Beta Carotene

Beta Carotene

Pure Beta Carotene Causes Cancer Study Questioned By Experts

Pure beta carotene may not be bad for smokers after all. The findings that smokers have to shun pure beta carotene may not yet be as conclusive as the need for them to quit smoking. This has been the standpoint of a German professor from the Institute for Biological Chemistry and Nutrition at the University of Hohenheim. Prof. Hans Konrad Biesalski asserts that the population-based study announcing that long-term intake of pure beta carotene and other carotenoids may increase likelihood of cancer in smokers is flawed. He questioned the validity of the methodology, statistical evaluations and speculative explanations of the said study.

The professor said that the study conducted by researchers from the University of North Carolina at Chapel Hill depended on a questionnaire which was critical to its shortcoming. Using the said questionnaire, subjects were asked to recall on the specifics of food supplements that they had taken, which for some was ten years ago. Because of this intervening time, the professor finds it hard to believe that the participants of the study were able to accurately remember the details of their intake, including frequency of intake, sequence, and composition of the products containing micronutrients, four or ten years ago. Hence, he finds some portions of data gathered using the questionnaires on supplement consumption very hard to follow. For this reason, he questions the plausibility of the questionnaires and most importantly the inferences that was made from them.
Another point in the study that he questioned was the statistical analysis done by the proponents. Prof. Biesalski is not surprised that the proponents conjectured that what increases the risk of lung cancer is not the absolute dose but the period of intake. This is because he doubts the recollection of dosing more than the recollection of preparations. What accounts for the weakness of the study is the inclusion in the analysis of data on intake that has been years ago and with memory as its only basis.

Furthermore, the German professor also pointed out that the arguments of the researchers were tentative and sometimes inconsistent. He cited as an example that the study said that the incidence of lung cancer was not dependent on the dose but was only associated with the period of supplementation. But the study in question also said that large amounts of ingestion disrupts the absorption, transport and circulation of other nutrients and may have a negative effect on other micronutrients.
For Prof. Biesalski, a balanced diet rich in carotenoids and vitamins has been shown by many epidemiological studies to ward off cancer. What this study in question has shown is that the sole reliance on micronutrients cannot counteract the ramifications of smoking.
Andrew Shao, PhD, Vice President of Scientific Affairs, CRN, a trade association also made a remark on the study emphasizing the limited number of lung cancer cases among nonsmokers which makes it inadequate for the classification of the effect of antioxidant supplements on this group of subjects. He deems that the study in question has demonstrated that the risk of cancer is increased by smoking.

With these flaws pointed out, there is no conclusive evidence that pure beta carotene can increase the lung risk of cancer among smokers.