[mumblemumble]

The article itself would also serve as a source:

Another demographic who can benefit from extra protein? The elderly. That’s because as we age, we need more protein to retain muscle mass. But we also tend to eat less protein as we get older because our taste-buds begin to prefer sweet over savoury.

[xenocratus]

True, however they just didn't link to anything (unlike other parts, e.g. in the paragraph prior to that one, where they send you to published research).

[mumblemumble]

That, though, would be a reason to aim a [citation needed] at the BBC, not at someone who's just offering a TL;DR type summary of what the BBC said.