Although the marriage of milk and calcium has been highly publicized over the past two decades (got milk?), there are dozens of sources of calcium other than milk. Calcium is an abundant mineral in the body with a wide variety of functions, primarily skeletal, as 99 percent of calcium in the body is stored in bone and teeth. Calcium plays other essential roles in cell communication, enzymes and proteins. Whether you are intolerant, allergic or simply choosing not to drink milk, adequate amounts of calcium can be consumed through non-milk foods to achieve your daily calcium requirements. Additional steps when preparing and storing these foods can be practiced to minimize calcium losses and increase bioavailability of calcium in foods.
Calcium needs vary throughout the life cycle. Average daily recommended amounts generally range from 1,000 milligrams to 1,300 milligrams, depending on age. Preteens and adolescents aged 9 to 18 years old require the most (1,300 milligrams), while most adults fall into the lower end of the scale.
Some are surprised to find out that vegetables, particularly green leafy veggies, can deliver a significant amount of calcium. Bok choy (1/2 cup cooked has 79 milligrams of calcium) and kale (1/2 cup cooked, 61 milligrams) are particularly good sources, as are broccoli, collard greens, okra, cooked spinach and turnip greens.
Spinach and Swiss chard, among others, contain oxalic acid, which can significantly decrease calcium absorption. By cooking these greens, calcium availability may be increased. Generally, high oxalate-containing foods shouldn't be counted on for their calcium contributions.
Legumes, Nuts & Seeds
While typically popular for their contribution of fiber, legumes, nuts and seeds also are capable of delivering amounts of calcium worth mentioning.
Among legumes, black-eyed peas (1/2 cup cooked contains 105 milligrams), soybeans (1/2 cup cooked, 88 milligrams), chickpeas, white beans and navy beans, cup for cup, have some of the highest calcium contents among beans.
When comparing the calcium content among nuts and seeds, almonds (1 ounce contains 75 milligrams), sesame butter (2 tablespoons, 126 milligrams), flax seeds, hazelnuts and Brazil nuts have highest amounts of calcium.
Some legumes contain phytates, as well as oxalates, which interfere with calcium absorption. Phytate levels can be reduced by soaking beans for several hours, discarding soaking water, and then cooking in fresh water.
Processed foods -- cereals, breads and snacks -- may be fortified or enriched with calcium, though some processed foods may have less healthy components. Processed or not, some of the grains containing higher amounts of calcium include amaranth (1/2 cup cooked grain contains 138 milligrams of calcium), carob flour (1/2 cup flour, 179 milligrams), chickpea flour, quinoa flour and tapioca flour.
Wheat bran contains high amounts of phytates, therefore inhibiting calcium absorption. For this reason, wheat bran should not be consumed simultaneously with calcium rich foods..
Consuming fish, with small bones included, can deliver impressive amounts of calcium. Sardines (3 ounces, 321 milligrams), salmon (3 ounces, 181 milligrams) and mackerel are particularly high in calcium.
Some sea vegetables are also high in calcium, including kombu (edible kelp) and nori (edible seaweed).
Optimizing Calcium Intake From Foods
Optimizing calcium intake from foods can be achieved by taking steps to increase bioavailability and decrease nutrient loss.
As mentioned, several vegetables, legumes and whole grains contain high enough amounts of phytates and oxalates to negatively affect calcium absorption. By soaking grains and legumes, the effects of these can be reduced.
Excess alcohol and caffeine consumption can negatively affect calcium status.
Carbonated beverages -- including those also containing caffeine -- negatively impact calcium status. Also pay attention if these beverages are taking the place of calcium-fortified beverages.
- Advertising Educational Foundation: On-Campus Classroom Resources
- Linus Pauling Institute: Micronutrient Information Center
- Cornell University: Healthy Eating Program at Gannett Health Services
- National Institutes of Health, Office of Dietary Supplements: Dietary Supplement Fact Sheets
- National Osteoporosis Foundation: Food and Your Bones