What Is the Connection between Vitamin a and Beta Carotene?
Vitamin A is a general term for a group of related substances that the human body can use for good health. Beta carotene is a specific molecule in a group of molecules called carotenoids, some of which can be converted into one type of vitamin A by the body. Source of beta carotene are plant-based, whereas preformed vitamin A only comes from animal sources.
Beta carotene is only one of a variety of molecules that can be converted into vitamin A. The other molecules present in an average Western diet are alpha carotene and beta-cryptoxanthin, and all together, these substances fall into a group of molecules called the carotenoids. Carotenoids are pigments, which means that they give color to the plant they grow in. Carotenoids in food come only from plants, so vitamin A and beta carotene play a role in the ingestion and absorption of plant nutrients, and not animal nutrients.
Once the body ingests beta carotene, it has to alter it to turn it into vitamin A. It does this one of two ways, either chopping up the beta carotene molecule in the middle of the chain, or cutting it up from the outside in. The breakdown and production of vitamin A and beta carotene happens in the small intestine, after the food passes through the stomach. The process involves an enzyme called beta-carotene dioxygenase, and the specific product of this vitamin A and beta carotene process is called retinol. Retinol is only one form of vitamin A, and others can be produced from other types of vitamin A raw material, like other carotenoids.
Storage of this product of the vitamin A and beta carotene process occurs in the liver. This has implications for the potential animal sources of vitamin A, as the livers of certain predators, such as polar bears or fish, can contain high levels of vitamin A. If too much preformed vitamin A is ingested by a human, sickness can occur.
If a person eats high levels of beta carotene, though, poisoning does not typically occur, as the body only makes enough vitamin A as it needs, and simply stores the beta carotene in its original form. When the body needs more vitamin A, it makes it from the beta carotene stored in the fat of the body. Too much beta carotene can make the skin turn yellow, but this appears to be a relatively harmless condition. Conversely, too little vitamin A can produce developmental problems in children, result in blindness, and increase the risk of dangerous infections.
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![Some animal livers, including those of polar bears, contain extremely high levels of vitamin A.]()
By: ILYA AKINSHINSome animal livers, including those of polar bears, contain extremely high levels of vitamin A. -
![Beta-carotenes are partly metabolised into vitamin A in humans.]()
By: Studio GiBeta-carotenes are partly metabolised into vitamin A in humans. -
![Vitamin A eye drops may be used to help heal or treat cataracts.]()
By: JackFVitamin A eye drops may be used to help heal or treat cataracts. -
![Beta carotene -- which gives carrots their orange color -- is converted into vitamin A when consumed.]()
By: DionisveraBeta carotene -- which gives carrots their orange color -- is converted into vitamin A when consumed. -
![An insufficient amount of vitamin A may result in blindness.]()
By: arturas kerdokasAn insufficient amount of vitamin A may result in blindness. -
![Vitamin A supplements are often accessible in the form of a tablet or capsule.]()
By: monticelllloVitamin A supplements are often accessible in the form of a tablet or capsule.
Discussion Comments
@SarahGen-- If you must take beta carotene as a supplement, get one with mixed carotenoids. I heard that this is much more effective.
I don't think most of us will ever need a supplement, if we eat enough fruits and vegetables. Beta carotene is rich in orange fruits and veggies like carrots, cantaloupe and squash. It's full of antioxidants and is good for eye health and a healthy immune system.
@SarahGen-- It's always better to supplement with beta carotene because like the article said, when the body has enough vitamin A, it can store beta carotene in its original form to use later. But if someone supplements directly with vitamin A, it has to be stored as is and it can cause toxicity.
There is a risk of toxicity with all fat soluble vitamins. But the risk is reduced if you get vitamin A through beta carotene instead of taking it directly.
If someone needs to supplement with vitamin A, which is better to take -- beta carotene or vitamin A?
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