Up until about 20 years ago, the way to meet your daily needs for calcium were simple:
The message became so clear that it gradually seaped out of the public conscioiusness that you had other alternatives.
Of course, drinking milk is a relatively new phenomenon to the human diet. It first happened about 8,000 years ago in the fertile crescent, whereas the majority of the human diet was formulated between 0.5 and 1.4 million years ago.
Non-dairy diets give you a variety of options to fulfill your needs for calcium, and the chestnut “Milk is essential for strong bones” has quite a few unintended consequences.
Vegetarian Sources of Calcium
It’s true that milk is a good source of calcium. One glass gives you about 300 mg, which is nice. It’s also absorbed pretty well…..but that doesn’t mean milk is king of the hill.
For a vegan or vegetarian that needs calcium, dark leafy greens are an excellent source of calcium that, per gram are almost just as good as milk and are actually absorbed better by the body.
Here’s a useful graph from the American Journal of Clinical Nutrition of different foods and their calcium potency:
Leafy greens (with the exception of spinach) are great sources of calcium that are digested readily by the body. They also have the benefit of providing lots of magnesium, another mineral vital to bone health.
If you make a point to eat lots of salad, you should get plenty of calcium.
You May Not Need As Much Calcium As You Think
The standard RDA for calcium is 1300 mg/day. It’s the most abundant mineral in the body, mostly because it’s used in your bones, among other things.
However, I’d suggest a more useful recommendation:
You probably need 1300 mg/day of calcium on a typical western diet.
The amount of calcium you need is influenced by the following factors:
- your genetics (perhaps up to 60% of your ability to absorb calcium)
- your body’s state of calcium homeostasis
- the amount of protein, sodium, and other minerals in your diet
The role of genetics plays an underreported role in the nutrition of calcium.
For example, Inuit Indians typically survive on 20 mg of calcium a day! They can do this because they have a hyper-sensitive vitamin D receptor that allows their body to absorb calcium very efficiently. One of the problems Inuits have had when indoctrinating themselves to western diets is the extra calcium, which results in hypercalciuria…..a disease that comes from having too much.
Blacks regularly have higher bone mineral densities than whites, because they naturally retain calcium better.
Your body regulates its calcium metabolism the same way it regulates its calories. It forms “set points” for what it thinks its going to need, and then stores and throws out calcium based on that figure.
Which is why groups of people that regularly have lower calcium intakes can have the same calcium balance in their body as people who digest more. East asian and african populations have lower intakes of calcium and dairy, but also have lower rates of osteoporosis and bone fractures.
Vegans Might Need Less Calcium Than Meat Eaters
To build on the points mentioned previously, it’s possible that people who eat less meat have lower calcium requirements. In addition to different “set points”, animal proteins have lots of sulfur containing amino acids, which cause the body to excrete more calcium in urine, and also makes the body more acidic.
Your body naturally maintains a certain pH in the blood, and it uses calcium from the bone as a buffer to raise its pH when metabolic acids seep into the bloodstream. The two biggest culprits for this phenomenon are sulfur containing amino acids and sodium, both of which are found in much higher levels in omnivorous diets.
So given that green vegetables have a higher rate of absorption, and vegans have less complimentary nutrients in their diet that raise their calcium requirements, it’s quite possible that most people could get by with less calcium than one needs on an omnivorous diet.
At least one study published in the Journal of Bone and Mineral Metabolism supports this observation. It found that vegans typically consumed about 30% less calcium than meat eaters, but had higher levels of absorption and insignificant differences in calcium balance.
Milk Isn’t Good For Your Bones….and Neither Is Meat
One of the supposed benefits of meat and dairy is that it will make your bones strong.
This isn’t true in the slightest.
While calcium might have positive effects on bone mass, there’s nothing particular about the calcium in dairy products that makes it especially beneficial.
Indeed, almost every epidemiology study points to the same thing: calcium is calcium. As long as your body is absorbing what it needs based on your dietary and genetic profile it makes no difference where it comes from.
And there’s a bit of evidence that suggests dairy has no effect or is harmful to bone health.
Here are the results from a wide scale epidemiology study comparing different diets of the world, and how often they suffered from bone fractures:
Northern europeans and Americans have the highest dairy intakes in the world. They also have the highest rate of bone fractures. East asian populations and africans typically have the lowest dairy in their diet…..and suffer far less from osteoporosis and bone fractures than the rest of the world.
And there’s more.
A fairly well known study published in the Journal of Public Health studied 77,000 women over twelve years and analyzed incidence rates of forearm and hip fractures compared to age, milk consumption, and other lifestyle factors.
These data suggest that more frequent milk consumption and higher dietary calcium intakes in middle-aged and older women do not provide any substantial protection against hip or forearm fractures.
And animal protein doesn’t fare much better. Here’s the result of a study conducted by the Yale School of Medicine on the relationship between animal protein and bone fractures:
So, no. Vegetarian diets don’t make you gaunt and wimpy. Just the opposite.
And all these studies miss the most important point.
Physical activity and body weight affect the health of your bones moreso than calcium intake.
In a sense, your bones behave like other muscles. They respond well to constantly being worked and suffer from prolonged stress.
And as an added benefit, you don’t have to worry about the increased risks of high blood pressure, hypertension, diabetes, or stroke 🙂
I’ve written about these topics before, and they all boil down to the same point: if the majority of your calories come from whole plants and grains, the nutrients you need will probabaly take care of themselves.
So if you’re wondering…..”where do vegetarians get their calcium?” don’t sweat it.
It’s in the plants, stupid!
Feskanich, Diane, et. al. “Milk, Dietary Calcium, And Bone Fractures in Women: A 12 Year Prospective Study” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1380936/pdf/amjph00505-0106.pdf
Weinsier, Roland, et. al. “Dairy Foods and Bone Health: Examination of the Evidence” http://www.ajcn.org/content/72/3/681.long
Abelow, Benjamin, et. al. “Cross Cultural Association Between And Hip Fracture: A Hypothesis” http://www.vivalis.si/literatura/4a95.pdf
Feskanisch, Diane, et. al. “Protein Consumption and Bone Fractures in Women” http://aje.oxfordjournals.org/content/143/5/472.full.pdf
Kohlenburg-Mueller, Kathrin. “Calcium Balance in Young Adults On A Vegan and Lactovegetarian Diet” http://www.springerlink.com/content/10jvvm8uk86wl10k/
Stewart, T L “Role of Genetic Factors in the Pathogenesis of Osteoporosis” http://joe.endocrinology-journals.org/content/166/2/235.full.pdf
Lutz, Josephine “Calcium Balance and Acid-Base Status of Women as Affected by Increased Protein Intake and By Sodium Bicarbonate Ingestion” http://www.ajcn.org/content/39/2/281.full.pdf
Heaney, Robert, M.D. “Calcium Balance and Calcium Requirements in Middle Aged Women” http://www.ajcn.org/content/30/10/1603.full.pdf
Braun, Michelle, et. al. “Racial differences in skeletal calcium retention in adolescent girls with varied controlled calcium intakes” http://www.ajcn.org/content/85/6/1657.full
Sellers, Elizabeth. “Adaptation of Inuit Children To A Low Calcium Diet” http://www.ecmaj.ca/content/168/9/1141.full
Welton, D.C. “Weight Bearing Activity During Youth Is A More Important Factor for Peak Bone Mass Than Calcium Intake” http://onlinelibrary.wiley.com/doi/10.1002/jbmr.5650090717/abstract