Dairy products, such as milk, yogurt and cheese, are naturally calcium-rich with a composition that allows maximum calcium absorption in the digestive system. Many individuals with sensitivities or allergies to milk protein (casein) or inability to digest milk sugar (lactose) require dietary alternatives to supply this essential mineral. Although calcium from dairy has high bioavailability, meaning it is effectively absorbed through the body's intestinal tract, alternative sources of calcium do exist in some nondairy foods and calcium-fortified foods.
Cabbages and Greens
Some green vegetables in the Chinese cabbage family, such as bok choy, are high in calcium that is readily available for absorption in the digestive tract. The calcium in one serving of some types of Chinese cabbage offers the same amount of bioavailable calcium as one serving of milk. Arugula, mustard greens and broccoli are also calcium-rich options. Beware of relying on such greens as rhubarb, turnip, Swiss chard and especially the calcium-dense spinach as calcium alternatives. Although among the most calcium-rich greens, they also contain high levels of oxalic acids that significantly inhibit calcium absorption. Due to poor calcium absorption, 16 servings of spinach are required to obtain the calcium equivalent of one glass of milk.
Fortified Milk Alternatives and Juices
Many juices and nondairy milk alternatives are fortified with calcium and vitamin D to aid in the absorption of calcium. Although not all juices or milk alternatives are fortified, check the label to ensure that the version you purchase is a calcium-enriched choice. Milk alternatives are vast and include almond, soy, rice, hemp and hazelnut milk. These alternative milk products are not always in the refrigerated section, so look for cartons on the shelves in your favorite market.
Beans and Nuts
One serving of white beans, such as cannellini and Great Northern, is widely accepted as a viable source of fiber, yet one serving also contains approximately one-third as much bioavailable calcium as a typical serving of milk. Red and pinto beans contain about half as much calcium as one serving of white beans, with roughly half the bioavailability of white beans. Raw or roasted almonds contain a moderate amount of calcium as an added bonus to the nutritious monounsaturated fats and fiber they provide. Walnuts and raw pecans also offer more calcium than many other nuts. Although not a significant source of calcium on their own, nuts and beans enrich a calcium-rich diet.
This highly concentrated form of cane sugar may not be your first choice as a general sweetener, but you may find ways to incorporate it into your diet in homemade baked goods as a brown sugar substitute. Molasses can also be used to make barbecue sauce or added to baked beans. Two tablespoons can provide as much as 400 mg of calcium, or nearly half the daily recommendation for adults.