Sweet potatoes, squash, pumpkin, carrots - beta-carotene is easily identified in the rich oranges of fall vegetables. But beware of large-dose beta-carotene nutritional supplements. Studies have pointed to potential problems, such as increased cancer risk.
Like other antioxidants, beta-carotene has been credited as having disease-preventing powers. Antioxidants destroy harmful free radicals, a natural by-product of the body's metabolic processes.
Cigarette smoking, pollutants, and other chemicals are thought to bump up the number of free radicals, possibly causing some normal cells to turn cancerous. Beta-carotene and other antioxidants are said to "mop up" these free radicals, thus protecting cells and DNA from free-radical damage.
Exactly how beta-carotene supplements could boost cancer risk is not clearly understood. In high-dose supplements, beta-carotene is thought to convert from its antioxidant role, instead of destroying free radicals, it may actually increase their production.
Beta-carotene from food sources is outstanding for your health. Studies have shown that people who eat more foods with beta-carotene have lower risk of cancer, cardiovascular disease, and early death from all causes.
The nutritional supplements, however, are a different matter.
In recent years, some clinical trials have shown that at high doses the supplements may actually increase cancer risk. Based upon current scientific evidence, there was no clear evidence of benefit from beta-carotene supplements and that there was even some evidence of adverse effects, particularly in smokers and possibly in drinkers as well.
Some studies also found no evidence that beta-carotene [supplements] protects against heart disease and cancer, specifically lung, prostate, colon, breast, or nonmelanoma skin cancer in middle-aged and older adults.
In fact, some studies have warned against taking beta-carotene nutritional supplements to prevent heart disease and cancer.
Heart disease and stroke
: Studies showed that who took beta-carotene supplements had a small but significant increase in deaths from all causes, including heart disease and stroke.
: A study was conducted on male smokers showed that those who took a daily beta-carotene nutritional supplement had an 18% higher rate of lung cancer.
A study of more than 120,000 people showed that in a 10-year period those who ate the most fruits and vegetables had a 20%-25% lower risk of lung cancer.
: In a study of 700 people who had a benign polyp removed, those who took beta-carotene nutritional supplements -- and who didn't smoke or drink -- had a marked decrease in colon polyps within the four-year follow-up period.
However, those who smoked or drank alcohol -- and took beta-carotene nutritional supplements -- had a modest increase in recurrence of colon polyps. If they smoked and drank more than one alcoholic drink per day, beta-carotene doubled their risk of polyp recurrence.
It may be that at a lower dose, beta-carotene nutritional supplements may have benefits -- that only higher doses are dangerous.
But a better strategy is to eat beta-carotene-rich foods -- such as carrots, oranges, sweet potatoes, squash, yams, apricots, collards, spinach, and mustard greens, she notes.
Possibly, beta-carotene and other compounds found naturally in food work together to enhance the effectiveness of each other.