Blue Zones longevity claims questioned after cited study on missing birth records

What was said

"He's published this really fascinating paper. He did a deep dive onto these blue zones and found out that only 18% of the people in these blue zones actually had birth certificates. So we don't even know who these people are. They just self-report their age."

Diet researcher David Ludwig argues that the popular “Blue Zones” longevity narrative is built on weak demographic foundations, citing Oxford demographer Saul Newman’s analysis of age validation in purported Blue Zone regions. Ludwig says Newman found that only 18% of people in those areas had birth certificates, meaning exceptional longevity rates may be distorted by poor record-keeping or misreported ages rather than diet.