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Why calcium is essential, and where, other than milk, you can get it from

Why calcium is essential, and where, other than milk, you can get it from
Milk poured into a glass. Image: Engin Akyurt / Unsplash

It’s a fairly common belief that milk should be a central part of our dietary requirements, particularly because it has often been lauded as a major source of calcium. Yet milk is not always an essential part of our diet. So where else can we get calcium from?

Calcium is essential for our health and well-being. Every human body needs to consume a certain amount of calcium in order to function efficiently and even thrive. It’s important to know what the mineral does for us, and where we can get it, especially for those of us who choose, for various reasons, not to consume dairy products. 

What is calcium and what does it do for us? 

Calcium is a mineral that is most often associated with the upkeep of our bone and dental health. However, the mineral does far more than just this. 

“Calcium and magnesium are the two major minerals that our bodies consist of,” says Dr Dalene Rottier, a classically trained dietician who has recently turned to nutrigenomics in her career. “Both play a key role in muscle contraction and muscle relaxation,” as well as the proper functioning of our nerves. As the heart is technically a muscle, consuming enough calcium is essential for it to function effectively. 

“It also plays an important role in blood clotting,” says Lila Bruk, a registered dietician in Johannesburg. Or, as this 2019 research paper asserts, “calcium ions play a major role in the tight regulation of coagulation cascade,” the process that is essential in the formulation of scabs so that we do not bleed out when we are cut or injured. 

What happens if we don’t get enough calcium? 

According to Rottier, our bodies are very good at maintaining a regular blood-calcium level. However, “if we don’t take in enough calcium through our diets, our bodies will start to take it from the bones. That is where the problem comes in because the body can do this for a prolonged time.” 

This can result in a condition called osteoporosis, in which the bones get increasingly weak and break more easily. It can also, says Bruk, cause osteomalacia, “which is basically where the bones soften, weaken, or don’t develop properly.” 

A calcium deficiency in children can be very serious. “Children still need their bones to fully form”, says Rottier, “they also need to harden their bones. If they are not getting enough calcium, they actually can’t grow their bones properly and will probably end up with an unsound skeletal structure.” Rickets, a childhood disease that causes all manner of symptoms such as dental problems, skeletal deformities, and fragile bones, can afflict children who are not getting enough calcium. 

“To a degree,” asserts Rottier, testosterone in men protects their bones from being used for blood-calcium levels in the body. In women, estrogen levels also protect. What we find, however, is that as menopause sets in and women’s estrogen levels drop significantly, we see rapid deuteriation in bone mass because of calcium needs that have not been met for a long period of time, which results in osteoporosis. It is quite a common thing to see in elderly women and men.” 

So, the body keeps itself functioning by maintaining regular blood-calcium levels, but it does so at the cost of one’s bones. 

Before your bones start to deteriorate, there are a few possible signs to look out for that might point to calcium deficiency. Rottier says that “brittle nails, or small white lines on the nails” might mean you need to up your calcium intake. She also mentioned a condition called “muscle tetany”, which will manifest in the form of involuntary muscle contractions, or in other words, spasms. 

How much calcium do we need? 

Bruk provides a list of the minimum amount of calcium required per day for various age groups: 

  • Babies 0-6 months = 200mg
  • 7-12 months = 260mg
  • 1-3 years = 700mg
  • 4-8 years = 1000mg
  • 9-18 years = 1,300mg
  • 19-50 =1,000mg
  • 51-70 females = 1,200mg
  • 51-70 males =1,000mg
  • 70 and older = 1,200mg

However, Rottier reminds us that this is the minimum recommended requirement and that our bodies are all different. “Some people might need more calcium than others, especially those that are more genetically prone to bone loss, or people that didn’t build bones very well.” Further, these recommendations are the requirements for our bodies to simply function, not to function at their peak. The amount of calcium needed to function at our very bests is still up for debate, according to Rottier. 

Where can we get calcium from?

Both Bruk and Rottier agree that dairy products, like yogurt, milk or cheese, are definitely a good source of calcium. However, they are certainly not the only ones. 

In fact, many foods are high in calcium, but our body absorbs calcium from some sources more easily than others. For example, most leafy greens contain a lot of calcium, but, Bruk asserts, those with high levels of the antinutrient oxalate have much lower absorption levels.  

Rottier divides calcium sources into four groups: high absorption (40% or more), moderate absorption (30-40%), fair absorption (20-30%), and low absorption (20% and below.) 

The first group, the most absorbable, includes any kind of fortified food, like cereal, fruit juice, and nut milks. Foods that have been fortified will say so on the packaging. Low-oxalate greens like broccoli, Chinese greens, mustard greens, and turnips are also considered a part of this group. Further, Bruk notes that fish with bones, like tinned sardines or salmon are very high in absorbable calcium. 

Tofu and dairy products (milk, yogurt and cheese) are considered moderate absorption calcium sources, while sweet potatoes, legumes and soymilk are thought of as fair. 

The vegetables that are high in oxalate are included in the low absorption range. Spinach, beet greens, swiss chard, and rhubarb are examples of these. 

But, Rottier reminds us, “if you can’t seem to get enough calcium from your diet, especially if you are post-menopausal, taking a small supplement of calcium is very doable and inexpensive.” She goes on to say that like certain foods, there is a range of absorbability in supplements too. “Citrate, malonate and gluconate are very well absorbed. These are the supplements you should be taking. Calcium carbonate and dolomite are not.” Like with all forms of supplementation, “it’s very important to know that you know the company that is making it, and that their products are good quality.” 

What else do we need in order to absorb enough calcium? 

“Vitamin D keeps calcium in the bones,” says Rottier. According to this study, maintaining a healthy level of calcium is absolutely dependent maintaining a healthy level of vitamin D. Soaking in some sun rays is a great way to get your fix of this essential vitamin. So is eating fatty fish like salmon, tuna, or mackerel. Egg yolks also contain a lot of vitamin D. 

“We also find,” says Rottier, “that the more acidic your diet is, the worse your calcium loss is. Dairy, meat, coffee, refined carbs, are very acidic.” This is good news for people who are vegetarian or vegan and choose to get their calcium from sources other than dairy. “Quite often people who are vegetarian and who eat more plants, even though they might not get in dairy or other sources of calcium, they nevertheless absorb and retain calcium better because their diets are more alkaline.” 

The key points that you should take away 

  • Calcium is essential for bone and dental health, as well as for proper muscle and nerve functioning.
  • Long term calcium deficiency — which results in the body taking calcium supplies from the bones — can cause diseases such as rickets or osteomalacia in children, or osteomalacia and osteoporosis in adults.
  • We need between 1,000-1,500mg of calcium daily. This varies a little depending on which age group you are a part of.
  • Calcium is abundant, in dairy products as well as dairy alternatives. However, certain sources of calcium are more easily absorbed than others. It is important to make sure you are eating enough of the highly absorbable calcium sources to fulfil your daily intake, or else to take a good quality supplement to fill in the gaps.
  • High levels of vitamin D are essential for calcium absorption.


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