The organic compound known as beta-carotene, is a compound naturally found in plants, which, when consumed is that chemically converted into vitamin A, in the human body. The compound also acts as a major antioxidant molecule and immune system strengthener. There are different chemical members of the antioxidant carotene family that includes compounds such as the cryptoxanthin, the alpha-carotene, the compound zeaxanthin, the compound lutein, and the compound lycopene - all of these compounds are found in plant foods that have bright colors. In contrast to beta-carotene, these other nutrients are not converted into the vitamin A in the body but rather, have different roles of their own in the body.
Supplemental forms of most beta-carotene sold in the market these days is of the synthetic variety, which is chemically made up of only one molecule called all the trans beta-carotene molecule. The synthetic variety of the compound differs from the natural beta-carotene that is normally found in plant foods. This form of the compound is made of two molecules, a trans beta-carotene and a 9-cis beta-carotene molecule.
When the compound was first analyzed in the laboratory, the clinical researchers could see no meaningful difference between the natural and synthetic forms of the beta-carotene compound. As time passed, this original view was questioned as the link between the natural beta-carotene found in foods and its preventive action over lung cancer could not be duplicated using just the synthetic pills in laboratory tests. In fact, the synthetic variety of the beta-carotene may not even be beneficial as the double blind study of smokers suggests, here synthetic beta-carotene was apparently the actual cause for an increased risks for lung cancer in the test subjects. In addition, clinical research conducted on animals has begun to identify the myriad ways in which the synthetic beta-carotene can induce damage to the lungs, especially in tests where the animals were exposed to cigarette smoke on a regular basis.
Most of the natural form of the beta-carotene compound found in fruits and vegetables is in the all trans form of the molecule - essentially the same as synthetic beta-carotene in chemical composition. In addition, most of the 9-cis molecule form of the compound that is found only in the natural form of the beta-carotene will undergo chemical conversion in the body to the synthetic molecule before eventually reaching the bloodstream of the person. The body's rate of absorption of the 9-cis form of the beta-carotene seems to be poor according to some scientist, though this finding is disputed by other clinical scientists.
The natural form of the beta-carotene may possibly posses chemical activity that is quite distinct from the synthetic form of the compound despite the overlap in chemical composition between the natural and synthetic forms of the compound. One good example of this difference is the strong antioxidant action displayed by the natural form of the compound, the synthetic form of the compound is reported to lack this antioxidant effect in both animals and people when the activity of the compound was tested in the laboratory. In addition, the natural beta-carotene compound in one trial, was able to revert the precancerous changes to normal tissue, the synthetic supplements of the compound was not able to induce the same effects in such tissues. The use of only natural beta carotene in supplements is increasingly recommended by most nutritionally oriented doctors, who all question the efficacy of the synthetic form of the compound. Animal tests that explore whether the precancerous effects induced by synthetic beta-carotene could also be induced from a combination of cigarette smoke and the supplements of natural beta-carotene are yet to be conducted. In the meantime, all smokers are advised to avoid using all beta-carotene supplements altogether and every one else should avoid synthetic beta-carotene supplements, till further tests determine the relative safety of supplementing with this compound whether in the natural or in the synthetic form.
When brought in supplemental form, the natural form of the compound can be identified by the phrases used on the product label; the natural form is usually advertised as being "from D. salina," or being "from an algal source," or being "from a palm source," or even simply as "natural beta-carotene". The label must be checked to ensure the right product is being brought. Beta-carotene synthetic supplements can be identified when nothing but "beta-carotene" is printed on the label.
Naturally occurring beta-carotene is abundant in dark green and orange to yellow colored fruits and vegetable, this natural form of compound is also sold in the form of dietary supplements in most supermarkets. In all events, the best way to obtain beta- carotenes is by consuming plenty of such dark green and orange or yellow colored vegetables and foods in the diet.
A vitamin A deficiency is much more likely to affect individuals who restrict or limit their consumption of the beta-carotene rich vegetables either by choice or by poor dietary planning - such people are at a higher risk of a deficiency of vitamin A and its attendant problems. Deficiencies of beta-carotene itself will never occur, however, due to the fact that the beta-carotene compound itself is not an essential nutrient.
A dose of 25,000 IU (15 mg) daily of beta carotene supplement is probably the most common intake during a typical supplementation regimen; however, doses of 100,000 IU (60 mg) daily have also been used by some people. At the same time, the real benefits of supplementing with beta-carotene for the average person are still not clear and the potential benefits of such a regimen are still to be worked out in studies.
There are no known side effects connected to the supplemental use of beta-carotene as yet. At the same time, consuming excessive amounts of the supplemental compound in excess of more than 100,000 IU, or 60 mg daily, may at times give the skin a yellow or orange hue, which is harmless. As prolonged supplemental use of beta-carotene can deplete the levels of the vitamin E in the body, all individuals who are taking beta-carotene for long periods of time should make sure to supplement along with the vitamin E. The use of supplements of the synthetic beta-carotene as mentioned above has now been concretely connected to an increased risk for lung cancer in smokers of all ages. In test animals administered synthetic beta-carotene for long periods of time, the appearance of precancerous changes in the lungs has been noticed, and this is especially evident in test animals that were exposed to tobacco smoke for prolonged periods of time. While some clinical research suggests that there are distinct chemical differences between the synthetic and natural form of the beta-carotene supplements, a conclusive scientific and laboratory verifiable proof of such a difference is yet to be concretely displayed.