Today's Top Stories. The Rise of the Cleanfluencer. Add these to your meals for an instant immunity boost. Health Benefits. Sweet Potatoes. Turnip Greens. Beet Greens. Winter Squash. Cabbage, especially Chinese pak-choi, is another great source of beta carotene. Advertisement - Continue Reading Below. This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.
Because these molecules derive from beta-carotene, researchers predict that a large amount of this antioxidant is accompanied by a larger amount of these anti-vitamin-A molecules, as well. Vitamin A provides its health benefits by activating hundreds of genes. This means that if compounds contained in a typical source of the vitamin are actually lowering its activity instead of promoting its benefits, too much beta-carotene could paradoxically result in too little vitamin A.
The findings also might explain why, in a decades-old clinical trial, more people who were heavily supplemented with beta-carotene ended up with lung cancer than did research participants who took no beta-carotene at all. The trial was ended early because of that unexpected outcome. The scientists aren't recommending against eating foods high in beta-carotene, and they are continuing their studies to determine what environmental and biological conditions are most likely to lead to these molecules' production.
But we have to study them further to know for sure. The study is scheduled for publication in the May 4, , issue of the Journal of Biological Chemistry. Previous research has already established that when beta-carotene is metabolized, it is broken in half by an enzyme, which produces two vitamin A molecules.
In this new study, the Ohio State researchers showed that some of these molecules are produced when beta-carotene is broken in a different place by processes that are not yet fully understood and act to antagonize vitamin A. Harrison is an expert in the study of antioxidants called carotenoids, which give certain fruits and vegetables their distinctive colors. Carotenoids' antioxidant properties are associated with protecting cells and regulating cell growth and death, all of which play a role in multiple disease processes.
For this work, he joined forces with co-authors Robert Curley, professor of medicinal chemistry and pharmacognosy, and Steven Schwartz, professor of food science and technology, both at Ohio State. Curley specializes in producing synthetic molecules in the pursuit of drug development, and Schwartz is an expert at carotenoid analysis. Curley manufactured a series of beta-carotene-derived molecules in the lab that match those that exist in nature.
The researchers then exposed these molecules to conditions mimicking their metabolism and action in the body. Of the 11 synthetic molecules produced, five appeared to function as inhibitors of vitamin A action based on how they interacted with receptors that would normally launch the function of vitamin A molecules. What we found was they don't activate those receptors.
Instead, they inhibit activation of the receptor by retinoic acid," Curley said. They compete for the site where the agonist binds, but they don't activate the site. Beta carotene, like all carotenoids, is an antioxidant. An antioxidant is a substance that inhibits the oxidation of other molecules; it protects the body from free radicals. Free radicals damage cells through oxidation. Eventually, the damage caused by free radicals can cause several chronic illnesses. Men who have been taking beta carotene supplements for 15 or more years are considerably less likely to experience cognitive decline than other males, researchers from Harvard Medical School reported in Archives of Internal Medicine November issue.
Oxidative stress is thought to be a key factor in cognitive decline, the researchers explained. Studies have shown that antioxidant supplements may help prevent the deterioration of cognition. Their study, involving 4, men, compared those on beta carotene supplements for an average of 18 years to others who were given placebo.
Over the short-term, they found no difference in cognitive decline risk between the two groups of men, but in the long-term it was clear that beta carotene supplements made a significant difference. The researchers emphasized that there may have been other factors which contributed to the slower decline in cognitive abilities among the men in the beta carotene group.
The BMJ published a report in March which showed that high blood beta carotene levels compensate for some of the damage to the lungs caused by oxygen free radicals. They measured the FEV1 of participants and measured their beta carotene blood levels. FEV1 measures how much air you can breathe out in one go.
They found that those with high beta carotene levels had much slower decline in FEV1 measures. If you follow a healthy diet rich in beta carotene you do not need supplements. As mentioned above, supplements can lead to undesirable excesses in beta carotene levels — this cannot occur if your source is from the food you eat. A French study involving adult females published in the Journal of the National Cancer Institute September issue found that smokers with high beta carotene levels had a higher risk of lung cancer and other smoking-related cancers than other smokers.
They also found that non-smokers with high beta carotene intake had a lower risk of lung cancer. Further research has suggested that the high intake among smokers is nearly always due to supplements, and not food intake.
Drug interaction refers to a substance interfering in how a medication works, by either making it less effective, increasing its potency, or changing what it is supposed to do.
Long-term alcohol consumption can interact with beta carotene, raising the chances of developing liver problems. Beta carotene supplements are available for purchase online.
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