Cobalamin deficiency may lead to folate deficiency, which, in turn, increases homocysteine levels and may result in the development of cardiovascular disease or birth defects.<ref>{{cite journal |author=Varela-Moreiras G, Murphy MM, Scott JM |title=Cobalamin, folic acid, and homocysteine |journal=Nutr. Rev. |volume=67 Suppl 1 |issue= |pages=S69–72 |date=May 2009 |pmid=19453682 |doi=10.1111/j.1753-4887.2009.00163.x}}</ref>

Some studies show iron-folic acid supplementation in children under 5 may result in increased mortality due to [[malaria]]; this has prompted the World Health Organization to alter their iron-folic acid supplementation policies for children in malaria-prone areas, such as India.<ref>{{cite journal |author=Pasricha S, Shet A, Sachdev HP, Shet AS |title=Risks of routine iron and folic acid supplementation for young children |journal=Indian Pediatr |volume=46 |issue=10 |pages=857–66 |date=October 2009 |pmid=19887691 |url=http://www.indianpediatrics.net/oct2009/857.pdf}}</ref>