What is Vitamin A?
Vitamin A is a fat-soluble vitamin that is vital for healthy eyes, skin, teeth, and tissues. In pregnancy, it is also important in baby development. A deficiency most often manifests as night blindness, where people struggle to see clearly in dim light. However, there is such a thing as too much vitamin A, and it can be very harmful to the body.
There are two forms of vitamin A:
- Retinol (preformed vitamin A) which comes from animal sources like cheese, eggs, oily fish, and liver.
- Carotenoids (provitamin A) which come from plant sources such as apricots, carrots and other red, yellow, and orange coloured fruit and vegetables
Retinol is the active form of vitamin A – it is the form that we can readily absorb and use for essential functions. Carotenoids are called provitamins because they can be converted by the body into vitamin A. As it isn’t preformed, the amount converted can be regulated by the bodies. Getting vitamin A this way may help reduce the risk of high levels of retinol which can be toxic.
What is the BCMO1 Gene?
BCMO1 influences our ability to convert beta-carotene into retinal beta-carotene (changing provitamin A into the form that we can use). It helps enable the splitting of beta-carotene into two retinal molecules which are then converted into retinol (active vitamin A).
Genes can take on the form of different variations known as alleles, they are like instructions for the same process but with slight differences. Generally each variation is characterised by a letter and we typically have two copies of each gene and therefore two alleles. The BCMO1 G allele results in the enzyme being less active than in individuals with the A allele. People with this allele have a reduced ability to convert to the active form of vitamin A, and had higher levels of carotene. This may increase the risk for vitamin A deficiency.
The GG genotype is seen in over 50% of Europeans. It is monogenic in a number of Asian populations and seen in about 80% African Americans. Overall, the genotype is found in about 80% of the general population.
Those with BCMO1 genotypes that result in less enzyme activity may need to consider possibly including more animal sourced vitamin A to prevent a deficiency.
Other genes that genes that are linked with vitamin A activity include: RBP4, TTR, CYP26B1
Regulation of carotenoid conversion into vitamin A