Vegan diets usually include some excellent sources of vitamin A–but it many take a little bit of planning to make sure you get enough on a regular basis.
While vegans don’t have any preformed vitamin A in their diet (it’s only in animal foods), it can be synthesized from compounds called carotenoids found in plant foods. The best known and most biologically active carotenoid is beta-carotene.
As recently as ten years ago, nutrition researchers believed than 6 micrograms of beta-carotene produced one microgram of active vitamin A. But newer research on absorption of carotenoids shows that it actually takes twice that much—12 micrograms of beta-carotene—to produce a microgram of vitamin A. That means that vegan intake of carotenoids is actually only about half the amount reported in earlier studies.
Vitamin A content of foods is measured as retinol activity equivalents (RAE) which is the amount of potential vitamin A activity in a food. Recommended intakes for vitamin A are 700 RAE for women and 900 RAE for men.
Meeting vitamin A requirements may actually be a little bit of a challenge unless you consume at least one very good source of this vitamin every day. The best foods for vitamin A are leafy green veggies, sweet potatoes and, of course, carrots.
In addition to making sure you’re getting enough of these vitamin A-rich foods in your diet, it’s also important to include small amounts of fat with meals and to cook some of your vegetables to enhance absorption of carotenoids. This is one more reason why raw foods diets and low fat diets are not the best choices for vegans.
Here are the best sources of vitamin A with the RAEs shown for each.
Apricots, 3 raw (102)
Hubbard squash, ½ cup mashed (236)
Cantaloupe, 1 cup chunks (270)
Collards, ½ cup cooked (386)
Kale, ½ cup cooked (442)
Spinach, ½ cup cooked (472)
Butternut squash, ½ cup cooked (572)
Carrots, ½ cup cooked (665)
Sweet potatoes, ½ cup cooked mashed (1291)
Is it possible to take too much vitamin A? I have heard that it can make one susceptible to colon cancer. The multivitamin I take (this one: http://www.vitacost.com/Liquid-Health-Complete-Multiple) contains 5000 IU of vitamin A. This seemed a bit high to me. I know that it’s not possible to overdose on RAEs, because your body only converts what it needs (or so I heard) but what about this supplement?
Thank you for your wonderful site. I am going back and reading a lot of your posts because they are so informative.
The upper limit where I live (Denmark) is 10,000 IU, so you you should be good. But yeah I agree, it seems quite high.
I’ve always tried to include a beta-carotene rich source in my diet every day (sweet potato, butternut squash, dark leafy greens) and after looking at the Vit A IUs of these vegies, assumed I was definitely getting enough. However, I am seeing a Traditional Chinese Medicine practitioner at the moment for treatment of a chronic condition and she told me that the conversion rate of beta carotene to Vitamin A can be very low in some people. I thought this was rubbish and dismissed it (as she is very pro-animal foods) but still did a bit of homework and found this article:
I am now worried that I am one of the so-called “low responders”. Is there any way of determining this? Do you think if my Vitamin A was low in a blood test (is there a Vitamin A blood test?) it would indicate that my food intake isn’t enough?
I love your website, by the way. I find it so helpful! Thank you for sharing all of your knowledge with us.
You can find out if you have some of the known genetic mutations that result in a reduced conversion rate of beta-carotene (and other carotenoids) to Vitamin A by doing a dna test. I found out I am one of those people when I had my raw dna data file from 23andme analyzed by a 3rd party program (Promethease) for a more detailed health analysis than 23andme provides.
Promethease covers all kinds of health issues and when I clicked on the section to see my “bad” genes, buried in the list it showed that I was mutated on 2 relevant SNPs for carotenoid to Vitamin A conversion. I discovered that I am heterozygote CT for the SNP rs7501331 and heterozygote AT for the SNP rs12934922. (Basically, one of the 2 alleles is mutated [the T’s] on each of those SNPs and as you’ll see below, this means that my ability to convert beta-carotene to Vitamin A is reduced by 69%, at least according to one study.)
Here’s my Promethease result for one of those SNPs below in case you’re curious what kind of info it generates… the other one just reads the same basically, so no point copying it as well:
Reduced conversion of beta-carotene to retinol
Reduced BCMO1 activity results in 32% lower ability to convert Beta-carotene to retinyl esters and higher serum beta-carotene levels. See also rs12934922.
rs12934922 (R267S) and rs7501331 (A379V) double mutant have a reduced catalytic activity of beta-carotene by 57%. Female volunteers carrying the T variant of rs7501331 (379V) had a 32% lower ability to convert Beta-carotene, and those carrying at least one T in both SNPs show a 69% lower ability to convert Beta-carotene into retinyl esters. rs7501331: the frequency of the wild-type C allele and variant T allele was 76 and 24%, respectively; 56% of the population was CC wild-type genotype, and 39% was heterozygote CT with the TT variant present in 5% of the population. rs12934922: the frequency of the wild-type A allele and variant T allele was 58 and 42%, respectively; 38% of the population was AA wild-type genotype, 40% was heterozygote AT, and 22% was TT homozygote
So that’s just one way of finding out. I should mention that there are other known SNPs that may affect carotenoid to vitamin A conversion. I’m focusing on the ones that affect me and really aren’t so uncommon surprisingly (at least in people of European descent).
Here’s a 2012 study related to these mutations: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3497927/
I’m also curious about testing for Vitamin A, as I am sure my beta-carotene serum level is high, but I wonder if it is high enough to keep my Vitamin A in a healthy range or not, given the huge reduction in my conversion rate.
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