Vitamin D and breastfeeding

La vitamine D est une hormone liposoluble connue pour son rôle dans le maintien de l'homéostasie du calcium (soit la régulation des valeurs normales du calcium dans l’organisme) et de l'intégrité osseuse (plus d’infos sur le calcium dans notre article “Calcium et allaitement”.

Ses fonctions sont largement reconnues, notamment son rôle dans le métabolisme du glucose, la formation de vaisseaux sanguins, l'inflammation et la fonction immunitaire, ainsi que dans la régulation de la transcription et de l'expression des gènes. Elle est également essentielle dans la minéralisation du tissu osseux du bébé.

La vitamine D est principalement obtenue par synthèse au niveau de la peau à la suite d'une exposition aux rayons ultraviolets B (exposition au soleil) et elle est également présente dans quelques aliments [1].

Un apport optimal en vitamine D est essentiel pour prévenir les carences de la mama et du bébé. Notre complément alimentaire allaitement Post essentials est une formule complète qui vous permet de faire le plein de minéraux et vitamines (dont la vitamine D) pendant l’allaitement.

Increased needs during breastfeeding

This increased need begins during pregnancy, when the foetus depends entirely on maternal intake. Moreover, the rapid development of the foetus during the latter part of pregnancy tends to deplete the mother's vitamin D reserves as calcium incorporation into the skeleton increases during the final trimester [2]. 
One study shows that infants born to mothers with vitamin D deficiency have a 3.8 times higher risk of developing vitamin D deficiency compared to those born to mothers with normal vitamin D levels [3].

During breastfeeding, you need to consume sufficient nutrients both for yourself and to provide them to your baby through your breast milk. For infants who are exclusively breastfed, breast milk will be their only source of this vitamin.

Some studies have found that exclusively breastfed infants had an increased risk of vitamin D deficiency compared to infants with sources of intake other than breast milk. The level of vitamin D in breast milk, like certain fat-soluble vitamins, is indeed dependent on maternal intake.

What happens if you are deficient in vitamin D?

Vitamin D is essential for preventing incomplete or defective mineralisation, which can lead to bone weakness.

Studies have shown a possible link between vitamin D deficiency and an increased risk of pre-eclampsia during pregnancy or preterm birth [4].

In children, vitamin D prevents rickets, a condition characterised by the inability of bone tissue to mineralise properly, leading to soft bones and skeletal deformities. Severe rickets can also lead to delayed growth and development, as well as dental abnormalities [5]. 

Insufficient vitamin D intakes

Most of us have insufficient vitamin D intakes: on average 136 IU/day, whereas the nutritional reference values for vitamin D in pregnant and breastfeeding women are 600 IU/day.
And even when the diet is perfectly varied and balanced, with an additional 500 kcal per day, studies show that the average intake is only 168 IU/day [6]. The reasons include limited sun exposure, urban lifestyles, and nutritionally depleted foods, as we will explore further on.

Eating foods rich in Vitamin D whilst breastfeeding?

Getting sensible sun exposure

The absorption of vitamin D through sun exposure depends on several factors, such as skin colour, age, season, clothing and, of course, time spent in the sun!

Some expert bodies and vitamin D researchers suggest, for example, that sun exposure of around 5 to 30 minutes, particularly between 10am and 4pm, every day or at least twice a week, on the face, arms, hands and legs, without sunscreen, is generally sufficient for adequate vitamin D synthesis.

The best way to get vitamin D is through sun exposure, and the National Health Service states: "Between late March/early April and the end of September, most people can get all the vitamin D they need from sunlight and a balanced diet."

Regarding your baby, direct sun exposure without protection is not recommended.

Possible causes of vitamin D deficiency

It is sometimes difficult to obtain a sufficient amount of vitamin D from natural (non-fortified) food sources alone.

During breastfeeding, as we have also seen above, even with an optimised diet and appropriate caloric supplementation, vitamin D intake did not meet recommended needs. So what can be done if we are not reaching the recommended levels? We can turn to supplementation. But in that case, which type of vitamin D should we take? Which supplement should we go for?

Vitamin D2 vs vitamin D3: which should you choose?

There are two forms of vitamin D: D3, or cholecalciferol, and D2, or ergocalciferol.

Vitamin D2 (or ergocalciferol) is produced by plants and fungi.
Vitamin D3 (or cholecalciferol) is found in many foods, particularly those of animal origin and in certain lichens, and is produced by the skin under the action of ultraviolet rays.

Vitamin D3 is formed when 7-dehydrocholesterol present in the skin is exposed to UVB rays from the sun, then converted into provitamin D3. In a heat-dependent process, provitamin D3 is immediately transformed into vitamin D. This form increases calcium absorption in the digestive tract, enhances its reabsorption in the kidneys, and supports bone mineralisation.

Vitamin D2, for its part, is produced exogenously through irradiation of ergosterol, and enters the body's circulation via food [10].

Several studies have reported that the bioefficacy of vitamin D3 is significantly greater than that of D2, and have indicated that supplementation should therefore be based on vitamin D3 [11].

The majority of vitamin D supplements are therefore made from vitamin D3, which can be extracted from lanolin (a fat derived from sheep's wool) or from boreal lichen, a plant-based source.

Vitamin D supplementation for the breastfeeding mother?

A study on pregnant women found a vitamin D deficiency in more than 75% of participants! [12]. Pregnant women and breastfeeding mothers are recommended to consume sufficient vitamin D or to take a supplement if necessary. Women who are unsure of their vitamin D status should carry out a simple blood test before choosing to take a supplement.

Although supplementing infants may be recommended, as we will see below, studies have shown that high-dose supplementation in the mother could be sufficient to meet both her needs and those of her baby. Indeed, one study found that at a dose of 6,400 IU/day, the breastfeeding mother had enough vitamin D for herself and her baby, with no adverse effects related to overdose — which could make it feasible to supplement only the mother [13]. Maintaining the mother's optimal vitamin D status is the key determinant in preventing deficiency in the child.

Do be mindful of overdosing, however. There are currently gaps in the assessment of the toxicity risk associated with excessive vitamin D supplementation. It is therefore advisable not to exceed 4,000 IU/day, as excess has been associated with hypercalcaemia. That said, nothing stops us from supplementing for our own benefit first!

It is always advisable to consult a healthcare professional to identify your own needs and determine any additional quantities required.

Vitamin D supplementation for the breastfed infant

Your child's vitamin D needs are 400 IU/day (according to the latest recommendations currently being updated), and the French Society of Paediatrics recommends supplementing all infants with vitamin D to ensure adequate status [14].

According to La Leche League, the risk of vitamin deficiency is higher in children with darker skin, those with limited direct sun exposure, those exclusively breastfed for an extended period by a mother with low calcium and vitamin D intake during pregnancy [15].

More specifically, infants depend on the vitamin D content of hindmilk (defined as the last milk of a feed), as studies show that this end-of-feed milk is richer in vitamin D than foremilk (the first milk of a feed) [16].
Did you know? Breast milk is more likely to contain higher levels of vitamin D in summer than in winter!

Moreover, breast milk is a poor source of vitamin D. Exclusively breastfed infants receive less than 20% of the daily dose recommended by the Institute of Medicine for infants during the first year of life [17].  
This supports the recommendation that vitamin D supplementation should be given to all children, at least until the age of 18 months. 

A ce jour, les éventuels problèmes liés à la supplémentation ne sont pas relatifs à la vitamine D contenue dans le produit mais plutôt aux excipients supplémentaires qui sont présents (additifs, ...). Alors quelle vitamine D choisir ?

Le mieux est d'opter pour une vitamine D3 d'origine végétale. Le complément ne doit pas contenir de substances controversées. 

Nos compléments Sunny sont adaptés pour vous et votre bébé : 

Sunny Mummy, la vitamine D allaitement, apporte de la vitamine D3 végétale et de la vitamine K2 pour une absorption optimale.

Sunny baby, la vitamine D bébé, apporte 400 UI de vitamine D3 végétale, soit la dose recommandée pour tous les nourrissons. 

Et pour un apport complet en nutriment, le complément alimentaire post partum Post essentials contient 17 vitamines et minéraux, dont la vitamine D3 et K2. Et bien sûr 100% compatible allaitement.

While these recommendations are being harmonised, it is important to be vigilant about dosage and to ensure you do not give too much vitamin D to your child or to yourself.

Be careful with self-supplementation! Before deciding to take any supplement, remember to seek advice from your doctor or your child's paediatrician, particularly to check the correct dosage.