Fruits, Teas and Vegetables May Reduce Cancer Risk in Smokers

Key Takeaways:

• Increased consumption of fruits, vegetables, and teas rich in flavonoids may potentially reduce smokers’ risk of developing lung cancer, according to a study by researchers at the University of California, Los Angeles (UCLA).
• Specific flavonoids such as catechin, kaempferol, and quercetin found in various fruits and vegetables appear to significantly contribute to this protective effect.
• Flavonoids may protect against lung cancer by preventing the formation of blood vessels that tumors need to grow, inhibiting the growth of cancer cells, and reducing the harmful effects suffered by the smoker’s DNA due to tobacco smoke.
• These findings are initial, and larger studies are needed to further confirm these results and to see whether flavonoids can also help protect against other types of cancers linked with smoking.
• A follow-up study is planned by the UCLA team to determine which fruits and vegetables contain the highest amounts of the most effective flavonoids, and to ascertain the optimal daily serving size for the best protection against lung cancer.

Increased consumption of fruits, vegetables, and teas rich in flavonoids may potentially lessen smokers’ risk of developing lung cancer, as per the findings of a study conducted by a team of researchers at the University of California, Los Angeles (UCLA).

Flavonoids are water-soluble pigments derived from plants that possess antioxidants and anti-inflammatory properties, which can effectively reduce tissue damage. The researchers from UCLA discovered this possible correlation through studying dietary habits of smokers both with and without lung cancer.

The Role of Specific Flavonoids

Certain flavonoids appeared to significantly contribute to this protective effect: catechin (found in strawberries and both green and black teas), kaempferol (present in Brussels sprouts and apples), and quercetin (found in beans, onions, and apples).

This crucial discovery, first released in a June edition of Cancer, can potentially prove pivotal as tobacco smoking remains the leading cause of over 90% of lung cancers.

The Potential of Flavonoids: Caution and Optimism

“Given that this study is the first of its kind, normally I would exercise caution before giving people dietary recommendations,” explained Dr. Zuo-Feng Zhang, a member of UCLA’s Jonsson Cancer Center and a professor of public health and epidemiology. He later added, however, “it wouldn’t harm for everyone to consume more fruits and vegetables and to drink more tea.”

How Flavonoids could Protect Smokers from Lung Cancer

Flavonoids, according to Zhang, might protect against lung cancer by preventing the formation of blood vessels that tumors need to grow and spread, a process known as angiogenesis. In addition, flavonoids might also inhibit the growth of cancer cells, allowing a natural cell death, or apoptosis, to occur.

The antioxidant properties of flavonoids may turn the tides against the harmful effects suffered by the smoker’s DNA due to tobacco smoke. According to Zhang, flavonoids also contribute to the development of lung cancer in smokers, but they do not display the same effect in nonsmokers.

“These naturally occurring chemicals may be working to reduce the damage caused by smoking,” Zhang explained.

Zhang stated that larger studies are needed to further confirm these results, and to see whether flavonoids also can help protect against other types of cancers that are linked with smoking, such as cancers of the bladder, head, neck, and kidneys.

Further Studies in the Pipeline

The UCLA team is currently planning a follow-up study to determine which fruits and vegetables contain the highest amounts of the most effective flavonoids, and to ascertain the optimal daily serving size for the best protection against lung cancer.

More Information

Learn more about flavonoids from this study by the Linus Pauling Institute at Oregon State University.