Vitamin D Supplementation For Babies

Vitamin D helps infants build strong bones by aiding in calcium absorption, a key component of skeletal health. Without sufficient vitamin D, babies are at risk of developing rickets, a condition where the bones become weak and deformed (1).

Vitamin D is also involved in the function of the immune system, helping to modulate inflammation and immune responses (2). For babies, this can be especially important as their immune systems are still developing and more susceptible to infections. Vitamin D helps the immune system recognize and fight off pathogens while also regulating the inflammatory response (2), which in turn may prevent the immune system from overreacting to potential threats. 

The American Academy of Pediatrics (AAP) recommends that children, from birth through adolescence, receive 400 IU of vitamin D daily (1). This recommendation is mirrored in other countries, including Canada, where the recommendation is for infants to receive 400 IU of vitamin D per day (3). The majority of European countries also recommend daily supplementation of 400 IU per day of Vitamin D for infants (4).

You may also be interested in this article: Better Together: Vitamins D3 & K2.

An alternative to directly supplementing your baby is maternal supplementation (or the supplementation of breastfeeding mothers). Research, including a large NIH-funded study published in the journal Pediatrics in 2015, found that when breastfeeding mothers took 6,400 IU of vitamin D daily, their breastfed infants achieved sufficient vitamin D levels without the need for additional drops (9). This method also ensures that the mother’s own vitamin D needs are met, which is essential for her overall health and mood (10).

In theory, yes — sunlight could provide enough vitamin D for your baby, but in practice, this is often difficult to achieve. Infants are not typically exposed to direct sunlight due to the risk of sunburn, and during the winter or in far northern regions, sun exposure may not be sufficient to produce adequate vitamin D. If you, as a breastfeeding mother, get plenty of daily unfiltered sunlight exposure, it could theoretically provide you with enough vitamin D to pass sufficient amounts onto your baby through your breast milk. However, outside of regularly testing your baby’s levels, the issue is that there is no way to truly be sure your baby is getting enough vitamin D. Even if you tested your own levels regularly, your vitamin D level serum — also known as the 25(OH)D value – does not necessarily correlate with the amount of active vitamin D that is passing through your breast milk (11).

Topical vitamin D creams or oils are sometimes cited as an alternative to oral supplementation. While there is some evidence that vitamin D can be absorbed through the skin (12,13), this method is not as widely supported by research, and the amount that is absorbed would be difficult to determine unless regular blood tests were being performed. Until more conclusive data is available, I tend to recommend sticking with proven methods in my practice, like oral drops or maternal supplementation.

Supplementation recommendations for infants and breastfeeding mothers:

• Breastfed infants: Start supplementing with 400 IU of vitamin D drops daily within the first few days of life.

• Formula-fed infants: Ensure they are consuming at least 32 ounces of formula daily to meet their vitamin D needs.

• Combination-fed infants: Consider supplementation based on how much formula the baby is drinking. In my practice, I like to calculate based on the idea that 32 ounces of formula provides 100% of the baby’s daily vitamin D needs (400 IU). So, if your baby drinks 16 ounces of formula per day, that provides 200 IU (50% of their daily requirement), meaning you would still need to supplement with an additional 200 IU of vitamin D to reach the recommended 400 IU daily.

• Breastfeeding Mothers: If exclusively breastfeeding, consider taking 6,400 IU of vitamin D daily to provide adequate levels through your breast milk instead of giving supplements to your baby.

Breastfeeding mothers should supplement either themselves with 6,400 IU of vitamin D daily or their babies with 400 IU of vitamin D daily - there is no need for both. Lower doses of vitamin D, such as the 2,000 IU found in my Prenatal & Postnatal Daily Nutrients, are perfectly fine for breastfeeding mothers to continue taking while also supplementing their infants to ensure adequate vitamin D intake.

1. Don’t Babies and Breast Milk Have Low Vitamin D for a Reason?

While the idea that our bodies are inherently wise and that babies and breast milk are naturally perfect without the need for supplementation is a comforting one, the reality is a bit more nuanced. Our bodies are indeed wise, but our modern lifestyle is lacking in key areas that impact vitamin D levels. Historically, humans spent far more time outdoors, where both mothers and babies could naturally synthesize adequate amounts of vitamin D from sunlight. Today, with more time spent indoors and reduced exposure to natural sunlight, babies are not receiving the same levels of vitamin D that our ancestors did. This lifestyle shift means that supplementation is often necessary to ensure babies get the vitamin D they need for proper bone development and immune function.

2. How Do I Get Vitamin D Drops Into My Breastfed Baby?

If your baby is not bottle fed, you may be wondering how to get vitamin D drops into your child. My favorite tip is to keep your vitamin D drops near your preferred nursing location, and simply put a drop on your nipple right before latching your baby. Alternatively, you could put a drop on your clean pinky finger or a pacifier and have your baby consume it that way. For older babies who are consuming solids, you could add a drop to a spoonful of applesauce.

Ensuring your baby gets enough vitamin D is important for their bone health and immune function. For breastfed infants, the AAP recommends supplementing with 400 IU of vitamin D daily, as breast milk alone doesn’t provide sufficient levels. Formula-fed babies who consume at least 32 ounces a day of fortified formula typically receive enough vitamin D, while combination-fed infants may need additional supplementation depending on their intake. Alternatively, breastfeeding mothers can take 6,400 IU of vitamin D daily to pass on adequate amounts through their breast milk. While sun exposure and topical creams may seem like potential sources, they are unreliable, especially in today’s modern lifestyle. As children grow, many still require vitamin D supplementation.