In the first years after I was diagnosed with Crohn’s disease, no one ever mentioned vitamin D to me but recently my gastroenterologist has been paying close attention to my levels. For good reason. A simple Google search on “vitamin D and Crohn’s disease” returns thousands of results talking about studies that have been conducted in the last few years. Although they differ in how they were conducted and exactly what disease mechanism they are investigating, they all report the same basic message: getting sufficient vitamin D is crucial for people with inflammatory bowel disease (IBD).
What is vitamin D and what does it do?
Vitamin D is a fat-soluble vitamin that is naturally present in very few foods and is also produced within the body when ultraviolet rays from sunlight strike the skin. Most people associate vitamin D with milk because it is added to conventional dairy to promote calcium absorption. Without sufficient vitamin D, bones can become thin, brittle, or misshapen and severe vitamin D deficiency can lead to rickets and osteoporosis. Additionally, vitamin D has a role in cell growth, neuromuscular and immune function, and reduction of inflammation. For more detailed information, see the vitamin D page at the National Institutes of Health (NIH) Office of Dietary Supplements.
What role does vitamin D play in Crohn’s disease?
Links have been shown between vitamin D levels and Crohn’s disease activity since a study in 2010 showed a trend toward fewer flares of disease activity among patients who were took supplemental vitamin D. Another study the same year shed some possible light on why this is so when it found that vitamin D acts directly on genes that have been linked to Crohn’s disease and that act as signalers to the immune system in the intestinal tract. Two studies reported at the 2013 Digestive Disease Week strengthened the link, with one study associating vitamin D deficiency with increased hospitalization and surgery related to IBD and the other reporting that vitamin D supplementation can improve muscle strength and fatigue in patients with Crohn’s disease.
How do I know if my vitamin D levels are adequate?
Ask your doctor to order a blood test. According to the NIH, vitamin D levels in healthy people should be higher than 50 nmol/L. Levels below 30 nmol/L are considered severely deficient, with levels between 30-50 nmol/L described as “inadequate.”
When my vitamin D levels were tested six months ago they measured in the teens, which is considered severely deficient. At the time, I had been on a grain free (but not paleo) diet for two months and my symptoms were my moderate with my hemoglobin and hematocrit in the near normal range for the first time in memory. My doctor prescribed an 8 week course of 10,000 IU weekly and I retested in the high 40s, just below the healthy level of above 50. My doctor was pleased with the improvement and advised me to keep trying to get additional vitamin D through moderate sun exposure and food and will be rechecked next month.
Does the paleo lifestyle provide sufficient vitamin D intake?
For children and adults, the recommended daily intake (RDA) of vitamin D is 600 IUs (international units) per day. Because vitamin D does not naturally occur in very many foods, most Americans eating a standard diet do not get anywhere near that amount, so synthetic vitamin D is added to dairy products like milk and yogurt. and three servings of fortified dairy provides approximately the RDA of vitamin D.
So does that mean that a paleo eater who eschews dairy is inevitably going to become deficient in vitamin D? On the contrary! The few foods that vitamin D does occur in are easily incorporated into a paleo eater’s diet.
|Food source||IUs per serving||Percent of RDA|
|Cod liver oil, 1 tablespoon||1,360||340%|
|Swordfish, 3 ounces||566||142%|
|Salmon, 3 ounces||447||112%|
|Tuna (canned), 3 ounces||154||39%|
|Sardines (canned), 2||46||12%|
|Liver, beef, 3 ounces||42||11%|
A simple way to make sure your vitamin D intake is adequate is to take a tablespoon of cod liver oil every 2-3 days, but that doesn’t appeal to everyone (me included, though I am working up the nerve to order a bottle of Fermented Cod Liver Oil, the darling of the paleo and real food world, and start forcing it down!).
Another way to get close to the RDA is by eating a diet that includes eggs every day, swordfish or salmon at least once a week, tuna or sardines a few times a week, and liver as often as your taste buds can handle (
liver is my own real food achilles heel… I keep trying, but I just can’t get past the distinctive taste). UPDATE! I’ve created not one, but TWO recipes that use liver and have found them to be delicious. Check them out: Nourishing Chicken Liver Spread and Beef Liver Pâté with Bacon and Rosemary.
Furthermore, if you are eating pasture raised eggs, you may be getting even more vitamin D than the 41 IUs the government analysis indicate. A study commissioned by Mother Earth News found that eggs raised out in the sunshine and allowed to eat bugs as part of their diet contain 4-6 times more vitamin D than their supermarket counterparts. That means that a three egg omelette made from pastured eggs could potentially have over 700 IUs of vitamin D, which is the entire RDA at breakfast! Who needs fortified milk?
Remember also that your body can make its own vitamin D through sun exposure. Some experts recommend that getting 5–30 minutes of sun exposure between 10 AM and 3 PM at least twice a week to the face, arms, legs, or back without sunscreen. While this can be difficult if you live in a more northern climate where the sun is less intense and the air temperature in winter may keep you from exposing those areas, healthy people can store up vitamin D in their liver and fat during the warm months and dip into that reserve during the cold months.
If I have Crohn’s disease, should I take a vitamin D supplement?
Unfortunately, even if you are eating a solid paleo diet and getting sun exposure, you might still need to take a vitamin D supplement if you have active Crohn’s disease. Because vitamin D is fat soluble its absorption depends on the gut’s ability to digest and absorb fat, which people with Crohn’s disease often have difficulty with, so you may need a larger amount than the standard RDA to maintain healthy levels.
Caution: Before you start a supplementation program, it is important that you have a doctor order the labs rather than self diagnose a vitamin D deficiency because there is some evidence that levels above 125 nmol/L can be problematic.
If you are found to be deficient in vitamin D, look for a supplement that contains 1000-2000 IUs and take it daily. Your doctor can also prescribe a higher dose that you take weekly or you could even get it intravenously. There are two forms: D2 and D3. According to the Vitamin D Council and other alternative medicine practitioners, vitamin D3 is the preferred form as it is more readily converted by the body into a usable form.
For more information on Vitamin D and one of the major ailments that can come from being deficient in it, read this excellent article from The Darling Bakers.
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