Aged person - 80 over - does he/she need animal proteins?

Animal meat contains animal fat also.
In human nutrition?as far as regions where heart disease is a more
common cause of death than starvation are concerned?animal fats are
often claimed to be unhealthy due to their association with high
cholesterol levels in the blood. Animal fat contains some cholesterol,
but saturated fat (a large component of animal fat) stimulates
cholesterol production in humans and so animal fat contributes in two
ways to cholesterol levels. While elevated blood cholesterol levels
have been linked to heart disease, there is no necessary relationship
between cholesterol intake and blood cholesterol level. A properly
functioning liver regulates the blood cholesterol level by storing and
releasing as well as producing and excreting cholesterol as
appropriate - primarily as bile.
<http://en.wikipedia.org/wiki/Animal_fat>
In order to have a prolonged lifespan, it is desirable to avoid animal
protein and substitute the same with fish protein.(It contains Omega3
fatty acid)