What you may have heard
Peanut butter consumption can increase your risk of cancer due to potential aflatoxin contamination.
What the science tells us
Aflatoxins are a family of carcinogenic compounds produced by mold and can be found on various crops, including peanuts, tree nuts, and corn. If contaminated peanuts are used in production, aflatoxins may be present in peanut butter products.
In many countries, food safety systems include regular monitoring and strict limits on aflatoxin levels in consumer products like peanut butter. In the United States, the FDA routinely tests peanut butter to ensure aflatoxin levels stay within safe thresholds. Because of these protections, the risk of significant aflatoxin exposure is low, and there is no evidence of increased cancer risk from peanut butter consumption.
However, aflatoxins are more common in regions with warm, humid climates and limited food safety infrastructure, such as sub-Saharan Africa, Southeast Asia, and parts of China. In these areas, peanut butter may pose a higher risk of aflatoxin exposure, so it is important for consumers to be aware of possible health risks.
Epidemiological Evidence
In countries with established food safety systems, such as the U.S., the U.K., Canada, Japan, and countries in the European Union, studies consistently show no link between peanut butter consumption and cancer. For instance, the Netherlands Cohort Study followed over 120,000 adults aged 55 to 69 for approximately 20 years and found no association between peanut butter consumption and cancer risk (Nieuwenhuis & van den Brandt). The cohort study also reported no relationship between peanut butter and overall mortality (van den Brandt & Schouten).
A three-year analysis in Zambia, sub-Saharan Africa, however, found high levels of aflatoxins in peanut butter products from the region (Njoroge et al.). This raises concern, as chronic exposure to aflatoxins has been linked to an increased risk of liver cancer (NCI). More research and regular monitoring are needed to better understand the extent of aflatoxin contamination in these regions and how it may specifically impact cancer risk from peanut butter products.
How to reduce your risk
- Purchase peanut butter from reputable brands that follow national or international safety standards.
- Store peanut products in cool, dry places to prevent mold growth.
- If you are in a region where aflatoxins are more common (sub-Saharan Africa, Southeast Asia, parts of China), look for peanut butter products that are tested, certified, or imported from countries with reliable food safety systems.
Bottom line
There is no consistent evidence that peanut butter causes cancer when it is produced under strong food safety regulations. If you live in a region of the world where food regulation is limited, choosing peanut products that are certified or tested can help reduce your risk. Peanut butter remains a nutritious food in most contexts, and for many people, its benefits outweigh potential concerns.