Blood beta-carotene measurement is used to assess the general nutritional status of the body, to confirm laboratory carotenoderma, and to assess malabsorption of fats and steatorrhea.
Beta-carotene is a fat-soluble micronutrient that is a precursor of vitamin A. Therefore, lack or reduction of beta-carotene can lead to vitamin A deficiency. Beta-carotene is a form of vitamin A from vegetable sources (green or orange vegetables and fruits). The body converts beta-carotene to vitamin A if the thyroid is functioning properly and the patient does not have diabetes.
Carotenoids are the most abundant pigment groups and lipid-soluble antioxidants in nature that are responsible for the yellow, orange, or red color of fruits, leaves, and flowers. In 2005 carotenoids were divided into two classes: pro-vitamin A (e.g., β-carotene, α-carotene, and β-cryptoxanthin) and non-pro-vitamin A compounds. Later, in 2013 naturally occurring carotenoids were classified into three groups: carotenes, xanthophylls, and lycopene. β-carotene, α-carotene, lycopene, lutein, and cryptoxanthin are some dietary carotenoids found in human blood. β-carotenes, which are precursors of vitamin A, have greater pro-vitamin A potential compared to α-carotene or β-cryptoxanthin because of the presence of a β-ionone ring linked to a chain of 11 carbons. β-carotene, α-carotene, and lycopene are composed only of carbon and hydrogen atoms, whereas xanthophylls are carotenoids with at least one oxygen atom. Zeaxanthin, lutein, α-and β-cryptoxanthin, canthaxanthin, and astaxanthin are important xanthophylls containing hydroxy and keto groups in their structures. The presence of conjugated double bonds in the structure enables carotenoids to accept electrons from reactive species, neutralize free radicals, and isomerize and help in oxidation in the presence of oxygen, light, and heat. Chemical reactivity, distinctive shape, and light-absorbing properties of carotenoids are attributed to the alternating double and single bonds present in the nucleus of a polyene chain that constitute a conjugated system with delocalized π-electrons. Different structural configurations and shapes exist because of the isomerism around C=C double bonds (e.g., trans or cis isomer) and possible rotation around C–C single bonds in the polyene chain. Carotenoids absorb light from the visible region in the wavelength range of 400–500 nm.
Epidemiological studies identified the association of high dietary carotenoid intake with reduced risks of breast, cervical, ovarian, colorectal, cardiovascular, and eye diseases.
The foods highest in beta carotene include:
- dark leafy greens, such as kale and spinach
- sweet potatoes
- carrots
- broccoli
- butternut squash
- cantaloupe
- red and yellow peppers
- apricots
- broccoli
- peas
- romaine lettuce
Beta carotene is also found in herbs and spices such as:
- paprika
- cayenne
- chili
- parsley
- cilantro
- marjoram
- sage
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
