Vitamin A for conception, pregnancy, breastfeeding (and life!)
We all heard it as kids.
"Carrots improve your eyesight. Eat up!"
Our parents weren't lying: carrots are high in vitamin A, which is critical for many of our bodies' systems proper function, including eye health. Vitamin A deficiency is incredibly common in children and women of childbearing age, and is the leading cause of preventable blindness in the world.
However, unfortunately for those of us who were easily fooled into cleaning our plates (special shoutout to those of us who thought we might just get to give up our eyeglasses!), eating orange fruits and vegetables won't help you magically achieve perfect vision.
In fact, for those who really went for it, the over-consumption of carrots may have lead to a temporary condition called carotenemia, a rare occurrence of orange coloring of the feet, hands, and areas of thicker skin on the body. That's right: some who ingest too many carotenoid-containing foods - and have a genetic variation that alters how they convert beta-carotene to vitamin A - really turn (a little) orange!
Rare conditions aside, vitamin A deficiency is a growing concern for almost half of the US population. In a survey of over 44,000 people, 43% were not consuming adequate amounts of vitamin A, completely missing the daily recommended intake values.
Vitamin A comes in multiple forms, each playing a different role in human health.
The various forms of vitamin A are important for the health of our:
- Reproductive system
- Immune system
- Thyroid gland
- Fetal health (in pregnant women)
So what is Vitamin A?
Vitamin A is a generic term that refers to fat-soluble compounds found as preformed vitamin A in animal products and as provitamin A carotenoids in fruits and vegetables.
The three most active forms of vitamin A in the body are retinol, retinal, and retinoic acid (beta-carotene is the less active form). Dietary supplements usually contain variations on these active forms, such as retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (provitamin A), or a combination of both preformed and provitamin A.
While critically low levels of vitamin A are not common in developed countries, subclinically low levels are surprisingly common. Defined as serum retinol, or concentrations lower than 0.70 μmol/L or 20 μg/dL, subclinical vitamin A levels are often dismissed by traditionally trained doctors and healthcare providers because they are higher than the conventional lab ranges for deficiency.
Optimal vitamin A levels are important for:
- Healthy vision and eye development in developing fetuses and adults, including normal color vision, normal vision in dim lighting, and normal dark adaptation
- Regulating the growth and differentiation of virtually every cell in the body, from embryos to adults (meaning, deciding which cells become which organs, and putting together body systems as a fetus develops)
- Healthy immune response to infectious diseases from fetal development through adulthood
- Normal red blood cell production, including integration of iron and oxygen-carrying capacity within those cells
- Normal iron levels in the blood
- Healthy thyroid function and thyroid stimulating hormone (TSH) levels
- Robust skin cell turnover and proper healing
How can we consume enough of the right kinds of Vitamin A for optimal health?
The truth is, the most active forms of vitamin A are found in animal-based foods that come to your table from healthy animals that are humanely raised and nourished in the way that is ideal for them. Understanding the quality of your food is extremely important.
Provitamin A does not equal preformed vitamin (why animal-based foods matter)
The best real foods for consuming the most active forms of vitamin A are:
- Beef liver
- Cod liver oil
- Pastured butter
- Pastured eggs (yolk, please!)
- Whole, organic milk
According to the US Institute for Medicine (IOM), dietary retinol (one of the preformed “active” versions of vitamin A) is 12-24 times more active than dietary beta-carotene and alpha-carotene. What's more, the bioavailability (or the immediate ability to be absorbed and put to use in the body) varies greatly from food to food, with different combinations, with the amount of fat consumed, and with each individual’s enzyme conversion activity.
While carotenoids like beta-carotene are not the most active form of vitamin A, they do convert to active vitamin A in the body in part, and are also utilized for non-provitamin A tasks, like potent antioxidants.
These plant-based foods are rich in carotenoids, which convert in varying amounts to the active forms of vitamin A8:
- Sweet potatoes
- Mustard, collard, turnip, and beet greens
- Swiss chard
- Winter squash
How much vitamin A is the right amount?
Vitamin A needs vary from person to person based on their genetics, gut health, health conditions, and stage of life. For the average person, quantities can be generalized based on sex and age. For example, needs for women generally look something like this:
- Adults (19+ years): 700 μg/day (2,331 IU)
- Pregnant (19+ years): 770 μg/day (2,564 IU)
- Breastfeeding (19+ years): 1300 μg/day (4,330 IU)
- Upper limit: 3000 μg/day (10,000 IU)
To break these numbers down, let’s clarify some often confusing metric terminology and conversions.
Each of the following is equivalent to 1 microgram (μg) of active vitamin A (retinol), with daily intake goals listed above:
- 1 μg supplemental vitamin A (retinyl acetate, or retinyl palmitate)
- 2 μg of supplemental β-carotene
- 3.33 IU of retinol
Units of measurement can be confusing when reading labels, and understanding how much active vitamin A you’re actually consuming is important. Converting micrograms into a standardized unit that measures the activity level is helpful. Retinol activity equivalents are used to measure the vitamin A activity of the type of pre- or pro- vitamin A consumed, and 1 IU of retinol is equivalent to 0.3 μg retinol activity equivalents (RAE).
Remembering that animal or supplement-based vitamin A in the form of retinoids are more reliable for absorption, their RAE ratio is 1:1 for what goes in and what can be used when the gut is healthy.
Alternatively, beta-carotene in food has a RAE ratio of 24:1, and in supplements holds a RAE ratio of 12:1. This means that it takes 12-24 times as much vitamin A from beta-carotene to have the same activity in the body as active vitamin A consumed from animal-based foods.
What does this mean in practice?
If one large egg has 80 μg of preformed vitamin A (retinol), 270 IU (80 μg RAE) is readily used in the body. There is no need to worry about your genes and how well (or unwell) you convert to the active, usable form.
Alternatively, one-half of a baked sweet potato does not contain any ready-to-use retinol, but does have 11,091 beta-carotene (961 μg RAE). In the perfect genetic conversion world, all of this converted vitamin A is readily used in the body, but when you consider vitamin cofactors needed for conversion, genetics, and gut health/digestibility, it’s understood that real life versus theory doesn’t always play out as calculated.
Facts versus fears
Fear-based statements are meant to scare people into not “overdoing it” on vitamin A.
Look at the facts. When it comes to supplementing with vitamin A, one common fear is that it is unsafe, especially when trying to conceive, or while pregnant or breastfeeding.
The truth is, many women are living with vitamin A deficiency, including those who are trying to conceive, are pregnant, or are breastfeeding. This is not optimal for mom or baby’s health at any stage of pregnancy, because studies show that vitamin A plays an important role in fertilization and embryo development.
In addition to genetic factors affecting conversion of provitamin A to preformed vitamin A, many women live with and experience conditions that reduce absorption or usability of vitamin A, including digestive conditions (Crohn’s, ulcerative colitis, irritable bowel syndrome, diarrhea, etc), thyroid issues, gallbladder issues, fat malabsorption, and more. These women may have higher needs than what the Recommended Daily Values assert.
Where to go from here
Nothing can replace a healthy diet, but even our best efforts may not get us all the way to our goals when we individually factor in stress and environment.
Supplementing with active vitamin A in safe amounts can be a great way to fill nutrient gaps, improve health, and ensure adequate usability in the body.
If you’re looking to prepare for pregnancy or deliver proper nutrition to your baby while breastfeeding, assess your diet and lifestyle and speak to a professional who specializes in nutrition, supplements, and women’s health.
Full Circle Prenatal multivitamin is an expert-formulated and recommended supplement including 750 μg (2,500 IU) of vitamin A as active retinyl palmitate. No need to worry about genetic factors, food combining, or other nuances in supplementing your diet to achieve adequate vitamin A stores when you put your trust in us.
- Al Nasser Y, et al. Carotenemia. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan. 2020 Aug 23.
- Fulgoni VL, et al. Foods, fortificants and supplements: Where do Americans get their nutrients? J. Nutr. 2011, 141, 1847–1854.
- "Vitamin A." National Institutes of Health, Office of Dietary Supplements. 14 Feb. 2020. Web. 10 Nov. 2020. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/.
- Higdon, Jane. Vitamin A. Edited by Libo Tan, 1 Jan. 2020, lpi.oregonstate.edu/mic/vitamins/vitamin-A.
- Underwood BA, Arthur P. The contribution of vitamin A to public health. Faseb J. 1996;10(9):1040-1048.
- Sherwin JC, et al. Epidemiology of vitamin A deficiency and xerophthalmia in at-risk populations. Trans R Soc Trop Med Hyg. 2012;106(4):205-214.
- Weber D, Grune T. The contribution of β-carotene to vitamin A supply of humans. Mol Nutr Food Res. 2012 Feb;56(2):251-8. doi: 10.1002/mnfr.201100230. Epub 2011 Sep 29. PMID: 21957049.
- Vitamin A. www.whfoods.com/genpage.php?tname=nutrient&dbid=106. Accessed 23 Nov 2020.
- Skowrońska P, et al. Follicular fat-soluble vitamins as markers of oocyte competency. Syst Biol Reprod Med. 2020 Apr;66(2):112-121. doi: 10.1080/19396368.2020.1718244. Epub 2020 Feb 14.