In one of the more recent Tips From Former Smokers television ads, a man named Roosevelt says, “Always thought that cigarette smoking just messed up your lungs. I never thought, at only 45, it would give me a heart attack.”
Roosevelt learned the hard way that tobacco does do a lot more than cause lung cancer. It also causes heart disease, the top killer in the United States. Combine that with the many other horrible and myriad effects of tobacco – from colon, liver and a whole list of other cancers to stroke, diabetes, male sexual dysfunction and even hip fractures – and you’ll understand why tobacco is a top target for health practitioners and organizations fighting death and disease.
What may not be quite so well-known is that number two on that target list is obesity. And while many people may understand that obesity causes heart disease, that number one U.S. killer, it’s also a cause of cancer, the number two killer in America. And how many people do you hear saying, “I knew fried chicken and doughnuts weren’t good for my heart. But I never thought they’d give me cancer.”?
Know that they can. The American Association for Cancer Research (AACR) estimates that 20 percent, or a fifth of all cancers, are related to being obese or overweight. Throw in the fact that the AACR also estimates that five percent of cancers are due to insufficient physical activity and five percent are due to poor dietary habits, and you’ve got 30 percent of all cancers related to diet and exercise – which is just behind tobacco, which causes 33 percent (or a third) of those cancers.
The National Cancer Institute (NCI) says that obesity is associated with increased risk of breast (after menopause), colon (especially in men), rectum, kidney, gallbladder, thyroid, pancreas, esophageal and endometrium cancers. One of NCI’s recent studies also showed that a higher level of leisure-time physical activity was associated with lower risk for 13 of 26 types of cancer, and a seven percent lower risk of developing any type of cancer.
As for why obesity is a factor in cancer, the NCI notes the following have been suggested:
· Fat tissue produces excess amounts of estrogen, which have been associated with higher risks of breast, endometrial, and some other cancers.
· Obese people often have increased levels of insulin and insulin-like growth factor-1 (IGF-1) in their blood (a condition known as hyperinsulinemia or insulin resistance), which may promote the growth of certain tumors.
· Fat cells produce hormones, called adipokines, which may stimulate or inhibit cell growth. Obese people, for example, have more leptin, which seems to promote cell proliferation, while adiponectin, which is less abundant in obese people, may have helpful anti-growth effects.
· Fat cells may also have direct and indirect effects on other tumor growth regulators.
· Obese people often have chronic low-level, or “subacute,” inflammation, which has been associated with increased cancer risk.
So what’s the takeaway here? The bad news is that being obese, overweight and physically inactive can have deadly consequences far beyond heart disease. The good news is that weight is a modifiable factor – just like tobacco. Greatly reducing the amount of death and disease in America comes down to two remedies, neither of which require vast amounts of money or years of research: Let’s just quit smoking and lose some weight.