What is Vitamin A?
Vitamin A is a name for a group of fat-soluble vitamins, including retinol and retinyl esters. Humans get Vitamin A from diet in two forms:
- Preformed Vitamin A: Retinol and retinyl esters are called preformed Vitamin A. They are found in animal-derived foods, such as dairy products, eggs, fish and organ meats. You can think of preformed Vitamin A as the already active form of Vitamin A that’s ready to do the work in the body.
- Provitamin A: A few carotenoids (pigments found in plant-based foods) are considered provitamin A. The most common provitamin A is beta-carotene, but there are a few others. These carotenoids need to be converted into Vitamin A in the intestines before they can function as Vitamin A in the body. Because carotenoids from plant foods can be difficult for the body to absorb, provitamin A is a less efficient source of Vitamin A than preformed Vitamin A.
What does Vitamin A do in the body?
Vitamin A is involved in multiple functions in the body, including immune function; cellular communication and development; and reproduction in both sexes. It’s also a key component of the light-sensitive protein in the retina, making it essential for our vision health.
Animal and human studies have suggested that Vitamin A is involved in many aspects of male and female reproduction. In men, Vitamin A is necessary for the formation of male reproductive organs, as well as production of sperm. In women, Vitamin A has roles in thyroid function, which impacts reproductive health; fertilization, embryo implantation and embryo development; and placental development.
Vitamin A is important during pregnancy
During pregnancy, Vitamin A plays a key role in the normal development of the baby's organs, including the central nervous system, bones, heart, lungs and eyes. During pregnancy, maternal Vitamin A also helps the baby’s immune system develop, so that it can fight infections properly after birth.
During pregnancy, Vitamin A needs go up by 10-20% to support the growing baby. The needs peak in the third trimester, as the baby develops further.
Multiple studies have suggested that having sufficient Vitamin A intake before and during pregnancy may increase the likelihood that the baby is born at full-term with normal birth weight. However, evidence is mixed on whether taking a Vitamin A supplement during pregnancy supports normal birth weight and full-term birth; several systematic reviews have found no evidence to support this hypothesis.
Mom’s Vitamin A needs increase even more after birth
Interestingly, your need for Vitamin A goes up after birth, when you breastfeed. Several animal and human studies have indicated that sufficient levels of Vitamin A facilitate breast milk production. Maintaining a healthy level of Vitamin A before birth has also been suggested as key to ensure that the baby receives enough Vitamin A from mom’s milk for healthy postnatal development.
How common is low Vitamin A?
Vitamin A deficiency can lead to poor vision in low light and eventually blindness. It can also make you more susceptible to infections, as the immune system needs Vitamin A to function properly. Vitamin A deficiency is an ongoing public health concern in low and middle-income countries where the diet doesn’t provide enough preformed Vitamin A and provitamin A. However, it is rare in the United States and other developed countries.
Too much Vitamin A can lead to birth defects
In developed countries, excessive Vitamin A intake can be a concern. Studies have found that women who take high doses of Vitamin A, especially in the early months of pregnancy, are more likely to have babies with birth defects affecting the cardiovascular and central nervous systems. Excessive intake of Vitamin A has also been associated with higher risks of miscarriages.
But how much Vitamin A is too much? The consensus is that risks of birth defects start rising at about 25,000 IU/day (or 7,500 mcg/day) of Vitamin A, and the safe upper limit is set at 10,000 IU/day (or 3,000 mcg/day).
Interestingly, studies have shown that this negative effects of too much Vitamin A does not apply to beta-carotene. For this reason, some prenatal vitamins that aim to deliver a meaningful amount of Vitamin A that can support prenatal and postnatal health while avoiding the risk of birth defects from too much Vitamin A include both preformed Vitamin A (like retinyl palmitate) and beta-carotene.
How much Vitamin A should be in your prenatal vitamins?
During pregnancy, aim for at least 770 mcg of Vitamin A equivalent per day. This can come from both foods and supplements. When nursing, you need 1,300 mcg of Vitamin A per day. How much of this should come from your prenatal vitamins partly depends on your diet.
If your diet is already high in Vitamin A, you probably don’t need the full daily value of Vitamin A in your prenatal vitamins. For example, a 3-oz portion of beef liver delivers over 6,500 mcg of Vitamin A in the preformed Vitamin A form, while a sweet potato contains about 1,400 mcg of Vitamin A – about how much you need when breastfeeding – in provitamin A (beta carotene) form.
On the other hand, if you don’t eat foods high in Vitamin A consistently, your prenatal vitamins may need to do more of the lifting. This also applies to women who have cystic fibrosis and gastrointestinal problems like Crohn’s diseases or Celiac, all of which interfere with absorption.
In general, experts consider the optimal dose of Vitamin A in prenatal vitamins to be between 900 mcg to 1,500 mcg. Most women do not need a separate Vitamin A supplement on top of their regular prenatal vitamins, and taking a stand-alone Vitamin A supplement with prenatal vitamins can increase your risk of having too much Vitamin A.
Vitamin A: Goldilocks’ vitamin
Vitamin A is a key nutrient during pregnancy and while nursing that supports multiple aspects of the mom’s health and baby’s health and development. However, since too much Vitamin A can cause birth defects, getting the right amount of Vitamin A each day is important – not too little, not too much. Decide how much Vitamin A you want in your prenatal vitamins, based on what your diet is like, and whether you have any risk factors for low Vitamin A.
Please reach out if you need help selecting the right prenatal vitamins from the Vitamin A perspective. We are with you.
