Śatapatha Brāhmaṇa ("of a hundred paths") 8.1.3.1

8.1.3.1

tadāhuḥ | kim prāṇāḥ kim prāṇabhṛta iti prāṇā eva prāṇā aṅgāni prāṇabhṛntyaṅgāni hi prāṇānbibhrati prāṇāstveva prāṇā annam prāṇabhṛdannaṃ hi prāṇānbibharti

As to this they say, 'What are the vital airs (prâna), and what the Prânabhritah?'--The vital airs are just the vital airs, and the Prânabhritah (holders of the vital airs) are the limbs, for the limbs do hold the vital airs. But, indeed, the vital airs are the vital airs, and the Prânabhrit is food, for food does uphold the vital airs.