Calcium content of cow’s milk vs plant-based milk alternatives
Milk is an excellent source of highly bioavailable calcium, of which we require 1 000 mg a day to ensure optimal bone strength during all life stages. The amount of calcium in a food or beverage and its bioavailability and absorbability are all vitally important for human health. Lactose, casein, and phosphopeptides are all found in cow’s milk and they all promote calcium absorption. The human gut can rapidly absorb 30% to 35% of the calcium in cow’s milk.
Plant-based beverages may well contain equal amounts of calcium. However, they are all fortified with either calcium tri-phosphates or calcium carbonate and may contain chemical compounds that inhibit calcium absorption, e.g. oxalates (nuts and beans) and phytates (beans, seeds, nuts, soy isolates and high-fibre whole grains, e.g. oats). Oxalates and phytates bind to calcium and form insoluble compounds, which are difficult to absorb. Regrettably, the human body only absorbs about 5% of the calcium in plant foods. Consequently, individuals who depend on plant sources for their calcium intake, have to eat very large quantities of such foods to obtain sufficient calcium for their body’s requirements, or take supplements. The calcium in one glass (250 ml) of milk is equivalent to 23 almonds, two cups of cooked spinach, three cups of beans or seven cups of cooked broccoli.