As you can see, we get asked very in-depth questions about vitamin A a *lot*.

“Am I taking too much vitamin A?”

“How many mcg RAE of vitamin A are in FullWell Prenatal?”

“Why do you have more vitamin A than other brands?”

“Can I keep eating liver while I take my prenatal vitamins?”

“I’m taking a medication my dermatologist gave me for my skin. Is it safe to take extra vitamin A?”

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 widespread in children and women of childbearing age and is the leading cause of preventable blindness worldwide.

However, unfortunately for those who were fooled into cleaning our plates (special shoutout to those who thought we might get to give up our eyeglasses!), eating orange fruits and vegetables won't help you magically achieve perfect vision.

In fact, for those who went for it, the over-consumption of carrots may have led to a temporary condition called carotenemia, a rare occurrence of an orange coloring of the feet, hands, and 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 - turn (a little) orange! (1). 

Rare conditions aside, vitamin A deficiency is a growing concern and its role in our overall health (particularly in terms of both fertility and pregnancy) cannot be understated.

Vitamin A comes in multiple forms, each playing a different role in human health.

The various forms of vitamin A are essential for the health of mom AND baby’s (2):

• Eyes
• Skin
• Reproductive system
• Immune system
• Thyroid glands

So what is vitamin A?

Vitamin A is a generic term for fat-soluble compounds found as preformed vitamin A (retinoids) in animal products and as provitamin A carotenoids in fruits and vegetables. 

The body's three most active forms of vitamin A are retinol, retinal, and retinoic acid. Dietary supplements usually contain variations on these active forms, such as retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (provitamin A, a less active form), or a combination of both preformed and provitamin A.

While critically low vitamin A levels are not typical 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 essential for

• Healthy vision and eye development in developing fetuses and adults alike, including normal color vision, vision in dim lighting, and 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
• Proper sperm maturation (due to high antioxidant capacity)

Are we as a population getting enough vitamin A? 

Nope. The robust U.S. survey on nutritional status known as NHANES found that from 2017 to 2018, vitamin A intake for women ages 20 and older was 616 mcg daily, less than the RDA of 770 mcg for pregnant women (3). 

For men, the same survey found that intake for men over 20 was around 682 mcg daily, which is less than the RDA of 900 mcg (3). So we know that deficiency is common, but we also know its reasons are multi-layered. Let me explain.

Cultural shifts and lifestyle factors

Vitamin A intake has decreased worldwide - even in developed countries like the US - for many reasons. Some are related to cultural shifts, like more people eating less organ meat, restrictive diets (e.g., low-fat, low-calorie), the increasing popularity of vegan and vegetarian diets, and more people ditching dairy (4). Other factors are tied to the economy, like the rising cost of food (especially when it comes to fresh produce) and the lower cost and convenience of processed and packaged food (4).

Genes

Genetics influence how well you convert beta-carotene into vitamin A in your liver. For example, many people have a genetic variation in the Beta-Carotene Oxygenase 1 (BCO1) gene, which breaks down beta-carotene into the active form of vitamin A (5). The science is conflicting on how much this genetic variant impacts Vitamin A levels but for the roughly 40% of the population estimated to have this variant, it is even more important that they consume foods that contain retinoids as beta carotene may not be enough. 

Reduced absorption

In addition to genetic factors, many people live with and experience conditions that reduce the absorption or usability of vitamin A, including digestive disorders and hormonal issues.

• Crohn’s
• Ulcerative Colitis
• Irritable Bowel Syndrome (IBS)
• Thyroid Issues
• Gallbladder Issues
• Fat Malabsorption

As a result, they may have higher needs than what the Recommended Daily Values assert.

Pregnancy

Many women live with vitamin A deficiency, but pregnant women are at an even greater risk. Pregnant women are more likely than healthy non-pregnant women to be deficient in vitamin A even with supplementation, which is cause for alarm. This deficiency directly affects baby's vitamin stores at birth (6, 7). 

Through each trimester, demand increases to support baby's rapid growth and help prepare for breastfeeding (8). In particular, deficiency during the third trimester can be associated with an increased risk of preterm delivery and anemia in mom (9). 

And, in case you’re not convinced of the importance of vitamin A during pregnancy, one study found that vitamin A deficiency in pregnant women with preeclampsia increased the risk of adverse pregnancy outcomes (10).

Similarly, research has shown that pregnant women with gestational diabetes are more likely to suffer from a vitamin A deficiency and should be closely monitored during pregnancy (11, 12).

What about men? 

When optimizing men’s health preconception, consuming adequate vitamin A is crucial. In animal studies, sperm production halted in vitamin A deficiency (13). More research is needed, but we know that the antioxidant capacity of beta-carotene plays a crucial role in capturing and neutralizing reactive oxygen species (ROS), which can damage sperm DNA. Retinyl palmitate, conversely, is essential for the production and maturation of sperm which we know is necessary for a healthy pregnancy.

Provitamin A does not equal preformed vitamin (animal-based foods matter)!

The best natural foods for consuming the most active forms of vitamin A (aka preformed vitamin A) are:

• Beef liver
• Cod liver oil
• Butter
• Eggs (yolk and all, please!)
• Whole 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.

The bioavailability (or the immediate ability to be absorbed and used in the body) varies greatly from food to food. Different combinations, the amount of fat consumed, and each individual’s enzyme conversion activity can play into this variance.

What about plants?

While carotenoids like beta-carotene are not the most active form of vitamin A, they partially convert to active vitamin A in the body. They are also utilized for non-provitamin A tasks and can be potent antioxidants.

These plant-based foods are rich in carotenoids, which convert in varying amounts to the active forms of vitamin A (14):

How much vitamin A should I be getting?

As we mentioned, vitamin A needs vary from person to person based on genetics, gut health, health conditions, and stage of life. The average person can generalize quantities based on sex and age. For example, needs for women generally look something like this (4):

• 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)

These are (in my professional opinion) highly conservative guidelines from The American Pregnancy Association and the National Institutes of Health Office of Dietary Supplements, and we’ll go into more detail about these shortly. But first, let’s clarify some confusing metric terminology and conversions to break these numbers down.

Each of the following is equivalent to 1 microgram (μg) of active vitamin A (retinol), with daily intake goals listed above (2):

• 1 μg supplemental vitamin A (retinyl acetate or retinyl palmitate)
• 2 μg of supplemental β-carotene 
• 3.33 IU of retinol

When reading labels, units of measurement can be confusing. But understanding how much active vitamin A you’re consuming is essential. Converting micrograms into a standardized unit that measures the activity level is helpful. Retinol Activity Equivalents 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 retinoids is more reliable for absorption, their RAE ratio is 1:1. What goes in can usually all be used by a healthy gut. 

Alternatively, beta-carotene in food has an RAE ratio of 24:1. In supplements, it holds an RAE ratio of 2:1 because every microgram of beta-carotene in supplemental form equals 1 RAE. This means 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 this means 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. You don’t need to worry about your genes or how efficiently you convert to the active, usable form because it’s already primed for use! Easy peasy. 

Half of a baked sweet potato contains no ready-to-use retinol but has 11,091 beta-carotene (961 μg RAE). In a perfect world, your body can readily convert and use this form of vitamin A. However, when you account for genetics, gut health/digestibility, and vitamin cofactors needed for conversion, real life is not likely to reflect that perfect scenario.

How much vitamin A is in your Women’s Prenatal? 

We aim for 1500mcg RAE total per serving. Half of that is from beta carotene, and half is from retinyl palmitate. So because the ratio is 2:1, it winds up being 750 mcg RAE and 750 mcg retinyl palmitate. 

Why is your Women’s Prenatal above the upper limit? 

So let’s come back to my thought on the RDA. Based on decades of research and experience, I’m among many health practitioners that have concluded that the RDA for vitamin A is set at a highly conservative level, as is the UL (upper limit). The UL is based on a no-observed-adverse-effect level (NOAEL). Governing bodies are simply looking at the highest intake at which no adverse effects have been reported. If data are inadequate to determine a NOAEL value, the lowest-observed-adverse-effect level (LOAEL) is utilized. The recommended ULs you see are usually several-fold lower than the no-observed level or lowest-observed. These levels are divided by an uncertainty factor. The severity of that uncertainty depends on both adverse effects and uncertainty about the data itself. Sure, a safety margin is provided, but the problem with erring on the side of caution means folks are less likely to focus on vitamin A, leading to suboptimal levels or deficiency

The upper level should be much higher. 

The upper limit of vitamin A is set to 10,000 IU (equivalent to 3,000 mcg) a day, but in the past 30+ years, the number of cases where excessive intake has been associated with congenital disabilities has been low. Ethical and safety issues hinder clinical trials on pregnant women (obviously). Still, animal studies have shown that between 25,000 to 37,000 IU/day of vitamin A was safe during human pregnancy when considering comparable weight adjustments from monkey to human (15). One study, in particular, found that high vitamin A intake later in pregnancy (around 50,000 IU per day) did not increase the risk of congenital disabilities (16). 

Supplementing has other benefits for pregnant people, too.

Yes, deficiency is common, so repletion is vital. Enter supplements! The bonus is that supplementing with vitamin A during pregnancy and postpartum has other benefits. It can prevent the depletion of vitamin A stores that occurs toward the end of pregnancy and possibly improve mom’s immune system and ability to see at night. Additional research is needed to determine whether vitamin A can positively impact birth outcomes and cognitive/motor development, but some recent studies are promising (14, 17).

Vitamin A also plays a significant role in the function of other vitamins and minerals in your body, like iron. Studies on pregnant and lactating women found that vitamin A supplementation reduced the risk of anemia by helping to increase hemoglobin levels (a protein in red blood cells that carries oxygen) and serum ferritin levels (your storage form of iron) (18). 

Fascinating, right? Ah, the magic of being a Registered Dietitian: we get to examine and educate on how nutrients work together in your body!

If I’m looking to get more vitamin A in my diet, what foods should I incorporate?

Circling back to our quest to increase our intake through real food, the NOAEL value for preformed vitamin A translates to about 3 ounces of beef liver or 4 ounces of chicken liver every day (not a typo). 

For many, a side of liver at every meal isn't exactly ideal (yet another reason why supplementing can save the day). If you want more info on how organ meats can fit into your routine with your FullWell Prenatal, check out this comprehensive blog post written by my expert colleague and FullWell supporter, Lily Nichols. A fellow RD, Lily goes into exceptional, science-backed detail about liver’s benefits and provides excellent strategies for incorporating organ meats into your diet, especially if you've historically shied away from them! Check it out (4):

Considering the vitamin A dose in your prenatal, can I take it with what I already eat daily?

We get this question a lot. Let me illustrate it with an example day of meals that factors in the amount of vitamin A we get from food and supplements combined.

As you can see, it's tough to overdo it on vitamin A unless you consistently eat large amounts of liver daily and supplement.

Let's put this information to use!

Nothing can replace a healthy diet. Still, our best efforts may not reach our goals when we individually account for stress and environmental factors.

Supplementing with active vitamin A in safe amounts can be a great way to fill nutrient gaps, improve health, and ensure usability in the body.

If you and your partner are preparing for pregnancy or are already pregnant or breastfeeding and trying to deliver proper nutrition to baby, assess your diet and lifestyle. Then, speak to a professional specializing in nutrition, supplements, and women’s health. If you have trouble finding one, you can look to our amazing Clinical Directory (coming soon!) or contact us with your questions.