CALCIUM ON A PLANT-BASED DIET » everything you need to know
Calcium in the plant-based diet is a hot topic.
What are the sources? Do you get enough? Are they as easily absorbed?
Let's answer these questions and more...
Calcium in Brief
Calcium is a mineral found in food. It's important to obtain from the diet for the structural integrity of bones.
We achieve our peak bone mass at around 20 years of age; after this the bone density gradually declines.
Although we can't stop the decline from happening, we can slow it down by making sure we get enough calcium from our food.
Food sources are always recommended first, as opposed to supplements.
It is absolutely possible to obtain all calcium needs solely from food, at the exclusion of any animal products.
Adults < 50 years: 1000 mg calcium daily
Adults > 50 years: 1200 mg calcium daily
Maximum: stay below 2000 mg/day from food + supplement combined
Plant-based Calcium Sources
Give this Mixed Berry Parfait with Cocoa Granola a try for breakfast
The following is a simplified summary of how we can meet the recommended amounts from food:
300 mg/day: offered by a well-balanced diet, excluding calcium-rich foods (small contributions add up!)
700 – 900 mg/day: to be consumed from high-calcium food sources (list below)
200-300 mg Elemental Calcium (Per Serving)
[source; always check the label]
Black beans (1 cup)
Bok choy or kale, cooked (1 cup)
Tofu, extra firm, in calcium sulphate brine (1 cup)
Tofu, pressed, in calcium sulphate brine (1/2 cup)
Fortified orange juice (1 cup)
Fortified rice, soy, almond, coconut milk (1 cup)
Fortified rice, soy, almond, coconut yogurt (3/4 cup)
100-200 mg Elemental Calcium (Per Serving)
[source; always check the label]
Cream wheat, cooked (1 cup)
Soybeans/white beans (1 cup)
Broccoli, cooked (1 cup)
Kale, raw (1/2 cup)
Almonds (1/2 cup)
Dried fig (5 medium)
Calcium Label Reading (Canadian Guidelines)
When reading a label, always look at the serving size first.
Skim down the label and find the % daily value of calcium (in this case 30%).
To know how many milligrams of calcium is in the serving size, simply add a ‘zero’ (in this case 300 mg).
Increasing Calcium Tips: Intake
We learned above that the basic well-balanced diet offers at least 300 mg calcium as a base. To achieve the remaining 700-900 mg of calcium, the following quick tips are recommended:
Adults < 50 years: aim for 2 servings of calcium-fortified non-dairy milk*/yogurt or calcium-set tofu daily
Adults > 50 years: aim for 3 servings of calcium-fortified non-dairy milk*/yogurt or calcium-set tofu daily
*Tip: to maximize your calcium intake, shake the container of the fortified plant-milk well; the calcium tends to sediment on the bottom otherwise
A Note on Calcium Absorption: Plant-Based Foods
Calcium from fortified non-dairy drinks, non-dairy yogurts and tofu are absorbed at the same rate and efficiency as those from cow's milk.
Dietitian's Definition: oxalates and phytates are natural components found in some plant foods.
Oxalates may negatively affect calcium absorption, but these foods should not necessarily be avoided! The benefits they offer far outweigh the small amount of calcium that is lost due to binding with these components. If you're concerned about calcium intake, aim to eat low-oxalate foods more often than high-oxalate foods:
Low-oxalate foods: broccoli, bok choy, kale, napa cabbage, watercress, mustard greens, turnip greens
Medium-oxalate foods: collards and dandelion greens
High-oxalate foods: beet greens, spinach, Swiss chard
Absorption of calcium from beans and nuts is moderate due to the presence of phytates, but again: some calcium is still offered and the overall nutrition offered by these foods is great - so no need to avoid them! Note: soaking beans and nuts overnight helps to decrease the phytate content as it leaches out into the soaking water. For more information on the benefits of soaking check out this PUL article.
Controversies Around Plant-Based Milks
There are some circulating questions surrounding specific ingredients in store-bought plant-based milks. Let's explore some of them:
1. Carrageenan: there are concerns over carrageenan and its effect on gut health, specifically with regards to causing inflammation and turning into a carcinogen (cancer-causing compound). Some serious allegations here. Carrageenan is a polysaccharide (a type of carbohydrate) used in many dairy-based products for its thickening, gelling and stabilizing properties - essentially it helps give plant-based milk the same creamy/thick texture as dairy milk. The evidence on this is a bit inconsistent, some claiming it to have potential health concerns and others ensuring its safety. Many studies have not been done on humans and/or study very large concentrations (more than the average person would consume).
3. Soy Lecithin: this is a mixture of various lipids (fats) and is used in food products for its emulsification properties (keeping things in solution).
In short, these ingredients are generally safe to consume and have not been scientifically shown to cause adverse effects when consumed in moderation (~2 servings/day). All have been deemed safe for use by Health Canada. With that said, all three are commonly used in processed foods, and as a general rule of thumb we recommend reducing the overall consumption of processed foods as a whole.
In addition, many readers ask: can we make our own homemade plant-based milk and dissolve a couple calcium supplement tablets in there? In theory, this sounds like a good idea, but there are a few concerns. First off, plant-based milks are typically fortified with a few other vitamins and minerals such as vitamin D, B12 so these will be missed. Second, little is known about how these dissolved supplements will hold up in your homemade milk, and for some people determining the dosage may be unprecise and even dangerous if they accidentally supplement with too much. There are many unknowns and if you rely on plant-based milks and yogurts for a large portion of your calcium intake, it's better to be safe with store-bought plant-based milks that have been regulated.
Lifestyle Factors That Diminish Calcium Stores
Salt: high salt intake increases calcium loss in the urine and has been shown to reduce bone density. Limit intake of processed foods.
Caffeine: go easy on the caffeine. Too much caffeine can decrease the amount of calcium your body stores. Limit to about 2 cups (250 mL = 1 cup) per day. Remember that colas and energy drinks also contain a lot of caffeine. Regular tea contains much less caffeine than coffee. Read more about coffee in our article here.
Calcium Supplements: Are They Needed?
Food sources are always recommended before supplements. This is because food sources provide added benefits such as energy, fibre, other vitamins and minerals and antioxidants. If it's not possible to obtain the recommended amount from food, supplement only the deficit. More is not necessarily better!
Here are some things to note if taking supplements:
Multivitamins: remember these can also contain calcium - consider this when calculating your total intake.
Reading labels: look for the word "elemental" on the supplement label when determining the amount of calcium it provides. If you have questions, as the pharmacist.
With food: take calcium carbonate and calcium phosphate with food. Other types can be taken anytime, with or without food.
Max dose: avoid taking more than 500 mg in one dose; the body can't absorb the calcium as efficiently in larger doses.
Vitamin D: although it is true that this increases calcium absorption, it does not have to be taken at the same time as the calcium supplement, but it can be taken at the same time if desired.
Supplement type: there is no difference in absorption if calcium supplements are liquid, chewable, or tablets.
Side effects: taking too much calcium (diet + supplement combined) can increase the risk of heart attack and stroke due to excess being deposited in the arteries, thereby hardening them. Also, excess calcium is hard on the digestive system and can cause constipation and bloating. This is why food first is preferred - these side effects have not been documented when calcium is obtained solely from food.
Eat dark green vegetables such as spinach, chard, kale, broccoli, Brussels sprouts etc. daily
If possible, soak raw nuts and dry beans overnight to increase calcium availability
Shake the container of your non-dairy milk well to bring the calcium into suspension
Consume 2 servings (< 50 years old) to 3 servings (> 50 years old) of fortified non-dairy milk/yogurt or calcium-set tofu daily
Avoid calcium supplements unless unable to achieve this. Be careful not to take more than just what is needed to avoid harmful side effects and potential complications.
Limit salt, caffeine and alcohol intake and abstain from smoking
If you have any concerns surrounding your bone health and/or calcium in your diet, consult with a local registered dietitian or with your family physician.
Want to learn more? Read the previous article in this series called Bone Health: Introduction & Osteoporosis
Read the next article in this series called Vitamin D & Nutrition: Do You Need Supplements?
What About You?
❤ Written by: Sadia