Calcium

You do not need to drink milk to get enough calcium. You will not make your bones stronger by drinking milk.

If you don’t believe these statements, don’t worry, you are not alone. Seventy years of marketing has convinced most health professionals that dairy foods, or a high-calcium substitute, are essential for human health. This is a rather narrow nutritional view when one considers that cow’s milk is only consumed by a minority of the world’s population, and for a relatively short period of human history. Most of the world’s population, including the majority of those of Asian or African descent, are lactose intolerant and suffer abdominal pain and diarrhoea if they drink milk.

While it is true that dairy foods are rich in calcium and that calcium is an essential nutrient for bone health, increased dairy consumption is not associated with stronger bones. In fact, a large Swedish study (Michaelsson et al 2014) found that higher milk consumption was associated with a higher rate of hip fractures (as well as a higher mortality rate). The higher prevalence of osteoporosis in countries that consume more dairy foods suggests that dairy products are not an effective preventative strategy.

You don’t need to reach for calcium fortified foods to get enough calcium on a whole foods plant-based diet

Like other minerals, calcium comes from the ground. Plants absorb it and animals in turn eat plants. Cows get their calcium from the grass. We can obtain all our calcium needs from whole plant foods, many of which have moderately high calcium levels. Some vegetables have a higher “nutrient density” for calcium than dairy foods (see Nutrient Density page). Interestingly, calcium is better absorbed from vegetables than milk, over 50% vs 32%. Many whole plant foods are rich in calcium – a cup of chopped kale, for example, provides as much absorbable calcium as a cup of milk.

Calcium content of food

FoodCalcium mg per 100 gCalcium mg per serveServing size
Oranges2337Medium orange
Strawberries2222100 g
Bok choy821311 cup
Broccoli26511 cup
Celery44281/2 cup
Green beans41291/2 cup
Kale2541711 cup
Sweet potato331131 medium potato
Oats (raw weight)402360 g
Wholemeal pasta (cooked)28 431 cup
Black beans57501/2 cup
Tempeh1115650 g
Total754 MG<1200 calories

Dairy (and ‘dairy alternatives’) has its own food group in the Australian Dietary Guidelines but this is no longer the case for the Canadian dietary guidelines. A liberal interpretation of ‘dairy alternatives’ might include beans, greens and other high calcium whole plant foods. A plant-based ‘milk’ with a similar calcium content to cow’s milk is not necessary. Indeed, it has been argued that a more appropriate comparator for plant ‘milks’ is human breast milk which has only a third of the calcium content of cow’s milk.

The recommended daily intake for calcium in Australia is extraordinarily high, up to 1300mg per day, a level which few people reach. It remains to be seen whether this will be revised in future guidelines given the evidence that high dietary calcium intakes are not protective against osteoporosis (Bolland et al 2015). The World Health Organization (2004) notes that calcium needs are increased by high intakes of animal protein and sodium. Dietary animal protein increases urinary loss of calcium and at very high protein intakes it can be difficult to absorb enough calcium to offset losses. WHO suggests a lower calcium requirement where animal protein intake is lower, and if sodium intakes were also lower as in developing countries then the calcium requirement would be even lower, e.g. 450mg (WHO 2004, p. 82).

A study of older Chinese men and women on a “plant-based diet” in the Journal of Bone and Mineral Research (Fang et al. 2016) suggested there was an optimal range for calcium intake, and that both very low and very high intakes were associated with higher fracture rates. It may surprise you to learn that this range of optimal intakes was 250-650mg/day for women and 275-780mg/day for men. In the discussion the authors suggest that policy makers rethink the dietary reference intakes for calcium and the policy of milk promotion in developing countries. These results provide evidence that older Chinese men and women eating a plant-based diet may require half as much calcium than their Western counterparts for fracture prevention – approximately 400mg per day. A typical whole foods plant based diet provides at least 500mg of calcium per day and more often 700-800g without having to reach for calcium fortified foods.

Calcium supplements are not effective in preventing osteoporosis and clinical trials have observed an increase in kidney stones and cardiovascular events. Australian doctors are now being urged to consider the risks and benefits before recommending calcium tablets. Osteoporosis is not caused by calcium deficiency and it is not prevented by calcium supplements. See Osteoporosis page (under construction). Getting enough calcium on a dairy-free diet of whole plant foods is a non-issue and there is no need to consume plant ‘milks’ for calcium.

Resources

Peer-reviewed articles:

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Page substantially revised 9 December 2019
Page last updated 30 December 2019