October 28, 2019 In Health By rebecca

Calcium, bone health, and vegan diets

Calcium is a frequently raised topic when it comes to plant-based eating. When dairy is not part of the diet often questions arise about how to get enough calcium, and will it lead to weak bones? The information below provides an overview of calcium and vegan diets.

 

Why do we need calcium?

Calcium is an essential nutrient required for healthy bone development, maintaining bone density, and muscle and nerve functions.

Vegans have been found to have a slightly lower bone mineral density (BMD) compared with omnivores. BMD is used in the diagnosis of osteoporosis and as a predictor for fractures. However, while some research has also shown a higher rate of fractures among vegans, this was due to low calcium intakes. When calcium intake was adequate, fracture rates did not differ between vegans and non-vegans. Other research has shown that the rate of bone loss is no greater for vegans or vegetarians compared with meat eaters.

During pregnancy if calcium intake is inadequate, baby’s needs will be met and calcium will be taken from the mothers’ bones to compensate.

It is therefore important to meet calcium requirements to ensure good bone health and prevent fractures. This is the case for both vegans and those who eat meat.

 

How to get calcium on a vegan diet

People who switch from eating dairy to choosing a vegan diet do not always replace the dairy foods with suitable alternatives. This then results in a low calcium intake.

However, meeting calcium requirements on a vegan diet is achievable when calcium rich plant foods are a regular part of the diet. Note that the belief held by some that vegans have a lower calcium requirement than meat eaters is not supported by current research.

Good sources of calcium include:

  • Calcium fortified foods (such as some plant milks and calcium set tofu)
  • Leafy greens (kale, bok choy, and choy sum)
  • Dried figs
  • Almonds
  • Unhulled tahini
  • Chia seeds
  • Edamame/soybeans

 

While spinach has a high calcium content, it is not considered a good source of calcium. This is due to the low bioavailability of calcium from spinach, caused by it’s high oxalate content.

Apart from plant milks, dairy substitutes such as dairy free cheese, ice-cream and yoghurt, are mostly useful as alternatives to common dairy foods rather than as a source of good nutrition. They are generally highly processed foods which are low in calcium and high in saturated fat, and should therefore be kept for occasional times.

Nutrients are best obtained from food, but if calcium requirements are unable to be achieved through diet alone, supplements may be needed.

An individual dietitian consult can assist with improving dietary nutrient intake and providing advice on supplementation if required.

 

Good bone health needs more than calcium

As well as calcium, several other factors play a role in ensuring good bone health by reducing bone loss and fracture risk.

 

Vitamin D

Ensure adequate vitamin D intake for calcium absorption and bone mineralisation. Vitamin D2 (ergocalciferol) is plant-based while vitamin D3 (cholecalciferol) is usually of animal origin. The majority of vitamin D requirements are met via sun exposure, though dietary sources also contribute. For vegans, vitamin D is found in fortified foods such as some plant milks.

 

Protein

Meeting protein requirements is important for strong bones, with protein having a positive impact on bone health. For instance, research has shown that vegetarians who consume at least ½ cup of legumes daily are >50% less likely to have a hip fracture compared with vegetarians consuming legumes less than once per week, independent of other factors.

Protein is found in legumes (eg lentils, chickpeas, kidney beans), tofu, soy milk, nuts, seeds, and grains.

 

Weight bearing exercise

This particular type of exercise contributes to improved BMD and includes activities such as netball, basketball, tennis, dancing, gymnastics, impact aerobics, running, resistance training, stair climbing, and brisk walking.

 

Vitamin B12

Aim to maintain adequate vitamin B12 levels as low vitamin B12 (as well as markers of vitamin B12 deficiency) is associated with reduced BMD and increased risk of fractures. Vitamin B12 supplements are required if animal products are excluded from the diet.

 

Fruits and vegetables

Fruit and vegetable intake has a positive association with bone health. This may be due to the nutrients potassium, magnesium, and vitamin C. These have been identified to have beneficial effects on BMD and fruits and vegetables are rich sources of these nutrients.

 

A healthy weight

Being over or underweight is associated with poorer bone health and an increased risk of osteoporosis.

 

Limit salt intake

Consuming high amounts of salt increases calcium excretion and leads to reduced BMD.

 

In Summary

  • Calcium intake can be inadequate in vegan diets if not appropriately planned
  • A low calcium intake leads to reduced bone density and increased risk of fractures and osteoporosis
  • Be sure to include adequate amounts of calcium rich foods daily
  • Several other factors are also important for bone health

 

Positive impact on bone health

Negative impact on bone health

Calcium Low B12
Vitamin D Overweight
Weight bearing exercise Underweight
Adequate protein High salt intake
Fruits and vegetables  

 

 

 

 

 

References

Appleby P, Roddam A, Allen N, Key T. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. Eur J Clin Nutr 2007;61:1400–6.

Ho-Pham LT, Nguyen ND, Nguyen TV. Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis. Am J Clin Nutr 2009;90:943–50.

Ho-Pham LT, Vu BQ, Lai TQ, Nguyen ND, Nguyen TV. Vegetarianism, bone loss, fracture and vitamin D: a longitudinal study in Asian vegans and non-vegans. Eur J Clin Nutr 2012;66:75–82.

Veganism, vegetarianism, bone mineral density, and fracture risk: a systematic review and metaanalysis. Iguacel, I; Miguel-Berges, ML; Gómez-Bruton, A; Moreno, LA; Julián, C. Nutrition reviews 2019; 77(1): 1-18.

Lousuebsakul-Matthews V, Thorpe DL, Knutsen R, Beeson WL, Fraser GE, Knutsen SF. Legumes and meat analogues consumption are associated with hip fracture risk independently of meat intake among Caucasian men and women: The Adventist Health Study-2. Public Health Nutr. 2014;17(10):2333-2343.

Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet 2016;116:1970-1980.

Mangels AR. Bone nutrients for vegetarians. Am J Clin Nutr. 2014;100(suppl 1):469S-475S.

Tucker, KL. Vegetarian diets and bone status. Am J Clin Nutr. 2014;100(suppl 1):329S-335S.

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