DEAR DR. ROACH: Recently, a well-respected consumer organization ran an article asserting that hundreds of thousands of people die every year just from eating deli meat! The problem is supposedly that the nitrates and/or nitrites in the meat combine to make nitrosamines, which are supposedly carcinogenic.

Just what evidence is there that nitrosamines cause cancer in humans? Is the case based on enormous doses given to animals? I don’t have to worry about stuff like hot dogs, bologna and salami. I hate these meats and never eat them. But deli turkey is a great food. Low in calories, almost no fat, a great source of protein. It can be a little high in salt, but if you watch your salt intake the rest of the day, it’s OK.

Most of us don’t have time to roast a turkey breast and slice it up. Are these low-fat turkey sandwiches really life threatening? Or is this advice like everyone should drink eight glasses of water a day or everyone over 50 should take a baby aspirin — both thoroughly debunked. What is the truth please, Dr. Roach? — R.E.

ANSWER: The truth is that there is pretty solid evidence that some types of processed foods, especially those made with nitrites, increase the risk of colon and stomach cancers. These data come from human studies, not animal studies, from the World Health Organization. They were confident enough in the data in 2015 to label processed meats as “carcinogenic.”

The magnitude of the risk is small. It’s estimated that eating a moderate amount of processed meat (about 2 ounces a day) will increase the lifetime risk of bowel cancer from 4.8% to 5.6%. That’s enough for me to recommend against making processed meats a regular part of your diet.

However, not all deli meats are processed using nitrites, and it’s not 100% clear that the nitrites are the sole or even the main cause of the increase in risk. Some of the foods you mention are made minimally processed, with very little if any ingredients that might increase the risk of bowel cancer. It takes some perseverance, but you can find out what your deli is serving and check to see how it is made.

Occasional amounts of these kinds of products are not very dangerous. A mostly plant-based diet has many benefits, including lower cancer risk. Having bacon every day is not a good idea for health, but adding in an occasional deli lunch is not a big risk.

The “hundreds of thousands” number seems more hyperbole than science to me.

DEAR DR. ROACH: My husband is being tested to confirm the pulmonologist’s tentative diagnosis of mycobacterium avium complex. He was a relatively healthy person up to this point, so could you please explain how he could have contracted this? The prognosis does not look good. Are there any new treatments available? — R.K.

ANSWER: Mycobacterium avium complex is caused by a group of bacteria that are closely related to tuberculosis, and cause pulmonary disease. In men, it often occurs with preexisting lung disease, especially from smoking. In older women, it more often occurs without any known lung disease. It is thought to be acquired by inhalation from water sources.

Treatment is with multiple antibiotics, generally for six months or longer. The prognosis is good for people with sensitive bacteria, but disease from resistant bacteria is hard to treat. Consultation with an expert is necessary in such cases, and surgery is an occasional option. Although new antibiotics are always being developed, I am unaware of any imminent breakthrough.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.

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