The Role of Vitamin A:
Vitamin A is crucial as it regulates gene expression and is essential to the fetal growth and development of most cells and organs, including the heart, eyes, lungs, and ears, as well as the immune system.
Lack of vitamin A is associated with infertility and an increased risk for anemia, c-section, depression, gestational diabetes, hypertension, preeclampsia, and premature rupture of membranes during pregnancy. It also puts the baby at greater risk of miscarriage, congenital heart defects, orofacial defects, intrauterine growth restriction, impaired lung function, and neural tube defects. The effects of maternal vitamin A deficiency reach far beyond in utero, putting that child at increased risk for insulin resistance, glucose intolerance, diabetes, and schizophrenia spectrum disorders in adulthood.
Clearly vitamin A is vital, but too much can have just as dire consequences, leading to birth defects of the central nervous and cardiovascular systems. As devastating as this all sounds, with a basic understanding of vitamin A and the right prenatal supplementation, mom and baby can thrive.
Forms of Vitamin A:
Our bodies cannot synthesize vitamin A, so we must get it from our diet or supplements. Vitamin A naturally occurs in food as two main sources:
- Preformed vitamin A, also known as retinol and retinyl esters, is found in animal sources like liver, meat, fish, eggs, and full-fat dairy.
- Provitamin A, also known as carotenoids, are precursors to vitamin A and must be converted to retinol to be used in the body. Carotenoids are found in colorful plant foods, including kale, grapefruit, broccoli, carrots and tomatoes.
The concern regarding excess vitamin A and birth defects, is only relevant for retinol and retinyl esters. Whether from diet, supplementation, or medications (think Accutane), preformed vitamin A is rapidly absorbed and slowly cleared from the body. This can lead to toxicity over time. However, because we rely on our liver to convert carotenoids to retinol, there is no risk associated with any amount of dietary or supplemental provitamin A.
Supplementation:
Supplemental vitamin A is either preformed (usually retinyl acetate or retinyl palmitate) or provitamin A (usually beta-carotene or mixed carotenoids). You may be thinking, why not simply focus on a plant-based diet and supplement with carotenoids, avoiding the risks of preformed vitamin A?
First, although hundreds of carotenoids exist in plants, only about 10% can be converted into active retinol. Still, for those that can be converted, it’s an inefficient process. It takes 28 mcg of beta-carotene to equal 1 mcg of retinol in your body. With a conversion rate of 28:1, only about 3% of beta-carotene is utilized as vitamin A. It’s even more bleak for those with a genetic variation or SNP that impairs the ability of the enzyme responsible for changing provitamin A to retinol. Many with this SNP are unaware and are in danger of developing vitamin A deficiency without supplementation in the form of retinyl acetate or palmitate. Lastly, research in pregnant women has demonstrated that mothers can have adequate levels of beta-carotene but be deficient in vitamin A, indicating that supplementation of carotenoids alone is not enough.
As my clients at JH Wellness can attest, I’m a big proponent of the notion that you cannot supplement your way out of a bad diet. However, fertility through postpartum is a life stage where I am adamant about quality supplementation. With vitamin A, the research is clear, eating an abundance of plant foods for carotenoids does not cut it. Conversely, relying on rich dietary sources of preformed vitamin A like liver is risky because it’s difficult to quantify just how much you’re getting. Instead, I recommend eating a variety of plant and animal foods and supplementing with a prenatal multivitamin/mineral like WeNatal that provides a combination of retinyl palmitate and carotenoids. This way you can be confident you’re getting both forms of vitamin A and in the right amount needed for optimal health for mom and baby.
