We tell people to “eat the rainbow” when it comes to fruit and vegetables — meaning that intensely colored ones have the most antioxidants and other health-promoting micronutrients.

Mushrooms are not colorful, yet they are nutritious. They are fungi, however, so the color rule doesn’t apply. Dr. Joel Fuhrman, author of several books, writes in “Eat to Live” that “mushrooms contain a variety of powerful phytochemicals and have been linked to decreased risk of chronic diseases, especially cancer.”

MUSHROOMS AND ERGOTHIONEINE: Mushrooms are the most important source of ergothioneine, an amino acid that is a potent antioxidant that protects mitochondria (the microscopic “power plants” inside cells) from free radical — the cause of harmful oxidative stress. In his book “How Not to Die,” Dr. Michael Greger says that “depriving human cells of this amino acid leads to accelerated DNA damage and cell death.” Ergothioneine is concentrated in parts of the body that experience a lot of oxidative stress, such as the liver and the eye lenses. It is also concentrated in tissues such as the bone marrow and semen that are particularly sensitive to oxidative stress.

CANCER: Mushrooms help prevent cancer by the following mechanisms:

· Angiogenesis refers to formation of new blood vessels. Cancer cells make angiogenesis promotors that enable them to multiply and metastasize. Compounds in mushrooms block this process, causing cancer cells to die.

· Some of the billions of cells in our bodies are always mutating. Mushrooms help optimize immunity, killing off these mutant cells before they can propagate and cause cancer.

· Excessive estrogen contributes to breast cancer, and aromatase is an enzyme involved in estrogen production. Aromatase inhibitors are used in chemotherapy used to treat breast cancer, and mushrooms contain a natural aromatase inhibitor. Asian women have a much lower incidence of breast cancer compared to women on a Western diet — part of the reason is thought to be due to the prevalence of mushrooms in Asian diets.

INFLAMMATION is implicated in many diseases including asthma, rheumatoid arthritis, and heart disease, and mushroom have anti-inflammatory properties. Furthermore, Dr. Fuhrman credits mushrooms as being one of the few food sources of VITAMIN D.

Dr. Greger points out that “mushrooms make a great, chewy replacement for meat.” His favorite way to eat mushrooms is to drizzle balsamic vinegar on them and grill them at low heat, turning them frequently. Recipes for tasty mushroom stroganoff can be found on the internet and in vegan cookbooks.

There are two caveats about eating mushrooms (other than being very cautious when gathering your own in the wild):

· Raw edible mushrooms have a mild toxin called agaritine, which fortunately is destroyed by cooking. Morel mushrooms have a higher level of this toxin and even cooked morels can release this toxin when combined with alcohol.

· Some commercial mushrooms are grown with fertilizer containing chicken dung, that often contains arsenic, because arsenic-containing compounds are often fed to chickens. However, the amount of arsenic that people get from eating the quantity of mushrooms that most people eat is not enough to be problematic.

Bottom line: Mushrooms are good for you, so eat them a few times a week, but don’t eat huge quantities and avoid raw ones.

Dr. Feinsinger is a retired family physician with special interest in disease prevention and reversal through nutrition. Free services through Center For Prevention and The People’s Clinic include: one-hour consultations, shop-with-a-doc at Carbondale City Market and cooking classes. Call 970-379-5718 for appointment or email gfeinsinger@comcast.net.