As a vegan, you probably get asked about how you get protein all the time. Few people will ask you about where you get your calcium. While there are plenty of plant-based sources of calcium and fortified foods which contain calcium, the scary truth is that many vegans may not be meeting their calcium requirements. Here are some important facts you need to know about calcium as a vegan.
Yes, Vegans Are at a Higher Risk for Osteoporosis
Vegans like to tout their diet as being the healthiest, and point out that all the nutrients in an omnivorous diet – with the exception of B12 — can also be found from plant foods. This is true, but it doesn’t mean that it is easy to get all of those nutrients on a vegan diet. Calcium is one of those nutrients which may be hard for vegans to get.
Numerous studies have found that vegans (though not necessarily vegetarians) are at a higher risk for osteoporosis, fractures, and low bone density. It isn’t just low calcium intake which is causing the increased risk. Vegan diets can also be low in magnesium, vitamin D (good luck getting enough from sunlight in the winter!), and vitamin K2 – all of which are very important for absorbing and utilizing calcium.
This doesn’t mean that all vegans are going to get osteoporosis or suffer from weak bones. But it is something that vegans should acknowledge so they make sure to get enough calcium and bone nutrients.
High Protein Diets Don’t Leach Calcium from Bones
For a long time, vegans have clung to the belief that high-protein diets acidify blood and cause calcium to be leached from bones. Thus, many “experts” claims that vegans need lower amounts of calcium because their diets don’t have as much protein.
Unfortunately, this belief has been shown to be false. Vegan RD Jack Norris points to new research on the subject, noting that, “It shouldn’t be surprising. Protein is an integral part of bones and it also improves calcium absorption.”
The bottom line? Don’t skimp on the calcium. Or the protein for that matter!
Not All Sources of Calcium Are the Same
If you are vegan, then you should know what bioavailability is. Basically, bioavailability means how well your body absorbs a certain nutrient. Not all sources of a nutrient have the same bioavailability.
For example, spinach is often cited as a good source of calcium. While spinach does contain a lot of calcium, your body only absorbs a fraction of this calcium – about 5%!
We have a biological need for about 250-300mg of calcium per day. When calculating RDAs, agencies go by averages and estimates based on what “normal” populations eat. The calcium RDA in the USA for most adults is set at 1000mg. This is because they know that about 1/3 of the calcium from milk is absorbed by our bodies. So, if you get 1000mg of calcium from milk and absorb about 1/3 of it, you will meet your biological needs.
Don’t worry. There are plenty of bioavailable sources of vegan calcium (click the link to see them and a bioavailability chart). One of the best vegan sources of calcium is turnip greens. 1 cup of cooked turnip greens has more bioavailable calcium than milk!
Fortified Plant Milk is as Good as Dairy Milk
As far as bioavailability goes, calcium from plant milks is just as good as the calcium from diary: your body will absorb about 1/3 of the calcium. Note that plant milk is not a “natural” source of calcium – the calcium is only in fortified plant milks! Unless you are eating several cups of cooked leafy greens per day, you’ll probably want to choose a fortified plant milk or other fortified vegan foods to help you meet your RDAs. See these calcium vegan meal plans to see how you can get enough calcium on the vegan diet.
Vitamin D Is Hard to Get In Winter
Unless you live in a sunny paradise where you can walk in bare sleeves all year round, you might not be getting enough vitamin D during winter. You only really need about 10-30 minutes of exposure to sunlight in order to get enough vitamin D. But those calculations were made based on the idea that your skin is exposed – not just your face exposed while the rest of you is wrapped up in bundles of jackets and hats. If you have dark skin, then you are going to need even longer exposure to sunlight in order to get enough vitamin D.
Also remember that vitamin D can’t go through windows – so sitting in a sunny spot inside won’t help you get vitamin D. Absorption is also hindered by sunblock.
Vegans aren’t the only ones at risk of vitamin D deficiency. The problem is so widespread that the Journal of Clinical Nutrition called it a pandemic! Find out other reasons you might not get enough vitamin D here.
I take a vegan vitamin D supplement during winter to make sure I get enough of this crucial bone nutrient.
Your Bones Also Need Vitamin K2
You’ve never heard of vitamin K2 before? Until recently, even researchers didn’t know about this vitamin and its crucial role in our bone health.
Vitamin K2 basically acts like a public transportation system for calcium. You consume calcium through food, vitamin D helps it get into the bloodstream, and vitamin K2 takes the calcium to where it needs to go. Without vitamin K2, calcium can end up hardening in your arteries as plaque – hence why taking calcium supplements is linked to higher rates of heart disease! Learn more about vitamin K2 and its role in bone health here.
If you are going to take a calcium supplement, make sure it also contains vitamin K2. I use Jarrow’s Bone Up vegan formula because it contains K2, D, magnesium, and other important bone cofactors.
Supplements should never be used in place of good nutrition. But if you think that you might need a bit of help meeting calcium RDAs on the vegan diet, check out this list of vegan bone supplements.
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Additional References:
http://www.ncbi.nlm.nih.gov/pubmed/24898237
http://www.ncbi.nlm.nih.gov/pubmed/17299475
http://www.theveganrd.com/2013/08/calcium-and-protein-and-bone-health-in-vegans.html
