We all know calcium is essential for development of our skeletal system and for cardiac function, and dietary calcium can be found in many foods other than the humble glass of milk! To reach the recommended daily intake of 1000mg for both men and women, or 1300mg for post-menopausal women, there are some vegetarian foods such as beans, some green vegetables, and nuts and seeds, that have a higher bioavailability than dairy foods (meaning more calcium is absorbed in your body).
Did you know, however, there are many factors that affect the absorption of calcium?
Eating too much sodium - dietary sodium can increase calcium losses because they are linked in the kidneys.
Amount of protein in diet - similar to sodium, protein affects urinary calcium excretion. Both too little and too much protein can affect blood calcium levels.
Eating only animal-derived calcium - consuming too much animal protein has been shown to remove calcium from bones. Also calcium from many vegetarian foods is absorbed at significantly higher rates than dairy foods. Although having less calcium per serve, brussels sprouts is absorbed at a rate of 65% whereas milk is only absorbed at a rate of closer to 30%.
Not consuming enough other nutrients - calcium requires other nutrients such as vitamins D, C, K , E, magnesium, and boron to be absorbed and utilised in the body.
Eating too many oxalate-containing sources - oxalates, present in spinach, rhubarb and silverbeet, inhibit calcium absorption. Ensure other calcium rich greens, such as kale and bok choy, are present in your diet.
So, how do you reach 1000mg calcium every day? A diet containing the following foods daily could be a good way to start:
Smoothie including 1 cup fortified soy milk, 1 cup spinach, 1 cup yoghurt
(dairy or dairy free, fortified if dairy free)
Calcium content = 640mg
Salad including 1 cup kidney beans and 2.5 cups kale
Calcium content = 100mg
Stir fry containing 100g tofu, 1 cup bok choy, and 1 cup broccoli
Calcium content = 470mg
1 tbsp almond butter
Calcium content = 55mg
Total daily calcium = 1265 mg
(note does not account for individual rate of absorption or alteration that may occur when foods are heated)