Hamburger Report Not Well Done

Remember when Lawrence Livermore National Laboratory scientists used to make bombs? Now, they just publish them.

Lawrence Livermore researchers just reported in the Journal of the National Cancer Institute that cooking hamburgers at lower temperatures for shorter periods of time reduces the formation of cancer-causing substances.

Frying hamburgers at a pan temperature of 320 degrees Fahrenheit and turning them every minute reduces the formation of a class of compounds called "heterocyclic amines" while still killing bacteria, according to the researchers.

They claim that reducing the formation of heterocyclic amines is prudent because heterocyclic amines are "multi-site carcinogens in animals" and "recent epidemiologic studies have shown a positive association between intake of well-done meat and increased risk of lung cancer, breast cancer and colorectal cancer."

It's not surprising that laboratory experiments report higher rates of cancer among animals administered heterocyclic amines. The animals are bred to be genetically predisposed to cancer and they are force-fed extremely high levels of the compounds.

Researchers recently estimated that 85 percent of chemicals tested in laboratory animals by the U.S. government's National Toxicology Program had some carcinogenic or anti-carcinogenic effect. They concluded, "This suggests that most chemicals given at high enough doses will cause some sort of perturbation in tumor rates."

So let's look at the three studies of humans cited by the researchers associating well-done meat consumption with lung, breast and colorectal cancer.

Study No. 1

A 1998 study by National Cancer Institute researchers published in Cancer Causes and Control reported a weak statistical association between estimated consumption of well-done meat and lung cancer. Under virtually any circumstances, a weak statistical association isn't very persuasive, but in this case it's ludicrous.

The study subjects with lung cancer were all current or former heavy smokers — an average of a pack of cigarettes per day for 48 years.

The researches sheepishly acknowledged the problem at the end of their report: "Our finding ... needs to be viewed in the context of other risk factors, such as smoking. Smoking is by far the biggest risk factor for lung cancer..."

Study No. 2

In the study allegedly linking well-done meat with breast cancer, the researchers have no idea how much meat was actually consumed, much less its doneness, for any of the study subjects.

The study's weak statistical associations largely rely on the women's stated "preference" for doneness. It's a relatively small study — one touted statistical association relies on 12 cases of breast cancer. Key risk factors for breast cancer — such as history of benign breast disease, age at menstruation and age at live first birth — were ignored.

Study No. 3

The study claiming a link between well-done meat and colorectal cancer didn't even look at colorectal cancer. The health endpoint examined was adenomas — benign tumors that only might become malignant. A recent study in the journal Surgical Oncology noted, "By the age of 70 years, at least 50 percent of the Western population will develop some form of colorectal tumor, spanning the spectrum from an early benign polyp to an invasive adenocarcinoma. It is estimated that approximately 10 percent of the benign polyploid lesions will progress to invasive carcinoma."

The study — again reporting weak statistical associations between consumption of well-done meat and colorectal adenomas — failed to consider family history of colorectal cancer as a confounding risk factor. A recent study reported that family history of colorectal cancer increased the risk of colorectal cancer by 14-fold — an order of magnitude greater than risk reported for consumption of well-done meat.

Where's the beef? Beats me. Here's mine.

The three studies claiming to link consumption of well-done meat with lung, breast and colorectal cancer have something in common other than faulty science — they all involve researcher Rashmi Sinha of the National Cancer Institute. Not only was the new study published in the Journal of the National Cancer Institute, but the NCI provided funding to the Lawrence Livermore National Laboratory researchers, including Sinha's oft-time cohort, Mark Knize.

It seems a small, inbred group of NCI-affiliated researchers has convinced itself — and now is trying to convince us — that well-done meat is a cancer risk. It's too bad their evidence isn't too well-done.

Undaunted, they've moved on, from science to the culinary arts, instructing us how to fine tune cooking meat. But the cooking is a high wire act. Stray from the prescribed regimen of temperature and turning and you run the risk of cancer — according to Sinha and company — or food poisoning.

Thanks, but no thanks. I'd rather minimize the very real risk of food poisoning from bacteria like E. coli O157:H7 than avoid a little extra charbroiling because of a make-believe cancer risk.

— Steven Milloy is a biostatistician, lawyer, adjunct scholar at the Cato Institute and publisher of