The Mukhya Upaniṣads

Aitareya · Adhyāya 1 · Khaṇḍa 3 · The Search for Food, and the Discovery of Who Asks

Passage 10

तदपानेनाजिघृक्षत्तदावयत् सैषोऽन्नस्य ग्रहो यद्वायुरन्नायुर्वा एष यद्वायुः ॥ १० ॥

In plain words

He tried to seize it with apāna (the downward breath); [apāna] drew it in. That indeed is the seizer of food — the vāyu (breath) that is the life of food; for this vāyu is indeed [what is meant].