Vitamin D and Breastfeeding

Vitamin D is essential for healthy bones and growth of the skeleton. Deficiency can lead to developmental delay, seizures, rickets and osteomalacia (softening of the bones), it is also linked with autoimmune disorders and some cancers. Unlike other vitamins which we can get from a healthy diet, few foods contain vitamin D (fatty fish, egg yolk, plus some artificially fortified margarines, breakfast cereals or yoghurts). Our chief source of vitamin D comes from our bodies making it when skin is exposed to sunlight.

Vitamin D and breastfeeding

If a woman has sufficient vitamin D levels before and during pregnancy, her baby will be born with good vitamin D stores. After birth, these stores combined with regular sunlight on the baby’s skin plus the small amount of vitamin D in breast milk would historically provide enough vitamin D for the breastfed baby. In recent years however, there has been a growing realisation that many women (and men) are deficient in vitamin D which can reduce both the baby’s vitamin D body stores and the levels of vitamin D available in breast milk. This article looks at why there is a problem with vitamin D, what this means for the breastfed baby and discusses the recommendations for vitamin D supplements for mother and baby.

Many people are deficient in vitamin D

It’s very difficult to get enough vitamin D from diet alone because the body relies on making its own vitamin D when the skin is exposed to sunlight. And because of changes in lifestyle in some countries—such as limiting our time outdoors in the sun, or using a lot of sun protection—many of us are at risk of vitamin D deficiency. Those of us who are particularly at risk of low vitamin D stores include those who:

  • Have little exposure to the sun or who cover their skin all the time with clothing or sun screen (babies often fall into this category)
  • Live further north from the equator where day light hours are reduced for example in the UK between October and April most people are deficient in vitamin D 1
  • Have dark skin (more sun is needed to make the same vitamin D compared with that of a fair skinned person).
  • Are obese with a BMI above 30.

Pregnant women

If a mother-to-be is at risk of having inadequate vitamin D stores, correcting her vitamin D levels during pregnancy will prevent her baby being born with low vitamin D stores. The Royal College of Obstetricians and Gynaecologists (RCOG) have a comprehensive document Vitamin D in Pregnancy, 2014 discussing recommendations for vitamin D supplementation in pregnancy for groups of women at high risk of vitamin D deficiency or eclampsia. Refer to the document for guidance and treatment plans.

Breastfeeding women

Breast milk naturally has relatively low levels of vitamin D because daylight on baby’s skin is ordinarily the main way for the baby to make the rest of this vitamin. If the mother is deficient in vitamin D herself, her breast milk will have even lower levels.

Raising vitamin D levels in breast milk

Some sources state that a deficiency in vitamin D in a baby can’t be reversed by breast milk alone even if the mother starts to replenish her own deficient vitamin D status 2. Other researchers suggest that when a breastfeeding mother has high enough doses of vitamin D, adequate levels of vitamin D in breast milk will be reached.

What sort of doses in the mother will raise vitamin D in breast milk?

The 2013 article Vitamin D During Pregnancy and Breastfeeding on the Vitamin D Council website and an article by Robert Heaney, MD 3 discuss research studies that indicate specific high levels—5,000-6,000 IU/day—of vitamin D supplementation by the mother that can significantly increase vitamin D in her breast milk. However Balasubramanian 4 and others 56 caution that the safety of such high-dose vitamin D supplementation in lactating women has not been proven.

Child looking up at pregnant mother in sunshine

Recommendations for vitamin D and breastfeeding

Recommendations for vitamin D supplementation vary between organisations even as much as a ten fold difference. Balasubramanian (2011) says:

there is no consensus on the dosage of vitamin D that needs to be supplemented to pregnant women nor is there robust scientific evidence to support implementation of a vitamin D supplementation programme for pregnant and lactating mothers.

Vitamin drops for baby

Most health recommendations currently centre on giving oral vitamin D drops to breastfed babies to ensure they are receiving adequate vitamin D. However, others such as Robert Heaney MD 7 favour giving sufficient supplements to the breastfeeding mother so that mother and baby both have enough vitamin D in preference to giving vitamin drops to the baby.

Guidance in the United Kingdom

The Scientific Advisory Committee on Nutrition (SACN) produced a new report in July 2016 8 upon which Public Health England (PHE) base their recommendations. They recommend 340 to 400 IU per day for all breastfed babies from birth to one year of age unless they have more than 500ml of fortified formula per day and 400 IU per day for a breastfeeding mother:

SACN is now recommending:

  • a reference nutrient intake (RNI) of 10 micrograms [400 IU] of vitamin D per day, throughout the year, for everyone in the general population aged 4 years and older
  • an RNI of 10 micrograms of vitamin D per day for pregnant and lactating women and population groups at increased risk of vitamin D deficiency
  • a ‘safe intake’ of 8.5 to 10 micrograms [340-400 IU] per day for all infants from birth to 1 year of age
  • a ‘safe intake’ of 10 micrograms per day for children aged 1 to 4 years.

Children aged 1 to 4 years should have a daily 10 microgram [400 IU] vitamin D supplement. PHE recommends that babies are exclusively breastfed until around 6 months of age. As a precaution, all babies under 1 year should have a daily 8.5 to 10 microgram vitamin D supplement to ensure they get enough. Children who have more than 500ml of infant formula a day do not need any additional vitamin D as formula is already fortified.
Dr Louis Levy, Head of Nutrition Science at PHE, said:
“A healthy, balanced diet and short bursts of sunshine will mean most people get all the vitamin D they need in spring and summer. However, everyone will need to consider taking a supplement in the autumn and winter if you don’t eat enough foods that naturally contain vitamin D or are fortified with it. And those who don’t get out in the sun or always cover their skin when they do, should take a vitamin D supplement throughout the year”

The Breastfeeding Network has a handout Vitamin D and Breastfeeding, BFN, 2014 by breastfeeding author and pharmacist Wendy Jones. Their handout, based on 2014 Public Health England recommendations 9 advises mothers in the UK that:

  • All pregnant and breastfeeding women should take a supplement of 10 μg (400 IU) vitamin D per day.
  • If a mother HASN’T taken vitamin D supplements during pregnancy her baby should receive his own oral vitamin D drops containing 7-8.5μg (280-340IU) per day from one month of age until five years.
  • If a mother HAS taken vitamin D supplements during pregnancy this will give her baby a few months worth of vitamin D stores. From six months all babies should receive oral vitamin D drops containing 7-8.5μg per day until five years old.

Guidance in USA

The American Academy of Pediatrics (AAP) recommends that all breastfed babies receive 400 IU of oral vitamin D drops, starting during the first few days of life and continuing until they are drinking vitamin D-fortified formula or milk (500 mL or about 17 oz) (healthy 2015)

The Health and Medicine Division (HMD) 10—previously known as The Institute of Medicine (IOM)—has a table of recommendations on their website. Their recommended dietary allowance (RDA) of vitamin D for pregnant and lactating mothers is 600 IU/day with an upper level intake of 4000 IU.

The Vitamin D Council discuss their recommendations for pregnant and breastfeeding mothers and include those of The Food and Nutrition Board and The Endocrine Society in their 2013 article Vitamin D During Pregnancy and Breastfeeding. The article discusses how to take sunshine exposure into account when deciding on supplementation for the nursing mother. The Vitamin D Council recommends that if a mother is taking 6,000 IU of vitamin D per day her breast milk will be rich in vitamin D and she won’t need to supplement her baby. If she is not taking a supplement, or not getting good sun exposure or taking less than 5000 IU per day she should give her baby a vitamin D supplement.

…while 5,000–6,000 IU may initially seem high, it is important to remember how much the sun produces for us. A single 15 minute whole body exposure to sun at mid-day in summer produces well over 10,000 IU.

Summary—more research needed

Many people are deficient in vitamin D due to a general lack of sunlight in modern lifestyles. If a breastfeeding mother’s vitamin D levels are low, the levels in her breast milk will also be low. Many health organisations recommend giving vitamin D supplements to mothers and babies as a safety measure—however there is some disagreement over the recommended amount. Some studies111213 have indicated that pregnant and breastfeeding mothers need much higher doses of vitamin D than those in many of the official recommendations discussed above. On Medsmilk, medications author and pharmacist Thomas Hale, MD explains that supplementing 400 IU/day to the mother may be worthless as such a dose won’t increase milk levels of vitamin D, he adds that 4000 IU/day may be required. However, others believe more research is needed to evaluate the long-term effects of giving such high doses to the lactating mother. In the mean time, oral vitamin D drops are often recommended to be given direct to baby.

The need for vitamin D supplementation varies across the globe according to climate and lifestyle. The recommendations above may change as more research is revealed. Discuss the latest recommendations advised in your part of the world with your own health professionals to find the right advice for you and your baby.