Calcium is a mineral necessary for life. It helps our body build and maintain strong bones, teeth and nails, helps our muscles work and our heart beat. Chronic calcium deficiency can lead to rickets and poor blood clotting. It can lead to osteoporosis and cause some other health conditions. When we are getting older, we need to increase it because calcium is washing out of our bodies, so we have to consume more.
Our body cannot produce calcium on its own; the food we eat is the only source of calcium supply. Without any doubts, milk and milk products are champions in calcium content and its bioavailability. But some people are lactose-intolerant or allergic to milk and cannot consume non-fermented dairy products. Other people, such as vegans, intentionally avoid milk products for ethical reasons. So, alternative sources of that vital mineral have to be fruit and vegetables.
Many vegetable sources of calcium exist, including seaweeds such as kelp, wakame and hijiki; nuts and seeds like almonds, hazelnuts, sesame, and pistachio; blackstrap molasses; beans (especially soy beans); figs; quinoa; okra; rutabaga; broccoli; leaves; and kale. But here the problem of calcium bioavailability arises.
Bioavailability is the degree to which a nutrient is absorbed and utilized by the body.
Recommended daily intake for calcium for an average healthy person of 20-50 years old is 1,000mg.
Vitamin D is needed to absorb calcium.
The bioavailability of calcium is an important factor to keep in mind when calculating its daily consumption.