Calcium is essential in maintaining normal body functions from muscle contractions to transmission of nerve impulses and coagulation of blood. Still, our bodies are unable to produce this mineral, emphasizing the necessity of a calcium-rich diet. Consider how our bones are constantly being remodeled: 5-10% of our skeleton is reabsorbed and replaced by new bone every year, and with it calcium supplies are continuously being lost. If more calcium is removed than replaced during remodeling, bones become brittle and will break, not to mention a compromised nervous and circulatory system.
For those following a plant-based diet, ensuring that the recommended dietary allowance (RDA) for calcium is met (approximately 1,000 mg per day for both men and women) is critical. Transitioning away from both dairy products and refined, processed foods typically fortified with calcium can lead to short-term deficiencies without adequate supplementation and education on plant-centric calcium-rich food sources. Although it may seem easier to continue to use dairy products as a means of obtaining calcium, it’s important to remember that these products are accompanied by addictive lactose sugar, animal growth factors, contaminants, and high levels of fat and cholesterol. Studies also point to a lack of correlation between consumption of dairy and strong bones: a 2004 Report of the Surgeon General published a 12-year Harvard study following 78,000 women, which revealed that those who drank milk three times a day broke more bones than those who drank little to no milk.
Consider the following abbreviated list taken from the U.S. Department of Agriculture’s National Nutrient Database assessing calcium found in plant food sources.
Calcium-Rich Plant Foods:
- Tofu, calcium fortified (1/2 cup): up to 861 mg
- Orange Juice, calcium fortified (1 cup): 349 mg
- Collards (1 cup, boiled): 268 mg
- Soybeans (1 cup, boiled): 261 mg
- Spinach (1 cup, boiled): 245 mg
- White beans (1 cup, boiled): 161 mg
- Chick peas (1 cup, canned): 109 mg
- Swiss chard (1 cup, boiled): 102 mg
- Black beans (1 cup, boiled): 102 mg
- Kale (1 cup, boiled): 94 mg
- Butternut squash (1 cup, boiled): 84 mg
- Sweet potato (1 cup, boiled): 76 mg
- Broccoli (1 cup, boiled): 62 mg
- Brussel sprouts (8 sprouts): 60 mg
- Navel orange (medium): 60 mg
- Green beans (1 cup, boiled): 55 mg
As with any vitamin or mineral, deriving these micronutrients directly from whole foods ensures the greatest bioavailability of nutrients and subsequent assimilation in the body; however, supplementation may be required if daily intake is not met. Resources such as https://cronometer.com/ can help you track your daily macronutrient (carbohydrates, fats, proteins) and micronutrient (vitamins and minerals) intake to determine your personal needs and the necessity for supplements.
Supplements and Superfoods:
- Vitamin D: Calcium derived from food cannot be absorbed in the small intestine and carried throughout the body without the presence of Vitamin D. If you aren’t spending time in the sun, consider introducing a Vitamin D supplement, which works synergistically with calcium and is critical in maintaining, repairing, and remodeling your bones.
- Vitamin K: Vitamin K works synergistically with both Vitamin D and with calcium; however, by consuming an abundance of fruits and vegetables daily, you need should be easily met.
- Vegan supplement: If you are unable to derive enough calcium from whole foods, supplement with a vegan calcium supplement, such as Garden of Life MyKind Organics Plant Calcium, extracted from algae and organic plants. This supplement also includes vitamin D, K, and magnesium.
- Superfoods: Drinking chia seeds soaked in water beginning at breakfast and throughout the day is an important addition to any plant-based diet, as an excellent source of omega-3 fatty acids. Omega-3 fatty acids reduce inflammation in the body and have been recently linked to the production of connective bone tissue that helps to maintain bone rigidity.
A final note:
Although some greens, like spinach, theoretically contain an impressive amount of calcium, the oxalic acid found in spinach binds to calcium and can limit absorption in the body. Still, 2 cups of raw spinach contains almost 300 micrograms of Vitamin K, 300% of the recommended daily value. Given that Vitamin K is believed to assist with the regulation of bone growth by supporting bone mineralization, the suppressing effect oxalic acid has on calcium could be negligent, or at the very least, reduced. By eating a variety of calcium-rich plant foods, paired with regular exercise, meeting your recommended dietary allowance of calcium is achievable.