Impact of Vitamin D in Children - FAQs

Q. We keep hearing about the important role that Vitamin D has to play in growing children. Being a mother of couple of toddlers myself, kindly elaborate and advise.

Vitamin-D is a fat-soluble vitamin which is synthesized under the skin on sunlight exposure. Some of the requirements are also through dietary intake. The active form of the vitamin is produced only after processing through the liver and then the kidney. It is important to understand that it is the active form that acts like a ‘catalyst’ for effective and satisfactory utilization of available calcium & phosphorous, and hence towards stronger & healthy bones in a child.

Lack of Vitamin-D in a growing child may cause a condition called “Rickets”. This essentially is lack of mineralization (by calcium & phosphorous) of the bony matrix resulting in weak bones prone to deformity on continual weight-bearing. Thus, one comes across conditions like progressive ‘bow-legs’ or ‘knock-knees’.

It is important to understand the difference between ‘Rickets’ & ‘Osteoporosis’. Although both result in weak bones making them prone to fractures, the former has “more bone matrix” (due to stimulation by the lack of mineralization), and the latter has “less bone matrix” per se. Hence Rickets and not Osteoporosis is the consequence of lack of vitamin-D in children.

Vitamin-D requirements are very high in the 1st 2 years of life and later during pubertal phase as there is a maximum bone formation requiring mineralization during this period. It is generally accepted that for proper bone health, a serum level of vitamin-D3 needs to be > 30ng/ml and any level below 20 ng/ml will lead to symptoms.

Apart from low dietary intake,children suffering from intestinal, hepatic, renal, dermatological disorders and inflammatory rheumatological conditions alsomay have Vit D deficiency. Vit D deficiency is a common problem inIndia due to several factors:

  1. Changing food fads and food habits contribute to low dietary calcium and Vit D intake.
  2. With modernization, the number of hours spent indoor have increased thereby preventing adequate sun exposure. This s particularly true in the urban Indian children.
  3. Increased pollution can hamper the ultraviolet rays to adequately synthesize Vit D in the skin.
  4. Cultural and traditional habits prevalent in certain religions like “Burqa” and the “pardah” system in Muslims have been well known.
  5. Repeated and unplanned, unspaced pregnancies in dietarydeficient patients can aggrevate Vit D deficiency in themother and the foetus.
  6. Genetic factors like enzyme deficiencies needed to convert the inactive form of vitamin-D to active form.

Rickets is diagnosed by eliciting a proper history, thorough clinical examination, appropriate blood work-up and x-rays. The treatment is aimed at effecting adequate mineralization at the long bone ends gradually, by administering high doses of the vitamin through oral route usually. In children who may have intestinal malabsorbtion (lactose intolerance for eg), liver or kidney disease or if there is a high risk of oral non-compliance due to any other cause, intra-muscular route may be employed. A regular monitoring of the child in terms of blood work-up is essential to ensure that there is no unnecessary over-treatment. Latter can cause cumulative accumulation of this fat soluble vitamin which can be potentially harmful.

Prevention is better than cure. Hence focusing on an appropriate nutritious diet (fortified vitamin-D food-stuff too) for their child, and prescription of oral supplements of vitamin-D and calcium in appropriate doses in infants and children go a long way to ensure healthy bones in children. If the deformities especially of the lower limbs persist in an older child, there could be a need for appropriate surgeries.

Dr Ramani Narasimhan
Senior Consultant Pediatric Orthopaedic Surgeon
Indraprastha Apollo Hospitals, New Delhi
E-mail: ramanirn@hotmail.com