Bone Health and Calcium for Vegans

There was a time when we didn’t expect to get our calcium from cows. Bone health and calcium for vegans is a topic that we should all be aware of as there are plenty of non-dairy calcium-rich foods out there, and you may be consuming more of them than you think. I’ve compiled a list of some of the top non-dairy calcium-rich foods to include in your diet and tips on how to maximize absorption for bone health.

What foods are high in calcium? Contrary to popular belief, calcium doesn’t only come from cows! Crazy huh? A lot of marketing money stemming from the Dairy Industry has led us to believe that dairy is the one and only superstar in the battle against osteoporosis. Whether you are a vegan, environmentalist, lactose intolerant or just love your green leafy vegetables, there are other dietary options for healthy bones. Here are my top tips for bone health and calcium for vegans.

How Much Calcium Do We Need?

What Is The Recommended Dietary Allowance For Calcium?

The Recommended Dietary Allowance (RDA) is the average daily level of intake that is thought to be sufficient to meet the nutrient requirements of nearly all (97-98%) of healthy individuals. The RDAs for the amounts of calcium were set for the required amount for bone health and to maintain adequate rates of calcium retention in healthy people.

How Much Calcium Do We Need In A Day?

Calcium requirements vary based on age and stage of life. Below are the RDAs for calcium:

• Age 1-3 years old – 700mg per day
• Age 4-8 years old – 1,000mg per day
• Age 9-13 years old – 1,300mg per day
• Age 14-18 years old – 1,300mg per day
• Age 19-50 years old – 1,000mg per day
• Female age 51-70 years old – 1,200mg per day
• Male age 51-70 years old – 1,000mg per day
• Age 71 years old and over – 1,200mg per day

What Are The Calcium Requirements During Pregnancy and Lactation?

Surprisingly, calcium requirements do not go up during pregnancy and lactation. This means that it is even more important that mom consumes enough calcium. The baby is the main priority during pregnancy and lactation, so any calcium deficiency in the diet can have detrimental effects on the mother. Below are the RDAs during pregnancy and lactation:

• Pregnancy and lactation, age 14-18 years old – 1,300mg per day
• Pregnancy and lactation, age 19-50 years old – 1,000mg per day

Do Vegans Need More Calcium?

Vegans and ovo-vegetarians (who eat eggs but no dairy products), may be at risk of calcium deficiency because of the avoidance of dairy foods, and also the increased consumption of plant products containing oxalic and phytic acids. In the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition, bone fracture risk was similar in meat eaters, fish eaters and vegetarians, but higher in vegans, likely due to their lower mean calcium intake (1).

Current recommendations do not support a higher intake of calcium for vegans and ovo-vegetarians than the current RDAs, but by following the tips outlined below one can help ensure calcium requirements are being met.

What Are The Best Sources of Calcium For Vegans

Sourcing your calcium solely from plant foods can be challenging but not impossible. Here are some more top contenders of calcium-rich plant foods:

• Chia seeds, (2 Tbsp) – 143mg
• Dulse, Red Laver Seaweed, (½ cup) – 50-140mg
• Rose Hips, Saskatoon Berries, (½ cup) – 50-140mg
• Collard Greens, 1/2 cup cooked – 113mg
• Figs, 5 – 88-137mg
• Oranges, 1 med – 52mg
• Tofu, silken firm 1/2 cup – 40mg
• Seaweed, 1/2 cup raw – 67mg
• Okra, 1/2 cup cooked – 50mg
• Broccoli, 1/2 cup cooked – 30mg
• Kale, 1/2 cup raw – 90mg
• Bok Choy, 1/2 cup cooked – 78mg
• Chinese cabbage flower leaves, 1/2 cup cooked – 239mg
• Chinese mustard greens, 1/2 cup cooked – 212mg
• White beans, 1 cup cooked – 226mg*
• Pinto beans, 1 cup cooked -90mg*
• Almonds, 1/4 cup – 80-115mg*
• Sunflower seeds 1/4 cup – 42mg*
• Tofu, firm, calcium-set, 1/2 cup – 860mg
• Fortified soy and nut milks, 1 cup – 300mg

The above are low oxalate options.

See post Milk Alternatives – Which One Is Best For You for more information on Milk Alternatives.

*These foods are high in phytates which may somewhat affect the absorption of calcium. Soaking and sprouting help to reduce the phytate content of these foods.

What Causes Calcium Loss From Our Body?

Calcium Excretion From Our Bodies

No matter how much calcium we consume, there is always the normal process of calcium loss in our urine and feces.  It is important to be aware of some dietary factors that can increase these losses from our bodies, which we want to avoid to keep our bones strong and healthy.

Proteins Effect on Calcium Excretion

Amino acids are the building blocks of protein, and some of these amino acids contain sulfur which has an acidifying effect on the blood. A high protein diet, made up of high amounts of sulphur-containing amino acids can increase the acidity of the blood. How the body attempts to neutralize the blood is by drawing calcium, which is basic, from the bones.

Although any type of excess protein, even from plants, can lead to calcium losses, it is meat that is especially high in the sulphur-containing amino acids, leading to higher rates of calcium loss.

Sodium and Its Effect on Calcium Losses

Sodium or salt is present all around us, and often we take in more than we need. When we eat too much sodium, our kidneys excrete the excess sodium and take small amounts of calcium along with it. Having a moderate amount of sodium, and avoiding highly processed foods that are very high in sodium is good practice for bone health.

Soft Drinks and Coffees  Effects on Calcium Losses

Don’t worry coffee lovers, up to 3 cups of coffee per day appears to have a negligible effect on calcium balance, though it is possible that more than this amount could increase calcium loss. Soft drinks such as cola are high in phosphoric acids, which can leach calcium from the bones, increasing calcium loss. Note that not all sodas are high in phosphoric acid.

Oxalates and Calcium Absorption

Certain foods are high in oxalic acids, such as spinach, beet greens, Swiss chard, and rhubarb. Oxalates in food can bind to calcium, decreasing the calcium absorption by our bodies. It is important not to rely on these foods as good sources of calcium.

Alcohol and Calcium Absorption

Excess amounts of alcohol can reduce the absorption of calcium in bodies, and long-term effects of excess alcohol consumption can lead to osteoporosis. Alcohol also limits the liver’s ability to convert Vitamin D, another important nutrient in bone health, to its active form. See my post Vitamin D Foods For Vegetarians.

What Increases Calcium Absorption In Our Bodies

Calcium Absorption In Our Bodies

Some foods may appear to be a good source of calcium but there are a few things to keep in mind when considering how much of that calcium is absorbed by our bodies.

Timing of Calcium Rich Meals

Our body absorbs more calcium from food when small amounts of calcium-rich foods are eaten over the day, and we don’t do well with a large amount of calcium at one time. Eating calcium-rich foods throughout the day rather than all at once will increase overall absorption.

Bioavailability of Calcium

Bioavailability means the amount of a nutrient in a food, such as calcium, that we can actually use. Just because a food is high in calcium, doesn’t mean that our bodies can access it all.

• The calcium in green vegetables has a high bioavailability and approximately 40-60% of the calcium is available.
• Calcium-set tofu has about a 30% bioavailability of calcium.
• The calcium from soy beverages, or other milk alternatives – often fortified with tricalcium phosphate – is a little lower at 24%.
• Legumes, almonds, sesame seeds and sweet potato have lower bioavailability at approximately 20%.

For comparison, milk has a bioavailability of around 30%.

Fruits and Vegetables

When we eat an excessive amount of protein, especially animal protein, as well as grains, this can increase calcium excretion from our bodies due to the metabolic acid state of the body (see above in Protein Effects On Calcium). Fruits and vegetables help shift the acid-base balance by producing bicarbonate, which reduces calcium excretion. Aim for at least ½ plate of vegetables at lunch and dinner.

Soaking, Sprouting and Fermenting

When a legume, nut or seed is soaked in water, some phytate will be removed. Phytates bind to calcium in your body (and other minerals – see How To Get Enough Zinc For The Vegans and Vegetarians), making calcium less absorbable. Sprouting and fermenting have the same effect and help increase the available calcium in food. See How To Make Sprouts & The Health Benefits Of Sprouting Foods for more information on sprouting.

Vitamin D Increases Calcium Absorption

Vitamin D is essential for the active absorption of calcium in our body and helps absorb dietary calcium in our gut. There are not many food sources of vitamin D – oily fish and eggs being the main contenders. We get most of our vitamin D from sunlight, but unfortunately, from October to March for anyone above the 45th latitude, there is not enough UV light for adequate vitamin D production. See my post Vitamin D Foods For Vegetarians for more information on how to get enough vitamin D.

Want Good Bone Health and Adequate Calcium for Vegans? Start Young

Building Strong Bones

The overall process to achieve maximum bone strength takes about 20-30 years. Up until the age of 8, we achieve approximately 45% gain in bone mass, with another 45% occurring from ages 8-16. The last 10% occurs over the next decade and a half. After age 30, bone mass starts to decline.

Start Young For Strong Bones

Regardless of if you are following a vegan diet, if you are still in your 20s there is still time to build up your bones. Make sure you are consuming at least 1,000mg of calcium per day, or 1,300mg per day if you are aged 14-18. This is when your bones are the most hungry for calcium and will set the foundation for your older years.

Weight-Bearing Exercise

Both weight-bearing exercises, such as walking, running, and activities where one’s feet leave and hit the ground and work against gravity, as well as resistance exercises such as callisthenics and those that involve weights, support bone health. Exercising can also help us maintain muscle strength, coordination, and balance, which in turn helps to prevent falls and related fractures.

Keeping Your Bones Strong On A Vegan Diet

Are you past the age of 30? Don’t worry. If you are consuming a healthy diet with adequate calcium from vegetables that are low in oxalates, avoiding excess salt and sodas, and keeping up with weight-bearing exercises you are doing fine. Adequate vitamin D is as important as getting enough calcium for vegans. Best to speak to your health care professional or Registered Dietitian if you have any questions about your individual needs.

 

References Bone Health and Calcium for Vegans

1. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. European Journal of Clinical Nutrition. 2007.

More References Bone Health and Calcium for Vegans

Website: PEN Nutrition
Book: Becoming Vegan – Brenda Davis, RD