Native Americans who often ate processed meat in a can, generically known as "spam" and a common food on reservations, one subsidized by the government -- had a two-fold increased risk of developing diabetes over those who ate little or none, according to a U.S. study.
Native Americans are at especially high risk of developing diabetes, with nearly half having the condition by age 55.
Researchers writing in the American Journal of Clinical Nutrition surveyed 2,000 Native Americans from Arizona, Oklahoma and North and South Dakota to look into potential reasons for the high rate.
"A lot of communities in this study are in very rural areas with limited access to grocery stores... and they want to eat foods that have a long shelf life," said Amanda Fretts, the lead author and a researcher at the University of Washington School of Medicine.
None of the survey participants, whose average age was 35, had diabetes at the start of the study when they answered questions about diet and other health and lifestyle factors.
After five years, a follow-up survey found that 243 people had developed diabetes.
Among the 500 people in the original study group who ate the most canned processed meat, 85 developed diabetes. In contrast, among the 500 people who ate the least amount of "spam," just 44 developed the disease.
Though Spam is a brand-name pork product, the lower-case term is also used to describe any kind of processed, canned meat, Fretts said. Canned meat is available freely to many Native Americans on reservations as part of the U.S. Department of Agriculture's food assistance program.
Fretts and her colleagues found that unprocessed meat did not have the same relationship with diabetes, with people equally likely to develop diabetes regardless of how much hamburger or cuts of pork or beef they ate.
"I think what this study indicates is processed meats should be a priority for reduction (in the diet), especially among American Indians where they can go to food assistance programs and they can get discounted spam," said Dariush Mozaffarian, a professor at the Harvard School of Public Health who was not involved in the study.
Mozaffarian and his colleagues two years ago conducted an analysis that found that processed meats were tied to a 19 percent higher diabetes risk, while unprocessed meats were neutral.
"I think the biggest difference between processed and unprocessed meats is sodium," he said, though he added that there is no clear explanation for the link of processed meats and diabetes.
Fretts and her colleagues noted that the people who ate the most processed meats tended also to be heavier, with larger waistlines, raising the possibility that processed meats contribute to obesity, which raises the risk of diabetes.
In an emailed statement to Reuters Health, The American Meat Institute, which represents companies that process meat, said that "processed meats are a safe and nutritious part of a balanced diet."
Fretts said the study could not prove that eating processed meats was to blame for the increased risk of diabetes.
"I think there needs to be more follow-up," she said.