The problem with Vitamin A is that people think it’s good for you, but almost nobody questions if it’s bad for you. That’s why people are trying to feed malnourished children with Vitamin A nanoparticles in staple foods, golden rice is engineered to have more carotenes in it, all the nutrition meals/plans such as Ensure, Soylent, Huel will include it, someone is trying to make Vitamin A enhanced ultrasonic rice, Vitamin A is added to sugar in some countries, Vitamin A is added to all low-fat milk in the USA. You get my point; I’ll stop listing things.
The difference between this and adding something like the B vitamins are that the B vitamins are water-soluble and excreted. The difference between this and chlorinating the water is that we know chlorine isn’t good for people, but we accept the necessary trade-offs for potable water. Vitamin A lies in a blind spot where although the risk of hypervitamintosis A is acknowledged, people still try to include some amount of it in foods, not aware of its accumulation in the liver over time.
Regarding the modern health crisis due to our food and environment poisoning us (increase in neoplasms, obesity, decreased testosterone, fertility, allergies, etc.), there are many culprits. The common ones: microplastics, PFAS, car emissions, tire nanoparticles, non-stick pans, pesticides. The societally-accepted-as-necessary-ones that strike a third rail for many if you disagree with them: water chlorination, fluoridation, vaccines, electromagnetic fields, x-rays. The food: Added B vitamins, antinutrients, enriched iron, processed wheat, Vitamin A, cyanocobalamin, vegetable oils.
As an individual, I don’t need to convince anyone that these common ones are bad. We need to share solutions for how to mitigate them. The societal ones are a hot political topic at this moment. There are already enough arguments why vegetable oils are bad; I think this battle is won. Of the other issues in food, I think only Vitamin A is in the very bad category yet simultaneously not talked about.
It’s also the only one that has an astoundingly easy proof: a proof by counterexample. A rat that survives and reproduces with zero serum retinol and liver stores demonstrates that it being a vitamin (something that an animal cannot grow without) is invalid.
Given that Vitamin A is known to be poisonous in high doses, this proof would move it into the realm of toxic substances and then it would no longer be added to all our foods.
Note
Why you should stop consuming Vitamin A
Just take a look at the ingredients the next time you shop.
Vitamin A added in the form of retinyl palmitate or retinyl acetate are known as preformed Vitamin A and have no limits on systemic absorption. Provitamin A includes carotenes, such as the colors in various plants such as carrots, and are converted into preformed Vitamin A.
All of the added Vitamin A in foods tends to be preformed Vitamin A. If it were beta-carotene, it probably wouldn’t be that bad (outside of turning people orange). This means all yogurts (basically the entire Costco aisle of yogurts) created using low-fat milk (since it is federally mandated), food products that use low-fat milk (Americans eat a huge amount of processed food), and so on accumulate huge amounts of Vitamin A.
Note
I’m going to make the historical argument too: nobody consumed large amounts of retinyl palmitate in their food 50 years ago, so why should you now?
Measurement
Vitamin A is specified as: 0.3ug retinol = 1 IU = 0.6ug beta-carotene.
The History
Meta-summaries
There are two good summaries I’m aware of. The first is Multiple Functions of Vitamin A (1984) by George Wolf. The second is Vitamin A (1957) by Thomas Moore. They are good for numerous connections to the literature and seeing how the field developed.