A new report looking at what causes stomach cancer found three new somewhat surprising links: alcohol, processed meat and obesity.
All three are linked with several other cancers, including colon cancer and breast cancer, but this is the first time they've been associated with stomach cancer.
The report also finds more typical causes: smoking, eating food preserved with salt, and infection with a bacteria called Helicobacter pylori.
"Obesity is now linked to 11 types of cancer and we want Americans to know there are steps everyone can take for cancer prevention and better health, like eating more vegetables, beans, fruits and other plant foods along with squeezing in a few more steps every day," said Alice Bender of the American Institute for Cancer Research (AICR), which conducted the study.
AICR, which focuses on the links between diet and cancer, analyzed 89 studies covering 17 million adults and 77,000 cases of stomach cancer.
Stomach cancer is a major killer. According to the National Cancer Institute, 21,000 people in the United States are with gastric cancer and nearly 11,000 die of it every year. It's the fifth most common cancer globally, affecting 950,000 people a year.
It causes vague symptoms, so it's usually advanced by the time it's diagnosed and only about a quarter of patients survive.
Stomach cancer is unusual. It was one of the first cancers linked to an infectious disease — Helicobacter — and that discovery flummoxed doctors who thought spicy and salty food was to blame. It's now known to be by far the main cause of the most common type of stomach cancer, non-cardia stomach cancer.
But the AICR wanted to tease out what might cause the remaining cases, and what might protect against stomach cancer.
It found smoking is to blame for about 11 percent of stomach cancers.
"There is strong evidence that consuming approximately three or more alcoholic drinks per day increases the risk of stomach cancer," the report adds.
And eating 1.8 ounces of processed meat every day — the equivalent of one hot dog a day — raises the risk of stomach cancer by about 18 percent, the report found. "Processed meat is meat that has been preserved by smoking, curing or salting, or by the addition of preservatives. Examples include ham, bacon, pastrami and salami, as well as hot dogs and some sausages," the report reads.
The World Health Organization's International Agency for Research on Cancer caused a ruckus late last year when it said flatly that processed meat causes cancer. Stomach cancer was one of the types it named, along with pancreatic and prostate cancer. Heavy meat consumption has also been linked with breast and colon cancer.
And being obese also raises the risk, the report finds. The more a person weighs in relation to height, the higher the risk of stomach cancer.
More than a third of Americans are obese and another third are overweight.