Subject: Does the ability to absorb minerals decline with age? What are the %'s?

I heard a nutritionist claim that there was a significant decline in 
the ability to absorb nutrients from the diet and he gave some 
percentage, but I have seen no supporting data for that claim. 
I would like to know how much that decline is (roughly) at different 
ages, or the rate of decline, or SOME rule of thumb for an elderly 
person to follow in taking supplements, _if_ this is a real issue. 
(It sounds reasonable, but that doesn't make it true).

Re: Does the ability to absorb minerals decline with age? What are the %'s?