Calcium and Vitamin D Supplements

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

Inflammatory bowel disease (IBD) is a condition of chronic inflammation of the digestive tract and includes both Crohn’s disease (CD) and ulcerative colitis (UC). The chronic inflammation can cause a wide range of symptoms and complications. Low bone density is one common complication caused by IBD.

What is bone density?

Studies suggest that around 30 to 60 percent of people with IBD also have lower-than-average bone density. Low bone density can take several different forms in people with IBD, including:1

  • Osteoporosis, in which the bones become weak and brittle
  • Osteopenia, low bone density
  • Osteomalacia, in which the bones become softened

Bone density refers to the rigidity of a person’s bone mass. Low bone density can cause back pain, changes in posture, and an increased risk of bone fractures.1

Throughout life, a person’s bones will repeatedly go through two processes of bone remodeling: bone resorption and bone formation. When these two processes are working at the same rate, then bone density is maintained. However, when bone resorption begins to happen at a quicker rate than formation bone density will begin to decline. While some loss of bone density is normal after age 35, patients with IBD tend to develop this condition at a much earlier age, and it is more common among women than men.1

What is the link between inflammatory bowel disease and low bone density?

There are a number of reasons why people with IBD could develop a loss of bone density. Two common reasons are:1

  • A decrease in calcium absorption
  • Vitamin D deficiency

A vitamin D deficiency is common among people with IBD, especially those with CD. During the process of digestion, vitamin D is absorbed from food as it passes through the small intestine. Inflammation in the small intestine due to CD can prevent the digestive system from absorbing enough vitamin D from food, which is called a vitamin D deficiency. Vitamin D deficiency is also directly linked to lower-than-average bone density. Vitamin D is necessary for the absorption of calcium; therefore, a lack of Vitamin D can result in bone loss.1

Many people with IBD take medications called corticosteroids in order to reduce inflammation of the digestive tract. However, this type of medication can have serious side effects related to the bones. There are a number of ways corticosteroids can affect the formation of new bone, resulting in lower bone density.1

What are calcium and vitamin D supplementation?

Healthcare providers use examination and blood tests to determine whether a person with IBD has experienced a loss of bone density.1,2 If so, the patient will often be advised to consume more calcium in the food they eat in order to help counteract the loss of bone density.

Adequate amounts of calcium intake are a lifelong necessity when it comes to optimal bone health. One of the best ways to get an adequate daily dose of calcium is through a balanced diet. Milk and other dairy products are good dietary sources of calcium, as well as:3

  • Collard greens
  • Black-eyed peas
  • Salmon
  • Trail mix
  • Baked beans

For patients who are unable to get enough calcium through a balanced diet, a calcium supplement may be recommended. Depending on a patient’s individual circumstances, a healthcare provider will recommend a specific daily dose requirement.

Patients with IBD, and especially those with CD, are at a greater risk of developing vitamin D deficiency because inflammation in the small intestine prevents enough of the vitamin from being absorbed from food during the digestion process. Because vitamin D is necessary for the absorption of calcium, a deficiency of vitamin D can cause a deficiency in calcium. This can be a cause of lower-than-average bone density.1

Dietary sources of Vitamin D include:1

  • Fortified milk, juices, and cereals
  • Saltwater fish
  • Liver

Some people are not able to absorb enough vitamin D through their diet, so may be advised by their healthcare provider to take a vitamin D supplement. If a patient is suspected of not having enough vitamin D, a blood test can be used to diagnose the deficiency. The patient will then work with their healthcare provider to figure out a specific daily dose requirement.

Taking an oral supplement of vitamin D or calcium can increase nutrient intake for people who are unable to acquire the daily intake through their food. Supplements are usually available over-the-counter. Many calcium supplements come with a dose of vitamin D, which can be a convenient option for patients who need both. However, it is very important that you talk with your healthcare provider in order to obtain an appropriate daily dosage before purchasing a vitamin D or calcium supplements. Taking too much of either nutrient can have negative side effects.

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