Vegetarian and vegan diets are associated with a lower risk of osteoporosis. Ellis F et al. Am. J. Clin. Nutr., 1972, 25, pp 55-8. Reducing animal protein and refined, highly processed foods will help. Sugar intake causes an increase in urinary excretion of calcium, so reduce refined sugar in the diet. Avoiding caffeine and alcohol and fizzy drinks is also necessary.
It is important to have a diet rich in calcium. Good sources of calcium are: Salmon, sardines, seafood, green leafy vegetables, almonds, cooked asparagus, black strap molasses, food yeast, broccoli, buttermilk, cabbage, carob, cheese, dandelion leafs, dulse, figs, hazelnuts, kale, cress, mustard leafs, oats, plums, whole ground sesame seeds, soya beans, tofu, turnip leafs, whey and yogurt. Vegetables are a better source of calcium than milk because they also contain magnesium, which is essential for proper calcium absorption. Also, since milk is pasteurized and homogenized, the calcium it contains is harder to assimilate.
It is likely that the calcium intake is quite adequate but that calcium is not being absorbed well due to poor magnesium levels or high blood acidity. A magnesium supplement is therefore very important. Magnesium helps calcium to be absorbed, and also contributes to the conversion of vitamin D to its most active form, and helps to balance calcitonin and parathormone production. I recommend Salus Haus liquid magnesium as the most easily absorbed form.
Calcium carbonate is one of the least soluble forms of calcium: citrate or gluconate are better. A.Vogel's Assist Calcium absorption will help with the uptake of calcium into bones. Physical exercise is also very important – 20-30 minutes walking daily is a good start.