You need at least as much calcium as magnesium, but not more than twice as much.
If 400 mg mag, then 400 - 800 mg cal; if 1000 mg cal, then 500 - 1000 mg mag (NOT recommended).
You need at least as much omega-6 as omega-3, but not more than twice as much.
If 1000 mg o-3, 1000 - 2000 mg o-6; if 2000 mg o-3, 2000 - 4000 mg o-6.
You need at least as much vitamin A as vitamin D, but not more than twice as much.
If 5000 IU vit A (the RDA), then 2500 - 5000 iu vit D; if 5000 iu D, then 5000 - 10,000 iu A.
* * *
With cal:mag and o-6:o-3, the closer you get to 2:1 the more benefit; as
soon as you cross over into 2.1+:1, it switches over into harmful.
With vit A:vit D, 1:1 is ideal. As you go from 2:1 towards 1:1, benefit
increases; as soon as you get more D than A, you switch over to harm.
(Dr. Cannell of the Vit D Council is very anti-A, but A - like D - is
fat-soluble, so we store it; I think he's assuming most Americans have a
ton of A stored, and need to avoid it while getting increased D. Would
be nice if he would clarify it's a temporary, corrective measure.)
Absolute amounts also matter.
You can't get 100 mg mag and 150 mg cal, and say, "It's in the ratio
Jeffrey said." You would clearly be deficient in both at that point. The
RDA for cal - 1000 - 1200 mg - was decided based on studying a vit
D-deficient population (the RDA for D - 400 iu - was/is about 1/10th
what we now know is the right amount). The RDA for mag - 350 for teh
wimminz, 400 for men - is probably just a little low.
[EDIT June 5, 2012: As calcium makes muscles constrict, and magnesium helps muscles relax, have cal morning and/or afternoon, mag before bed. Do NOT take cal and mag supplements at the same time. Even high calcium foods should be avoided from dinner on.]
You also can't get 20 grams of o-6 per day, and take 10 g o-3 per day,
and say "It's the right ratio." It is the right ratio, but your body
cannot safely metabolize those absolute amounts. They are WAY outside
what any human ingested on a regular basis before the 20th century.
[Note: amounts are from food (or sunlight, in the case of vit D) + supps.]