By Dr Ananya Mandal, MD
Vitamin D is an essential nutrient. It can be obtained both from diet and directly from sunlight. Vitamin D deficiency is important especially in pregnant and breastfeeding mothers mainly because it is important for the growth and development of infants and growing children.
Functions of vitamin D
Vitamin D helps in improving the absorption of calcium and phosphorous from food that occurs in the small intestine or gut. The blood levels of calcium that are important for bone growth and repair are regulated and balanced by Vitamin D levels.
Thus, strength of the bones depends on presence of vitamin D in diet. The skin can manufacture vitamin D when exposed to sunlight. This provides a source of this important vitamin.
Risk of deficiency of vitamin D
Some populations and age groups are particularly vulnerable to deficiency of Vitamin D. These include:-
Pregnant and breastfeeding women, especially in teenage or adolescent pregnancies or pregnancies at younger age groups.
Children under 5 years of age are at risk of vitamin D deficiency in diet. This could be due to faulty and fussy feeding habits
Populations over 65 years of age are also at risk of Vitamin D deficiency.
Persons who are not exposed to adequate sunlight and those confined indoors for long durations are also at risk.
Some ethnic minorities are also at risk of Vitamin D deficiency. These include those with darker skin, because their bodies are not able to produce as much vitamin D. Children of African-Caribbean and South Asian origin are also at a raised risk of Vitamin D deficiency.
Deficiency of Vitamin D
Deficiency of vitamin D leads to muscle weakness and bone deformities. In adults with this deficiency there is an increased risk of bone and joint pain, weakness of muscles and joints and repeated and delayed-healing fractures.
Among children there is a risk of bone deformities called rickets. Children and infants are more susceptible to deficiency of Vitamin D due to their increased demand for calcium and minerals allowing for rapid growth of bones. Rickets can be a crippling condition and usually affects children below 5 years of age.
How to detect low vitamin D levels
Vitamin D can be checked for levels in blood. Among pregnant women sufficient levels include those over 75 nanomoles/Litre (nmol/L). Those women who are deficient of Vitamin D during pregnancy need sun exposure and are given supplements of Vitamin D (oral 1000 international units vitamin D3).
Vitamin D in breastfeeding mothers
Mothers with a Vitamin D deficiency during pregnancy are likely to continue to be deficient of this vitamin while breastfeeding. This would be a deficiency of Vitamin D in an exclusively breastfed baby.
Due to an increase in the rate of vitamin D deficiency in recent years The American Academy of Pediatrics recommends that all breastfeeding newborns must receive a supplemental daily dose of vitamin D 400 IU/d in order to prevent rickets. The mother is advised supplements if deficient.
If the blood levels of vitamin D are found normal in a breastfeeding mother she is advised diet rich in vitamin D. This includes fatty fish (salmon, herring and mackerel), liver, eggs, margarine and enriched dairy products along with regular periods of skin exposure to the sun.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)