The popularity of almond milk as a dairy alternative has led to scrutiny of its nutritional profile, especially its calcium content. Consumers often rely on the high calcium numbers listed on the label, but the key question is whether the body can absorb this calcium effectively. The absorption, or bioavailability, of any mineral is influenced by its chemical form and the presence of other compounds in the food matrix. Understanding these factors determines if the calcium in almond milk provides a meaningful health benefit.
Calcium Fortification: The Type Used in Almond Milk
The calcium content in commercial almond milk is not naturally occurring; it is added through a process called fortification. The most common fortificant used is calcium carbonate, chosen for its low cost and high elemental calcium content, providing about 40% calcium by weight. Another form occasionally used is tricalcium phosphate, which also serves as a source of the mineral phosphorus. These inorganic calcium salts are highly insoluble in water, creating a physical challenge within the liquid.
Because of this insolubility, the calcium particles settle and precipitate to the bottom of the carton over time. This sedimentation explains the instruction to “shake well” often printed on the packaging, as shaking is required to re-suspend the calcium particles evenly throughout the milk. If the carton is not shaken, the consumer receives mostly almond-flavored water with minimal calcium.
Bioavailability Inhibitors in Plant-Based Milks
Beyond the physical challenge of keeping the calcium suspended, the inherent composition of almonds introduces biological inhibitors that can reduce mineral bioavailability. Almonds naturally contain compounds called oxalates and phytic acid, or phytates, which are known to chelate minerals. Oxalates, in particular, are present in almond milk at higher concentrations than in cow’s milk.
These compounds bind tightly to calcium ions in the digestive tract, forming an insoluble complex, such as calcium oxalate crystals. When calcium is bound in this manner, it is no longer available to be absorbed through the intestinal wall into the bloodstream. Although commercial processing reduces the final oxalate content compared to raw almonds, the remaining inhibitors still interfere with the absorption of the added calcium.
How Almond Milk Calcium Absorption Compares
The absorption efficiency of calcium from fortified almond milk is a complex metric, but studies indicate it can be comparable to dairy milk under the right conditions. Calcium absorption from cow’s milk, which is often considered the benchmark, is estimated to be around 30% to 35%. For fortified almond milk, the bioavailability of the added calcium carbonate, when fully suspended, has been shown to be similar to the calcium naturally found in cow’s milk.
However, the specific fortificant matters. Fortification with tricalcium phosphate may result in a calcium absorption rate that is approximately 25% lower than that of cow’s milk. The key difference is that the calcium in dairy is naturally integrated into the milk proteins, making it highly bioavailable, whereas the calcium in almond milk is a mineral salt added as a separate component.
Practical Tips for Optimal Calcium Uptake
Maximizing the calcium absorbed from almond milk begins with addressing the physical settling of the fortificant. It is essential to shake the carton vigorously before every pour to redistribute the calcium particles evenly throughout the liquid. If the product is not mixed thoroughly, the intended calcium dose will not be delivered, making absorption impossible.
Another important factor is the co-consumption of Vitamin D, which is often added to fortified almond milk. Vitamin D is required for efficient intestinal calcium absorption. Without sufficient levels of this vitamin, the body cannot effectively take up calcium regardless of its source.
Furthermore, the body can only absorb a limited amount of calcium at one time. Consuming the mineral in smaller doses is recommended for optimal uptake throughout the day. Ideally, this means no more than 500 milligrams of elemental calcium in a single sitting.