Beta Carotene: Sources and Properties

Beta Carotene: Sources and Properties

Beta carotene: introduction

Beta carotene belongs to the category of carotenoids , vegetable pigments which represent the precursors of vitamin A (retinol); however, the nutritional importance of beta carotene is not only that of being the precursor of the aforementioned vitamin. Among the hundreds of carotenoids, in fact, beta carotene has gained its true independence, as we will see in the course of this article where the properties, side effects and recommended dose will be discussed.



The etymology of the term “carotene” is curious and connects us to carrots . In fact, this pro-vitamin was so called by the scientist Wackenroder, who managed to isolate the compound, in fact, from the carrot root. It then had to wait until 1907 (Willstatter and Mieg) to clarify the structure of beta carotene, until 1911 for its direct isolation from carrots (Willstatter and Escher), and until 1950 for its chemical synthesis (Milas et Al .; Karrer and Euguster).

Sources of beta carotene

Carotenoids are highly pigmented substances, whose color varies from red to orange, fat-soluble (they do not dissolve in water) and sensitive to light and heat; beta carotene is found in many fruits, cereals , oils and green leafy vegetables, sweet potatoes , squash, spinach , apricots , peppers… and of course in carrots.



Alpha and gamma-carotenoids are other forms of pro-vitamin A, but as anticipated, Beta carotene certainly has the greatest nutritional importance, as:

  • boasts antioxidant properties , counteracting the onset of free radicals
  • it is the main source of vitamin A for vegetarians : if necessary, beta carotene is converted by the body into vitamin A, involved in very important biological functions (for example the synthesis of glycoproteins)
  • is converted into retinol (essential for vision ), which in turn is converted into retinoic acid, essential for cell growth and differentiation: in fact, if vitamin A is not formed, the organism is in shortage, with resulting in abnormal bone growth , dry corneal eye (xerophthalemia) and reproductive disorders.
  • its potential usefulness against the onset of cancer and diseases affecting the cardiovascular system is being tested: more in-depth studies will have to await to ascertain this possible effect.

Beta carotene is commercially available in many supplement formulations; it can be produced in the laboratory, but it can also derive from algae or fungi.

Studies on Beta carotene

After the work carried out by Moore (1957) brought the certainty that carotene represents the precursor of vitamin A, we had to wait until the end of the twentieth century to learn, thanks to two scientists, Garewal and Diplock, that beta carotene transforms in vitamin A only if the body actually needs it. In fact, the excess beta carotene is deposited on the skin , which appears yellow (not to be confused with jaundice ) : this is a reversible condition, because it is enough to decrease the dose taken to ensure that the “carrot effect” (carotenodermia or carotenosis) disappears.

Beta carotene poisoning?

Apart from these episodes of carotenosis, it can be said that chronic beta-carotene poisoning is absolutely unlikely in the context of a correct diet : just to give a practical example, a person can safely take even 20,000 IU of vitamin A derived from carotenoids, without running into any danger. It should be considered, however, that if the 20,000 IU of vitamin A derives from retinol – which is found in high doses in bovine liver (30,000-50,000 IU per 100 g depending on cooking), in butter , in margarine (3,000 IU per 100 g ), in eggs (1,800 IU per 100 g) and in full-fat cheese (1,000 IU per 100 g) – problems may arise in the body, as we are talking about immediately active and available vitamin A.

Indicative dosages

If the recommended daily dose of Beta-carotene ranges from 2 to 4 mg, supplementation in smokers – which in theory is useful in counteracting the increased oxidative stress linked to smoking habits – could, in reality, be contraindicated: in fact studies have been conducted on smokers who did not take beta carotene supplements and compared them to those who did not; Despite expectations, there was a higher incidence of lung cancer in the group taking the supplement. In other studies, excessive beta carotene supplementation
has been found to increase the risk of prostate cancer , but not only:Cardiovascular problems and intracerebral hemorrhage are possible consequences of excess beta carotene in smokers and people who have been exposed to asbestos .

Excess and deficiency

Another possible side effect deriving from an excessive consumption of Beta carotene is to block the recovery capacity of fat-soluble vitamins from the liver, such as vitamin D , preventing the formation of a reserve of these vitamins : this side effect can become particularly important in countries far from the Equator, where the deposit of vitamin D is essential to face the scarcity of winter light .

No symptoms of beta-carotene deficiency are recorded , unless there is also an underlying retinol deficiency; in this case the symptoms include vision disturbances, skin problems and susceptibility to infections.

A generous intake of beta carotene would be advisable in people who are exposed to the sun for long periods, in the elderly , against senile maculopathy , and in those who consume alcohol , because ethanol destroys the reserves of vitamin A in the liver. Given the potential side effects, however, it is advisable to consult your doctor first before taking beta-carotene supplements . To be clear, 2 mg of beta carotene (daily dose) are contained in each of the following portions:

  • 25 g of carrots
  • 40 g of beets
  • 45 g of formino cheese
  • 50 g of spinach
  • 55 g of red pepper
  • 65 g of mango
  • 110 g of melon
  • 130 g of apricots
  • 140 g of persimmons

Positive effects of beta carotene

  • Beta-carotene appears to be especially effective for women who are at high risk of getting breast cancer
  • can prevent sunburn in people with sensitive skin
  • It can prevent bronchitis and breathing difficulties in smokers
  • it may potentially reduce the risk of ovarian cancer in postmenopausal women , although there are no certainties yet
  • may reduce the risk of pregnancy -associated death
  • prevents night blindness
  • can improve oral leukoplakia
  • may improve physical performance in the elderly


From what has been explained in the article, the importance of a correct nutritional education is evident once again , rather than the excessive use of supplements, driven by excessive enthusiasm for such practices. In fact, if beta-carotene demonstrates all its potential benefits within a balanced diet and taken through foods that are rich in it, the isolation of this provitamin and its administration in high doses have often produced opposite effects. to those hoped for, even increasing the risk for the development of pathologies against which preventive action was hypothesized. Hence the importance of optimizing your diet first of alland lifestyle, and then possibly consult a doctor or a nutrition expert to ascertain the actual need for a supplementary intake of beta-carotene or other nutrients .



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