Old English hælþ "wholeness, a being whole, sound or well," from Proto-Germanic *hailitho, from PIE *kailo- "whole, uninjured, of good omen" (source also of Old English hal "hale, whole;" Old Norse heill "healthy;" Old English halig, Old Norse helge "holy, sacred;" Old English hælan "to heal"). With Proto-Germanic abstract noun suffix *-itho (see -th (2)).
Of physical health in Middle English, but also "prosperity, happiness, welfare; preservation, safety." An abstract noun to whole, not to heal. Meaning "a salutation" (in a toast, etc.) wishing one welfare or prosperity is from 1590s. Health food is from 1848.
fem. proper name, Russian, probably from Norse Helga, literally "holy," from Proto-Germanic *hailaga (from PIE *kailo-; see health). The masc. form is Oleg.
It is wrong to say that certain articles of food are healthy or unhealthy. Wholesome and unwholesome are the right words. A pig may be healthy or unhealthy while alive; but after he is killed and becomes pork, he can enjoy no health, and suffer no sickness. [Eliza Leslie, "Miss Leslie's Behaviour Book," Philadelphia, 1839]
Healthsome is from 1530s in the sense "bestowing health."
Old English hælan "cure; save; make whole, sound and well," from Proto-Germanic *hailjan (source also of Old Saxon helian, Old Norse heila, Old Frisian hela, Dutch helen, German heilen, Gothic ga-hailjan "to heal, cure"), literally "to make whole" (from PIE *kailo- "whole;" see health). Intransitive sense from late 14c. Related: Healed; healing.