TUESDAY, Aug. 31 (HealthDay News) -- Eating a wide variety of
fruits and vegetables may help protect some smokers from lung
cancer, a new European study suggests.
But, the researchers stressed that quitting smoking will do far
more to reduce risk than "an apple a day" or having a salad for
In the study, participants who ate a diet that contained a
diverse mix of fruits and vegetables appeared to have a 27 percent
lowered risk of a common type of lung cancer, the researchers
"First and foremost, the best way to reduce one's risk of lung cancer is to quit smoking. That is of paramount importance," said principal investigator Dr. H. Bas Bueno-de-Mesquita, project director of cancer epidemiology at the National Institute for Public Health and the Environment in the Netherlands. "However, we realize that there are still millions worldwide who cannot and don't want to quit smoking. To just ignore them would be somewhat of a pity. This study shows there is a possibility of reducing one's risk even if one is a smoker."
Keep in mind that "wide variety" meant more than a banana with
breakfast and a helping of peas and carrots with dinner. Think kale
and spinach; berries and melons; cabbage, cauliflower and eggplant
-- some 40 different fruits and vegetables in all.
The researchers analyzed data on more than 450,000 adults from
10 European countries. Participants filled out questionnaires about
dietary habits and lifestyle, including occupation, medical
history, tobacco and alcohol use and physical activity.
Over the course of nine years, 1,613 of the people were
diagnosed with lung cancer.
Vegetable consumption was divided into eight categories: leafy
vegetables; fruiting vegetables; root vegetables; cabbages;
mushrooms; grain and pod vegetables; onion and garlic; and stalk
vegetables. Vegetables did not include legumes, potatoes and other
The 14 fruits tracked included fresh, dried and canned fruits
but excluded nuts, seeds and olives.
Participants were then divided into four groups, or quartiles,
based on the diversity of their diet. Those in the highest quartile
ate between 23 and 40 different types of fruits and vegetables
during the prior two weeks. Those in the lowest quartile ate less
than 10 different types of fruits and vegetables.
Smokers who ate the greatest variety of fruits and veggies were
27 percent less likely to get squamous cell lung cancer, which
accounts for about 25 percent to 30 percent of all lung cancers,
than smokers who ate the least variety.
"It is important to realize the risk reduction one can achieve by eating a greater variety of fruits and vegetables will be minor in relation to quitting smoking," Bueno-de-Mesquita stressed.
The study is published in the September issue of
Cancer Epidemiology, Biomarkers & Prevention. It should be noted that the study relied on "self reports" -- in which the participants described to the researchers their fruit and vegetable consumption. Such studies, while valuable, are not considered the "gold standard" of research -- a double-blind, placebo-controlled study.
But what is it about fruits and vegetables that may ward off the
changes in cells that cause tumors to grow?
There probably isn't one "magic" compound in the fruits and
vegetables, Bueno-de-Mesquita said, but instead many compounds that
interact with each other and the body in ways that aren't yet
It can be dangerous to put too much stock in any one substance,
he added. A study in Finland found smokers who took the antioxidant
beta carotene and vitamin E supplements actually had an increased
risk of lung cancer.
Previous research has also linked fruits and vegetables with
lowered risk of cancer. A 2007 World Cancer Research Fund/American
Institute for Cancer Research report concluded that fruits probably
protect against lung cancer, but there was no evidence that
But other research has suggested eating a variety of vegetables
can reduce the risk of other types of cancers, including
colorectal, gastric, breast, oral and pharyngeal cancer and
squamous cell esophageal cancer.
Marjorie McCullough, strategic director of nutritional
epidemiology at the American Cancer Society, said fruits and
vegetables may help to protect against lung cancer, but every
smoker should be working on quitting.
"Quitting smoking is far and away the most important way to lower the risk of lung cancer, but eating a variety of fruits and vegetables may further help lower the risk of several cancers," McCullough said.
Eating lots of fruits and vegetables can also help prevent
obesity, which is a risk factor for certain cancers, she added.
U.S. National Cancer Institute has more on lung