From the Guidelines
For individuals seeking alternative calcium sources to dairy, calcium-fortified plant-based milks, leafy green vegetables like kale and bok choy, and calcium-set tofu are excellent options. These alternatives provide comparable or even higher calcium absorption rates than dairy products, with some leafy greens having absorption rates over 50% 1.
Key Calcium Sources
- Calcium-fortified plant milks, such as almond, soy, oat, and rice milk, contain 300-450mg of calcium per cup, similar to cow's milk.
- Leafy green vegetables, especially kale, bok choy, and collard greens, are rich in calcium with high absorption rates.
- Calcium-set tofu provides about 200-400mg of calcium per half-cup serving.
- Seeds and nuts, like chia seeds, almonds, and tahini, offer moderate calcium amounts.
- Beans and legumes, such as white beans and chickpeas, contribute modest calcium.
- Calcium-fortified foods like orange juice, breakfast cereals, and breads can significantly boost intake.
Considerations
- Oxalic acid in some foods, like spinach and rhubarb, reduces calcium absorption, but this is not a concern with kale, bok choy, and other recommended leafy greens 1.
- High sodium and protein intake can increase urinary calcium excretion, potentially reducing calcium availability 1.
- Calcium-rich mineral waters and fortified plant-based products are also good sources of calcium 1.
From the Research
Alternative Calcium Sources to Dairy
There are several alternative calcium sources to dairy, including:
- Plant-based milk alternatives, such as soy-based products, which can be fortified with calcium and vitamin D 2
- Kale, finger millet, and fortified white bread, which have been identified as good sources of bioaccessible calcium 3
- Calcium supplements, such as calcium carbonate and calcium citrate, which can help meet calcium requirements 4
- Calcium-fortified beverages, such as soymilk, which can have equivalent calcium bioavailability to cow's milk 5
Bioavailability of Calcium in Alternative Sources
The bioavailability of calcium in alternative sources can vary, with some sources having higher bioavailability than others. For example:
- Kale has been shown to have high bioaccessibility of calcium, with approximately 5 times more bioaccessible calcium than 1 serving of skimmed milk 3
- Fortified white bread has also been shown to be a good source of calcium, with high bioaccessibility due to the use of calcium carbonate as a fortification agent 3
- Calcium-fortified soymilk has been shown to have equivalent calcium bioavailability to cow's milk in young women 5
Factors Affecting Calcium Bioavailability
Several factors can affect the bioavailability of calcium in alternative sources, including:
- The type of calcium present, such as calcium caseinate, micellar calcium phosphate, and soluble calcium 6
- The presence of other nutrients, such as lactose and casein-phosphopeptide, which can promote calcium absorption 6
- The solubility of the calcium source, with more soluble sources having higher bioavailability 6