The evidence is overwhelming: diet plays a huge role in your vulnerability to cancer. If you know what foods to avoid and which to embrace, you lower your risk substantially. The avoids are fairly obvious -- processed foods, high-fat items, deep-fried and charred items, meats, things laden with sugar, anything not organic. So too are the helper foods -- leafy greens, fruits, green tea, food high in antioxidants. Research keeps reinforcing these facts, and now a new study has found that smokers can actually influence genetic changes that would otherwise lead to lung cancer by eating the right foods.
The study, out of the Lovelace Respiratory Research Institute in Albuquerque, New Mexico, involved 1100 current and former smokers, 75 percent of whom were female. All the subjects had at least a 15-year smoking habit of a pack or more daily. At the outset, the subjects provided samples of spit and completed questionnaires about their eating habits. The research team then analyzed the spit for methylation of the cells, a process that "turns off" genes, blocking their function by depositing methyl molecules. Smoking causes methylation, one of the chief reasons smoking causes cancer. As Dr. Jacob Kagan of the Cancer Biomarkers Research Group commented, "Aberrant gene methylation is a known mechanism in the development of cancer from cigarette smoke carcinogens." The researchers particularly wanted to know if methylation had occurred in those genes responsible for suppressing tumor growth and repairing DNA, because when methylation occurs in those genes, lung cancer risk increases substantially. Even more, they wanted to see if dietary intake would affect the rate of methylation, and so they analyzed the connections between methylation and 21 dietary variables.
And guess what they found? The more leafy green vegetables the subjects ate, the less methylation they had in their genes. The researchers assumed that the high levels of folates in the green vegetables were responsible for the effect, although they also found significant reduction of methylation in subjects who took multivitamins.
According to study director Dr. Steven A. Belinsky, director of the Lung Cancer Program at Lovelace, "There was a dose response with consumption of vegetables and sustained vitamin use, and increased duration was associated with better protection. Multivitamins and leafy green vegetables have things other than folate, although that is the common link…"
Interestingly, only the leafy green vegetables protected against methylation. The researchers found no benefit from other foods (including other high folate vegetables), which on analysis throws doubt on the idea that folates alone made the difference. After all, fruits, beans, liver, and even fortified cereals have plenty of folates. Could it be, then, that calorie-for-calorie, leafy greens simply have more nutritional punch than most other foods, and that their balance of minerals, vitamins, phytonutrients, flavenoids, and fiber works together in a unique and powerful way? (Certainly folates have benefits, and those benefits extend beyond their anti-carcinogenic properties. They've also been found to benefit the cardiovascular system, to lessen depression, and to protect against birth defects. But again, a close look at the study makes it doubtful that folates alone are the key to preventing lung cancer.)
Given the results, the researchers recommend that smokers make like Popeye and eat their spinach. "Most cancers arise through inactivating genes by methylation, so I don't think consumption of leafy green vegetables and a multivitamin would do anything negative, and it could help," Dr. Belinsky admits.
Meanwhile, a simultaneous study found that drinking a cup of green tea daily has a profound impact on lung cancer prevention, even among smokers. The study, from Chung Shan Medical University in Taiwan, found an amazing 13-fold lower risk among green-tea drinking smokers and a seven-fold lower risk among non-smokers. Participants included 170 lung cancer patients and 340 healthy patients. In this case, the researchers credit the antioxidants in green tea for the benefit. It's also worth noting that demographic studies have indicated that green tea consumption might provide a possible explanation as to why the Japanese, who are among the world's heaviest smokers, have such a low incidence of lung cancer.
That said, the experts expressed concern that the irresponsible public will learn of these studies and go haywire smoking because they now will know how to counter the effects. The head of the American Lung Association, Dr. Norman Edelmen, said, "What the American Lung Association is really afraid of is that people will look at this and think, 'Oh, well, I can smoke as long as I have a few cups of green tea.' Nothing could be further from the truth. Smoking is extremely toxic, obviously, and extremely detrimental to your health. And nothing changes this fact. So the most important thing here is that we don't want anyone to get the message that it's okay to smoke so long as I drink green tea."
Let's hope we're not that stupid. In any event, to paraphrase Dr. Belinsky, it sure couldn't hurt to drink green tea, especially if you have a history of smoking. Better yet would be to not smoke at all, drink green tea anyway, and eat lots of organic chard, kale, spinach, collards, and the like.