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Intestinal disorders may be caused by too little vitamin D

Intestinal disorders may be caused by too little vitamin DIrritable bowel is the most common intestinal disorder and affects around 15 percent of the population. The symptoms are typically unstable digestion, flatulence, constipation, diarrhea, stomach pain, and intestinal cramps. Several studies have shown that lack of vitamin D may cause the symptoms, and that taking a vitamin D supplement helps. This is because vitamin D is highly important for the intestinal immune defense and for controlling inflammation.

Irritable bowel syndrome (IBS) affects around 15 percent of the population and the condition is associated with a lot of discomfort and impaired quality of life. Irritable bowel is categorized into three subgroups depending on the digestion: Irritable bowel with diarrhea, irritable bowel with constipation, and irritable bowel with both constipation and diarrhea. Irritable bowel has become increasingly common in the past decades.

Things that cause irritable bowel disorder

There are many theories about what causes irritable bowel, for instance unhealthy eating habits, low-grade inflammation in the gut mucosa, overgrowth of harmful bacteria or thrush, and intolerance towards foods such as gluten and dairy products. Antibiotics and pain-relieving medication may also cause damage to the gut mucosa and the digestive tract. Other theories deal with disturbances in the brain-gut axis where several neurotransmitters signal in both directions. Scientists have observed a higher rate of irritable bowel among patients suffering from stress, anxiety, depression, and other mental disorders. On the other hand, irritable bowel in itself may cause mental disturbances, and in many cases, patients feel relieved once their digestive function is restored.

Bowel function and the mental balance

Our gut is also referred to as our second brain. This is because of the billions of gut bacteria that produce many of the neurotransmitters that help the brain function normally. Imbalances in the intestinal bacterial flora may therefore lead to depression, ADHD, autism, and Alzheimer’s disease

The link between vitamin D intake and irritable bowel

A number of studies have shown a link between vitamin D levels and irritable bowel. The lion’s share of the immune system is situated in the intestines, and this also happens to be the part of the body that is in primary contact with microorganisms from the surrounding environment. Scientists believe that vitamin D plays a significant role in stimulating the immune defense and, at the same time, counteracting undesirable inflammation. The intestinal mucosa also has vitamin D receptors that are important for other parts of the digestive system. It is known that depression, which can provoke or aggravate irritable bowel, is more common among people with low vitamin D levels. Low levels of the nutrient have been found in several studies of irritable bowel. In 2015, Tazzyman and his colleagues showed in a study that 82 percent of patients with irritable bowel were vitamin D-deficient.

Why is vitamin D deficiency so common?

Lack of vitamin D may be caused by many different factors. The sun is our primary source of vitamin D, but many people at this latitude become deficient of the vitamin during the winter period, where the sun sits too low in the sky to enable vitamin D synthesis in the skin. Also, spending too much time indoors and listening to sun awareness campaigns that cause fear of the sun contribute to the problem and may even result in chronic vitamin D deficiency.
The diet only contains very little vitamin D, and if people have issues with their lipid absorption it may worsen their deficiency. Finally, older people, individuals who are overweight, diabetics, and people with dark skin synthesize less vitamin D. Lack of magnesium even makes it difficult to activate the form of vitamin D that we get from sunlight or from supplements.

Vitamin D supplements may help relieve an irritable bowel

Even people that live closer to Equator, where the sun is positioned high in the sky and shines most of the time, may become vitamin D-deficient if they are veiled, if they stay out of the sun, or if they use sunscreen with a high protective factor. In a recent Saudi Arabic study of 112 adults with irritable bowel and vitamin D deficiency, the participants were divided into two groups that were similar with regard to age and gender One group got 50 micrograms of vitamin D daily for six months, while the other got matching placebo during the same period.
It turned out that the patients who took the vitamin D supplement improved significantly compared with those on placebo. The supplement was well tolerated, and the researchers view vitamin D supplementation as an effective strategy for treating irritable bowel in patients that lack vitamin D. The study is published in The Saudi Journal of Gastroenterology.
According to the science journal Medicine, researchers plan to conduct a larger study based on a number of databases from different countries. Here, they plan to analyze several studies and evaluate the effect of vitamin D on patients with irritable bowel. To begin with, the researchers plan to look at the nutrient’s impact on stomach pain. Afterwards, they plan to look at stool pattern and quality of life. The results of the study are expected to be revealed in a future review article.

Irritable bowel is often stress-related and increases the need for nutrients

When we are stressed, the body channels blood from the gut to the brain and muscles to help us function optimally both physically and mentally. In return, the digestive system is underprioritized. Therefore, it does not help much to take supplements of fiber and lactic acid bacteria, as the nervous system is overloaded and needs treatment. A good way to support the nervous system is to take supplements of magnesium, B vitamins and vitamin C

Other useful advice for an irritable bowel

  • Eat a diet that is coarse, green and full of fiber
  • Low-FODMAP diets help some people (The term FODMAP is an acronym, derived from "Fermentable Oligo-, Di-, Mono-saccharides And Polyols). This involves reducing the intake of indigestible sugars and avoiding wheat, barley and rye, asparagus, cabbage, onion, leeks, legumes, apples, pears, and soft cheese.
  • Avoid highly refined foods such as white bread and sugar
  • Limit the size of your food portions
  • Avoid oxidized and burnt fats
  • Drink plenty of water and make sure to maintain a proper liquid balance
  • Exercise at least 30 minutes daily
  • Get plenty of sleep
  • Don’t rush it when you have a bowel movement in the morning
  • Go to the toilet as soon as you feel the urge
  • Consider a daily fiber supplement


Shi, Sheng-Mei MB et al. Effectiveness of vitamin D for irritable bowel syndrome. Medicine 2019

Doaa El Amrousy et al. Vitamin D supplementation in adolescents with irritable bowel syndrome: Is it useful. A randomized controlled trial. Saudi J Gastroenterol 2018

Simon Tazzyman et al. Vitamin D associates with improves quality of life in participants with irritable bowel syndrome: outcomes from a pilot trial. BMJ Open Gastroenterology 2015

Role of magnesium in Vitamin D Activation and Function. The Journal of the American Osteopathic Association. March 2018


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