An interesting article that showed up in my e-mail recently was a study just published about prickly pear cactus dried supplements as a source of supplemental calcium.
In Mexican women aged 35-55 years old, using dried nopales (the “leaves” or pads of the plant) reduced the incidence of osteopenia and osteoporosis. More mature nopales (135+ days old) are dried and ground into powder. They afford 34 mg of calcium for every gram of powder (2).
Most of us don’t have access to nopales or even nopales extract. It’s not the supplement that I’m in awe of, it’s the fact that this is a regional vegetable that is commonly eaten in Mexico and an excellent non-dairy source of calcium.
One of the most common questions people ask me is “How do I get my calcium intake if I can’t eat dairy?” Or a variation on that “Is it really safe for my child to not drink milk? Where will he get his calcium from?” Milk really isn’t the best source of calcium. In fact, it’s hypothesized that too much dairy and animal products (especially highly-refined garbage packaged and fast food) actually creates such an environment within your body that your body must pull calcium from your bones in order to offset the acid-inducing effects of animal products (this is still debated, however, and it is believed that a vegan diet is more detrimental to bone health than animal products in healthy amounts (5, 6)). Drinking milk does not reduce your risk of osteoporotic fracture, according to the study by Kanis and colleagues in 2005 (3). In the longest study conducted (12 years), no association was found between milk consumption in childhood and reduced risk of bone fracture (4).
Ask yourself–what did humans do before they began milking other animals?
Vegetables is the answer. One cup of cooked collard greens affords 36% of the recommended daily value of calcium (women need 1300mg+ per day, men need 1000mg per day). Kale, turnip greens, broccoli, arugula, and okra are also all good sources of calcium.
Although diet is huge in the prevention of osteoporosis, there are other factors that are important. Regular weight-bearing exercise ensures your bones are “being exercised.” Weight-bearing means upright (not swimming or seated exercise bike). Putting pressure on bones, like how gravity does, makes sure that calcium is not taken from that bone by your body to be used in other metabolic processes. Being upright is essential because your spine and legs, the most common areas of osteoporotic fracture, are holding up your weight.
Vitamin D is necessary for laying calcium into bones. Get outside into the sun, without sunscreen, periodically. People are crazy about skin cancer nowadays. I am of the opinion that sun is good for you in healthy amounts. Depending on your latitude and your climate, it is generally recommended that you get 15 minutes of sunscreen-less sun exposure on arms and legs between 10am-3pm twice per week (1). Considering vitamin D recommendations are always changing (being increased mostly), I’d say it’s safe to bump that up to 3 times per week. See my post on hypercholesterolemia to learn what cholesterol has to do with vitamin D synthesis.
Trace minerals like zinc, copper, and boron, are also essential for healthy, strong bones. Because your bones are a matrix of minerals and protein (connective tissue), calcium needs the help of other minerals to form a strong skeleton. Trace minerals are often found in nuts and seeds.
Work with what you’ve got. You don’t need to run out and buy nopale powder. You don’t need to chug cups of milk per day. You need to eat a balanced diet with raw and cooked vegetables at every single meal. A good quality multivitamin should help bridge any nutritional variants daily once your diet is complete.
(1) Holick MF. Vitamin D deficiency. N Engl J Med 2007;357:266-81.
(2) Angeles Aguilera-Barreiro M, et al. Intake of dehydrated nopal (Opuntia ficus indica) improves bone mineral density and calciuria in adult Mexican woman. (2013) Food & Nutr Research. 57: 19106 – http://dx.doi.org/10.3402/fnr.v57i0.19106
(3) Kanis JA, et al. A meta-analysis of milk intake and fracture risk: low utility for case finding. (2005) Osteoporos Int 16: 799–804.
(4) Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. (1997) Am J Public Health 87:992–7.
(5) Heaney RP. Protein intake and bone health: the influence of belief systems on the conduct of nutritional science. (2001) Am J Clin Nutr. 73(1): 5-6.
(6) Smith AM. Veganism and osteoporosis: a review of current literature. (2006) Int J Nurse Pract. 12: 302-306.