10 Calcium-Rich Foods for Athletes

Marta Aguilar

Graduada en Nutrición Humana y Dietética, Universidad Pablo de Olavide (2018). AND-817. Título de Experto en Nutrición Avanzada: Presente y Futuro de la Nutrición, Universidad Pablo de Olavide. Máster Oficial en Alimentación en la Actividad Física y el Deporte, Universitat Oberta de Catalunya.

Athletes, this post is for you. Do you know why calcium-rich foods belong in your diet? They are important for injury prevention and much more.

Let us begin!

What Is Calcium?

Calcium is essential for health and the body’s most abundant mineral, found mainly in bones and teeth. 

The mineral calcium supports many functions, including bone structure, nerve impulses and blood clotting. Daily calcium-rich foods are important because the body cannot produce calcium and must obtain it through food. 

The amount of calcium needed varies with age, sex and general health. As a reference, recommended adult daily intake is approximately 1000 to 1200 milligrams. 

What Are Calcium’s Properties?

These functions make calcium-rich foods essential in a balanced diet:

• Building and maintaining strong bones and teeth. Calcium maintains bone structure and strength, helping prevent osteoporosis and other bone diseases.
• Regulating muscle contraction and nerve transmission. Calcium supports nerve signalling and muscle contraction, including the heart and muscles controlling breathing and digestion.
• Blood clotting. Calcium is a cofactor in blood clotting, helping stop bleeding after injury.
• Heart rhythm regulation. It regulates heart rhythm and cardiac muscle contraction.
• Absorption of other minerals. Calcium also supports absorption of minerals such as iron and zinc.
• Reduced chronic disease risk. Intake may reduce risks of conditions such as high blood pressure and diabetes. 

Which Foods Contain the Most Calcium?

These are the 10 calcium-rich foods listed by calcium per 100 grams:

1. Parmesan cheese: 1184 mg of calcium
2. Canned salmon with bones: 382 mg of calcium
3. Greek yoghurt: 197 mg of calcium
4. Cheddar cheese: 721 mg of calcium
5. Kale: 150 mg of calcium
6. Dried figs: 162 mg 
7. Canned sardines with bones: 382 mg of calcium
8. Mozzarella cheese: 280 mg of calcium
9. Firm tofu: 350 mg of calcium
10. Almonds: 264 mg of calcium

The amount of calcium varies with food type and preparation. Age, gender, health and other nutrients also affect absorption and use. The priority is a varied diet with different calcium-rich foods. 

Do Some Foods Contain More Calcium Than Milk?

Yes! Although milk comes to mind first, several foods contain more calcium than milk. The list of 10 calcium-rich foods above does not include milk.

Indeed, milk is not among these 10 foods. It contains approximately 113 mg of calcium per 100 ml. 

Is Calcium from Plant Foods Beneficial?

Yes, calcium from plant foods supports health, although absorption may be lower than from dairy or fortified foods.

The category calcium-rich plant foods includes spinach, kale, broccoli, nuts, seeds and certain types of tofu.

Some plant foods contain absorption inhibitors such as oxalic and phytic acids. However, most studies suggest no significant effect on overall dietary calcium absorption.

On a vegan diet, obtain enough calcium from varied calcium-rich plant foods and foods fortified with calcium and vitamin D. Adequate vitamin D also supports calcium absorption. 

What Determines Calcium Bioavailability?

Remember the distinction between calcium consumed , what we eat, and calcium absorbed , what the body actually uses.

The term bioavailability refers to how much calcium is absorbed and used after consumption. 

Consider it when choosing foods and supplements to favour calcium that is readily absorbed and used.

Among foods with highly bioavailable calcium are dairy, oily fish, some greens such as kale and broccoli, nuts and tofu.

Factors affecting calcium bioavailability:

• Fibre content. Excessively high fibre intake may bind calcium and reduce intestinal absorption.
• Individual calcium needs. People with higher requirements may absorb more from food and supplements.
• Vitamin D. Low levels can reduce calcium bioavailability.
• Age. Bioavailability may decline with digestive and other age-related changes.
• Other nutrients. Vitamin K and other nutrients influence bioavailability. Oxalic-acid-rich foods such as spinach and beetroot can reduce calcium absorption.
• Intestinal pH. Absorption is greater in acidic conditions, so acid-reducing medicines may lower it.
• Health status. Inflammatory bowel disease, coeliac disease and gastric surgery can affect absorption.
• Excess salt. High salt intake may increase urinary calcium loss and raise urine and blood pH, potentially reducing intestinal absorption.
• High caffeine intake. Caffeine increases urinary calcium excretion. Some studies suggest more than 300 mg daily, approximately 3 coffees, may reduce absorption. Others find moderate intake below 300 mg daily has no significant effect in healthy people. Caffeinated foods such as tea and chocolate also provide calcium and other bone nutrients. Completely eliminating caffeine to improve absorption is therefore not recommended.
• Physical activity. Regular exercise can stimulate bone formation and calcium uptake through mechanical loading. Sedentary behaviour can reduce bone density and calcium uptake, particularly in older people.

Are There Foods with Calcium and Vitamin D?

Yes! Examples include:

1. Fortified dairy products: milk, yoghurt and cheese are often fortified with vitamin D and calcium.
2. Fish: salmon and canned sardines with bones provide calcium and vitamin D.
3. Leafy greens: spinach, kale and chard contain calcium; some plant-based drinks are fortified with vitamin D.
4. Dried fruit: dried figs and raisins provide calcium.
5. Fortified foods: some breakfast cereals and orange juices may be fortified with calcium and vitamin D.

Why Is Vitamin D Important?

Besides food, sunlight helps ensure adequate vitamin D because the body synthesises it when skin is exposed.

The nutrients calcium and vitamin D work together for bone health and osteoporosis prevention: vitamin D is necessary for intestinal calcium absorption. 

Without sufficient vitamin D, the body cannot absorb all the calcium needed for strong bones.

Vitamin D also regulates blood calcium levels and calcium balance. When blood calcium is low, vitamin D stimulates calcium release from bone to increase blood levels.

Adequate calcium and vitamin D together support strong bones and teeth and prevent conditions such as osteoporosis.

Calcium’s Role in an Athlete’s Diet

Athletes need enough calcium because its roles relate to sports performance. Key examples include: 

• Bone health and injury prevention. Calcium maintains bone health and helps prevent fractures, particularly in high-impact sports.
• Muscle contraction. Calcium supports proper contraction and a normal heart rhythm.
• Blood clotting. Calcium is essential for clotting and supports the body’s response to contact-sport injuries.
• Muscle fatigue. It helps maintain acid-base balance, potentially helping prevent fatigue.

What Are Calcium Deficiency Symptoms?

Symptoms of calcium deficiency range from mild to severe according to its severity and duration. 

Remember that calcium deficiency symptoms may have other causes. Consult a healthcare professional to understand their origin. 

Common symptoms include:

• Insomnia, as calcium deficiency can affect sleep patterns. 
• Muscle weakness and cramps. Inadequate calcium can impair contraction and cause weakness and cramps, particularly in the legs. 
• Bone pain and fragility, increasing fracture risk.
• Dental problems. Deficiency increases cavities and other dental problems.
• Heart problems, such as reduced heart rate.

Now you know calcium’s role, you may want more calcium-rich foods. Unsure how? Explore our subscription options and work with one of our sports nutritionists . Let us get started!