Re WDDTY vol 14 no 3, while it is true that calcium and magnesium are both needed by humans in a ratio of 2:1 (as found in plant foods), there is much more to be said on this subject.
To supplement with calcium alone depletes magnesium whereas to supplement with magnesium alone enhances calcium absorption. Dairy foods have an 8:1 ratio of calcium to magnesium, and all white flour has, by law, added calcium, but not magnesium. Since the majority of the population consume dairy and white-flour products, most people are likely to be magnesium-deficient.
The reason coffee, alcohol, smoking, and so on leach calcium from the system is that they make the blood highly acidic, and the calcium is used to buffer the acid. Our society's acidic habits also include the consumption of sugar, fizzy drinks, chocolate and all kinds of drugs. Simpler societies only need 300-400 mg/day of calcium to maintain strong bones.
Given these points, it would be more beneficial to supplement with calcium and magnesium in a 1:1 ratio - or with just magnesium. The calcium should also be as a citrate or amino-acid chelate, in which case, a far lower dose will be effective. - Helen Jarvis, Derbyshire