Vitamin D synthesis from UVB radiation is significantly reduced with age, with a 70-year-old producing only about 25% of the vitamin D a 20-year-old produces.

“aging skin produces far less vitamin D from sunlight (a 70-year-old makes roughly 4x less than their 20-year-old self)”

“At age 70 produce 4x less from skin than when 20.”

“also age so aging decreases the efficiency of your skin to make vitamin D so a 70-year-old makes four times less vitamin D than their 20-year-old former self”

“age also as we age the enzymes in the skin that convert 7 dehydr cholesterol into Vitamin D3 become less efficient as everything does with age and so a 70-year-old actually produces four times less vitamin D in their skin from the Sun than their former 20-year-old self”

“while other sources have suggested a seventy-year-old may produce four times less vitamin D than their former 20 year old selves”

“So a 70 year old person makes 20, like literally 25% of what they made as their 20 year old self.”

“so as we age you know everything is less efficient um so you know a 70-year-old makes about I think it's four times less vitamin D3 in their skin than their former 20-year-old self”