Why vitamin A is good for you

Vitamin A is essential for healthy eyes as it helps the eyes to function properly in all conditions, even the dark. Vitamin A is essential in preventing night blindness.

Vitamin helps to prevent a leading case of blindness in the elderly called age-related macular degeneration (ARMD).

Vitamin A helps the immune system fight infection and illness by helping the epithelial tissues (the cells that make up the skin, line the mouth, nose, eyes, throat, lungs, digestive and urinary tracts and which keep out infective agents) grow and repair themselves. Without enough vitamin A, these cells become stiff, dry and much more likely to let their guard down and when that happens, germs can easily pass through them and into the body.

All humans (especially children and teenagers) need vitamin A for a wide range of body functions, including to help the body cells repair, grow properly and to keep bones and teeth strong.

Important vitamin A facts

• Vitamin A is a fat-soluble vitamin
  Since vitamin A is a fat-soluble vitamin, it requires some fat to be eaten at the same time, to enable it to be digested and absorbed properly so that it can be used by the body as required.
• Vitamin A is a potent antioxidant
  Vitamin A’s antioxidant properties are very potent – it acts to scavenge free radicals in the body that may otherwise do damage to DNA and raise risk of cancer and heart disease. Vitamin A reduces the oxidative damage that may otherwise occur in the cells of the body, from free radicals causing damage to them, if it was not available to neutralise and remove them.
• Vitamin A exists in the epithelial and mucous tissues, as well as the retina
  Vitamin A is found in the mucous (respiratory, gastrointestinal) and epithelial (urinary) cells of the body. The vitamin A in these cells helps to keep these cells moist and flexible, so that when any foreign substance (pathogen such as virus or bacteria) enters, these cells and tissues are able to eject the pathogen easily and resist infection. Without vitamin A, these cells may become stiff and dry, thus not providing the correct defense and allowing in the pathogen and enabling infection.
• Vitamin A is only found in animal food sources
  Vitamin A is only found in animal and animal product food sources. Vitamin A in animal foods (and animal products such as egg yolks, milk, fish, cheese) comes pre-formed, so that the body does not have to process it in order to be able to absorb it – the vitamin A simply goes to the intestines where it is absorbed and used as required (including some storage in the liver).
• There are three forms of preformed vitamin A
  The forms are – retinol, retinaldehyde and retinoic acid
• Retinol is easily destroyed
  Retinol is destroyed by light, high temperatures as well as when using copper or iron cooking utensils.
• The highest source of vitamin A is the polar bear liver
  It has 13,000IU-18,000IU per gram of liver!! More than enough to give vitamin A poisoning, even if only a tiny bit was eaten.

Vitamin A works best with

• Vitamin B1
• Vitamin B2
• Vitamin B3
• Vitamin B5
• Vitamin B6
• Vitamin B12
• Vitamin C
• Vitamin D
• Vitamin E
• Choline
• Essential fatty acids
• Calcium
• Phosphorus
• Zinc

Vitamin A and health

• Boosting the immune system fight off infection – vitamin A has an enhancing effect on the immune system due to its powerful antioxidant properties
• Helps with respiratory illnesses – many studies show that people who suffer from asthma, sinusitis and bronchitis improve significantly and have less incidence of infection and severity of symptoms when they are given vitamin A supplements. Studies also show that vitamin A builds resistance to the respiratory infections and illness
• Reduces hay fever and associated allergies – many studies show that people who suffer from allergic rhinnitis (or hayfever, which can happen all year-round, not just in spring) get major relief from their symptoms when they are supplemented with vitamin A.
• Necessary for good eyesight – Vitamin A is found in the mucous cells of the respiratory system and it helps to keep these cells moist and flexible, so that when any pathogen such as virus or bacteri) enters, these cells and tissues are able to eject the pathogen easily and resist infection
• Helps with night blindness – vitamin A helps you see better in the dark, because it tops up all the Vitamin A in your retina
• May prevent cataracts – vitamin A (and betacarotene) help mop up the free radicals which damage the lens of the eye and cause cataracts
• May prevent macular degeneration – vitamin A (together with vitamin C and vitamin E) is so vital for preventing or slowing down the development of progression of macular degeneration, which is the leading cause of blindness.
• Prevents heart disease – research shows that people who eat foods high in vitamin A (and betacarotene) have a much lowered risk for developing any type of heart disease (high blood pressure, high cholesterol levels, high triglycerides) and this reduces the risk for heart attack or stroke.
• Preventing heart attacks and heart disease – people who eat foods high in Vitamin A (and betacarotene) have fewer heart attacks and strokes

Groups at risk of vitamin A deficiency

There are many people who may be at risk of vitamin A deficiency:

• People who are on a very low fat diet
  People that are on a very low fat diet may not be eating enough foods that are rich in vitamin A, because most foods high in vitamin A tend to be high in fat also. This type of low fat diet could contribute to a deficiency of vitamin A and supplementation may be required.
• People that drink alcohol excessively
  People that drink excessive amounts of alcohol may be deficient in vitamin A because the alcohol prevents the body from transporting and using vitamin A properly. In addition, people who drink excessive amounts of alcohol may not be eating enough food, so may not get enough vitamin A from their foods anyway.
• People who have recently undergone surgery
  People that have undergone surgery may be deficient in vitamin A, as all the reserves will be used to help the body heal from the surgery, so may need vitamin A supplementation.
• People who smoke cigarettes
  Tobacco reduces the amount of vitamin A that is absorbed from foods eaten, so people who smoke cigarettes may become deficient in vitamin A and need supplementation.
• People who take certain medications
  Many prescription as well as over-the-counter (OTC) medications cause a decreased absorption of vitamin A, which could cause a deficiency (while some medications cause an increased absorption of vitamin A). People who take any type of medication should seek advice from their doctor before trying any vitamin A supplements to ensure it is suitable for their individual circumstances.
• People under a lot of stress
  People who experience physical or physiological stress, such as overwork, fatigue, not eating enough/properly, exercising too much all create free radicals which lower vitamin A levels. If the stress is constant and prolonged, this uses up most of the vitamin A reserves. Vitamin A helps to combat free radicals that are produced at times of stress and could be deficient and may need supplementation.
• People with certain illnesses
  People with certain illness may have low vitamin A levels – illness such as cystic fibrosis, liver disease and chronic diarrhoea. People with any type of illness should seek advice from their doctor before trying any vitamin A supplements to ensure it is suitable for their individual circumstances.
• People with chronic infections
  People with chronic infections (such as bronchitis) usually have low levels of vitamin A due to the infection and may have used up most of their vitamin A reserves to combat the free radicals that are produced at times of infection, so could be deficient and may need supplementation. Illness or chronic infection produces free radicals, which lower vitamin A levels
• People with recent severe burns
  People that have recent severe burn may be deficient in vitamin A, as all the reserves will be used to help the body heal from the severe burns, so may need vitamin A supplementation.
• Strict vegetarians and vegans
  Vitamin A only exists in food that is of animal origin – meats and meat products such as milk, cheese, eggs and butter. People that do not eat animal foods (or only very little animal products) may be at a high risk of being deficient in vitamin A and could need supplementation.
• Users of birth control pills
  May have high levels of vitamin A in their blood, but low levels stored in the liver (the pill does not have this effect on Vitamin A)

Talk to a medical professional about vitamin A supplements before taking them.

Symptoms of vitamin A deficiency

Deficiency of vitamin A occurs when blood levels are less than 10mcg / litre of blood.

General symptoms of deficiency

• abscesses forming in the ear
• diarrhoea
• dry hair, scalp, rough skin, dry itchy eyes
• fatigue
• frequent cold and respiratory infections, such as asthma, allergic rhinitis (hay fever), bronchitis
• insomnia
• skin disorders, such as acne, eczema, boils and a bumpy skin
• slow healing from injuries
• sinusitis

People with any of these symptoms should seek advice from their medical practitioner.

More severe symptoms of vitamin A deficiency include:

• Blindness
• Eyesight problems
• Lack of tear secretion
• Night blindness
• Poor bone growth
• Reproductive problems
• Slowed growth
• Ulcerated cornea and blindness
• Weakened tooth enamel
• Weight loss

People with any of these symptoms should seek advice from their medical practitioner.

Vitamin A in food

Vitamin A recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Retinol equivalents (IU and mcg)

The above recommended dietary allowances of Vitamin A are given in Retinol Equivalents (RE) of vitamin A (in mcg).

The following shows the International Unit (IU) equivalents of Vitamin A:

One Retinol Equivalent (RE) of Vitamin A (in mcg) equals
6 International Units (IU) from beta-carotene
10 IU from other carotenoid-rich plant foods
4.10 IU from milk and yogurt
3.33 IU from animal sources and fortified foods

Toxicity

Vitamin A is toxic at doses greater than 22,500mcg (or 75,000IU) per day.

Vitamin A toxicity is known as also known as hypervitaminosis A.

Vitamin D supplementation helps to reduce vitamin A toxicity, so should be taken together.

Vitamin A is toxic in large doses. To avoid vitamin A toxicity, either take the recommended daily intake of Vitamin A or take betacarotene or eat foods rich in this vitamin.

Vitamin A toxicity can occur due to excessive intake of vitamin A over a short period (acute toxicity), or higher than normal intake of vitamin A over a long period, where levels of vitamin A build up over time and are not excreted by the body (chronic toxicity).

While acute vitamin A toxicity can be far more dangerous than chronic vitamin A toxicity, both are bad for your health. If you suspect you have had too much vitamin A, see a doctor immediately.

Overdosage and toxicity symptoms

High levels of vitamin A should not be taken for long terms as it can cause adverse health effects. Higher than the tolerable upper limit should only be taken for a short term and only under medical supervision. Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of vitamin A is highly unlikely to cause overdosage.

To avoid vitamin A toxicity, eat foods rich in this vitamin.

Acute vitamin A toxicity

Taking over (> 75000IU per day) causes the following symptoms:

• Birth defects (in pregnant women)
• Elevated calcium levels
• Fatigue
• Headache
• Insomnia
• Irritability
• Lethargy
• Menstruation stops (usually temporarily)
• Nausea and vomiting
• Painful bones
• Skin rashes that peel off

Chronic vitamin A toxicity

Taking higher than the tolerable upper limit causes the following symptoms:

Symptoms of overdose in adults

• Abnormal bone growth
• Birth defects (in pregnant women)
• Blurry vision and headache
• Bone and muscle pain
• Drowsiness, lethargy and loss of appetite
• Hair loss
• Headache
• Increased blood lipid levels
• Irritability
• Itching
• Jaundice (yellowing of skin/eyes)
• Loss of appetite
• Menstruation stops (usually temporarily)
• Vomiting and diarrhoea

People who experience any of the above toxicity symptoms should discontinue their vitamin A supplements and seek the advice of their doctor.

Symptoms of overdose in children

• bone pain
• fontanelle bulging (the soft spot on an infant’s skull)
• irritability
• lethargy
• loss of appetite
• stunted growth

Certain people should not take high vitamin A supplements:

• Women who are pregnant
  Women who are pregnant should not take more than the upper tolerable limit of vitamin A due to the risk on the unborn foetus. High levels of vitamin A supplements could cause birth defects.  Women of child-bearing age should not take more than 8,000IU of vitamin A per day for this very reason.

Certain people should not take vitamin A supplements without first consulting their doctor for advice:

• People who drink excessive alcohol
  People who drink alcohol excessively are advised not to take high levels of Vitamin A as their liver may be too sensitive from the alcohol abuse and more susceptible to liver toxicity of vitamin A. The liver may not be able to metabolise and use the vitamin A properly causing toxicity effects.
• People with cystic fibrosis
  People with cystic fibrosis may have low levels of vitamin A (as this vitamin is needed for ensuring healthy mucous membranes and it is not healthy in people with cystic fibrosis) and could need supplementation.
• People with diabetes
  People with diabetes may have low levels of vitamin A due to their condition and could need supplementation.
• People with gastrointestinal disorders (with diarrhoea)
  People that have any type of gastrointestinal disorder that has associated diarrhoea may be excreting a lot of their vitamin A out in their diarrhoea and could need supplementation.
• People with kidney disease
  People with kidney disease may have low levels of vitamin A due to their condition and could need supplementation.
• People with liver disease
  People with liver disease may have low levels of vitamin A due to their condition and could need supplementation.
• People with overactive thyroid function
  People with an overactive thyroid may have low levels of vitamin A due to their condition and could need supplementation.
• People with disorders of the pancreas, including viral pancreatitis
  People with disorders of the pancreas (including viral pancreatitis) may have low levels of vitamin A due to their condition and could need supplementation.

Interactions with medications and supplements

The following are the medications and supplements that are more likely to cause a reaction with vitamin A supplements:

• Antacids – any type of antacids can reduce absorption of vitamin A (as well as any of the other fat-soluble vitamins too)
• Calcium supplements – high levels of vitamin A supplements can reduce the effectiveness of calcium supplements if they are taken at the same time
• Cholestyramine and Colestipol – the medications Cholestyramine or Colestipol, which are used to lower LDL (“bad”) cholesterol levels can reduce the rate of absorption of vitamin A from foods
• Neomycin – the antibiotic Neomycin, can reduce the rate of absorption of vitamin A from foods
• Oral contraceptives – the oral contraceptive can increases the amount of vitamin A in the body and could cause some toxicity, so excessive vitamin A supplementation is not recommended
• Retin-A – Retin-A, a medication used for treating facial acne is high in vitamin A, so people taking vitamin A supplements at the same time as this medication will increase their risk for vitamin A toxicity
• Vitamin E – vitamin E supplements work very synergistically with vitamin A supplements, but when the intake of vitamin E supplements is at very high levels, they can deplete the vitamin A stores in the liver and cause a deficiency

References

• Ambalavanan N, Tyson JE, Kennedy KA, et al. Vitamin A supplementation for extremely low birth weight infants: outcome at 18 to 22 months. Pediatrics 2005;115(3):e249-e254
• Barker ME, Blumsohn A. Is vitamin A consumption a risk factor for osteoporotic fracture?. Proc Nutr Soc. 2003;62:845-850
• Bates CJ. Vitamin A. Lancet. Jan 7 1995;345(8941):31-5
• Chang L-C, et al. Retinoic acid induced glandular differentiation of the oesophagus. Gut, Dec 2006 doi:10.1136/gut.2006.097915
• Cox SE, Arthur P, Kirkwood BR, et al. Vitamin A supplementation increases ratios of proinflammatory to anti-inflammatory cytokine responses in pregnancy and lactation. Clin Exp Immunol. 2006 Jun;144(3):392-400
• Fletcher AE, Breeze E, Shetty PS. Antioxidant vitamins and mortality in older persons: findings from the nutrition add-on study to the Medical Research Council Trial of Assessment and Management of Older People in the Community. AJCN, 2003; Vol 78(5): 999-1010
• Genaro Pde S, Martini LA. Vitamin A supplementation and risk of skeletal fracture. Nutr Rev. Feb 2004;62(2):65-7
• Griffith HW. Minerals, Supplements and Vitamins – The Essential Guide. 2000 Fisher Books, USA
• Hathcock JN, Hattan DG, Jenkins MY, et al. Evaluation of vitamin A toxicity. Am J Clin Nutr. Aug 1990;52(2):183-202
• Lieberman S, Bruning N. The Real Vitamin and Mineral Book – Using Supplements for Optimal Health. 3rd Edition. Avery Publishing, New York, 2003
• Office of Dietary Supplements USA – has the official USA RDI for all vitamins (these are also adopted by Australia), accessed 9 August 2005
• Osiecki, Henry, The Nutrient Bible 2002, BioConcepts Publishing
• Wolbach SB, How PR. Tissue Changes Following Deprivation of Fat-Soluble A Vitamin. The Journal of Experimental Medicine 1925, Vol 42, 753-777

Last reviewed and updated: 29 April 2025

Why betacarotene is good for you

Betacarotene is responsible for the orange colour of carrots and other other orange coloured fruits and vegetables.

Some of the betacarotene in foods eaten gets converted to Vitamin A in the liver and small intestine, as necessary by the body, while the rest acts as a powerful antioxidant within the body to remove free radicals.

Betacarotene is needed to ensure the immune system functions at optimal levels, by increasing the number of white blood cells and protecting the body against infection and illness.

Important betacarotene facts

Betacarotene is a very important nutrient for the body.

• Betacarotene is a fat-soluble vitamin – betacarotene is one of the few vitamins that is fat-soluble and so it requires some fat to be eaten at the same time, to enable it to be digested and absorbed properly so that it can be used by the body as required. As most betacarotene sources are from animal food sources, they will also contain some fat helping with its absorption
• Betacarotene is a potent antioxidant – betacarotene’s antioxidant properties are very potent. It acts to scavenge free radicals in the body that may otherwise do damage to DNA and raise risk of cancer and heart disease. Betacarotene reduces the oxidative damage that may otherwise occur in the cells of the body, from free radicals causing damage to them, if it was not available to neutralise and remove them
• Betacarotene is the precursor of vitamin A – some of the betacarotene, the precursor of vitamin A, gets converted into vitamin A (by the thyroid hormone thyroxine) in the body when it is required and the rest is used by the body as a powerful antioxidant. The body uses as much of the betacarotene that is required to be convert into vitamin A and the rest is used as an antioxidant. Research shows that less than 50% of the betacarotene in foods eaten is converted into vitamin A, which means a significant portion of betacarotene being used as an antioxidant by the body.
• Betacarotene is converted into vitamin A in the intestines – betacarotene is converted into vitamin A in the intestines, through a complex process involving bile (from the liver) and thyroxine (from the thyroid).
• Betacarotene is responsible for the colour in orange fruits and vegetables – betacarotene is the substance that is responsible for the orange colour of raw fruits and vegetables that are rich in this vitamin. Other non-orange coloured vegetables also contain high levels of betacarotene too. Food rich in betacarotene are: apricots, carrots, endive, green and red lettuce, kale, rockmelon, pumpkin, red capsicum and peppers, spinach, sweet potatoes, tomatoes, watermelon.
• Cook vegetables for more betacarotene – the carotenes in vegetables are better absorbed if they are either cooked or steamed lightly
• Don’t soak vegetables and fruit in water – betacarotene rich vegetables and fruit should not be soaked in water for long periods, as the nutrient can be lost
• Betacarotene supplements are essentially non-toxic – large doses of betacarotene are almost non-toxic and therefore preferable to vitamin A supplements – which can be toxic at higher levels
• Betacarotene is abundant – carotenes are found in almost all fruit and vegetables

Betacarotene works best with

Betacarotene works in synergy with the other major antioxidant vitamins:

• Vitamin B1
• Vitamin B2
• Vitamin B3
• Vitamin B5
• Vitamin B6
• Vitamin B12
• Vitamin C
• Vitamin D
• Vitamin E (but not excessive dosage of either supplement)
• Choline
• Alpha-lipoic acid
• Co-enzyme Q10
• Essential fatty acids
• Calcium
• Phosphorus
• Selenium
• Zinc

Groups at risk of betacarotene deficiency

Deficiency of betacarotene is quite rare. Certain groups of people may be more susceptible to risk of betacarotene deficiency:

• Alcoholics – alcoholics tend to eat poorly, so their vitamin intake is low and alcohol blocks absorption of many nutrients, as well as excreting much of it that is absorbed. It’s better for this group to supplement with vitamin A instead of betacarotene. This is due to the detrimental effect betacarotene may have for them
• People taking certain medications – certain medications may reduce the absorption of betacarotene from foods causing a deficiency in this important antioxidant vitamin. People who are taking any type of medication should consult their medical doctor for advice.
• People who are exposed to environmental toxins – people who are constantly exposed to environmental toxins such as cigarette smoke, toxic chemicals, industrial and exhaust fume pollution, could have an elevated amount of free radical activity in their body and may have lowered betacarotene levels because it is being very quickly used up to mop up and neutralise the existing free radicals and it may not be enough to be effectively.
• People who are under major stress – people who are undergoing any type of major (and ongoing) stress, such as physical or physiological stress, overworking, fatigue, not eating enough or properly and exercising too much all create free radicals which lowers betacarotene levels and may cause a deficiency.
• People with cataracts – people with cataracts may have lowered levels of both betacarotene and vitamin A. The eyes need sufficient levels of both of these vitamins to ensure that the eye functions effectively and eyesight is healthy.
• People with certain illness – people with certain illnesses such as liver disease, cystic fibrosis or chronic diarrhoea all may have lower betacarotene levels.
• People with chronic infections – people with chronic infections may have lowered immunity resistance due to the higher levels of free radicals in the body. This may cause them to have lowered betacarotene levels, which could cause deficiency in this vitamin.
• Smokers – usually have low levels of all antioxidants, including low betacarotene. It’s better for this group to supplement with vitamin A instead of betacarotene. This is due to the detrimental effect betacarotene may have for them
• Women who use oral contraceptives – may have high levels of betacarotene in their blood, but low levels stored in the liver so this could signify a deficiency of this vitamin.

People in any of these groups should seek advice from their doctor before trying any betacarotene supplements to ensure it is suitable for their individual circumstances.

Symptoms of betacarotene deficiency

Deficiency of is quite rare, as there are so many common, easily accessible foods that contain this very useful nutrient.

General symptoms of betacarotene deficiency include:

• Cataracts
• Increased infections (flu and colds)
• Increased LDL (“bad”) cholesterol levels
• Increased risk of gastritis
• Probable increased susceptibility to cancer

People with any of these symptoms should seek advice from their medical practitioner to determine if betacarotene supplementation is warranted in their individual situation.

People who have cancer must consult their doctor about taking any type of supplement before trying them, as there could be an adverse reaction between their medication and the betacarotene supplements.

Betacarotene and health

Betacarotene is essential for good health. Some of the main health benefits for betacarotene are:

• Helps the immune system fight off infection – betacarotene has an enhancing effect on the immune system due to its powerful antioxidant properties. It is necessary to activate the white blood cells used for fighting infection
• Preventing night blindness – betacarotene helps the eyes see better in the dark, because it tops up all the vitamin A in the retina, which is needed to enable the vision to function properly
• Preventing cataracts – betacarotene helps mop up the free radicals which damage the lens of the eye and cause cataracts in susceptible people
• Preserving eyesight – betacarotene helps prevent the condition age related macular degeneration (ARMD) which causes blindness in older people. Betacarotene does this by reducing levels of free radicals
• Betacarotene helps to lower LDL (“bad”) cholesterol – studies show that betacarotene has a very protective effect on the whole cardiovascular system and can help to lower and prevent oxidation of LDL (“bad”) cholesterol, while increasing levels of HDL (“good”) cholesterol. High levels of LDL (“bad”) cholesterol are implicated in heart disease and betacarotene reduces this risk
• Betacarotene protects the heart – studies show that people who eat foods high in betacarotene have fewer heart attacks and strokes. The Harvard university Physicians Health Study looked at the heart health of over 22,000 male doctors. This study showed that those doctors who took a betacarotene supplement every second day had a 50% less chance of heart attack, stroke and death than doctors who did not take a betacarotene supplement. The study also showed betacarotene supplements had a much better and more protective effect on the heart than aspirin
• Betacarotene may reduce risk of cancer – studies have shown that people who have low levels of betacarotene are generally more at risk of developing a number of cancers, while increased levels of betacarotene are associated with a lowered risk for many types of cancers. Studies show that higher levels of betacarotene are especially associated with 80% less risk of cervical cancer and 30% less risk of lung cancer. In other studies of patients with cancer, who were undergoing chemotherapy, the patients who were supplemented with betacarotene (and vitamin A) lived longer, had a better response rate and less side effects to the chemotherapy treatment than the patients who did not get any betacarotene (and vitamin A) supplements
• Betacarotene may help with HIV and AIDS – studies have shown betacarotene supplements used in conjunction with conventional drug treatment for people infected with the human immunodeficiency virus (HIV) increased the number of white blood and immunity (CD4+) cells responsible for fighting infection and preventing virus replication

Talk to a medical professional about betacarotene supplements before taking them.

Betacarotene in food

Betacarotene recommended daily intake (RDI)

The recommended daily intake of betacarotene, is the recommended minimum intake required to maintain good health. The tolerable upper intake for betacarotene, is the maximum intake possible without causing any toxicity effects.

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Toxicity

When betacarotene supplementation is over 15mg, it must be given with supplementation of the following antioxidants too – vitamin A, vitamin C, vitamin E, zinc, selenium and possibly co-enzyme Q10 to reduce any possible toxicity effects.

Betacarotene can produce reversible toxicity at doses greater than 60mg per day.

Overdosage

Betacarotene is a really safe vitamin, even in relatively high doses, but extra high supplements of this vitamin can cause the following side effects:

• Enlarged liver
• Hypercarotenaemia (yellow-orange colouring of the skin)
• Lower blood pressure
• Weakness
• Weight loss

Betacarotene is in general, a non-toxic vitamin and even if the side effects listed above should occur, they will only be temporary and will not usually cause any lasting effects. Betacarotene overdosage symptoms are usually reversible.

Smokers, former smokers and heavy drinkers should not take betacarotene supplements. This group should get their betacarotene requirements from the fruits and vegetables they eat.

Precautions

Certain people should not take high levels of betacarotene supplements without first consulting their doctor for advice:

• Current and former heavy smokers – a fairly recent large study (in 1996), the CARET (beta-Carotene and Retinol Efficacy Trial) tested betacarotene as well as vitamin A supplements in people who were at high risk for lung cancer — such as smokers and former smokers. The study was conducted to determine if betacarotene and vitamin A had anti-cancer protective effects on the lungs of these study subjects, because it was already known that people who had a diet high in fruits and vegetables rich in betacarotene had a lowered risk for lung (and other) cancers. Unfortunately, the study was stopped before it was completed because it was discovered the people taking the betacarotene supplements (they took up to 30mg per day) had a higher incidence of lung cancer and higher mortality rate than the people who were taking a placebo (no betacarotene supplement). The betacarotene supplements increased the lung cancer risks only in people who smoked more than a pack a day and/or drank “above-average” amounts of alcohol. Another large Finnish study published two years earlier showed similar results.
• Current and former heavy drinkers – the CARET study also tested betacarotene and vitamin A on current and former heavy drinkers, alcoholics and found the same results as for smokers – the betacarotene supplements provided in the sudy seemed to enhance the development of lung and other cancers. The study was stopped and the authors advised people who were current or former heavy drinks to not take betacarotene supplements and to get their intake from food sources. The betacarotene supplements increased the lung cancer risks only in people who smoked more than a pack a day and/or drank “above-average” amounts of alcohol. Another large Finnish study published two years earlier showed similar results.
• People that have been exposed to asbestos – similary, people who had been exposed to asbestos were part of the CARET study and the same types of results occured for those people too and they were similarly advised not to take betacarotene supplements, but to instead get their intake from food sources.

People who fall into these groups (heavy smoker, former smoker, current or former asbestos-industry workers and heavy drinkers) should not take betacarotene supplements. These people should instead get their betacarotene requirements from the foods they eat.

Betacarotene interactions with medications and supplements

Betacarotene has detrimental interactions with the following medications and supplements:

• Statins – Atorvastatin (Lipitor), Fluvastatin (Lescol), Lovastatin (Mevacor), Pravastatin (Pravachol).
  Medications that lower cholesterol (Statins) when taken with betacarotene, selenium, vitamin C, vitamin E may decrease the effectiveness of the statins. Research has not yet identified if betacarotene alone can cause the statins to become ineffective or whether it is the combination of the antioxidant supplements which decreases the effectiveness of the statins.
• Orlistat
  The weight loss medication Orlistat can interfere with the absorption of betacarotene, reducing it by as much as 30%. Orlistat also interferes with the absorption of other fat-soluble vitamins.
• Verteporfin (Visudyne)
  Verteporfin, a medication used to treat macular degeneration or fungal eye infections should not be taken together with betacarotene, as the betacarotene may decrease the effectiveness and blood levels of verteporfin in the body.
• Niacin (Vitamin B3)
  Betacarotene, together with selenium, vitamin C, vitamin E may decrease the blood levels of niacin (vitamin B3). Niacin helps to increase HDL (“good”) cholesterol and lowered levels of niacin may possibly reduce HDL (“good”) cholesterol

Betacarotene interactions with other substances

• Alcohol
  Excessive alcohol intake can reduce betacarotene levels in the body to such an extent that this can contribute to further liver damage.

Betacarotene’s effect on lab tests

There are none reported.

References

• Ahmed S, Leo MA, Lieber CS. Interactions between alcohol and beta-carotene in patients with alcoholic liver disease. Am J Clin Nutr. 1994 Sep;60(3):430-6
• Baron JA, Cole BF, Mott L, et al. Neoplastic and antineoplastic effects of beta-carotene on colorectal adenoma recurrence: results of a randomized trial. J Natl Cancer Inst 2003;95(10):717-7
• Cheung MC, Zhao XQ, Chait A, Albers JJ, Brown BG. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol. 2001 Aug;21(8):1320-6
• Gabriele S, Alberto P, Sergio G, Fernanda F, Marco MC. Emerging potentials for an antioxidant therapy as a new approach to the treatment of systemic sclerosis. Toxicology. 2000; 155(1-3):1-15
• Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002;360(9326):23-33
• Keefe KA, Schell MJ, Brewer C, et al. A randomized, double blind, Phase III trial using oral beta-carotene supplementation for women with high-grade cervical intraepithelial neoplasia. Cancer Epidemiol Biomarkers Prev 2001;10(10):1029-1035
• Leo MA, Lieber CS. Alcohol, vitamin A, and beta-carotene: Adverse interactions, including hepatotoxicity and carcinogenicity. Am J Clin Nutr. 1999;69(6):1071-1085
• Office of Dietary Supplements USA – has the official USA RDI for all vitamins (these are also adopted by Australia), accessed 9 August 2005
• Niki E, Noguchi N, Tsuchihashi H, Gotoh N. Interaction among vitamin C, vitamin E, and beta-carotene. Am J Clin Nutr. 1995 Dec;62(6 Suppl):1322S-1326S
• Omen GS, Goodman GE, et al. Effects of a Combination of Beta Carotene and Vitamin A on Lung Cancer and Cardiovascular Disease. NEJM 2006 (May), Volume 334:1150-1155
• Omenn GS, Goodman GE, Thornquist MD, et al. Risk factors for lung cancer and for intervention effects in CARET, the Beta-Carotene and Retinol Efficacy Trial. J Natl Cancer Inst. 1996;88(21):1550-1559. [abstract]
• Osiecki, Henry, The Nutrient Bible 2002, BioConcepts Publishing
• Rapola JM, Virtamo J, Haukka JK, et al. Effect of vitamin E and beta carotene on the incidence of angina pectoris. A randomized, double-blind, controlled trial. JAMA 1996;275(9):693-698
• Schaumberg DA, Frieling UM, Rifai N, et al. No effect of beta-carotene supplementation on risk of nonmelanoma skin cancer among men with low baseline plasma beta-carotene. Cancer Epidemiol Biomarkers Prev 2004;13(6):1079-1080
• Woutersen RA, Wolterbeek AP, Appel MJ, van den Berg H, Goldbohm RA, Feron VJ. Safety evaluation of synthetic beta-carotene. [Review] Crit Rev Toxicol. 1999;29(6):515-542. (abstract)
• Zhi J, Melia AT, Koss-Twardy SG, Arora S, Patel IH. The effect of orlistat, an inhibitor of dietary fat absorption, on the pharmacokinetics of beta-carotene in healthy volunteers. J Clin Pharmacol. 1996 Feb;36(2):152-9

Last reviewed and updated: 9 May 2024

Why PABA is good for you

Para-amino benzoic acid (PABA) is one of the B vitamin co-factors. It assists the B vitamins to function more effectively.

Para-amino benzoic acid (PABA) is used to improve the way proteins are used in the body, it assists with red blood cell formation, as well as assisting in the manufacture of folic acid in the intestines. PABA also maintains correct intestinal flora.

PABA is used in sunscreen preparations since it can help protect the skin against ultraviolet radiation.

Important PABA facts

• PABA is a water-soluble vitamin, which means that it is easily absorbed in the body (as most of the body is made of water and so are most of the foods eaten),
• Some of the PABA in food may be lost in cooking
• PABA is a B vitamin co-factor, which means it is not quite a vitamin, but works with all of the B vitamins to help them perform their activities more effectively
• PABA can be made by the bacteria inside the intestines, so it does not need to be taken in the form of food in the diet (which is the reason why there is no established recommended daily intake for paba)
• PABA is involved in the synthesis (creation) of folic acid (folate) in the small intestine and it is also required to ensure red blood cells are of proper form and function.
• People suffering from vitiligo, over-pigmentation of skin, or without pigment in some spots, have reported an improvement of the skin after more PABA was ingested
• Certain drugs affect PABA absorption, such as antibiotics and also alcohol

PABA works best with

• Folic Acid
• Vitamin B5

PABA and health

• PABA is involved with red blood cell formation
  Since PABA is part of the folic acid molecule, it is involved in the formation of red blood cells and ensuring that the red blood cells created are healthy and structured properly and reduce risk of folic-acid deficiency anaemia.
• PABA is used in sunscreen to field UV light
  A specific form of PABA is used in sunscreen to screen out UV light, preventing sun burn and damage to the pigment of the skin and reducing risk of skin cancer.
• PABA assists with protein and amino acid usage in the body
  PABA helps to break down protein and enable it to be used properly by the body. Paba does this through its involvement with several enzymes that help to break down the proteins ingested from foods into their amino acids and help these amino acids to be used effectively by the various parts of the body as required.
• PABA may help to stop hair from going grey
  Animal studies have shown that when PABA supplementation is used in animals, it prevents their fur from turning white. There is only anecdotal evidence that PABA may help to prevent hair from greying in humans, there are no confirmed studies that consistently demonstrate this effect.
• PABA may help to prevent wrinkles
  PABA may actually help to rejuvenate older skin, by reducing the number of depth of wrinkles and in some people, even prevent the formation of wrinkles for longer.
• PABA may treat nervousness and irritability
  PABA has been shown in studies to manage mood problems. It helps to reduce anxiety, nervousness and irritability.

Groups at risk of PABA deficiency

Deficiency of PABA is extremely rare as it is freely available in many foods and the body can make enough of its own if required.

If a deficiency of PABA does occur it is usually because of malabsorption or malnutrition (whether from illness or being infirm).

Symptoms of PABA deficiency

Deficiency of PABA is extremely rare. If a deficiency does occur it is usually because of malabsorption or malnutrition and the following symptoms may occur:

• Constipation
• Depression
• Extreme tiredness, faigue or lethargy
• Irritability
• Nervousness
• Patchy, itchy areas on the skin
• Skin irritation and weeping eczema

People with any of these symptoms should seek advice from their doctor.

PABA in food

PABA is actually part of the folic acid molecule, so it will be found in folate-rich foods, such as:

• Beans
• Eggs
• Green leafy vegetables
• Lentils
• Organ meats
• Yeast

PABA recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Toxicity

PABA may produce side effect symptoms in some people at doses greater than 1000mg per day. Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of paba is highly unlikely to cause overdosage.

Toxicity symptoms

PABA is an essentially a non-toxic vitamin (exception when taken in high doses over a long period) and some people do have a sensitivity to it and have reported some side effects of toxicity from higher dosage of supplements, as follows:

• Diarrhoea
• Fever
• Liver disease
• Nausea
• Rash
• Vomiting

People experiencing any of the above toxicity symptoms should discontinue their PABA supplements and seek medical advice.

Precautions

Certain people should not take PABA supplements at all:

• People with any type of liver disease
  People that have any type of liver disease should not take PABA supplements at all because high levels of PABA can produce liver toxicity and liver disease symptoms, which can be dangerous in people with existing liver problems.

Interactions with medications and supplements

The following are the medications and supplements that are more likely to cause a reaction with paba supplements:

• Antibiotics
  People who are taking antibiotics should avoid taking paba supplements at the same time, as the paba can decrease the effectiveness of the antibiotics, making them ineffective in reducing any infection.
• Sulfonamides (or other sulfa medications)
  People who are taking sulfonamides (or other sulfa medications) for ulcerative colitis should avoid taking paba supplements at the same time, as the paba can decrease the effectiveness of the Sulfonamides (or other sulfa medications).

Other interactions with paba

There are also other substances which have an interaction with PABA as follows:

• Alcohol
  Alcohol can decrease the absorption and effectiveness of PABA, so supplementation may be required.

PABA’s effect on lab tests

There are none.

References

• Griffith HW. Minerals, Supplements and Vitamins – The Essential Guide. 2000 Fisher Books, USA
• Jakobsen J, Pendersen AN, Ovesen L. Para-aminobenzoic acid (PABA) used as a marker for completeness of 24 hour urine: effects of age and dosage scheduling. EJCN 2003, Vol 57(1); 138-142
• Lieberman S, Bruning N. The Real Vitamin and Mineral Book – Using Supplements for Optimal Health. 3rd Edition. Avery Publishing, New York, 2003
• Office of Dietary Supplements USA – has the official USA RDI for all vitamins (these are also adopted by Australia), accessed 9 August 2005
• Osiecki, Henry, The Nutrient Bible 2002, BioConcepts Publishing

Last reviewed and updated: 9 May 2024