Written by Slawomir Gromadzki, MPH


Due to the fact that England is one of the world’s most cloudy countries almost all adults living here are deficient in Vitamin D. Unfortunately, this problem affects also infants. Researchers make it very clear that in most cases, mother’s milk and formulas for babies do not provide recommended doses of Vitamin D. That’s why medical authorities recommend that mothers should give their babies a minimum of 400 IU of Vitamin D3 (in the form of drops) per day, starting in the first few days of life.

Babies need vitamin D for healthy growth and development as well as strong immune system. It helps them build strong, healthy bones and teeth. A lack of vitamin D can cause bones to become soft and weak leading to rickets in infants. Due to chronic deficiency of Vitamin D and low calcium levels babies can also develop seizures or even heart failure.

In the last few years, numerous studies have linked a deficiency of Vitamin D to numerous health problems associated with weakness of the immune system such as recurrent infections and autoimmune diseases.

Excellent immune system booster & regulator

Vitamin D3 plays a critical role in enhancing the immune system making it more effective in fighting bacterial and viral infections including Covid-19, flu or colds in infants.

Vitamin D also plays important role in preventing immune system from attacking own body and causing autoimmune diseases. According to the 2001 Finnish study, “Vitamin D supplementation for infants could help to reverse the increasing trend in the incidence of type 1 diabetes”.

Vital for strong bones, teeth & muscle development

Babies need vitamin D to help the body absorb calcium and phosphorus as these minerals are important for proper bone, teeth and muscles development. Infants who are chronically deficient in Vitamin D can develop weak bones, skeletal deformities and increased risk of fractures. Vitamin D deficiency has been also linked to early childhood tooth decay.

Supports normal brain function and healthy nervous system

Resent discoveries suggest Vitamin D may be as important for proper brain and nervous system development and function in infants as the neuroactive steroids – glucocorticoids, estrogen and testosterone.

Some of the Vitamin D receptors in the brain are found in the areas that are related to the development of low mood. For this reason, Vitamin D deficiency has been linked to mental health problems.


Babies (including newborn babies) need at least 400 IU of supplemental vitaminD3 every day in the form of a liquid on a nipple or added to a milk formula. Please, keep in mind that even if a mother takes supplemental vitamin D3, it cannot be efficiently transferred with her milk into babies’ organism. For this reason, babies must be given vitamin D3 in the form of a liquid.

Another very important thing to remember is that vitamin D supplements require magnesium (for its conversion in kidneys and proper absorption) as well as vitamin K2 to prevent vitamin D from leading to calcification. Therefore, for proper conversion and absorption of vitamin D, breastfeeding mothers must take about 200mg of supplemental magnesium (such as free from additives magnesium citrate powder or magnesium bisglycinate) twice daily and Vitamin K2 MK7 (100-200mcg daily) as without these two nutrients supplemental vitamin D will be useless (inactive) and overtime it may lead to a side effect in the form magnesium deficiency (with all its consequences) and calcification of soft tissue. If a baby is on a milk formula, make sure it contains a sufficient amount of magnesium (if not, add about 50mg of magnesium bisglycinate liquid or powder). Babies need 50-100mg of magnesium every day.


“The safe upper limit for supplemental vitamin D is 1,000–1,500 IU/day for infants and 4,000 IU/day for pregnant and lactating and women”. (>>). It means that even if a baby receives more than 400 IU of vitamin D3 every day, it will not be harmful. In fact, in some studies babies received a daily dose 0f 1000-2000 IU of vitamin D3 without any side effects.


Recommended Daily Intake: Breastfed babies and infants, 10 drops daily (0.5ml) given orally. 10 drops contain 400IU of vitaminD3.


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