Beta-carotene in the human body – why is it so important for maintaining homeostasis?
Beta-carotene is an important substance, one of the most significant carotenes found in nature. Known for its colouring properties, it is becoming increasingly important due to its beneficial effects on the human body. An adequate supply of this substance should be a priority – low levels cause a deficiency... vitamin A. What are the characteristics of beta-carotene and why is it crucial for maintaining homeostasis?
Beta-carotene - what is it?
Beta-carotene is an organic chemical compound, a precursor of vitamin A and its most important isomer. The substance was isolated in 1831 from carrot root. It is believed that beta-carotene accounts for as much as 30% - 35% of the vitamin A consumed by humans, which makes the compound a very important and often irreplaceable source.
Beta-carotene occurs naturally in plant-based products, but it is not absorbed in its entirety - absorption from food ranges from 5% to 65%. The discrepancy is due to the type of food, or rather the fat content in relation to fibre - fat has a positive effect on bioavailability, while fibre interferes with the process. Food, even that rich in beta-carotene, is not enough to guarantee an adequate supply.
Apart from the problem of absorption, there are several other reasons for low beta-carotene levels in the body. Experts mention the following in particular:
- an unbalanced diet
- malnutrition
- obesity
- diseases that reduce nutrient absorption (e.g. malabsorption syndrome)
- hyperthyroidism
- hormonal contraception
Beta-carotene and vitamin A
There are two types of vitamin A in the human diet:
- preformed vitamin A (such as retinol or retinyl ester)
- provitamin A (carotenoids, including the most important beta-carotene, but also alpha-carotene and beta-cryptoxanthin)
The body is able to effectively convert beta-carotene into retinol. The main difference between the two substances is that vitamin A can be harmful if taken in excess, while in the case of beta-carotene, the body only processes the amount it currently needs.
Obviously, too low a supply of beta-carotene is usually synonymous with vitamin A deficiency and all the consequences associated with it:
- fatigue
- dermatological problems
- recurrent infections
- vision problems
Beta-carotene as a universal colouring agent
Beta-carotene gives many vegetables and fruits their red, yellow and orange colour (e.g. pumpkin, carrots, oranges). The substance is also found in leafy vegetables (e.g. spinach, kale), but its colour is masked by the green pigment chlorophyll.
A long-term excess of beta-carotene in the human body can easily be seen with the naked eye. It manifests itself as a yellow-orange discolouration of the skin, resulting from the accumulation of the substance in the stratum corneum. Although the discolouration can affect the entire body, it is particularly visible on the hands and feet. Carotenodermia is a harmless condition and disappears after discontinuing beta-carotene.
Beta-carotene - properties and effects on the body
Beta-carotene has many important functions. It has antioxidant properties - it protects against the harmful (and common) effects of free radicals. It plays an important role in the prevention of metabolic syndrome (a group of conditions that increase the risk of developing diabetes and heart disease) and prevents atherosclerotic processes by reducing cholesterol absorption in the intestines while increasing the excretion of dangerous lipids.
Beta-carotene contributes to the protection of the lining of the digestive tract and respiratory tract, and also determines the proper keratinisation of epithelia. Studies show that it protects the lungs from metaplasia, a process in which cells that are morphologically and functionally different from the matrix are formed (the supplement is particularly effective in combination with alpha-tocopherol and ascorbic acid).
Beta-carotene supports the immune system, and long-term supplementation may reduce the development of age-related mental changes - it has been proven to have a positive effect on cognitive function and memory. The substance is often used in the treatment of skin diseases (such as dryness, eczema and psoriasis) and vision disorders. Beta-carotene reduces the risk of cataracts, and in combination with vitamins C and E and zinc it can have an impact on the development of macular degeneration (AMD).
Beta-carotene and sunbathing
According to research, consuming adequate amounts of beta-carotene can strengthen the skin's protection against harmful UV radiation (comparable to SPF4 sunscreen). It alleviates damage and defects caused by sun exposure, which include loss of collagen and skin elasticity, as well as the formation of wrinkles. It prevents premature ageing, improves skin condition, evens out and maintains skin tone.
The optimal concentration for effectiveness is achieved approximately 10 weeks after starting supplementation. However, it is important to remember that beta-carotene is an excellent supplement to UV protection, but should not be used as a substitute for sunscreen.
Its UV-protective properties are often used in medicine to treat conditions characterised by painful sensitivity to the sun. These include photodermatoses (e.g. polymorphic light eruption and solar urticaria) and erythropoietic porphyria.
Beta-carotene - testing
It is well known that nutritional requirements vary greatly and depend primarily on age, health and lifestyle. This is no different with beta-carotene. The level of the substance can be tested by precise measurements of its concentration in the blood serum. Tests are performed not only to check beta-carotene concentration, but also in cases of suspected vitamin A deficiency in the body or as a control during supplementation.
Beta-carotene and a few facts
A meta-analysis of 41 observational studies (involving a total of 500,000 people) suggests that adequate beta-carotene levels are associated with lower mortality. However, this does not mean that the supplement can be used in all cases.
Among the contraindications, specialists mention primarily severe liver and kidney failure. Beta-carotene interacts with drugs used to lower cholesterol, and bile acid sequestrants and proton pump inhibitors may reduce the absorption of the substance. The supplement should not be used with isotretinoin and acitretin, as they contain vitamin A derivatives.
However, beta-carotene is completely safe for most people. To date, no upper tolerable intake level has been established – it is unlikely that the supplement will cause health problems, even if taken in high doses. Nevertheless, it is important to remember to always follow the manufacturer's or doctor's recommendations.
The world heard about beta-carotene almost 200 years ago, and since then, attempts to thoroughly understand the substance and its properties have continued. There is growing evidence of the beneficial effects of this compound on the human body, and although beta-carotene is not an essential nutrient, it is often the most important source of vitamin A – and that makes a big difference.