I live in the great Northwest, and as beautiful as it is, it also comes with fairly long, chilly winters meaning less frequent sun exposure to my skin. Considering the majority of my pregnancy has taken place through these winter months, I have made a conscious effort to get enough Vitamin D. Also known as the "Sunshine Vitamin,” your body converts sunlight into vitamin D after it hits unprotected skin.
Why is Vitamin D Important During Pregnancy?
Because vitamin D supports normal fetal growth during pregnancy, including bone, neurologic, and immune system development. Other research suggests if a woman has low vitamin D levels during pregnancy, her baby may have an increased risk of getting eczema through the first year of life (1). A relationship between vitamin D and eczema has been established in the non-pregnancy population too.
Also, low maternal vitamin D levels (
Vitamin D also increases calcium absorption, which is another important nutrient during pregnancy.
Here are some tips to ensure you and your baby are receiving adequate amounts of vitamin D.
Are You at Risk for Vitamin D Deficiency?
Women at risk of low vitamin D levels are those who follow a vegetarian or vegan diet, have darker pigmented skin, have limited sun exposure, and a body mass index >30 (3).
Vitamin D Recommendations
The recommended amount of Vitamin D supplementation during pregnancy varies depending on what source you’re reading. This makes it very difficult to know how much vitamin D is necessary to support a healthy body. Best bet is to talk to your doctor.
Here are vitamin D recommendations from a few health agencies willing to even commit to providing a number, and as you can see, the recommendations are extremely different!
- Institute of Medicine, Food and Nutrition Board: 600 IU for everyone up to age 70 (4)
- Vitamin D Council: 6,000 IU for pregnant and lactating women (5)
- GrassrootsHealth: 4,000 IU for pregnant women after 12 weeks gestation (6)
How Should I Take My Vitamin D?
Vitamin D is effective when taken any time of the day, with or without food. It's preferred to take your vitamin D on a daily basis rather than a huge amount once per week, especially if breastfeeding. This avoids large peaks, followed by low levels, when your baby drinks breastmilk.
How Does Vitamin K Benefit Vitamin D?
Studies now show Vitamin K greatly enhances the benefits of vitamin D, in terms of bone strength and cardiovascular health. Vitamin D supports bone health by helping with calcium absorption. However, it is vitamin K that directs calcium to your skeleton, to prevent it from being deposited in the wrong areas.
Several different forms of vitamin K exist, with the primary form being vitamin K1, or phylloquinone, found primarily in green vegetables. Another form of vitamin K, known as vitamin K2 or menaquinone, is found primarily in animal products such as meat or eggs, as well as in foods such as cheese and natto, a fermented soy product. While most of the benefits of vitamin K were previously attributed to vitamin K1, recent research has identified important benefits for vitamin K2.
Mixing Sun Exposure and Vitamin D Supplementation
If you’re lucky enough to live in a sunny place, it is okay to use both sun exposure and intermittent vitamin D supplementation to receive your vitamin D. The solution: simply do not take your vitamin D supplement on the days when you receive adequate sun exposure. Studies suggest 5–30 minutes of sun exposure midday, at least twice a week to the face, arms, legs, or back without sunscreen usually lead to sufficient vitamin D levels for most people (4).
If you're like me and live north of the 37th parallel, the skin makes very little vitamin D from the sun, except during the summer months, so taking a vitamin D supplement is important. People who live in these areas are at relatively greater risk for vitamin D deficiency.
What Type of Vitamin D Do I Take?
Vitamin D3—the label will say cholecalciferol, which is the most bioavailable form of vitamin D and is equivalent to the vitamin D formed in our skin from ultraviolet B light.
Don't Rely on Prenatal Vitamins for Vitamin D
According to Mayo Clinic, most prenatal vitamins do not include optimal amounts of vitamin D. Talk to your doctor about other sources of vitamin D to boost your levels. I like this liquid vitamin D because it's super easy to take, doesn't have much flavor, and is super pure with only olive oil as the other ingredient. I also like this vitamin D3/K2 supplement because it is a chewable tablet that dissolves quickly in your mouth and tastes good.
If you would like to read more pregnancy blogs, check out Prenatal Vitamins During Pregnancy, and Probiotics During Pregnancy.
Bottom Line: Further studies are required to determine the optimal dose of vitamin D supplementation during pregnancy. For now, ensure you’re getting at least the minimum daily recommendation of 600 IU. Be sure to talk to your healthcare provider about vitamin D.
In Health and Happiness,
Kelly Harrington, MS, RDN
Registered Dietitian Nutritionist for Healthy Goods
