Celiac Disease and Vitamin D Deficiency

Many people recently diagnosed with celiac disease find they are deficient in vitamin D, a critical nutrient for both bone health and overall immune system strength. But vitamin D deficiency in celiacs isn't limited to the recently diagnosed—it seems to be common in adults and children who have been diagnosed with celiac for a while, even if they comply strictly with the gluten-free diet.

In fact, research shows that vitamin D deficiency occurs in 64% of men and 71% of women with celiac disease, making it an extremely common problem in those with celiac, although it's also common in the general population.

The issue for those with celiac disease could be continuing malabsorption, or it could be a lack of sun exposure and adequate dietary intake. Both of these may be exacerbated by the fact that, unlike many conventional gluten-containing grain products, gluten-free foods generally are not fortified with extra vitamins and minerals.

Regardless of the reasons, you should consider getting tested to determine your vitamin D level, and, if you turn out to be low in vitamin D, talk to your healthcare provider about supplements.

Vitamin D Deficiency Linked to Malabsorption

In patients with celiac disease who haven't yet started the gluten-free diet, and in some patients who fail to stick to the diet, villous atrophy causes malabsorption, meaning you simply aren't absorbing vitamin D and other nutrients from the foods and supplements you're consuming.

Vitamin D deficiency also leads to calcium deficiency, since you need adequate levels of vitamin D to absorb calcium in foods. Of course, many celiacs avoid dairy products due to lactose intolerance, meaning they don't consume much calcium in their diets anyway and may already be at risk for calcium deficiency.

Symptoms Include Weak Bones, Osteoporosis

Most cases of vitamin D deficiency present no noticeable symptoms, so you probably won't realize you suffer from it.

Severe vitamin D deficiency can cause bone diseases such as rickets in children and osteomalacia in adults. In rickets, a child's bones fail to develop properly, and the child's arms and legs often become bowed. In osteomalacia, meanwhile, bone structure is lost, resulting in pain and soft bones.

Osteoporosis also results in weakening of the bones and can lead to fractures. People with celiac disease are at high risk for osteoporosis.

Vitamin D deficiency also can cause muscle pain and weakness, and these symptoms may be more common than bone problems. People with celiac disease often report muscle and joint pain when they've consumed gluten, so it might be difficult to tell whether your particular case stems from accidental gluten exposure or something else.

Research Links Vitamin D Levels to Cancer, Autoimmune Diseases

Although cause and effect hasn't yet been proven, medical researchers have linked low levels of vitamin D to heightened risks for numerous health conditions, such as colon cancer, breast cancer, prostate cancer, hypertension, and autoimmune diseases.

Studies have shown that people living in higher latitudes, where there's less sunlight, experience higher rates of type 1 diabetes, multiple sclerosis, and rheumatoid arthritis. Although this doesn't prove cause and effect, some healthcare providers are urging these patients to supplement with vitamin D.

One study that looked at vitamin D levels in people with celiac disease found that 25% were deficient and that low vitamin D levels raised the risk of the autoimmune skin condition psoriasis, which has been linked to gluten consumption. But that study didn't find that low vitamin D makes people with celiac more vulnerable to additional autoimmune diseases.

High Doses May Be Needed to Restore Normal Levels

Scientists haven't agreed on what the optimum vitamin D level should be, but a level of less than 20 nanograms per milliliter (ng/mL) is considered deficient, while a level between 20 ng/mL and 29 ng/mL is insufficient. Some experts believe the ideal range is between 50 and 60 ng/mL.

If you've just been diagnosed with celiac disease and further testing shows you're deficient in vitamin D, your healthcare provider may recommend that you take very large doses in order to bring your level up quickly. However, you should never take large doses without careful monitoring of your vitamin D level by your healthcare provider, since it's possible to overdose on vitamin D taken orally.

The Endocrine Society has set the safe upper limit of vitamin D supplementation at 2,000 IU/day, although this may change with further research. The current U.S. Recommended Daily Allowance of vitamin D is 600 IU for children and adults under 70, and 800 IU for those over 70.

It's possible to get vitamin D testing without involving your healthcare provider through the Vitamin D Council, a non-profit group dedicated to improving research and public awareness of vitamin D's benefits. If you choose this route, however, you should follow up with your healthcare provider before deciding to take high doses of vitamin D supplements.

A Word From Verywell

If your healthcare provider doesn't think you need shots or supplements to raise your vitamin D level, you also can seek to raise your vitamin D levels through your diet—fatty fish and vitamin D-supplemented dairy products are good choices—and the old fashioned way, by soaking up the sun.

If you regularly spend about 20 to 30 minutes in the sun (longer if you have dark skin) with much of your skin uncovered during the spring, summer, and fall months, you can generate significant vitamin D, according to the Vitamin D Council. Just be careful not to burn your skin, since this raises your risk of skin cancer without providing any additional vitamin D benefit.

Even if you can't have dairy, you can look for foods that are high in calcium, such as calcium-fortified orange juice and canned salmon, and incorporate those into your diet.