Bioflavonoids Help Smokers Protect their Lungs from Cigarette Damage
Over 90 percent of lung cancer is caused by cigarette smoking. However, three servings of fresh fruit and vegetables a day may protect smokers’ lungs from carcinogens.
It’s a given that people who smoke are damaging their health. But, however repugnant the smoking habit is, it is still legal, and there are many smokers who are unable or unwilling to quit.
The next best thing to quitting may be to up their intake of fruits, vegetables and tea.
Smokers who eat three servings of fruits and vegetables per day and drink green or black tea may be protecting themselves from lung cancer, according to a first-of-its-kind study by UCLA cancer researchers.
Flavonoids and a Reduced Risk of Lung Cancer
Flavonoids are water-soluble plant pigments that have antioxidant and anti-inflammatory properties, both of which can counteract damage to tissues.
For the study, researchers looked at 558 people with lung cancer and 837 people who did not have lung cancer and analyzed their dietary history.
“What we found was extremely interesting, that several types of flavonoids are associated with a reduced risk of lung cancer among smokers,” said Dr. Zuo-Feng Zhang, professor of public health and epidemiology and a researcher at UCLA’s Jonsson Cancer Center, in Los Angeles.
“The findings were especially interesting because tobacco smoking is the major risk factor for lung cancer.”
Zhang said flavonoids protect against lung cancer by blocking the formation of blood vessels that tumors develop so they can grow and spread, a process called angiogenesis.
They also stop cancer cells from growing, allowing for naturally programmed cell death, or apoptosis, to occur.
The antioxidant properties found in the flavonoids also may work to counteract the DNA damaging effects of tobacco smoking, he said, explaining why they affected the development of lung cancer in smokers but not in non-smokers.
The Three Most Cancer-Protective Flavonoids
Strawberries, tea, beans, onions, Brussels sprouts and apples had the highest levels of the flavonoids protecting smokers from lung cancer.
Dr Zhang said the flavonoids that appeared to be the most protective included catechin, found in strawberries and green and black teas; kaempferol, found in Brussels sprouts and apples; and quercetin, found in beans, onions and apples.
“These naturally occurring chemicals may be working to reduce the damage caused by smoking,” he said.
So, is this a let-out for smokers? All they have to do is eat more fruit and vegetables and drink tea and forget about quitting? Not necessarily.
Quitting smoking is the best course of action, Dr Zhang said, but pointed out eating more fruits and vegetables and drinking more black and green teas wouldn’t hurt, and would benefit smokers and non-smokers.
Further Research into Flavonoids’ Cancer Protection
Since this study is the first of its type, Dr Zhang said larger studies to confirm these findings needed to be done, as well as further research into the cancer protective effects of flavonoids.
Laboratory-based studies of flavonoids on cell lines and animal models would be needed to determine how they protect smokers from developing lung cancer.
In addition, other studies could be done to see if the protective effects of flavonoids extend to other smoking-related cancers, such as bladder, head and neck and kidney cancers.
Dr Zhang and his team also plan to study which types of fruits and vegetables have the highest levels of the flavonoids and the optimal number of servings per day to provide the greatest protection.