Blood tests and supplements

Melinda Dennis MS, RDN, LDN

Q: Should I get some kind of vitamin blood test done yearly? What type of supplements or vitamins should I be taking? My doctor just says to stay on a gluten-free diet.


It’s true that the only proven treatment for celiac disease is a life-long gluten-free diet. But you are correct that there are other steps to take, including monitoring nutrient levels and celiac blood work to improve and maintain your health.

First, please see Q&A from July 2018 to review celiac antibody blood work and how to follow up with your providers after a diagnosis.

Next, please see Q&A from July 2018  to review nutrition labs to consider checking following a celiac diagnosis.

On a yearly basis, the following labs are most commonly checked in our adult patients at the Celiac Center at Beth Israel Deaconess Medical Center:

  • Celiac serology
  • CBC (complete blood count)
  • Vitamin D
  • B12
  • Iron and/or ferritin
  • Calcium, magnesium, thyroid levels (usually available in medical record)
  • Any lab that is being monitored

Click here for more information on other labs and tests related to celiac disease.

Additional points: I really can’t emphasize enough the importance of aiming for the healthiest diet possible from food sources FIRST. And then, beyond food, the following vitamins and minerals are the most commonly recommended in supplement form by our BIDMC clinicians, based on blood work and diet evaluation: vitamin D, calcium, B12, iron, zinc and a multivitamin.

Here are a few details:

Vitamin D is not found readily in food sources and, along with calcium and other minerals, is very important for bone health, among many other benefits. It is a common supplement in a celiac clinic.

While we try to reach calcium goals first by food alone for the best absorption, it is not always possible as a patient may have lactose intolerance caused by celiac disease, a dairy allergy, or another reason to avoid milk products. There are numerous sources of dairy and non-dairy calcium rich foods. If adequate calcium intake cannot be met through food, we recommend gluten-free labeled calcium supplements.  Bone disease is a common concern among patients since celiac disease can cause malabsorption of multiple vitamins and minerals in the small intestine.

Supplemental iron is only recommended by a clinician, as needed, based on lab values. Iron supplements are discontinued once the levels return to normal.

Vitamin B12 is a water soluble vitamin that becomes more difficult to synthesize and absorb as we age. In addition, pernicious anemia is an autoimmune disease that affects the mucosal lining in the stomach and can ultimately lead to vitamin B12 deficiency, if left untreated. We commonly check B12 levels in our patients and recommend either a multivitamin that contains adequate but not excessive levels of B12, a separate B12 supplement, or a B complex  (a combination of B vitamins), as needed by the patient. See the National Institute of Health’s B12 factsheet for a summary of vitamin B12.

Supplemental zinc is only recommended if the patient’s zinc level is low. BIDMC clinicians recommend a specific dose (and sometimes a specific formulation of zinc) for the patient to take for ~ 8 weeks. The zinc level is then retested and discontinued as soon as the level is normal. At BIDMC, we check a copper level if zinc deficiency does not resolve.

Multivitamin/mineral supplements are selected, as needed, based on the patient’s age, gender, current diet and lab values.

Choose supplements that are labeled gluten-free. You can also see the various gluten-free certification symbols on some of the gluten-free supplements.

Speak to your clinician to help you monitor labs and choose appropriate supplements, as needed.

Reviewed and updated, October 4, 2022.

Note: This information is provided by NCA and Melinda Dennis, NCA's Senior Consulting Dietitian. This information is meant for educational purposes and is not intended to substitute for personalized medical advice or replace any medical advice provided directly to you by your health care provider. This information can be printed and used in consultation with your physician or dietitian. No liability is assumed by NCA, Ms. Dennis or her nutrition consulting service Delete the Wheat, LLC. by providing this information..

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About Melinda Dennis MS, RDN, LDN

Melinda Dennis, Senior Nutrition Consultant for NCA, is an expert celiac dietitian and and Nutrition Coordinator for the Celiac Center at Beth Israel Deaconess Medical Center in Boston, MA. Diagnosed with celiac disease in 1990, she specializes in the nutritional treatment of patients with celiac disease and gluten-related disorders.

Melinda lectures internationally and has written extensively on the nutritional management of celiac disease including the award-winning book Real Life with Celiac Disease. Melinda was the original founder of NCA in 1993 and so it is only fitting that she comes back to us in this capacity. We are truly honored to have her on our team.