Bet meat and oil are processed as essential for life (10)

'essential for life' is the definition.
(a metabolite is a substance needed for metabolism)

'bet meat and oil are processed' is the wordplay.
'and' is a charade indicator (letters next to each other).
'are processed' indicates anagramming the letters.
'bet'+'meat'='betmeat'
'betmeat' after 'oil' is 'oilbetmeat'.
'oilbetmeat' with letters rearranged gives 'METABOLITE'.

'as' acts as a link.