> Imagine this possibility. Everyone gets cancer and dies at 65 years old. Everyone starts taking vitamins and therefore starts sleeping better, getting stronger, etc. They all still die at 65 years old though because of cancer. Suddenly, cancer is cured. All those people now live to 85, except the ones who still don't take vitamins. They only live to 66. Vitamins caused a 20 year increase in lifespan, but this was undetectable because cancer was killing everyone at 65. In all cases though, everyone slept better and were stronger after taking vitamins.
Cancer isn't killing everyone at 65 years old. Not everyone dies of cancer at all. Even if you assume that vitamins have no effect on cancer rates, if they decrease mortality due to other causes, people who take vitamins should have lower overall morality than people people who don't take vitamins.
So again, you would have to have a situation where vitamins are improving sleep and strength, which are both inversely correlated with mortality, but somehow not decreasing mortality, as I said in my previous comment.
Cancer isn't killing everyone at 65 years old. Not everyone dies of cancer at all. Even if you assume that vitamins have no effect on cancer rates, if they decrease mortality due to other causes, people who take vitamins should have lower overall morality than people people who don't take vitamins.
So again, you would have to have a situation where vitamins are improving sleep and strength, which are both inversely correlated with mortality, but somehow not decreasing mortality, as I said in my previous comment.