Does vitamin D Cause Constipation?
The influence of vitamin D on constipation is not clear. Some researchers indicate that it can cause constipation, while others counter this claim.
For instance, a study on patients with intestinal motility disorders showed that they have lower levels of vitamin D. This disorder often leads to constipation. Therefore, the results of this study indicate that vitamin D deficiency can be a risk factor for constipation in this disorder [1].
Also, in another study, more than half of patients with chronic constipation had a vitamin D deficiency [2]. This further underlines the possible influence of vitamin D on constipation.
However, these studies do not include healthy people and how they are influenced by vitamin D deficiency or supplementation. On the other hand, in cases of vitamin D overdose, some patients can have constipation [3, 4, 5].
What are the benefits of vitamin D supplementation?
Supplementation of vitamin D has many health benefits.
Among other vitamin D, it promotes bone health and regulates calcium-phosphate metabolism [6]. Vitamin D also potentially protects from muscle weakness and fractures [7].
Additionally, vitamin D supplementation lowers the risk of many diseases, such as:
- diabetes mellitus type 1 and 2,
- autoimmune diseases,
- cardiovascular diseases,
- neurological problems,
- several types of cancer [8].
Another benefit of vitamin D supplementation is the reduced risk of bacterial and viral infections such as COVID-19 [9].
Generally, vitamin D supplementation can lower the all-cause mortality rate [8].
These findings are reported from observational studies. When the clinical trials were performed to confirm the benefits, only some of the results were confirmed by the scientists [10].
Can you overdose vitamin D?
A vitamin D overdose, while rare, is possible. The condition of vitamin D overdose is referred to as vitamin D hypervitaminosis or toxicity [11].
Vitamin D toxicity can occur in people with a vitamin D blood concentration from 150 to 1220 ng/mL [12].
The primary way of getting an overdose of vitamin D is through supplementation. Natural vitamin D intake comes from sunlight and food and is regulated. It is difficult to overdose on vitamin D in the natural way [11].
What are the signs and symptoms of vitamin D overdose?
Vitamin D overdose, hypervitaminosis D, or toxicity can manifest in several ways. The symptoms of vitamin D overdose include:
- vomiting [12],
- pain [12],
- loss of appetite [12],
- nausea [11],
- weakness [11],
- dehydration [12],
- increased urination and thirst [4, 5],
- constipation [3, 4, 5].
A common secondary symptom of vitamin D overdose is hypercalcemia. It occurs when the calcium level in the blood is higher than usual. Hypercalcemia can, among others, lead to arrhythmias and kidney failure [11].
Dehydration in cases of vitamin D overdose is a secondary symptom. It is caused by the vomiting [12, 13].
Loss of appetite over time can lead to weight loss [3, 4, 5].
The pain from a vitamin D overdose can be generalized in the whole body or can be local [12].
In severe cases, vitamin D overdose can lead to neurological symptoms such as confusion and abnormal vision [5].