Vitamin D Deficiency in Babies
The short answer
Vitamin D is essential for calcium absorption and healthy bone development. Breast milk alone does not provide adequate vitamin D, so the AAP recommends all breastfed and partially breastfed infants receive 400 IU of vitamin D daily beginning within the first few days of life. Formula-fed babies who drink less than 32 ounces per day also need supplementation. Severe deficiency can lead to rickets, a condition causing soft and weak bones.
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By Age
What to expect by age
0-3 months
Newborns have limited vitamin D stores, especially if the mother was deficient during pregnancy. The AAP recommends starting 400 IU of vitamin D drops daily within the first few days of life for all breastfed or partially breastfed infants. Formula-fed infants who consistently consume at least 32 ounces of vitamin D-fortified formula daily do not need additional supplementation. Liquid vitamin D drops designed for infants are widely available.
3-6 months
Continue daily vitamin D supplementation of 400 IU for breastfed babies. Signs of deficiency at this age are rare but can include poor growth, delayed motor milestones, or unusually soft skull bones (craniotabes). Babies with darker skin tones or those who live in northern latitudes with limited sun exposure may be at higher risk. Never rely on sun exposure alone for infant vitamin D, as direct sunlight is not recommended for babies under 6 months.
6-12 months
As complementary foods are introduced, some vitamin D can come from dietary sources like fortified cereals, egg yolks, and fatty fish. However, it is difficult for infants to get enough vitamin D from food alone. Continue supplementation of 400 IU daily unless your pediatrician advises otherwise. Babies who spend most of their time indoors or wear sunscreen consistently remain at higher risk for deficiency.
12 months+
Toddlers need 600 IU of vitamin D daily. Vitamin D-fortified whole milk (introduced at 12 months) provides about 100 IU per 8-ounce serving, contributing to but rarely meeting the full daily requirement. Fortified foods, fatty fish, and egg yolks can supplement intake. Many pediatricians recommend continuing a vitamin D supplement, especially for picky eaters or children with limited outdoor time. Your pediatrician can check a 25-hydroxyvitamin D blood level if deficiency is suspected.
What Should You Do?
When to take action
- Your breastfed baby is receiving 400 IU of vitamin D supplementation daily and growing well
- Your formula-fed baby is drinking at least 32 ounces of vitamin D-fortified formula daily
- Your toddler drinks fortified milk and eats a varied diet that includes vitamin D-containing foods
- Your baby is meeting motor milestones and has no bone abnormalities
- Your baby seems to have unusually soft or flexible skull bones
- Your baby or toddler is falling behind on growth curves or motor milestones despite adequate calories
- Your child has very limited dietary intake of vitamin D-fortified foods and does not take a supplement
- Your baby or toddler has visible bowing of the legs, bone pain, or fractures from minimal trauma, which could indicate rickets
- Your baby has seizures or muscle spasms, which can occur with severe vitamin D and calcium deficiency
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
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Related Feeding Concerns
When to Introduce Allergens to Baby
Current guidelines recommend introducing common allergens (peanut, egg, cow's milk products, tree nuts, wheat, soy, fish, shellfish, sesame) starting around 4-6 months when your baby is developmentally ready for solids. The landmark LEAP study showed that early introduction of peanuts (by 4-6 months) reduced peanut allergy risk by 80% in high-risk infants. Do not delay allergens - the old advice to wait until 1-3 years has been reversed because early exposure actually prevents allergies.
I'm Worried My Baby Is Aspirating During Feeds
Aspiration means liquid or food enters the airway instead of the stomach. Occasional coughing during feeds is common and does not usually indicate aspiration. True aspiration is less common and may present as recurrent respiratory infections, a wet or gurgly voice after feeds, or chronic cough. If you are concerned, a swallow study can provide a definitive answer.
When Does My Baby Need Amino Acid Formula?
Amino acid-based formulas (also called elemental formulas) are prescribed for babies with severe cow's milk protein allergy, multiple food protein intolerances, or conditions like eosinophilic esophagitis who cannot tolerate standard or extensively hydrolyzed formulas. They are the most hypoallergenic formula available because the proteins are broken down into individual amino acids, making allergic reactions virtually impossible.
Could My Baby Be Aspirating During Feeding?
Aspiration occurs when food or liquid enters the airway instead of the esophagus. Signs include coughing or choking during every feed, a wet or gurgly voice after eating, recurrent chest infections, and breathing changes during meals. Silent aspiration can occur without obvious coughing. If you suspect aspiration, contact your pediatrician as a swallowing study can diagnose it.
Baby Biting Nipple While Nursing
Biting during breastfeeding is a common challenge, especially when babies start teething. It can be startling and painful, but it is almost always a phase that can be managed. Babies cannot actively nurse and bite at the same time because their tongue covers the lower teeth during proper sucking. Biting typically happens at the beginning or end of a feed when the latch is not active. With some gentle strategies, most babies learn quickly that biting ends the feeding session.
My Baby Keeps Clamping Down on the Spoon
Clamping down on the spoon is very common, especially during teething or when babies are learning new oral motor skills. It is often a sensory exploration behavior rather than a feeding problem. Using a soft silicone spoon and placing food on the front of the spoon can help.