Cancer is a result of multiple factors including our genetics, environmental exposures, and lifestyle choices.  While we cannot change our genes, we can have a major impact on our lifestyle, and thereby the expression of our genes.  It is estimated that 70% of all causes of mortality can altered by behavioral and environmental factors.

Screening Tests:  Screening is used to find cancers at early stages when the chances of survival are greater.  Pap smears have been proven to show early changes (cervical dysplasia) which can be treated thereby preventing the development of cervical cancer.  Mammograms and PSA testing are controversial at the moment with many experts arguing that they do not have any benefit on survival.  (A screening test that finds cancer at a younger age – but doesn’t change the age at which one dies- is one that increases anxiety and does not improve health.)  A recent editorial discussing the controversy about mammograms can be found on Medscape here. The nonprofit Breast Cancer Action created this useful pamphlet that summarizes the evidence for mammograms.

Risk Calculator:  A risk calculator for breast cancer  This is a useful tool that helps you see your own personal risk for developing breast cancer thereby helping you decide how aggressively you might wish to be screened.

Lifestyle choices turn out to have an enormous impact on cancer prevention.  A healthy diet, regular physical activity, and avoidance of environmental chemicals are all important. Daily we are learning more and more about epigenetics.  These are proteins on our DNA that turn genes on and off and are impacted by our lifestyle choices.  The largest amount of evidence is for nutrition, but stress and laughter have also been shown to create epigenetic changes.

Physical Activity: 30 minutes a day of physical activity appears to be the “magic” amount to prevent chronic disease including cancer.

Mediterranean Diet: multiple studies reveal reduced risk of cancer, cardiovascular disease, and Alzheimer’s disease in people who follow a Mediterranean diet. (See specific cancer prevention diet here)

Environmental Chemicals: over 87,000 industrial chemicals are in use in the United States.  A significant percentage are or may be carcinogenic. While this can be both frightening and overwhelming – a number of practical strategies exist to reduce your exposures. (See my website page on reducing environmental exposures.)

Organic Food Choices Minimize Cancer Risk

One of the most common questions I receive from people relates to the value of organic food. Simply put, my patients want to know, “how important is it to eat an organic diet?” Unfortunately, there is no easy answer, but here is the advice I give to those who are interested in learning more about organic food and beverages.

Clearly, organic produce, dairy, chicken and meat cost more. At the same time, we know that choosing organic reduces your exposure to pesticides, which may increase the risk of cancer directly or indirectly through endocrine-disrupting actions. It also reduces exposure to antibiotic byproducts, arsenic and genetically modified foods. Here are some strategies I give my patients to help make wise organic choices.

The Environmental Working Group ( publishes a list each year ranking the amount of pesticides in the 53 most commonly eaten fruits and vegetables. Choosing organic for the most contaminated fruits and vegetables at the top of the list, the so-called “dirty dozen,” and buying conventional for those with the least contamination, the “clean fifteen,” can lessen your exposure to pesticides and save money on purchasing organics. EWG has calculated that if you choose five servings of fruits and vegetables a day from the clean fifteen instead of the dirty dozen, you will reduce your daily consumption of pesticide by 92 percent.

Organic dairy protects you from a different set of problems. While outlawed in Canada, Australia, New Zealand, Japan and the European Union, the U.S. allows use of recombinant Bovine Growth Hormone (rBGH) in dairy production. Two problems emerge: While cattle treated with rBGH produce 10 to15 percent more milk, they also have a higher incidence of mastitis, necessitating more frequent treatment with antibiotics.  Cows treated with rBGH also have elevated levels of insulin-like growth factor-1 (IGF-1) in their meat and their milk. In people, higher IGF-1 levels may be associated with an increased risk of colon, breast and prostate cancers. A useful website that rates the quality and ethical issues around organic dairies is

Purchasing organic chicken is important for yet another set of reasons. Chickens are not treated with hormones. Instead, many are given FDA-approved forms of arsenic, used to promote growth of the animals, feed efficiency and to improve the pigmentation of the meat. In the chicken’s digestive track it is metabolized into arsenite and arsenate–inorganic forms of arsenic, which are carcinogens.   It is also widely found in chicken manure used as fertilizer on many of our crops.

The term organic is sometimes also used with regard to fish, but its meaning is murkier. Wild fish are not in a controlled situation where only organic feed is given. The organic label for fish also addresses sustainability–which is great for our environment. Farmed fish are raised very differently if they are vegetarians like tilapia (easy to feed organic feed) or carnivorous like most salmon (must be fed wild fish.) The standards are still being created. One useful resource is the Seafood Watch from the Monterey Aquarium (

Two final points about organic: One, the organic designation is expensive to achieve. Some of your local farmers may be following organic practices and avoiding the use of most synthetic pesticides, rBGH, antibiotics and other dangerous farming practices to your health and the environment. If you get to know your local farmers at a farmer’s market or by visiting their farms, you may feel really good about supporting locally produced vegetables, fruits and meats even without an organic designation. Second, consider becoming an activist for organic. With some regularity, the designation is threatened. Let your local, state and federal officials know that you value these high standards as a means to protect your health and that of your family.