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September 2013

Vitamin D May Not Reduce Diarrhea in Infants

A new study suggests that vitamin D supplementation may not reduce the risk of diarrhea in infants.

Vitamin D is found in many dietary sources, such as fish, eggs, fortified milk, and cod liver oil. The sun also contributes significantly to the daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. The term "vitamin D" refers to several different forms of this vitamin. Two forms are important in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants. Vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet B (UVB) rays from sunlight. Foods may be fortified with vitamin D2 or D3.

In a recent study, researchers randomly assigned 3,046 1-11 month-old infants to receive 100,000 international units of vitamin D3 or placebo every three months for 18 months. Data on diarrhea frequency was collected through active observations from researchers throughout the follow-up period.

The researchers found that significant differences between the vitamin D3 and placebo groups were lacking for the number of diarrhea episodes, with 3.59 and 3.43 per child-year in the vitamin D3 and placebo groups, respectively. Furthermore, significant effects on the risk for recurrent diarrhea were also lacking.

The authors concluded that vitamin D3 supplementation in infants may not reduce the risk for diarrhea. Additional research in this area is warranted.

While vitamin D may lack beneficial effects for diarrhea, multiple studies in developing countries found that zinc supplementation in malnourished children with acute diarrhea may reduce the severity and duration of diarrhea, especially in children with low zinc levels. There is also good evidence that supports the use of daily Lactobacillus GG (a probiotic) to prevent diarrhea in children. Further research is needed to determine the dose and timing that will generate the best results.

For more information about integrative therapies for diarrhea, please visit Natural Standard's Comparative Effectiveness Database.

For more information about vitamin D, please visit Natural Standard's Foods, Herbs & Supplements Database.

To comment on this story, please visit Natural Standard's blog.


  1. Aluisio AR, Maroof Z, Chandramohan D, et al. Vitamin D3 Supplementation and Childhood Diarrhea: A Randomized Controlled Trial. Pediatrics. 2013 Sep 9.
  2. Natural Standard: The Authority on Integrative Medicine. 

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