Spotlight on calcium – are we getting enough?

calcium in diet

What is Calcium?

Calcium is a mineral that is necessary for life. in our bodies. Our bones and teeth contain around 99% of all calcium in our bodies: this makes calcium crucial for the right functioning of both. It is worth mentioning, however, that the rest of calcium is involved and is paramount for the following processes in our bodies: blood flow support, muscle functions, nerve transmission, intracellular signalling, and hormonal secretion.(1)

What does research say about Calcium intake and requirements?

Different age groups have different calcium RDI requirements guidelines. In accordance with WHO recommendations, adults and kids older than 4 year old would need to consume between 1000 and 1300 milligrams (mg) of calcium per day.(2)

It is easy to get the recommended amount of calcium through one’s diet. The most common calcium-rich foods can provide the following amounts: 100g of hard cheese would contain around 1000mg; 100g of milk or yogurt would provide between 100mg and 180mg; 100g of unfortified (doesn’t contain additional calcium) cereal would provide around 30mg; 100g of nuts and seeds can provide up to 600mg; and 100g of certain green vegetables can provide up to 150mg.(3)

What population groups are at risk of Calcium deficiency?

There are a few major population groups, which might be at risk of calcium deficiency. Most studies would point out the following groups: people with milk allergy or lactose intolerance due to dietary restrictions of calcium-rich foods; postmenopausal women due to hormonal changes which might be affecting bone mineralisation processes (more research required); adolescents due to dietary changes and potential reduction and substitution of dairy products; elderly due to dietary changes, medication interactions, chronic diseases, and reduced calcium absorption in the body. (more research required).(3)

There is ongoing research into calcium deficiency and how it might be affecting different population groups, and what might be potential health consequences. For example, a couple of years ago calcium deficiency was has been linked with male infertility, as an optimal calcium concentration is required for a strengthened sperm function.(4) Calcium deficiency has been also linked with various mental disorders. Back in 2012, a small study found a link between low calcium intake and depression in middle-aged women (more research required).(5)

What are the most common symptoms associated with calcium deficiency?

During early stages of calcium deficiency, people quite often would be asymptomatic. However, as the deficiency is progresses, one might develop the following symptoms: muscle spasms, cramps, numbness and tingling in the hands and feet; confusion and memory loss.(6)

Our bones and teeth contain around 99% of all calcium in our bodies

Before you consider calcium supplements

There is no denying that calcium is beneficial for people of all ages, but most studies point at the importance of dietary calcium in particular.(7) It is also worth mentioning that the excess intake of calcium almost never would be from foods, so one can safely try and increase their calcium intake through their diet.(7)

When it comes to dietary calcium, there are a few things to keep in mind: humans only absorb around 30% of calcium present in different foods; certain foods might also interfere with calcium absorption in our bodies.(7) Foods like spinach, sweet potatoes, beans contain compounds which would bind calcium and make it less bioavailable for us; too much protein and salt might increase urinary calcium excretion; alcohol has been shown to affect calcium absorption, though there are no studies defining the amount of alcohol needed to intervene with the absorption; caffeine from tea and coffee also may reduce calcium absorption, though, there are studies showing that this can be easily offset by adding milk in these drinks.(7)

And what about calcium supplements?

Calcium supplementation is a widespread practice for all age groups, and the public generally believes that calcium is always good for their health.(8) However, recent studies have shown that an excess calcium intake may occur as a result of calcium supplementation and lead to adverse effects, such as kidney stones, constipation, problems with prostate and cardiovascular functions.(9) This might be due to calcium-rich foods containing many other nutrients, which ensure a better calcium metabolism and absorption in our bodies, something the supplements wouldn’t have.(1)

It goes without saying, that calcium supplements might be a good alternative for at risk population groups and other individuals with diagnosed calcium deficiency. Also, for those who struggle to get the right amount of calcium through their diet alone.(8) However, more research is needed to determine if calcium supplements are helpful to the general population, what are the benefits and risks for different age groups, genders, and ethnicities.(8)

Until then, there is only one certain recommendation, an individual should only use calcium supplements if prescribed by their medical professional, and should follow the guidelines and dosages accordingly.(11)


The Role of Calcium in Human Aging


Calcium Intake and Health

Possible Mechanisms for The Effects of Calcium Deficiency on Male Infertility

Low dietary calcium is associated with self-rated depression in middle-aged Korean women


Dietary Reference Intakes for Calcium and Vitamin D: Overview of Calcium

The good, the bad, and the ugly of calcium supplementation: a review of calcium intake on human health

Dietary Reference Intakes for Calcium and Vitamin D: Tolerable Upper Intake Levels: Calcium and Vitamin D

Calcium intake and urinary stone disease

Author Bio

Daria is a qualified Nutrition and Lifestyle coach, CI Level 4, Institute of Health Sciences. Her main area of expertise is daily balanced nutrition and lifestyle to support individual’s optimal health. @dariasplate