(The New York Times News Service) -- WEST PALM BEACH, Fla. -- Prevention and early detection are cancer mantras. I just read an article about cancer prevention.

Astoundingly, a Harvard study concluded that up to 80 percent of cancers are due to lifestyle. If so, most could be prevented with lifestyle changes. What are they? How do we change them?

Some cancers are caused by carcinogens -- cancer-causing elements. The most common are cigarette smoke and tobacco products.

If Americans stopped smoking and chewing tobacco, almost 30 percent of all cancers might be eliminated.

Other carcinogens are all around us. Asbestos, radon and pesticides are just a few. The Environmental Protection Agency works to limit carcinogen exposure. Fortunately our bodies are equipped with an immune system designed to fight off the dangers of certain carcinogens, but it would be better not to have them in the first place.

Our diet plays a role in cancer prevention. Obesity causes cancer. Take breast cancer. Women produce estrogen in fat cells.

The more fat cells, the more estrogen, a hormone that fuels breast cancer.

Obesity causes cancer in men too. If all Americans could maintain an ideal body weight, there would be up to a 30 percent reduction in the incidence of cancer.

Socioeconomic constraints make this virtually impossible.

Nutritious, cancer-fighting foods are not in the average budget.

Instead, we eat less healthy fast food, drive-through, takeout, and order in and fall short of the recommended daily servings of fruits and vegetables to bolster our immunity and ward off cancer.

Vitamins are touted as essential to cancer prevention, but this is controversial. There is a consensus that Vitamin D is essential.

Over 50 percent of Americans are deficient, even in sunny Florida.

Because Vitamin D is fat soluble, doctors and patients used to fear that it might be toxic in high doses. Not true. The RDA went from 400iu a decade ago to 800iu and will probably go up again. A blood level of 30 or more is good, but 45 to 65 is ideal.

Antioxidants aid in cancer prevention. Vitamins C, E, selenium, glutathione, resveratrol, CoQ10, and a host of others may be helpful. In particular, omega 3 free fatty acids are excellent in decreasing inflammation that leads to cancer. Fish oils are an excellent source, as are flaxseed and chia seed.

When taking supplements people often ask how much they need.

Sadly we don't know exactly how much of these is essential for each person, nor are we certain of their interactions or impact on other medications.

For example, selenium can be toxic. A handful of almonds contains more than the RDA of selenium. Patients who eat nuts and take multivitamins as well as separate antioxidants could be at risk for selenium toxicity. Remember, if a little is good, a lot is not necessarily better and avoid mega doses.

Patients may balk at taking vitamins. They may be too expensive.

And, there is no good way to be sure they are absorbed. Patients complain their urine is neon green after taking vitamins and worry they are losing the nutrients to the toilet.

They could get nutrients from food. Cruciferous vegetables like broccoli, Brussels sprouts and kale promote good health. But, they are unpopular. Kids often don't like them.

Luckily, there is an easier way. Add greens, berries, and omega 3 powders to juices, soups, or sauces. Make a smoothie with these, juice and yogurt for a delicious and nutritious breakfast or snack.

Exercise counts as lifestyle. It decreases heart disease in addition to cancer, and makes you look and feel better. But getting into shape is daunting. Start slowly and incorporate a sport that you will stick with forever.

Walking is as good as running. Even gardening is good. Manual laborers incorporate exercise in the workplace. The rest of us must set aside time in our already stressed-out lives making exercise more of a luxury. It is worth it. Besides preventing cancer, it decreases stress and I have yet to meet someone who is not stressed!

The biggest obstacle to preventing cancer is socioeconomic. As mentioned, proper nutrition puts a big dent in the wallet. In addition, subpopulations don't emphasize nutrition. For example, native Americans smoke and drink alcohol at a higher rate.

Hispanics tend to eat fewer vegetables. Radically changing their approach to diet is like asking them to give up a key element of their identity.

Hope springs eternal. I encourage the healthy person hiding in each of us to come out. If the article I read is true, we could save billions of health care dollars by educating the public and finding cheaper ways to get better nutrition to those who need it most.

Until then, we'd better keep working on early detection ... but that is the subject of a different column.

Dr. Melanie Bone is a cancer survivor and gynecologist who practices in West Palm Beach, Fla.

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