01/28/2026
Soy, Red Meat, and Cancer Risk: What the Evidence Shows
Large human studies do not show that eating soy foods increases cancer risk. Major cancer organizations, including the American Cancer Society (ACS) and the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR), consider whole soy foods safe when eaten in typical dietary amounts.
Soy foods include tofu, tempeh, edamame, miso, and soymilk (not the weird soy isolates you'll find in processed foods and protein supplements). These foods contain phytoestrogens, which are much weaker than human estrogen and do not behave the same way in the body. Early concerns about soy largely came from animal studies using extremely high doses or from isolated soy or isoflavone supplements, not from normal human diets.
In human populations, soy consumption is associated with either no increase or a lower risk of certain cancers, including breast cancer. Studies in breast cancer survivors also show no increased risk of recurrence with moderate soy food intake, and some studies suggest improved outcomes.
Most cancer organizations clearly distinguish between soy foods and soy or isoflavone supplements. Cancer prevention guidance applies to foods, not high-dose supplements.
In contrast, the link between red meat and especially processed meat and cancer risk is much stronger and more consistent.
Processed meat (such as bacon, sausage, hot dogs, deli meats, and pepperoni) has been classified by the World Health Organization’s International Agency for Research on Cancer (IARC) as carcinogenic to humans, meaning there is sufficient evidence that it causes colorectal cancer.
The American Cancer Society and WCRF/AICR recommend:
-Limiting red meat intake to less than 12-18oz a week
That amount is roughly equivalent to:
2–3 deck-of-cards–sized portions for the whole week
Did I mention the environmental impact as well? 🤔
