin D is a great place to start.

Vitamin D and immunity.

While vitamin C and zinc have earned gold-standard status for boosting immunity and protecting against cold and flu, the truth is, getting enough vitamin D is just as important.

Optimal vitamin D levels have been shown to positively affect the innate and adaptive immune system in a variety of ways including boosting genetic expression of white blood cells during winter months, helping the immune system adapt and ward off infection, reducing inflammation, and reducing the chance of upper respiratory infections.

Vitamin D deficiency has also been associated with a variety of autoimmune diseases including multiple sclerosis, lupus, diabetes, rheumatoid arthritis, and thyroid diseases such as Hashimoto’s and Grave’s disease. And this is just a small sampling of the research linking optimal vitamin D levels with improved immunity.

Vitamin D and cancer.

When it comes to cancer, recent findings on epigenetics and the slow growth rate of many cancers, it’s a comfort to know we wield enormous power in our ability to prevent a worst-case scenario. Optimizing your vitamin D levels is one simple, affordable, and incredibly effective way to go about this.

Vitamin D insufficiency is commonplace in many types of cancer, most notably breast, prostate, lung, thyroid, and colorectal cancer; with 77 percent of patients either deficient or with suboptimal levels. And the lower their levels, the more aggressive the cancer. Optimal vitamin D levels have also been shown to affect cancer outcomes by decreasing mortality rates.

Vitamin D and inflammation.

Inflammation is now recognized as a causal factor in nearly every chronic condition―from heart disease and depression to cancer.

As a functional medicine physician, I can tell you, it’s no exaggeration to say inflammation has become a worldwide epidemic. The good news is there is plenty we can do to keep our inflammatory levels in check, including eating a balanced diet with plenty of fruits and vegetables, reducing stress, limiting our intake of processed foods, exercising, getting enough sleep, and getting enough anti-inflammatory vitamin D.

How does vitamin D help inflammation? It works by modulating the release and proliferation of cytokines―chemical messengers that initiate inflammation. And while some inflammation can be a good thing―like the protective swelling that occurs after a physical trauma―chronic inflammation is problematic as it causes body breakdown.

Vitamin D and gut health.

While probiotics are all the rage in promoting good gut health, vitamin D has been shown to play a crucial role in restoring beneficial gut bacteria, which, in turn, has a positive effect on metabolism. Further, a variety of studies have shown vitamin D plays a key role in the health of the gut mucosal lining, acting as an anti-inflammatory, anti-infective, and immune booster to protect against viruses and other pathogens.

Labs to request for vitamin D deficiency.

The safest and smartest way to optimize your vitamin D consumption is to monitor your blood levels. To do so, have your doctor specifically order a 25-hydroxy vitamin D test, also known as the 25-OH D test. The optimal (not just "normal") amount you want to see is 45 to 65 ng/mL, and in some cases, even higher levels are appropriate.

How to get more vitamin D. 

The amount of vitamin D required to replenish deficiencies depends upon your lab tests, so check with your provider for individual recommendations and follow these guidelines:

Sources of whole vitamin D-boosting foods include:

Vitamin D and sun exposure.

In my experience as a physician and based on the current research, moderate sun exposure is best. Therefore, I recommend getting some unprotected sun exposure every day based on the Vitamin D Council’s recommendations for your skin type, location, etc. (see below), and to never let your skin burn. Then be sure and protect yourself with a nontoxic sunscreen thereafter.

Here are the Vitamin D Council’s sun exposure guidelines based on skin type:

To recap: