Calcium is needed for our heart, muscles, and nerves to function properly and for blood to clot.It is the most important mineral of the human body ( approx 1 kg) . Inadequate calcium significantly contributes to the development of osteoporosis. Many published studies show that low calcium intake throughout life is associated with low bone mass and high fracture rates. (source US NIH )
| Categories : life stage/group | Daily requirement of calcium (US food and nutrition board 2010) |
| Everyone over 5 years except the below mentioned groups | 1000 mg  ( 1 gr) |
| Women over 50 years, Men over 70 years | 1200 mg |
| 9 to 18 years old | 1300 mg |
Critical calcium level often observed: not only for vegans!!
In USA nutrition surveys have shown that most people are not getting the calcium they need to grow and maintain healthy bones. (source: NIH – Us National Institute of Health)
Other European Surveys (Oxford Epic, University of Brussels) are also reporting critical levels of calcium intakes for the vegan consumers (0.6 /0.7 gr per day, thus -30 to 40 % less than the recommendations, in average).  While many vegans are very concern with their protein and vitamin B 12 intakes, the role of calcium tends to be underestimated. Many people think that calcium only matters in the growing & senior phases and for pregnant /lactating women , while it is important everyday for everyone.
Lacking calcium could be compared with smoking cigarettes: no significant effect are seen in the short term but the long term consequences are huge and often irreversible.
The table below shows the necessary daily intakes to achieve the target of 1 gr of calcium/day
Calcium content in some foods (source US National Osteoporosis foundation)
| Food | Portion size oz | Portion size grams | Calcium per portion | % of daily requirement adult 1 gr |
| Broccoli fresh cooked |   8 oz | 225 g |  60 mg (0.06 g) |  6% |
| Soybean ,green,boiled |   8 | 225g | 180 mg (0.18) | 18% |
| Orange | Â Â 1 piece | Â 55Â mg | 5.5% | |
| Figs dried | Â Â 2 pieces | Â 65Â Â mg | 6.5% | |
| Almond milk enriched | Â 8 oz | 225g | 300Â Â mg | 30% |
The above means for example that we need 1250 g (44 oz) of soybean green boiled to reach a daily supply of one gram of calcium (theorically ,because there are always several sources ) but it illustrates the quantities requested : not so easy to achieve if we don’t pay attention .
Calcium supplement: to cover easily the daily requirement
The calcium supplements are useful to ensure a satisfactory daily intake easily. Two simple rules should be observed for their best efficacy
a)Calcium supplements are better absorbed when taken in small doses (50% of daily needs or less) several times throughout the day. In many individuals, calcium supplements are better absorbed when taken with food (because the stomach acidity during digestion helps to the absorption). In order words: do not go for a tablet or a capsule that provide 100% of the daily requirement, a major part of it would be rejected. Furthermore it is useless to overconsume calcium, which requires a higher kidney’s activity. Since we have always supplies of calcium from the food, the quantities brought by the supplementation should be limited in most cases to some 30 to 60% of the RDA .
- b) Vitamin D (and vitamin K) have a key role for the fixation of the calcium in the body , it is thus important to ensure their satisfactory level , especially in winter time when the natural production of vitamin D is low . A supplementation is also an easy way to achieve this. Unlike the calcium (or the vitamin C) an excess of Vit D or K does not require any significant extra activity of the kidneys to eliminate them because of their very little dose (RDA of 0.07 and 0.01 mg respectively)
