The recommended amount of calcium is still skeptical: The German, Austrian and Swiss Dietetic Associations recommend 1000 mg/day for adults an, while the World Health Organization merely suggests 450 mg. Current studies with vegan living people show that 600 mg /day are sufficient to avoid fragile bones.
Sources of calcium:
- Green vegetables (broccoli, green cabbage, pak choi (?), fennel, chinese cabbage, dandelion, nettle)
- Fortified soya milk
- Mineral water rich of calcium
- Sesame/Tahini, poppies, almonds
- Tofu with calcium chloride
Recommendable are green vegetables low in oxalic acid, mineral waters rich of calcium, fortified soya milk, sesame/tahini, sind grüne Gemüsesorten mit niedrigem Oxalsäuregehalt, calciumreiches Mineralwasser, angereicherte Sojamilch, Sesam/Tahini, tofu with calcium chloride, poppies and almonds. Oxalic acids are in vegetables like spinach, mangold and rhubarb and can highly reduce the resorption of calcium. For that reason they are not a valuable source for available calcium. Also phytic acid in sesame and wholemeal products lower the availability of calcium. Vegan nutrition has a low supply of sulfurous amino acids that are mostly found in animal products and increase the loss of calcium in the bones. A determining fact to improve the availability of calcium is vitamin D.
Iron in vegetable products makes the absorption process less efficient than from animal products. Therefore is the recommended value for vegetarians and vegans 1.8 times higher than for omnivors. It is 27 mg for women and 18 mg for men on a daily basis, for omnivors it is 15 mg for women and 10 mg for men. Ferrous products are legumes, wholemeal, nuts and seeds, green vegetables and dried fruits. Vitamin c and other organic acids in fruits can increase the availibility of iron up to 5 times. Phytic acids (sesame / wholemeal), oxalic acids (spinach, mangold and rhubarb), fibers, coffee, tee and calcium inhibit the absorption. Specific methods of preparing foods can improve the absorption of iron (e.g. sourdough leavening process or sprouting grain).
Sources of iron:
- Legumes (lentils, beans, chick peas)
- Amaranth, quinoa, millet
- Wholemeal products
- Nuts and seeds (pistachios, sesame, sunflower seeds)
- Green vegetables (broccoli, pak choi?)
- Dried fruits (figs, apricots)
- Molasse and sugar beet molasses
The best thing to do is to add vitamin Cin the form of orange juice, lemon juice, capsicum, kiwi or parsley.
The recommended value for Germany and Austria is 200 µg/day, in Switzerland and the United States it is 150 µg/day. The required amount of iodine can be covered with iodized salt (10 g are equal to the daily need) and/or kelp. Kelp contain a great amount of iodine and should not be ingested to often. The correct dose of iodine is to be followed. Maybe mineral water is also a source if it is rich with iodine elementally.
For women the recommended dose is 7 mg/day for men it is 10 mg/day. Vegan nutrition is low with zinc. Beside this fact the bioavailibility seems to be not as good as for omnivors because zinc is bonds to phytic acids. Plant products rich with zinc are soya products, legumes, pumpkin seeds, cashew nuts, sunflower seeds, other kinds of seeds and nuts and wholemeal products.
Value of reference is 30 - 70 µg/day for an adult. The amount of selenium depends on the local conditions of the soil and can widely differ from time to time. Some studies have shown that vegans ingest a little less selenium than omnivors. According to its antioxidantic effect it is of advantage to increase the ingested amount of selenium. Brazil nuts are rich with selenium, 2 or 3 nuts per day are enough.