Vitamin D deficiency may contribute to IBS symptoms, while vitamin D supplements may help some people with IBS. Research on the link remains controversial.

The exact cause of irritable bowel syndrome (IBS) is unknown, but researchers are investigating many possible factors.

Recent research has explored the link between vitamin D levels and the onset or worsening of IBS. Here’s what has been found.

Emerging research suggests vitamin D deficiency is associated with the occurrence and development of IBS.

Several studies have reported a high prevalence of vitamin D deficiency in children and adults with the condition.

A 2017 study on children and adolescents with IBS found that only 7% had sufficient levels of vitamin D, while more than 50% had vitamin D deficiency.

In a 2015 study, researchers found vitamin D deficiency in 82% of adults with IBS, compared with 31% of people without IBS.

A research review from 2022 also suggests vitamin D plays an important role in gut health, such as maintaining the intestinal mucosal barrier. Vitamin D deficiency may therefore lead to gastrointestinal symptoms related to mucosal damage.

More research from 2022 found an association between vitamin D deficiency and mental health conditions such as depression and anxiety, which have also been linked to IBS.

While these studies show a connection between vitamin D deficiency and IBS, there isn’t enough evidence yet to establish a cause-and-effect relationship. Researchers are continuing to explore this potential connection.

Vitamin D is known as the “sunshine vitamin” for good reason. Most people get at least some of their vitamin D from exposure to sunlight.

Yet, many people do not get enough vitamin D from sun exposure alone. There are several reasons for this:

  • Limiting skin exposure to sunlight helps reduce the risk of skin cancer.
  • Some people live in areas where it’s not possible to get enough sun exposure year-round.
  • People with darker skin may produce less vitamin D from sun exposure.

Other sources of vitamin D include foods and dietary supplements.

Foods

Good natural food sources of vitamin D are fatty fish such as:

  • trout
  • salmon
  • mackerel
  • tuna

Fish liver oils are also a good source of vitamin D. Other foods that have variable amounts of vitamin D include:

  • beef liver
  • egg yolks
  • cheese
  • mushrooms

In North American diets, fortified foods provide most vitamin D. Examples of fortified foods include:

  • milk
  • milk alternatives, such as oat milk and almond milk
  • breakfast cereal
  • orange juice
  • yogurt
  • margarine

People with IBS who are following a low FODMAP diet may want to avoid some of these foods, including:

  • dairy products, such as milk and yogurt
  • mushrooms

Those foods contain carbohydrates that are difficult to digest, which may worsen IBS symptoms in some people.

Dietary supplements

Dietary supplements may contain vitamin D2 or D3. Both forms of vitamin D can help people meet their vitamin D needs.

Vitamin D3 provides a greater boost to serum 25(OH)D levels and maintains these levels longer than vitamin D2.

Although dietary supplements can help people get enough vitamin D, excess amounts of vitamin D can be toxic, leading to serious health problems.

The recommended maximum daily intake from all sources of vitamin D is 100 micrograms (4,000 IU) for adults, according to the Institute of Medicine.

Still, everyone is different, so it may be a good idea to have your current levels of vitamin D checked with a healthcare professional to determine how much supplementation you need.

Some research suggests vitamin D supplements may be a promising therapy for IBS, but results are mixed.

A 2022 research review examined evidence across four randomized controlled trials of vitamin D supplementation in people with IBS. The researchers found that vitamin D supplementation effectively improved the symptoms and quality of life in people with IBS.

A 2023 analysis found similar evidence regarding vitamin D supplementation helping reduce symptoms of IBS in some people.

However, these reviews had several limitations, including:

  • the research included only a small number of clinical trials (four to six total)
  • the clinical trials involved small sample sizes
  • most trials were performed in Iran or Egypt where diets may differ from those in the U.S.

Another study found no benefit of vitamin D supplementation for people with IBS.

Research on this topic remains controversial. Some researchers recommend taking vitamin D supplements to help reduce IBS symptoms, while others recommend taking vitamin D supplements only for general health reasons.

More research is needed to confirm the potential benefits of vitamin D supplements for people with IBS. If you have questions about your levels of vitamin D, consider asking a healthcare professional about ways to test them and supplement, if needed.

Consulting a healthcare professional about your vitamin D serum levels is advised before supplementing or increasing your intake.

The amount of vitamin D you may need from dietary supplements depends on how much you get from other sources, such as sun exposure and foods.

Generally, medical experts may recommend the following average daily intake of vitamin D:

AgeMaleFemale
0–12 months10 mcg (400 IU)10 mcg (400 IU)
1–13 years15 mcg (600 IU)15 mcg (600 IU)
14–18 years15 mcg (600 IU)15 mcg (600 IU)
19–50 years15 mcg (600 IU)15 mcg (600 IU)
51–70 years15 mcg (600 IU)15 mcg (600 IU)
> 70 years20 mcg (800 IU)20 mcg (800 IU)

These values assume that most people get minimal exposure to the sun and therefore need dietary sources of vitamin D.

Consider talking with a doctor about vitamin D supplements. They may assess your overall health to determine if you would benefit from supplementation or what other sources of vitamin D you may need to include in your daily life.

There’s no evidence to suggest you can cure IBS with vitamin D.

Some research suggests vitamin D supplementation may improve symptoms and quality of life for people with IBS with vitamin D deficiency. Yet, IBS is a complex disorder and its cause is still unknown.

Experts believe a variety of issues may contribute to the condition, including:

  • stressful early life events
  • mental health conditions, such as depression and anxiety
  • bacterial infections in the digestive tract
  • an increase or change in the type of bacteria in the small intestine
  • food intolerances that cause digestive symptoms
  • genetics

Treatments for IBS aim to manage and reduce the symptoms you experience. This may include diet and lifestyle changes, medications, probiotics, and mental health therapies.

Emerging research shows vitamin D deficiency is common in people with IBS. Vitamin D supplements may help reduce symptoms of IBS for some people.

Yet, results have been mixed and more research is needed to explore the potential benefits of vitamin D supplements for people with IBS.

If you live with IBS, talk with a doctor about whether taking vitamin D supplements is right for you.