You may think, as I did, that if you’re taking a prenatal vitamin, you are getting all the right amounts of vitamins and minerals that you and your growing baby needs. However, the 400 IU of Vitamin D that most prenatal vitamins contain is a far cry from the amounts that are actually necessary!

What is Vitamin D?

Vitamin D, sometimes referred to as the “sunshine vitamin,” is technically not a vitamin! It is a “steroid hormone precursor” that is NOT naturally present in food. Your skin produces vitamin D when exposed to sunlight (sans sunscreen). Its major role is to increase the flow of calcium into the bloodstream, and is also necessary for bone growth.

What do we need vitamin D for?

According to Medical News Today, there are many reasons your body  needs adequate levels of Vitamin D:

It is crucial for the absorption and metabolism of calcium and phosphorous, which have various functions, especially the maintenance of healthy bones.

It is an immune system regulator.

It may be an important way to arm the immune system against disorders like the common cold, say scientists from the University of Colorado Denver School of Medicine, Massachusetts General Hospital and Children’s Hospital Boston.

It may reduce the risk of developing multiple sclerosis. Multiple sclerosis is much less common the nearer you get to the tropics, where there is much more sunlight, according to Dennis Bourdette, chairman of the Department of Neurology and director of the Multiple Sclerosis and Neuroimmunology Center at Oregon Health and Science University, USA.

Vitamin D may have a key role in helping the brain to keep working well in later life, according to a study of 3000 European men between the ages of 40 and 79.

Vitamin D is probably linked to maintaining a healthy body weight, according to research carried out at the Medical College of Georgia, USA.

It can reduce the severity and frequency of asthma symptoms, and also the likelihood of hospitalizations due to asthma, researchers from Harvard Medical School found after monitoring 616 children in Costa Rica.

It has been shown to reduce the risk of developing rheumatoid arthritis in women.

A form of vitamin D could be one of our body’s main protections against damage from low levels of radiation, say radiological experts from the New York City Department of Health and Mental Hygiene.

Various studies have shown that people with adequate levels of vitamin D have a significantly lower risk of developing cancer, compared to people with lower levels. Vitamin D deficiency was found to be prevalent in cancer patients regardless of nutritional status, in a study carried out by Cancer Treatment Centers of America.

The Vitamin D Council adds that current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.

Vitamin D and Pregnancy

Vitamin D deficiency during pregnancy has effects on both the mother and fetus. The Vitamin D Council implicates it in cases of c-section, preeclampsia, gestational diabetes, and bacterial vaginitis.

During pregnancy, the active form of vitamin D increases significantly, according to Mayo Clinic, particularly in the second and third trimesters. During this time, the baby’s bones are developing, as are the brain, the nervous system, and the other organs.Your levels of vitamin D also play a role in determining your baby’s health later in life. Vitamin D deficiency been linked with low birth weight. It also appears that sufficient vitamin D in early life may decrease the risk of serious health problems such as newborn lower respiratory tract infection, diabetes, asthma, weak bones, schizophrenia, autism, brain tumor, heart failure, and a host of other maladies. (Read more here.)

The American Academy of Pediatrics (AAP) recently recommended that all pregnant women have a 25(OH)D blood test, because Vitamin D is vital  for normal fetal development .  If your obstetrician has not referred you for this test, you may want to consider asking that he/she does.

The Sun Exposure Quandary

For decades dermatologists have been warning about the hazards of sun exposure and skin cancers. We know that excessive sun exposure is dangerous, and have been cautioned to stay out of the sun,  wear sunscreen, and protective garments if we will be outdoors. At the same time, Vitamin D deficiency is at epidemic levels in the US (80-90% according to one expert). Getting just enough daily sun exposure to produce necessary levels of Vitamin D may actually be important for your health.

Further studies are required to address this dilemma. However, some health authorities are starting to change their recommendations. Medical News Today quotes the Cancer Council, Australia (2009):
“Sun exposure is the cause of around 99% of non-melanoma skin cancers and 95% of melanomas in Australia. However, exposure to small amounts of sunlight is also essential to good health. A balance is required between avoiding an increase in the risk of skin cancer by excessive sun exposure and achieving enough exposure to maintain adequate vitamin D levels.”

Getting Enough Vitamin D

The current U.S recommended daily allowance is 200 international units of vitamin D, however the current “tolerable upper limit” is 2000 IU. The Canadian Pediatric Society and other Vitamin D advocates suggests that this level may be appropriate for winter pregnancies. (Mayo Clinic) Some experts suggest that pregnant women need even higher levels than this, up to 5000 IU.  Speak to your doctor, as too much Vitamin D can be toxic.

The Vitamin D Council recommends 3 ways for adults to ensure adequate levels of vitamin D:

• Regularly receive midday sun exposure in the late spring, summer, and early fall, exposing as much of the skin as possible (being careful to never burn).
• Regularly use a sun bed (avoiding sunburn) during the colder months. (For more info on this topic: Are Tanning Beds Safe?)
• Take 5,000 IU per day for 2–3 months, then obtain a 25-hydroxyvitamin D test. Adjust your dosage so that blood levels are between 50–80 ng/mL (or 125–200 nM/L) year-round.