o you ever wonder how much control you have over your own personal risk of developing cancer? I do, too, and it prompted me to do some research for us. Did you know that cancer is still the second leading cause of death in this country after heart disease? Although the number of people who develop cancer is dwarfed by the widespread impact of heart disease, one out of four Americans will eventually develop some form of cancer. Specifically, half of all men and one third of all women will develop cancer in their lifetimes, usually after age 55.

There is some good news, though! We hold plenty of power when it comes to preventing cancer. The most significant controllable factors in cancer risk are smoking, diet and exercise. There are many things that we still do not know about cancer, but there is one thing we know for certain: tobacco smoke, both first-hand and second-hand, causes cancer. Cigarette smoking is responsible for at least 30% of all cancer deaths. If you want to significantly lower your cancer risk, don't smoke and avoid exposure to second-hand smoke.

Both what you eat and how much you eat seem to play an important role in cancer prevention. Being overweight is the biggest dietary risk factor in the development of cancer. Overweight women are at higher risk for endometrial cancer and post-menopausal breast cancer. Overweight individuals are at higher risk for developing colon, esophageal and kidney cancers and there is also an association between excess weight and cancers of the pancreas, gallbladder, thyroid, ovary, cervix, and prostate, as well as multiple myeloma and Hodgkin disease. The American Cancer Society states that between 14% and 20% of cancer deaths are related to overweight. It is believed that excess fat produces hormones that are active in the cancer causal chain, especially in breast cancer cases, and that losing excess weight lowers hormone levels and therefore lowers overall cancer risk. If you are obese, overweight or even just weigh more than you used to when you were younger, you need to make healthful dietary changes that you can live with in order to get back to your healthiest weight. I know many of us reminisce fondly about how svelte we were when we graduated from high school, and if you were at a healthy weight when you were 18, then I strongly encourage you to work at getting as close to that weight as possible. Gaining more than five pounds after the age of 18 is associated with the development of breast cancer in women and possibly other cancers in both men and women (as well as type II diabetes, heart attacks and strokes). If you're not sure if you are overweight or at a healthy weight, then come visit me at your local Gelson's this month and I will test your body fat to find out if you're carrying too much or just enough fat. As I said, though, any weight gain isn't good for your health and we should work to get you back to your "pre-weight gain" weight.

Making healthy dietary choices can help lower your weight and, therefore, your risk of developing certain cancers. However, there is not much evidence that what you eat has a direct link to cancer prevention. Much is still unknown about the effects of food choice on cancer. However, studies show that a lifetime of healthy eating and healthy weight offers more protection than does a change to healthier eating and weight later in life - prevention is more powerful than change, but change is still important. Just as quitting smoking won't make your lungs look like those of someone who has never smoked but will lower your risk of developing lung cancer later on, improving the healthfulness of your diet and achieving your healthiest weight will help lower your risk of developing certain cancers later, too.

Eating a mostly plant-based diet is highly recommended for cancer prevention and overall health. Vegetables, fruit, whole grains and plant proteins should form the basis of your diet, which means that this diet tends to be higher in fiber and lower in total and saturated fats than more meat-centered diets. Plant foods are rich in antioxidants that are important in the fight against free radicals (which can damage DNA and initiate cancer if their reactions are not repaired by antioxidants). Specific nutrients in vegetables and fruits are believed to offer anti-tumor protection. Those in the cruciferous vegetable family are of particular importance. Broccoli, cauliflower, Brussels sprouts, bok choy, cabbage, arugula and kale are all believed to contain compounds called sulphoraphanes that are especially good for inhibiting prostate, colon, stomach and breast cancers. Orange and green vegetables and fruits contain beta carotene, which is believed to help protect against cancers of the breast, stomach and colon. Pomegranates contain phytonutrients that seem to halt the growth of prostate tumors and possibly other types of tumors, too. Tomatoes, especially cooked tomatoes, are rich in lycopene, a phytonutrient similar to beta carotene. Populations that consume lots of lycopene-rich foods have lower risks of prostate, lung, cervical, breast, bladder, skin, and digestive tract cancers. Green tea and, to a lesser extent, black tea seem to help reduce the risk of developing skin, esophageal, and stomach cancers. Beans, legumes and whole grains are high in fiber and are therefore believed to help prevent certain types of cancers by binding to hormones that circulate in the blood and carrying them out of our bodies quickly. Another significant benefit of a plant-based diet is that it tends to be low in calories, which is helpful for weight control.

A plant-based diet is also recommended for cancer prevention because of the association between meat consumption and cancer risk. The frequent consumption of red meat and processed meats (such as smoked, salted or nitrite-containing sandwich meat, including ham, turkey and chicken) has been shown to increase the risk of stomach, colon and rectal cancers. Eating more than three ounces of red or processed meat daily can increase the chance of developing these cancers by about 50%. If and when you do eat fresh meat, poultry or dairy products, make sure that they are hormone free (choosing organic is the easiest way to ensure that they are), since minimizing hormones seems to be a key factor in the prevention of many cancers.

High-fat diets, especially those high in saturated fats, are associated with an increased risk of colon, rectal, prostate, uterine and breast cancers. There is evidence, though, that certain fats are protective when eaten in the optimal ratio compared to other fats. Population studies also show that people who use olive oil as their primary source of fat have decreased risks of stomach, breast and ovarian cancers. Omega-3 fats, which are so good for our hearts, also seem to be beneficial for our overall health. There is growing evidence that they may help prevent prostate and breast cancers and reduce the risk of breast cancer recurrence in survivors. Omega 3's come from fatty fish such as salmon, tuna and black cod, as well as flaxseeds, walnuts and soybeans, and should be the type of fat that we prioritize in our diets. Ideally, we want to eat as many omega 3's as we do omega 6's, which are ubiquitous in processed foods, vegetable oils (except olive and canola oils), bakery goods and frozen foods. Following a plant-based, whole-food diet makes it much easier to optimize this ratio because processed foods are minimized.

Finally, alcohol consumption, though it may be good for your heart, is not good for your cancer risk. There is a very strong link between drinking just a small amount of alcohol a day and the development of breast cancer. Alcohol consumption is also associated, though not as strongly, with oral, esophageal, colon, liver and other cancers. If you do drink, please do so in moderation (up to two drinks a day for men and one a day for women).

What is most important is your overall diet. Just drinking green tea and eating whatever you want will not work, but if you are careful with your overall diet, then you will likely get some cancer protection from it. Similarly, taking dietary supplements that isolate what we believe to be the protective phytonutrients and vitamins from fruit, vegetables, grains and legumes are unlikely to offer any cancer protection because of the unique packaging of fiber and nutrients that naturally exist in plants and because it is not totally clear which nutrients are the important ones. Forget about those broccoli pills-your best bet for optimal health and disease prevention is to eat between seven and 11 servings of produce daily. Eating a plant-based diet can be easy if you treat it with flexibility. I personally eat two vegetarian meals a day and one meal that contains up to four ounces of fish, poultry or red meat a day. That makes it easier to keep variety and interest in my diet while still meeting my produce requirements.

Being inactive or underactive is a big risk factor for cancer. If you are at a healthy weight, then 30 minutes of moderate activity five or more days a week will offer you some cancer protection. However, if you are not at your healthiest weight and you are inactive, then you are at higher risk for breast, colon, endometrial, kidney and esophageal cancers and you will need to put in some extra time to help lower your risk. About 60 to 90 minutes of moderate to vigorous exercise on most days of the week is recommended to both combat that extra risk and to help you shed extra weight.

Exercise is beneficial for several reasons. First, it can help burn calories and therefore the fat that is a risk factor for many cancers. It also helps reduce levels of circulating hormones that, when elevated, are linked to several types of cancers. Physical activity boosts the immune system, which helps fight off potential carcinogens and diseases. Exercise is important in the digestive process because it can tone gut muscles and help food move through you quicker, so that your exposure time to harmful substances is reduced. Being physically active on a regular basis has also been shown to increase survival rates and life expectancy for those with breast and colon cancers.

Moderate to vigorous exercise is what is most strongly recommended for cancer prevention. That means 30 to 60 minutes of activity that is "change-your-clothes-and-wear-special-shoes," full-blown exercise. Your everyday activities, though they may be brisk, do not count toward that time goal. Although it is not the case with food, when it comes to exercise, more is better. Moderate exercise options include: golfing, walking, dancing, skating, and bike riding. Vigorous options are: running or jogging, aerobics, racquetball, soccer, swimming and weight training. Whichever level you choose, you still need to do at least 30 minutes at least five days a week. If you are currently sedentary, talk to your doctor before beginning an exercise program of any type or level.

Cancer risk is different for each individual depending on their genes, family history, where they grew up, and may other factors that we don't have control over. Although genes play a role in cancer, either through inherited risk or genetic damage acquired over your lifetime, we can't always control our inherited DNA or our exposure to carcinogens. However, weight, diet, exercise and tobacco use are factors that we do have control over and they carry a lot of significance when it comes to lowering cancer risk and preventing or delaying cancer. For these reasons, I urge you to live the healthiest life that you can to help reduce your controllable risk factors and boost your overall health as much as possible.