Study Links Diet of Cured Meats to Leukemia

Eating cured meats may lead to an increased risk of leukemia in children and young adults, according to a Harvard School of Public Health study recently published in the BioMed Central Cancer journal.

The study found an association between consuming smoked or cured meat and fish more than once a week and an increased risk of acute leukemia. Conversely, researchers concluded that subjects who ate vegetables and tofu regularly along with cured meats showed reduced risk for leukemia.

The population-based case-control study, conducted in Taiwan, looked into the dietary habits of 515 subjects who ranged in age from two to 20 years-old. Researchers gathered data between 1997 and 2005.

According to Professor of Medicine David C. Christiani, the chemical culprit is most likely the nitrites added during the curing and smoking process. These chemicals transform into N-nitroso compounds—which are known carcinogens—in the acidic stomach.

“These are some very active compounds in your body,” said Christiani. “Have you ever heard of the hot-dog headache? That’s what you get after eating too many hotdogs.”

Other nitrite and nitrosame-containing foods implicated in this study include sausages, Chinese-style salted fish, and bacon.

Although the correlation is very strong, this study does not point to a causal relationship between eating cured meats and leukemia, said Christiani.

In order to show causation, researchers must look into the mechanism of how extracts from cured meats affect bone marrow at the cellular level.

“These results need to be confirmed in other studies before doctors can make strong recommendations,” he said. “We don’t want the cured meat and sausage industry on our tails.”

Researchers need to conduct long-term cohort studies or animal studies in order to gather further information, said Chen-yu Liu, a research fellow at HSPH and the primary author of the manuscript.

“Leukemia is the most important childhood cancer,” said Liu. “I’m concerned about the children, and what factors are associated with the disease.”

According to Christiani, the study’s original focus was not related to diet, but rather attempted to determine whether living in areas with strong pollution from petrochemical industries increases the risk of leukemia. The subjects’ diets were gathered as preliminary information that would later be used to adjust for environmental factors.

“We didn’t expect to see such a large difference, and [we] noted that it was worthy to look deeper into,” he said.

Although the study surveyed children and adolescents, Christiani said the results also apply to adults.

“In fact, adults can accumulate the carcinogenic agents over time, so theoretically the cured meats may be more harmful,” he said.

—Staff writer Helen X. Yang can be reached at hxyang@fas.harvard.edu.