Calcium Nutrition Guide: Best Food Sources, Absorption, Deficiency, Types + Supplements

Calcium Nutrition Guide: Best Food Sources, Absorption, Deficiency, Types + Supplements

Calcium is the most abundant mineral in the body and is most often associated with the health of bone and teeth. Calcium also plays a key role in blood clotting, helping muscles to contract and regulating normal heart rhythms.

In this blog post, you will learn:

👉🏼 Why do we need calcium?

👉🏼 What are the best food sources of calcium?

👉🏼 How much calcium should you consume each day?

👉🏼 What can help improve calcium absorption – and what decreases absorption?

👉🏼 Who is at risk of calcium deficiency?

👉🏼 When should you consider calcium supplementation?

👉🏼 What are the different types of calcium supplements – and which one is right for you?

Are you worried about nutritional deficiencies? Are you looking to optimise your diet and transform your health? Head to Consultations to see how I can help you start your journey to the healthiest version of yourself today!

Why do we need calcium?

Calcium has several important functions. Our bodies need it for muscle movement, carrying messages between the brain and every part of the body and it also helps to release hormones that affect many other functions. 99% of the body’s calcium is stored in bones and teeth, giving them structure and hardness, with the remaining 1% found in blood, muscle and tissues.

What are the best food sources of calcium?

The body gets the calcium it needs in two ways. The first is by eating foods or supplements that contain calcium. Foods such as dairy products, green leafy vegetables such as kale and okra, tofu, nuts and seeds, especially almonds, sesame and chia, fortified products (meaning the nutrient has been added to other food products) such as fortified soya drinks, bread and anything made with fortified flour, and tinned fish where you eat the bones, such as sardines.

The second way is by drawing on existing calcium from in the body. If someone isn’t eating enough in their diet, the body will remove calcium from the bones, but this calcium would need replacing at a later point from dietary sources.

How much calcium should we consume a day?

The UK recommended daily allowance (RDA) for copper is 700mg (for adults) which most people should be able to get from their diet. 

How can we improve calcium absorption?

There are a few things that can maximise calcium absorption but also a few things that can deplete it. 

The parathyroid hormone, which is what signals the bones to release calcium, may also activate vitamin D to improve the absorption of calcium in the intestines. This means people also need sufficient vitamin D to help the body to absorb calcium. Some studies have shown that without adequate vitamin D, the body absorbs no more than 10% to 15% of dietary calcium. Similarly, vitamin K2 is important to help our bodies absorb calcium.

When it comes to reducing calcium absorption, too much sodium (excessive salt) can interfere with calcium absorption, and excessive caffeine intake can cause the body to excrete calcium before the body can make use of it. 

Who is at risk of calcium deficiency?

As we’ve seen, vitamin D plays a key role in the absorption of calcium. So it is no surprise that a vitamin D deficiency can have a knock on effect and impact calcium absorption. This makes it really important to ensure you are meeting all of your nutritional requirements through diet or if required, supplements. 

Certain groups of people are more likely to be at risk of a calcium deficiency, including:

  • Postmenopausal women – the body absorbs and retains less calcium after menopause. 
  • People who don’t drink milk or eat other dairy products. Dairy products are rich sources of calcium, but people with lactose intolerance/milk allergies and vegans (people who don’t consume any animal products) must find other sources of calcium. Options include certain vegetables, such as kale and broccoli, calcium-fortified milk substitutes such as soy and almond, seeds including poppy seeds, pumpkin seeds, sesame seeds and chia seeds, as well as dietary supplements that contain calcium.
  • People with Coeliac disease – Coeliac disease affects the lining of the intestine and impacts the absorption of fat-soluble vitamins and minerals, such as vitamin D and calcium.

Should you consider a calcium supplement?

Most people should get their RDA of calcium from a healthy diet. However, having too little calcium can cause several conditions, including:

  • Osteoporosis, which causes weak, fragile bones and increases the risk of falls and fractures (broken bones)
  • Osteomalacia, which causes soft bones in children and adults

It may be worth consider supplementation if you are not getting your RDA through diet alone or at risk of a deficiency, but please speak to a healthcare professional before taking any supplements. It’s important to note that some calcium supplements can interact or interfere with certain medications, and some medicines can lower calcium levels in your body so always seek medical advice before taking any form of calcium supplement. 

What should you look for in a calcium supplement?

Calcium is in many multivitamin/mineral supplements and in supplements that contain other nutrients such as vitamin D. If you are taking a supplement, check the label on the back to determine the amount of calcium in the supplement.

The two main forms of calcium in dietary supplements are calcium carbonate and calcium citrate. Calcium carbonate is absorbed best when taken with food as it aids absorption whereas Calcium citrate is absorbed well on an empty stomach or a full stomach.  Calcium supplements are absorbed best when you take 500 mg or less at one time. 

As the form of the supplement can vary and is dependent on your specific needs, always seek medical advice before taking a calcium supplement.


Everyone’s nutritional requirements will be different, which is why I take a personalised approach with all of my 1:1 clients and tailor each nutrition plan (and supplement recommendation) to their unique needs and goals.

 This is just a small insight into the types of things I discuss with my 1:1 clients. If you’re looking to optimise your nutrition, transform your health and elevate your quality of life, please get in contact via Consultations or book a FREE 15-minute call and let’s chat about how I can help. 

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