Calcium on a vegan diet. Should it be supplemented?

A vegan diet requires paying special attention to the supply of many nutrients, including calcium. Although plant products may contain calcium, its bioavailability and actual coverage of requirements remain the subject of much debate. As a result, people on a vegan diet may be at risk of deficiencies, especially if their diet is not strictly monitored by a specialist. This is worth emphasising because many people base their diets on the tastiness of recipes rather than health considerations.

1. The role of calcium in the body
2. Calcium deficiency
3. Calcium in plants
4. Calcium supplementation in vegans
5. Expert recommendations

The role of calcium in the body

Calcium is an element that is extremely important for maintaining the proper functioning of the body, especially the skeletal system and teeth, where it is a key structural element. In addition, it participates in the regulation of nerve conduction, enabling the proper transmission of impulses between nerve cells, and plays a key role in the mechanism of muscle contraction, including the heart muscle.

Calcium deficiency

Calcium deficiency can therefore lead not only to weakened bones and an increased risk of fractures or osteoporosis, but also to muscle disorders, cramps, tremors, heart rhythm disturbances and even metabolic and hormonal problems. A long-term deficiency of this mineral also has a negative effect on blood clotting processes.

Calcium in plants

Although there are numerous plant sources of calcium, many of them have lower bioavailability than dairy products. Sources of relatively well-absorbed plant calcium include green leafy vegetables such as kale, pak choi, broccoli, rocket, as well as some seeds, mainly poppy, sesame and chia. However, it is worth knowing that many other popular plant products, such as spinach and Swiss chard, despite their high calcium content, contain large amounts of oxalic acid, which significantly reduces the absorption of this element.

The problem with plant-based drinks

Calcium-enriched products, including plant-based drinks, calcium-enriched tofu and breakfast products, can be an important part of a vegan diet, but their regular consumption must be controlled. The reason for this may be their high salt content. In addition, these are highly processed products, which contradicts some of the principles of veganism. Highly mineralised mineral water can also be a very important source of calcium, providing calcium in an easily absorbable form.

It should be remembered that people on a vegan diet should also monitor their vitamin D levels, as this vitamin has a significant impact on calcium absorption. There are no vegan sources of vitamin D3, which further complicates the situation for people who want to remain on a fully plant-based diet. Vegans must take vitamin D2, although its metabolic effectiveness may be lower than that of vitamin D3.

The richest sources of calcium

Calcium supplementation in vegans

Studies on calcium metabolism in vegans paint a rather ambiguous picture. Some scientific publications suggest that people who consciously follow a vegan diet, regularly consume plant-based foods rich in calcium and fortified foods, are able to achieve adequate levels of this element in their blood and proper bone mineral density. Nevertheless, analyses of the average results of human experiments and systematic reviews of studies emphasise that the average calcium intake of vegans is lower than that of people who consume animal products, which may threaten bone health.

Expert recommendations

As a result, experts often recommend that people on a completely plant-based diet monitor their calcium levels regularly, and if they have difficulty meeting their needs through diet alone, they say that it should be supplemented, preferably in combination with an appropriate form of vitamin D. Calcium citrate (due to its high bioavailability independent of stomach pH) and calcium carbonate are considered the best forms of calcium supplements. The recommended supplementation doses are usually between 500 and 1000 mg of calcium per day, depending on the level of calcium intake in the diet.

Sources:

• Ambroszkiewicz J, Klemarczyk W, Gajewska J, Chełchowska M, Franek E, Laskowska-Klita T. The influence of vegan diet on bone mineral density and biochemical bone turnover markers. Pediatr Endocrinol Diabetes Metab. 2010;16(3):201-204.
• Hsu E. Plant-based diets and bone health: sorting through the evidence. Curr Opin Endocrinol Diabetes Obes. 2020;27(4):248-252. doi:10.1097/MED.0000000000000552
• Tong TYN, Appleby PN, Armstrong MEG, et al. Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study. BMC Med. 2020;18(1):353. Published 2020 Nov 23. doi:10.1186/s12916-020-01815-3