Stomach cancer is the fifth most common cancer worldwide, but many of its major risk factors are modifiable. The single most impactful step you can take is getting tested and treated for H. pylori, the bacterial infection responsible for the majority of cases. Beyond that, a combination of dietary changes, maintaining a healthy weight, and avoiding tobacco can meaningfully lower your risk.
Get Tested for H. Pylori
The bacterium Helicobacter pylori infects the stomach lining and, over decades, can trigger a chain of changes from chronic inflammation to precancerous tissue to cancer. Treating the infection with a course of antibiotics is the most effective single prevention strategy available. A large clinical trial with nearly 12 years of follow-up found that successful eradication of H. pylori reduced stomach cancer incidence by 19% overall. The benefit was dramatically larger for younger people: those treated between ages 25 and 45 saw a 35% drop in incidence and a 43% reduction in death from stomach cancer.
The reason age matters is timing. H. pylori damages the stomach lining gradually, and the earlier you interrupt that process, the less precancerous change has accumulated. Testing is simple, usually a breath test or stool test, and treatment is a short course of antibiotics. If you have a family member who tests positive, household screening makes sense because the bacteria spread easily within families and reinfection from a partner or relative is common.
One complication: antibiotic resistance is rising globally. Current guidelines recommend that if your first round of treatment fails, your doctor should test which antibiotics the bacteria are still sensitive to rather than guessing with a second regimen.
Reduce Salt and Processed Meat
High salt intake is one of the most consistent dietary risk factors for stomach cancer. Salt damages the protective mucus lining of the stomach, making it more vulnerable to carcinogens and to the effects of H. pylori. The World Health Organization recommends keeping sodium intake below 2 grams per day (roughly 5 grams of table salt), a target most people in Western countries exceed by a wide margin. The biggest sources are not the salt shaker but processed and packaged foods: bread, cured meats, canned soups, soy sauce, and restaurant meals.
Processed meat carries its own independent risk. A meta-analysis published in Frontiers in Nutrition found that high consumption of processed meat (think daily or near-daily servings of bacon, sausage, ham, or deli meats) was associated with a 24% increased risk of stomach cancer. Moderate intake showed no significant increase, which suggests you don’t need to eliminate these foods entirely, but making them an occasional choice rather than a staple matters.
Eat More Fruits and Vegetables
Fruits and vegetables contain antioxidants and other compounds that help protect stomach cells from damage. A large dose-response meta-analysis of cohort studies found that every additional 100 grams of fruit per day (roughly one medium apple or a handful of strawberries) was linked to a 5% lower risk of stomach cancer. For combined fruit and vegetable intake, an extra 200 grams per day was associated with a 6% reduction.
The protective effect plateaus at around 200 grams of fruit per day, so you don’t need to eat enormous quantities. Two or three servings of fruit plus a few servings of vegetables daily puts you in the range where the benefit is strongest. Citrus fruits, berries, and leafy greens are particularly rich in vitamin C, which may help counteract the formation of cancer-promoting compounds in the stomach.
Maintain a Healthy Weight
Excess body weight raises the risk of cancer in the upper part of the stomach, near where it meets the esophagus (called the cardia). A pooled analysis of over 8,000 people found that obese individuals had a 57% higher risk of this type of stomach cancer compared to those at a normal weight. For people with a BMI of 40 or above, the risk roughly doubled. Overweight individuals (BMI 25 to 30) also showed an elevated risk, around 28% higher for cardia cancers.
The connection likely involves chronic acid reflux, which is far more common in people carrying extra abdominal weight. Repeated acid exposure damages the tissue at the top of the stomach over time. Losing even a modest amount of weight can reduce reflux frequency and, by extension, this particular cancer risk.
Quit Smoking
Smoking increases stomach cancer risk through multiple pathways. Tobacco chemicals are swallowed with saliva, directly contacting the stomach lining, and smoking also worsens the damage caused by H. pylori. The good news is that quitting works, but it takes time. A 15-year longitudinal study found that people who had quit smoking for more than five years experienced a 35% reduction in stomach cancer risk compared to current smokers. Recent quitters and current smokers showed no significant difference, which means the protective effect requires sustained cessation. Five years is the minimum threshold before measurable benefits appear.
Limit Alcohol
Heavy alcohol consumption irritates and inflames the stomach lining, compounding the effects of other risk factors like H. pylori and high salt intake. While the link between moderate drinking and stomach cancer is less clear-cut than for smoking, heavy and prolonged drinking consistently shows up as a risk factor in large studies. Keeping consumption moderate, or eliminating it, removes one more source of chronic stomach irritation.
Know Your Family History
A small percentage of stomach cancers are driven by inherited gene mutations rather than lifestyle factors. The most well-known is a mutation in the CDH1 gene, which causes hereditary diffuse gastric cancer. People who carry a dangerous CDH1 variant have roughly a 40% lifetime chance of developing stomach cancer, with some estimates as high as 80%. Unlike the more common form of the disease, which grows as a distinct tumor, hereditary diffuse gastric cancer spreads throughout the stomach wall in a way that’s nearly impossible to detect with standard screening.
For carriers of these mutations, preventive removal of the stomach is currently the recommended option. It’s a major surgery with lasting consequences for nutrition and quality of life, but it eliminates what would otherwise be a very high cancer risk. Genetic testing and counseling are appropriate if you have multiple close relatives who developed stomach cancer, particularly at young ages.
Even without a known gene mutation, having a first-degree relative with stomach cancer roughly doubles your risk. This may reflect shared genetics, shared H. pylori exposure within the household, or both. If stomach cancer runs in your family, H. pylori testing becomes especially important.
Workplace Exposures to Watch For
Occupational hazards account for a small but real fraction of stomach cancer cases. A population-based study in Sweden found that long-term work in the metal industry was associated with a 46% increased risk after adjusting for other factors, with the risk climbing the longer someone worked in the field. Exposure to phenoxy herbicides, chemicals historically used in forestry, agriculture, and along railways, increased risk by about 70%. Together, these workplace exposures accounted for roughly 12% of stomach cancers in the study population.
If you work in metalworking, forestry, or agriculture, following safety protocols for dust and chemical exposure is worth taking seriously. Proper ventilation, protective equipment, and minimizing direct contact with industrial chemicals are practical steps that reduce your cumulative exposure over a career.
Screening If You’re High Risk
Routine stomach cancer screening isn’t recommended for the general population in most Western countries because the overall incidence is relatively low (about 8 cases per 100,000 people annually in the United States). But screening with upper endoscopy is recommended for people at elevated risk, including first-generation immigrants from regions where stomach cancer is common, such as East Asia, Eastern Europe, and parts of Central and South America. If you fall into a higher-risk category due to family history, ethnicity, or a personal history of precancerous stomach changes, periodic endoscopy can catch problems at an early, treatable stage.