For a long time it has been a common practice to mislabel foods and supplements about Vitamin A.  For instance, you may read that kale and spinach contain a certain amount of Vitamin A. In reality, they don’t have any Vitamin A. What they have is the orange pigment beta carotene which can be converted into Vitamin A.  You don’t see the orange color because of the chlorophyll, which is dominant.

This conversion involves cleavage. You might say that beta carotene is two Vitamin A molecules (retinal) bound together. It takes an enzyme to separate them, and there is a specific gene which controls the production of that enzyme.

It turns out that people are very different at how efficiently they do this. There is a very wide range between individuals, which may be built into them genetically.  

“Provitamin A carotenoids from various foods have been shown to have an almost 8-fold difference in β-carotene conversion factors (on a weight basis) that ranged from 3.6:1 to 28:1. Human subjects have different abilities to convert provitamin A carotenoids to vitamin A. These differences in conversion efficiency may be due to the genetic variability in β-carotene metabolism of individual human subjects. Therefore, provitamin A carotenoids might not be a good vitamin A source for those subjects of the poor converter phenotype.

Another factor is that the higher the intake of beta carotene (from food and supplements) the lower the conversion rate.

Another consideration is that age may be a factor, and we know that aging reduces biological conversions across the board. You get older, and you don’t convert T4 to T3 as well. You don’t convert the pre-forms of Coenzyme Q to Q10 as well. You don’t convert methionine to taurine as well. The list goes on and on. Another big one is that you don’t convert ALA to EPA and DHA as well- or at all.

So, just as I think that it is a good idea to get some pre-formed EPA and DHA and not rely entirely on ALA for the longer-chain polyunsaturated fatty acids, I think it’s a good idea to get some pre-formed Vitamin A.

However, there has been a growing trend among vitamin manufacturers to use beta carotene exclusively in their multi-nutrient supplements and call it Vitamin A. Keep in mind that if you are eating a plant-based diet or mostly plant-based diet, you don’t need to take beta carotene as a supplement at all. There is plenty of it in food. It is extremely abundant in orange foods, such as carrots and sweet potatoes, but it is also abundant in green foods, as I mentioned. So, if you are eating a lot of colorful plants, you are certainly getting enough beta carotene.

But, how well are you converting it to Vitamin A? That’s a tricky question. I found a report about vegan children in Finland having lower levels of retinol in their blood, but it was unclear whether it was clinically significant. And you can’t always go by the blood level of something. For instance, you can’t judge a person’s calcium status based on the blood level of calcium because that is homeostatically controlled.

I am not concerned about gross Vitamin A deficiency in older vegans. I’ve seen no reports of that. Rather, what I am concerned about is the possibility of having sub-optimal Vitamin A status, where there are subtle compromises, perhaps in immune function or skin health, due to less-than-optimal Vitamin A.  

This is an area that needs more study, but in the meantime, I’m glad that my Core Multi from Klaire Labs does contain a little pre-formed Vitamin A. It’s Vitamin A provision consists of 50% natural carotenes and 50% retinol palmitate.

And that is A-OK with me. I would rather err on the side of caution when it comes to Vitamin A and all things nutritional.