Historical View and Study Changes
📌 In 1991, the IARC classified coffee as possibly carcinogenic based on animal data and weak case-control human studies suggesting a link to bladder cancer.
📈 Modern prospective studies (looking forward over decades) have largely replaced older, weaker evidence, leading to a shift in understanding.
✅ In 2016, the IARC reviewed over 1,000 studies and removed the "possibly carcinogenic" classification for coffee.

Coffee Consumption and Cancer Risk Reduction
🛡️ Overall, coffee drinkers show an 18% reduction in the risk of all cancers combined compared to non-drinkers.
💚 The link is strongest for liver cancer, showing about a 50% lower risk in high consumers (benefit appears linear up to 5-6 cups/day).
🚺 Coffee is consistently linked to lower risk of endometrial cancer, also showing a linear benefit up to 5-6 cups daily.
📉 For colorectal cancer, coffee shows either no effect or a modest protective effect, possibly by accelerating intestinal transit time.

Specific Cancer Correlations and Mechanisms
🟢 Most studies suggest a protective effect for prostate cancer, indicating about a 9–10% lower risk of incidence and mortality.
⚪ Breast cancer shows no significant overall effect, though some data suggests a protective effect in post-menopausal women via phytoestrogens.
☀️ Coffee is a major source of antioxidants (polyphenols) in the American diet, potentially contributing to protective effects like for melanoma.
💨 Early suggested links between coffee and lung cancer disappeared after adjusting for confounding factors like smoking.

Caffeine, Decaf, and Temperature Concerns
❓ It is not 100% clear if effects are due to caffeine; some studies show a protective effect from decaf, while others suggest caffeinated coffee is stronger.
🔥 The primary cancer risk associated with coffee preparation is from very hot beverages (above $65^\circ$ Celsius), which may increase the risk of esophageal and oral cancer.
💧 This temperature risk is not unique to coffee; very hot tea or mate share the same risk profile, emphasizing cooling down drinks.
⚠️ Coffee consumption is not recommended in moderation or should be avoided during pregnancy due to links with low birth weight and pre-term birth.

Key Points & Insights
➡️ Rely on prospective studies for strong evidence, as they have led the IARC to reverse its stance on coffee being possibly carcinogenic.
➡️ To mitigate potential risks, let your coffee cool below $65^\circ$ C to protect against esophageal cancer risk associated with high temperature.
➡️ Coffee consumption is strongly linked to significant risk reduction (up to 50%) for liver cancer and moderate reduction for endometrial cancer.
➡️ Acrylamide levels in roasted coffee are measured to be tiny and below thresholds of concern, despite past controversies.

📸 Video summarized with SummaryTube.com on Oct 06, 2025, 16:24 UTC