Calcium –  Improves bone health, cardiac function, kidney stones, cholesterol & more   


By Prof. Raphael Nyarkotey OBU

Calcium is the mineral the body has in abundance. It makes up the structures of your bones and teeth and also helps maintain typical muscle function, blood clotting, nerve transmission and other body processes. A study by Li et al.(2018) found that 99 percent of calcium in the body is found in the bones. Hence, the bones are like a calcium reservoir that the body seeks solace to restore balance.

Calcium can be found naturally in several foods, such as dairy products. Calcium-fortified foods are also readily available, and calcium supplements can help boost your calcium intake if needed. For calcium to work effectively, the body has to be provided with vitamin D  for proper absorption and maintenance of calcium levels.  One needs a balance of both nutrients for the body to function well.

Calcium – science

An article by Rosalie Rung(2023) explained the following benefits:

  • Bone health: Calcium is critical for the development, health and continued maintenance of bone. Women beyond menopause need calcium to maintain bone density and prevent osteoporosis.
  • Blood clotting: Calcium plays a role in your blood’s ability to clot. While many chemicals and nutrients are involved, calcium is an important factor.
  • Cardiac function: Calcium helps maintain the action of your heart muscle by relaxing the smooth muscles around your blood vessels. Calcium has also been linked to lower blood pressure (Lin et al. 2008).

The reason has been linked to the DASH diet (Dietary Approaches to Stop Hypertension) recommends a diet high in calcium-rich foods like yogurt or kefir because these are foods that help improve blood pressure. The natural fat found in dairy products has been shown to have certain benefits, so full-fat dairy is recommended over low-fat dairy.

  • Muscle contraction: Calcium can help balance muscle contraction. Calcium is released when a muscle is stimulated. This helps the muscle contract. When the calcium is pumped out of the muscle, it can relax.
  • Preventing pre-eclampsia: Consuming certain amounts of calcium during pregnancy can aid in lowering blood pressure, reducing the risk of pre-eclampsia.
  • Improved cholesterol levels: Calcium is also known to help improve certain cholesterol levels in the blood.
  • Cancer:  Studies explained that consuming calcium-rich foods is linked to a decreased risk of certain types of cancer, particularly colon and rectal cancers.  For instance, the American Cancer Society’s Cancer Prevention Study II Nutrition Cohort study revealed that men and women who had the highest intakes of calcium through both their diets and supplements had a reduced risk of colorectal cancer compared with those who had the lowest calcium intakes.

As it stands,  evidence is not currently strong enough to recommend calcium supplements for the prevention of colon cancer, but eating foods with calcium may have the same effect.

  • Weight health:  Bendsen et al.(2008) study found a link between higher calcium intake from foods high in calcium and lower body weight. The reason is that calcium in the diet can bind to fat in the digestive system, helping it be excreted and possibly preventing some fat absorption; therefore, helping lower the amount of calories that contribute to fat gain.

Calcium – Dosage

The amount of calcium needed depends on the age and stage of life. National Institutes of Health Office of Dietary Supplements(2024) provided the following recommended dietary allowance (RDA) of calcium in milligrams (mg):

Age Male Female Pregnant person
0–6 months 200 mg 200 mg  
7–12 months 260 mg 260 mg  
1–3 years 700 mg 700 mg  
4–8 years 1,000 mg 1,000 mg  
9–13 years 1,300 mg 1,300 mg  
14–18 years 1,300 mg 1,300 mg 1,300 mg
19–50 years 1,000 mg 1,000 mg 1,000 mg
51–70 years 1,000 mg 1,200 mg  
70+ years 1,200 mg 1,200 mg  

It is instructive to note that both males and females have the same need for calcium before the age of 50 years. Females need, however, increase slightly. Females need more calcium level, especially in their pregnancy stage as it decreases the risk of pre-eclampsia. Pre-eclampsia is defined as hypertension and proteinuria or thrombocytopenia during pregnancy, usually after 20 weeks gestation (Leeman et al. 2016).

It is a leading cause of maternal and neonatal morbidity and mortality that affects about 4 percent of pregnancies in the United States  (Ananth et al. 2013).

National Institutes of Health Office of Dietary Supplements(2024) revealed that calcium deficiencies happen as a result of a reduction in the calcium level in the blood – your serum calcium level – below 8.5 milligrams per deciliter (mg/dL).

When the reduction is drastic, you will experience the following symptoms of a calcium deficiency:

  • muscle spasms
  • depression
  • confusion
  • muscle cramps
  • hallucinations
  • weak and brittle nails
  • easy bone fractures
  • seizures

some health conditions or life changes could affect calcium deficiency. These can include:

  • menopause
  • hypoparathyroidism
  • malnutrition or malabsorption
  • pancreatitis
  • septic shock
  • certain medications, including steroids and some chemotherapy drugs
  • kidney failure
  • lack of a parathyroid gland (due to surgery)
  • frequent blood transfusions

Calcium foods

Calcium is naturally found in many foods. However, dairy products are the best-known source of calcium. Other non-dairy foods can also contain high calcium levels.

calcium-rich foods include:

Vegetables that contain calcium but have high oxalic acid levels, such as spinach, may reduce your body’s ability to absorb calcium.

Calcium supplements?

Li et al.(2018) explained that calcium supplements are ideal for those who are not getting enough. The amount of calcium in supplements varies, but most supplements contain between 300 and 500 mg of calcium.  Vitamin D is most often added to help in proper absorption.

The two most common forms of calcium in supplements are calcium carbonate and calcium citrate. Each of these forms contains different amounts of elemental calcium, which is the actual amount of calcium in the supplement. Calcium carbonate is 40 percent calcium by weight, whereas calcium citrate is 21 percent calcium by weight. Irrespective of the type you are taking, you should take it with food for the highest absorption; and doses are in the amount of 500 mg or less.


Few minor side effects such as gas, constipation, bloating or a combination of these symptoms had been found. You can reduce the dose or switch to a different supplement if you find any side effects. Abundant calcium levels (hypercalcemia) are rare in the general population; however, it could result from conditions such as cancer or primary hyperparathyroidism.

Those with highly elevated calcium levels could experience:

  • poor muscle tone
  • constipation
  • kidney issues
  • low phosphate levels (hypophosphatemia)
  • excessive urination
  • nausea
  • fatigue
  • higher risk of death from cardiovascular disease
  • unexplained weight loss
  • irregular heart rhythms (arrhythmia)

Calcium tends to also interact with some drugs. When this happens, it could cause the drugs not to work well, or the drugs could affect the amount of calcium in the body.

The following are drugs shown to interact with calcium, according to Healthline:

  • Levothyroxine: This drug is prescribed to treat hypothyroidism or thyroid cancer. Calcium carbonate supplements can prevent its absorption, so you should not take them within 4 hours of taking levothyroxine.
  • Lithium: Commonly used to treat bipolar disorder, long-term lithium use can result in hypercalcemia. Taking calcium supplements in addition to lithium can increase this risk.
  • Dolutegrevir: Used in HIV treatment, taking calcium supplements along with dolutegrevir can reduce the effectiveness of the medication. Careful timing of calcium supplements is recommended for people taking dolutegrevir.
  • Quinolone antibiotics: Calcium supplements are known to reduce the effectiveness of this class of antibiotic medication. Any calcium supplements should be taken at least 2 hours before or after this medication.

Take home

There are many calcium supplements on the market, each of which varies based on the type of calcium, dosage and ingredients it contains. When selecting a calcium supplement, be sure to consider all of these factors and look for products that have undergone third-party testing to ensure that you’re getting the highest quality possible.

Also, the type is important. For instance, calcium carbonate is more widely available and cheaper, and it contains a higher amount of calcium. But it could trigger gas and bloating (Li et al. 2018). Calcium citrate is more expensive but more easily absorbed in the body, which may be key for people who have low stomach acid or are taking proton pump inhibitors.

Also, it is important to check the ingredient label carefully and avoid products that have high amounts of fillers, additives, artificial sweeteners and preservatives. Most products also contain added ingredients like vitamin D, which can help in the absorption of calcium (Wimalawansa et al. 2018).

Finally, calcium requirements range from 1,000–1,300 mg daily for most adults. Supplements with 200–500 mg are usually enough to help fill in the gaps in your diet. Some will need a higher amount, such as those with certain dietary restrictions or health conditions.

Also, one large study (Balk et al. 2017) across  74 countries found that the average national dietary calcium intake ranged from 175 to 1,233 milligrams/day.

Compared to other minerals, we need a higher amount of calcium each day — making foods high in calcium very important for several reasons. We are told to have enough calcium in our bodies to constitute 2 percent of our total body weight. Failure can make one prone to the following:

  • Higher chance of developing osteopenia or osteoporosis
  • Tooth decay
  • Bone fractures
  • Muscle tension
  • High blood pressure
  • Hardening of the arteries and hypertension
  • Inflammation
  • PMS symptoms
  • Indigestion
  • Higher risk for kidney stones and gallstones
  • Higher risk for heart disease and diabetes
  • Higher risk for certain types of cancer


Prof. Nyarkotey has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions and medical associations to justify his write-ups. My articles are for educational purposes and do not serve as medical advice for treatment. I aim to educate the public about evidence-based scientific naturopathic therapies.

>>>The writer is a Professor of Naturopathic Healthcare, a medical journalist, and a science writer. He is also the President, Nyarkotey University College of Holistic Medicine & Technology (NUCHMT)/African Naturopathic Foundation, Ashaiman, Ghana. He is also the author ofLife in the Gambia -Tales from a Professor and an Aspiring Barrister’.

Email: [email protected]. for more.



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