I am a health fanatic and very big on nutrition.
I have several planets in Virgo. But these Virgo planets are in my 10th house (career). As far as the 6th house of health, I have Chiron there.
Is my attention to health/nutrition explained by Chiron in 6th, or the Virgo planets (Jupiter, Saturn), even though they're in a non-health-related house?
In other words, does the sign itself (regardless of house) contribute to the affairs of the house it would correspond to, if you have planets there? Or are the Virgo planets irrelevant in this case?
Good, interesting question.
Here is how I see it. As I understand it, a sign is an influence on the planet which is in that sign.
Planets are in signs and planets are in houses.
Houses are not in signs. Houses are arenas of life in which the planets act or manifest.
Traditionally, I would think that Virgo may refer to care, diligence, discrimination, home, hearth. I don't think there is anything that suggests that Virgo is particularly connected to health beyond taking care, being discriminating, which might cover being discriminating about illness/health, which I acknowledge is very important for our health! I also would note, though, that the house of one's health and well-being is the 1st house, rather than the 6th.
So if houses are the arenas of life in which a planet exerts more influence, if you have planets in the 6th house of illness and disease, its condition and cause, whether the illness will be short or long, curable or not, then your attention will be drawn to those matters in a fundamental way.
Coming back to your questions
In other words, does the sign itself (regardless of house) contribute to the affairs of the house it would correspond to, if you have planets there?
I would say no. It is modern idea that signs correspond to houses, like Aries with the 1st, Virgo with the 6th and not much historically or philosophically to support it. There are just signs on houses, based on the time of the chart.
Or are the Virgo planets irrelevant in this case?
I don't see planets in the 10th influencing the affairs of the 6th [or 1st] for health/illness matters unless those planets are somehow related by aspect or mutual reception or some other astrological relationship with bodies in the 6th or 1st. The sign of Virgo on a planet does not automatically connect to the affairs of the 6th or any other house.
That is how I understand it. I would be interested to hear how others do.