Vitamin B Reduces Lung Cancer Risk
Here's news that should make you breathe easier, even if you're a smoker. A study published in the Journal of the American Medical Association (JAMA) showed that higher levels of B6 in the blood cut the risk of lung cancer by half. The study, funded by the World Cancer Research Fund and other groups, analyzed the levels of four B vitamins (B2, B6, folate, and B12) as well as the amino acids methionine and homocysteine in the blood of participants recruited into the European Prospective Investigation in Cancer (EPIC) between 1992 and 2000.
Of the 519,978 participants, drawn from 10 European countries, some 385,747 gave blood samples. Among those, 899 lung cases of cancer were detected by 2006. The blood of those individuals was compared to that of 1770 healthy individuals. The researchers divided the participants into four groups based on the levels of B6 in their blood. After controlling for smoking, the analysis indicated that those with the highest levels of B6 in the blood reduced lung cancer risk by a whopping 56 percent. Those with the highest levels of methionine in the blood reduced their lung cancer risk by 48 percent.
What do B6 and methionine do? B6 is involved in a variety of metabolic functions. Among them, it is necessary for the production of red blood cells and immune system cells. It helps control blood levels of the potentially dangerous amino acid, homocysteine, which is associated with heart disease. B6 also helps the body manufacture several neurotransmitters and hormones that regulate mood and the body's clock. Methionine helps the system to break down fats, assists the digestive system, and works to remove heavy metals from the body. It is also an antioxidant and is involved in the metabolism of B vitamins. More significantly, both nutrients appear to protect against DNA damage.
Head researcher Paul Brennan, PhD, of the International Agency for Research on Cancer in Lyon, France, told WebMd, "We found that vitamin B6 and methionine are strongly associated with reducing lung cancer risk in people who never smoked, those who quit, and current smokers."
The experts contend that the anti-cancer effect may have to do with a factor other than the vitamin B6 or methionine, such as the beneficial effects of consuming a particular food that those nutrients are found in. In fact, Dr. Brennan cautioned against taking supplements in hopes of preventing lung cancer. "There is no evidence that vitamin supplements may reduce cancer risk and even some evidence that they may increase cancer risk," he said.
But "au contraire," a scan of the research didn't turn up any studies showing that B6 may increase cancer risk. Quite the contrary! A 2006 study out of Harvard Medical School, for instance, found that of 33,000 women, those taking the highest dose of vitamin B6 supplementation, five times the recommended daily intake, had the lowest incidence of colon cancer. That study also found that those women who had the highest levels of vitamin B6 in their blood had a 44% lower incidence of colorectal cancer and a 58% reduced risk of colon cancer. Several studies also point to lowered levels of breast cancer among women with high levels of vitamin B6 in their blood. A 2008 study found a 38% reduction in breast cancer among women over the age of 65 who supplemented with folic acid, vitamin B12, and vitamin B6.
Perhaps Dr. Brennan was referring to the ATBC trial that concluded that beta carotene supplementation potentially increased lung cancer risks in smokers. But that trial was fatally flawed in that it tested the use of synthetic beta carotene derived from acetylene gas, not a natural beta carotene complex. Synthetic beta carotene and natural beta carotene are about as similar as Ripple wine and a 1787 Chateau Lafite. Technically, you can call them both wine -- but beyond that...In any case, the ATBC trial did not examine B vitamins.
Dr. Len Horovitz, of Lenox Hill Hospital in New York also added a cautionary note, but he was concerned about dose rather than about the advisability of taking B6 supplements. "Optimizing B6 levels to reduce lung cancer risk is seemingly straightforward, and probably a good idea if not taken to excess," he said, "but precise dose is unclear. One message about taking any supplements to reduce risk is that the appropriate dose needs to be found, and that more is not necessarily better."
In fact, if you take too much vitamin B6, you can develop nerve problems in the hands and feet, but that's only if you take it in a form other than pyridoxamine, which leads to no such effects. In any event, toxicity doesn't usually develop unless you take more than 100 mg a day. Just check your supplements to make sure that the vitamin B6 is in the form of pyridoxamine. As for methionine, the doctor's warning actually may be appropriate. Studies have found that people taking more than five times the normal dose had elevated plasma homocysteine, problematic for heart health. One 2009 study found that high levels of methionine are associated with greater risk of Alzheimer's disease, and other research has linked the amino acid to hardening of the arteries, liver disease, and acidosis. Also, too much methionine has been known to exacerbate psychopathological symptoms in schizophrenic patients.
In other words, when it comes to methione, look to diet first, accompanied by light supplementation. Good sources of methionine include beans, garlic, lentils, onions, and fish. Dietary sources of B6 include bananas, whole wheat, free range eggs, avocado, brown rice, oats, chicken, fish, potatoes, and peanuts. But for lung cancer protection, your best bet is to avoid smoking, smokers, and dirty air, to the best of your ability. Oh, and keep in mind that the very act of smoking rapidly depletes B vitamins from your body.