Vitamin D Deficiency in Infants – Reasons, Signs & Remedies

Vitamin D Deficiency in Babies

Medically Reviewed By
Dr. Arti Sharma (Paediatrician)
View more Paediatrician Our Panel of Experts

Vitamins are micronutrients that are essential for the healthy functioning of human bodies. Vitamin D is a unique vitamin that is available through an environmental source – sunlight. When the good UV rays (UVB) from the sunlight fall on our skin, Vitamin D is produced in the skin and is then absorbed in the blood.

Video: Vitamin D Deficiency in Babies

What Is Vitamin D Deficiency?

As the name goes, a lower level of Vitamin D in the body is termed as Vitamin D deficiency. Then what is Vitamin D insufficiency? Well, it’s the blood level of Vitamin D measured in the form of serum 25-hydroxy-Vitamin D (calcidiol) that determines it. A level below 25 nmol/L is a deficiency and between 25-50 nmol/L is insufficiency. When the level is above 50 nmol/L, there is evidence of benefit to the bones, muscles, the immune system, and the insulin secretion.

Why Is Vitamin D Important for Babies?

Nutrition is very complex and needs a perfect balance for the optimal benefit. The body can compensate for slight deficiency and at times, even to an excess deficiency but only to an extent, especially in a growing baby. It is Vitamin D which will make your child able to play around without difficulty and with good strength and energy. The bones need calcium and phosphorous for strength, wear & tear and weight-bearing. It is Vitamin D that makes sure that the bones aren’t deprived of any. Vitamin D also makes the intestinal lining absorb calcium from food, process it in the blood and deposit in the bones. Calcium is important for the functioning of every cell in the body. It is responsible for opening the gates of the cells to receive molecules to produce energy and for initiating each muscle fibre contraction eventually giving power to your muscles. This helps us understand why Vitamin D is important for babies and how its deficiency will affect them.

Type of Vitamin D You Should Give Your Child

Vitamin D supplements are found both as Vitamin D2 (ergocalciferol) and D3 (cholecalciferol). Although traditionally both D2 and D3 are considered to be equally potent, studies have revealed that D3 can be at least 3 times more potent compared to D2. Hence supplements that contain D3 are the preferred form for supplementation. In fact, in most countries now, this is the only commercially available type of Vitamin D.


Children with one or more risk factors for low Vitamin D, with or without the signs and symptoms, can benefit from the following investigations:

  1. Serum Vitamin D (calcidiol) levels
  2. Serum calcium, phosphorus and alkaline phosphatase.
  3. In those with symptoms/signs of deficiency investigations regarding the following need to be done:
  4. Parathyroid hormone (PTH)
  5. Urine creatinine
  6. Perform X-ray wrist, ankles and clinical photography

Vitamin D Dosage for Babies

The dosage schedule may be a low dose every day or high dose once a week or once a month for 1-6 months duration depending on the age of the child and whether the deficiency is mild, moderate or severe.

The standard dose is:

– Up to 1 year age: 1000-5000 IU per day

– More than 1 year old: up to 10,000 IU per day

– The weekly dose is usually 50,000 IU and has better compliance.

– 6 monthly or annual 6L IU injections (usually not recommended for children)

The blood level is rechecked after 1 month in infants and after 3 months in the older children in moderate to severe deficiency. In mild cases, recheck is not necessary.

After the levels are in the normal range, a maintenance dose of 400 IU per day is continued for a considerable period.

With ongoing risk factor, once a year or so, keep checking the levels and continue the daily or annual maintenance dosing.

The forms of Vitamin D supplements available in the Indian market are:

  • Vitamin D3 – as oral drops 400 IU/mL
  • Syrup 400 IU/5mL
  • Oral tablets, 1000 and 2000 IU with blister packing
  • Powder form in a sachet with each sachet containing 60000 IU of Vitamin D3.

Supplementation of elemental calcium:

Higher doses of calcium are important in the early course of therapy. Later the doses are cut down to half for the next 1 to 2 weeks. When the Vitamin D supplement dose has been reduced to 400 IU /day with normal blood levels, calcium supplementation is not required in most cases.

Causes of Vitamin D Deficiency

The most important cause of Vitamin D deficiency is limited or no exposure to sunlight. However, even with ample sunlight, like in India, it is still prevalent. Why is that so? To understand other causes, you need to understand how Vitamin D is produced, processed, stored and utilized by the body.

On exposure to UV-B in the sun rays, the epidermis (upper layer of the skin) converts a cholesterol called provitamin D3 into Vitamin D3 that enters the blood and is transported to the liver. Vitamin D coming from the food/supplements is also absorbed from the stomach and sent to the liver. The liver converts it into the more potent form of calcidiol which is still inactive. It is then transported to the kidney where it is converted to calcitriol – the active ready to act form. So now it is easier to understand that in case of good sunlight, the Vitamin D deficiency can still result in the following circumstances.

Reduced Vitamin D synthesis: Dark skin, Ultraviolet rays blocking agents like sunscreen lotions and clothing, latitude (e.g. in the UK the UVB in sunlight is not very effective), season, air pollution, children and adolescents with disabilities which limit the time they spend outside, the lifestyle habits of indoor games, air-conditioned housing, tinted glasses, photosensitive skin conditions, etc. result in reduced Vitamin D synthesis.

Reduced intake of Vitamin D in food: Strict vegan diet, dietary habits (low intake of foods containing Vitamin D), exclusion diets (e.g. milk allergy), etc.

Reduced maternal Vitamin D stores: Exclusive breastfeeding where the mother doesn’t have enough Vitamin D stores in her body to nourish the child.

Malabsorption: pancreatic insufficiency, Celiac disease, biliary obstruction which prevents proper absorption of the vitamin.

Defective synthesis: Chronic liver disease, kidney disease, etc. can obstruct proper functioning of the organs that are required for production and absorption of Vitamin D.

Increased degradation: Drugs such as anticonvulsants, anti-tuberculosis, steroids which can be an obstacle to the process of Vitamin D production or absorption

Signs and Symptoms of Vitamin D Deficiency in Babies

The signs and symptoms vary as per the age:

Infant Vitamin D deficiency:

1. Stunted growth and developmental delay: Despite no known health problems and despite good food intake, your child is not up to mark as per the height, weight, and other developmental milestones.

2. Irritability, lethargy: The baby is no more playful and attentive and is abnormally cranky and irritated most of the time without any known cause.

3. Seizures: One of the causes of seizures in an infant is Vitamin D deficiency and needs immediate medical attention.

4. Tetany: It is a state of hypocalcaemia i.e. low level of calcium in the blood. There are many causes of calcium deficiency like poor dietary intake, poor absorption, Vitamin D deficiency, abnormal parathyroid hormone secretion, abnormal kidney function, etc. The baby will have apneic spells (episodes of sudden breathlessness), wheezing, muscular weakness, and seizures.

5. Cardiomyopathy: As low Vitamin D affects all the muscles in the body, the muscles in the heart also become weak.

Vitamin D Deficiency in Children:

1. Aches and pains: They will complain of frequent pain in hands, legs, body not proportionate to the physical development milestones of the child.

2. Muscle weakness: Muscle weakness causing delayed walking, difficulty climbing stairs, etc.

3. Rickets: Knock knees, progressive bowing deformity of legs, waddling gait, abnormal knock knee deformity, swelling of wrists and costochondral junctions, prolonged bone pain (>3 months duration).

4. Poor growth: Poor growth despite a healthy diet, active lifestyle and no previous medical conditions can indicate a Vitamin D deficiency.

5. Easy fractures: Easy fractures from minor injuries can be indicative of calcium not being absorbed properly due to Vitamin D deficiency.

6. Frequent lower respiratory tract infections: Vitamin D plays a significant role in pulmonary functions and immunity development and frequent infections can be due to a deficiency of the same.

7. Delayed anterior fontanelle closure: The anterior fontanelle is a diamond-shaped opening on the front part of the head. It is a gap between the skull sutures which gradually closes by 18-24 months of age. Due to impaired bone function, this will be delayed.

8. Delayed dentition: Like a delay in all other milestones, there is a delay in dentition or tooth eruption as there is not enough calcium.

9. Abnormal bone profile or x-rays: X-ray of the wrist or the ankle or the chest will show swelling of the bones and the abnormal bending of the long bones due to low calcium levels.

10. Abnormal blood tests: Low plasma calcium or phosphate level, raised alkaline phosphatase

Treatment for Vitamin D Deficiency

Vitamin D stores in the body require a long time to deplete after the synthesis has reduced or stopped. So naturally, it will also take a long time to replenish. The aim of the treatment is to restore and maintain Vitamin D levels ≥ 50 nmol/L.

Various options are:

1. Supplements:

– Daily low-dose supplements

– High-dose intermittent therapy

2. Ensure adequate calcium intake.

For the children who dislike cow milk, yoghurt, cheese and fortified soy dairy are useful sources of calcium. Consider medicinal supplements if intake is poor.

3. Sun exposure

Children and young people with dark skin can tolerate intermittent exposure in the sun and do not need sunscreen. Hats and sunglasses can be used. Encourage outdoor activity.

Supplements: Who should take supplements?

1. Exclusively breastfed infants without any signs or symptoms.

2. Breastfed infants of mothers with Vitamin D deficiency having at least one or more risk factors.

3. Infants on full formula feed who are not receiving adequate Vitamin D from the formula. Checking Vitamin D levels or adding daily supplements in babies with risk factors is recommended.

How to give baby Vitamin D:

Vitamin D is available as tablet form and as a liquid form and is also available in combination with calcium. You can powder the tablet or open the capsule and mix with the food.

How to Prevent Vitamin D Deficiency in Children?

In general, along with the supplementation if necessary, adequate sunlight exposure and consuming foods rich in Vitamin D will help augment the prevention strategy instead of mere supplements. Approximately, 5-15 minutes of sunlight exposure to the hands for light-skinned children and 30-45 minutes for dark-skinned children is helpful and natural. Preferably early morning sunlight is better as it has lower levels of harmful UV rays.

  • Maternal Vitamin D:

– The most important aspect that determines the Vitamin D level in infants is the Vitamin D status of the mother. Pregnant women should check their Vitamin D levels during the first trimester of their pregnancy. If found to be low it is best to be treated with 3000-5000 IU until it is more than >20 ng/dL followed by 400 IU /daily.

– High dose of Vitamin D (400-6400 IU) administered every day to breastfeeding mothers protects the child from Vitamin D deficiency without causing Vitamin D toxicity to the mother of the child.

  • Preterm infants:

-A supplement of 400-800 IU/day starting at birth is important as there is a possibility of inadequate transfer of Vitamin D from the mother.

-Other problems associated with prematurity like poor feeding ability, immature gastrointestinal tract affecting the absorption and in some cases liver and kidney impairment and should be tackled accordingly.

  • Infants:

Ensure adequate Vitamin D in child diet. It is usually appropriate to start supplements without investigations for exclusively breastfed infants with at least one other risk factor without symptoms/signs. Most of the infant formulas have 400 IU/L. Hence, the formula-fed infants may also need supplementation unless they are given at least 1 L of formula per day.

  • Toddlers and adolescents:

Children who are at risk like dark-skinned children, children veiled from sunlight, have reduced or no exposure to sunlight or the ones that have an underlying medical condition for which they are on the above-mentioned drugs should be given 400 IU every day to prevent deficiency of Vitamin D.

Best Foods of Vitamin D for Babies

Though plants synthesize Vitamin D, that form of vitamin cannot be utilized by the human body. So the only foods sourcing Vitamin D are animal foods. Unfortunately, the only animal food that babies consume, that is milk (cow’s milk: 3–40 IU/L) is not really a rich source of Vitamin D. Here comes the role of fortification (adding extra nutrients to food).

Fortified foods Rich in Vitamin D

  • Fortified milk 400/L
  • Fortified infant formulas 400/L
  • Fortified orange juice 400/L
  • Fortified soy milk 400/L
  • Fortified rice milk 400/L
  • Fortified Margarine 60/tablespoon
  • Fortified Cereal 40 IU /serving
  • Tofu fortified (⅕ block) 120
  • Fortified oil

The best foods that older babies can consume are:

1. Oily fish such as salmon, mackerel, and sardines, cod liver oil, liver. Frying fish reduces active Vitamin D content by ∼50%, whereas baking does not affect the Vitamin D content of fish

2. Organ meats

3. Egg yolks (20–25 IU per yolk)

Are There Any Risks If I Give My Baby Too Much Vitamin D?

Yes. Too much Vitamin D can cause toxicity. Vitamins B and C which are water-soluble (excess gets excreted out of the body). Vitamins A, D, E and K being fat-soluble get stored in the body and cause problems if in excess.

Conclusion: Even in a tropical country like India there is growing evidence of Vitamin D deficiency in adults and paediatric population. With adequate consultation from the paediatrician, it is best to combat the issue with proper care right in the beginning by adding vitamin D in the child’s diet to avoid any ramifications later on.

Previous article «
Next article »