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
- Unhulled tahini
- Chia seeds
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.
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.
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.
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.
- 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
|Weight bearing exercise||Underweight|
|Adequate protein||High salt intake|
|Fruits and vegetables|
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