After about fifty
What changes
The food does not change. How much of it you absorb does.
Three things shift with age and they are the reason a standard multivitamin stops being the right answer. Stomach acid falls, which affects B12. Skin synthesises less vitamin D from the same sunlight. And muscle mass declines steadily unless something is done about it.
What this is not
This is not about slowing ageing, and anyone selling you that is selling you a story. It is about covering three specific things that measurably change.
Worth knowing
If you take prescription medication, this is the section that matters most. Skip to interactions below before you buy anything.