It is a powerful antioxidant which studies have suggested may protect against a range of diseases and support the immune system, so it's popular as a supplement for supporting all-round good health.
It's one of a family of naturally-occurring nutrients called carotenoids, 60 of which occur in food.
Dr Sarah Brewer says: ‘Beta carotene is the most common carotenoid found in the diet and one of the most important. Along with a few other carotenoids it can be converted to vitamin A in the body and is sometimes described as pro-vitamin A. It may support eye health and cognitive function.’
What does beta carotene do?
Beta carotene is a dietary antioxidant, which helps to protect the body's cells from free radicals, unstable oxygen molecules caused by eating, breathing and other factors including smoking and air pollution. These can cause damage to cells and may play a role in the development of diseases, such as heart disease.
Beta carotene is also an important nutrient because our bodies can convert it into vitamin A when it is needed. This is essential for healthy skin, our immune systems, good eye health and vision.
Age-related macular degeneration (AMD) is a chronic eye disease that causes loss of central vision. It affects more than 600,000 people in the UK and is the leading cause of vision loss.
A major clinical trial, the Age-Related Eye Disease Study (AREDS), sponsored by the National Eye Institute in the US, found that people with early AMD who took high levels of antioxidants (including 15mg of beta carotene) were 25 to 30 per cent less likely to go onto develop advanced AMD, and their central vision loss was reduced by 19 per cent.
However, a later trial, AREDS II, replaced beta carotene with the antioxidants lutein and zeaxanthin, from the same family of nutrients, and achieved slightly better results. Another study, in India, looked at over 3,500 people aged 45 and over and found there was evidence to suggest carotenoids, including beta carotene can lower the risk of AMD.
Beta carotene may help maintain healthy brain function, and carotenoids may even help protect the brain against oxidative damage during the ageing process. A French study, which looked at more than 2,900 middle-aged adults over a 13-year period, found that those who increased their consumption of fruits and vegetables rich in carotenoids maintained their cognitive function for longer. However, further studies are needed to confirm this.
Getting beta carotene from your diet
The main food sources of beta carotene include yellow and red-orange fruits and vegetables such as carrots, squashes, grapefruit, melon, mango and apricots. Leafy green vegetables, such as spinach, kale and broccoli, are also rich in the pigment.
Whilst beta carotene is not destroyed by cooking, losses occur when it is exposed to light and air so it’s best to not store fruit and vegetables for too long before eating.
Getting beta carotene and vitamin A from your diet is safe, but toxic vitamin A levels can occur if you consume too many supplements, so it's advisable not to take more than 7mg a day of beta carotene.
Excessive levels of beta carotene could be toxic to the liver and it may interact with alcohol, increasing its liver toxicity. Beta carotene supplements are considered safe during pregnancy because it is only converted to vitamin A when needed, so high levels cannot build up.
A daily intake of more than 30mg may lead to hypercarotenemia, which can make your skin, soles of feet and palms of your hands turn yellow or orange temporarily. However, this is harmless and reversible.
Beta carotene supplements are not recommended for smokers as some researchers have found that long-term use of high-dose beta carotene was associated with an increased risk of lung cancer in current, but not ex-smokers. This association is still under investigation.
Beta carotene currently has no recommended daily allowance (RDA), but the Department of Health suggests taking no more than 7mg of beta carotene supplements a day, unless advised by a doctor.