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Calcium supplements are associated with cancer and atherosclerosis

Calcium supplements are associated with cancer and atherosclerosisWe all know that calcium is good for your bones, and many people actually supplement with calcium to prevent osteoporosis. But even without supplementation, we get plenty of calcium from dairy products, and too much calcium from supplements can lead to a tenfold increase in the risk of dying of cancer, according to a new study that is published in Annals of Internal Medicine.
Earlier studies reveal that too much calcium also increases your risk of atherosclerosis and inflammation, a common thread in most chronic illnesses. It is also important to know that your calcium ingestion should be properly balanced with magnesium. If the balance is right, most of the calcium ends up in the bones where it belongs instead of wreaking havoc in the blood vessels and in other soft tissues where calcium essentially does not belong.

Calcium is an essential mineral. Ninety-nine percent of the body’s calcium is stored in hard tissues like bones and teeth together with magnesium, phosphorous, and several trace elements. The remaining one percent of our calcium is involved in many other vital functions, including nerve transmission, muscle contraction, cardiac function, and blood pressure. Other than the small quantity needed to undertake these functions, cells in all of these soft tissues should ideally be nearly devoid of calcium. Otherwise, they overreact and trigger inflammation, oxidative stress and cell death.

  • Oxidative stress is an imbalance between free radicals and antioxidants
  • Free radicals are generated by our own metabolism as well as by environmental factors
  • If there is oxidative stress, we risk that free radicals attack our cells, our DNA, and cholesterol

Too much calcium in supplement form works like a cancerous toxin

Most calcium supplements also contain vitamin D, which is needed for proper absorption of calcium in the body. However, if you take more than 1,000 mg of calcium daily it may increase your risk of dying of cancer, according to a new study from Tufts University in Boston, USA. A total of 27,000 American adults participated in the study, and the whole purpose was to look closer at the relation between diet, nutritional supplements, and deaths related to cancer and cardiovascular disease.
A 12-year follow-up of the study showed that, among the participants who had taken more than 1,000 mg of calcium daily, 24 cancer-related deaths had occurred. Among those who had not taken calcium supplements, 12 had died of cancer. In other words, there were twice as many cancer-related deaths in the group that took calcium supplements.
The scientists also found that adequate dietary intake of magnesium and vitamin K was associated with a lower risk of premature death. They did not find a similar relation with nutritional supplements. This is most likely because the majority of supplements with magnesium and vitamin K have such inferior quality that the nutrients are not properly absorbed in the small intestine. With regard to magnesium, it is generally a good idea to choose a supplement with organic magnesium.
The researchers admit that their study has certain limitations. For instance, it was only a short-term study, plus it was based on the participants self-reported information about diet and supplement use. Still, their findings support earlier research showing that calcium taken as a stand-alone supplement may be bad for you. In fact, the widespread use of stand-alone calcium supplements in Western countries may be part of the reason why cancer rates are higher and we have not been able to bend the cancer curve. The study is published in the Annals of Internal Medicine.

High-dosed calcium supplements increase the risk of atherosclerosis

There also appears to be a link between calcium supplementation and the risk of developing atherosclerosis, according to a large, randomized, controlled study (Women’s Health Initiative). The scientists observed more deaths among the women that took more than 1,400 mg of calcium daily, just like the other study showed. In the 10-year Multi-Ethnic Study of Atherosclerosis (MESA), researchers also looked at how calcium from the diet and from supplements increases the risk of atherosclerosis. They studied 5,448 adult men and women aged 45-84 years, who had not been diagnosed with atherosclerosis earlier. Their calcium intake from the diet was assessed by means of questionnaires. Daily calcium intake was divided into five groups in the range 300 – 2,100 mg. The degree of atherosclerotic progression was measured at baseline and after 10 years in 2,742 of the participants. The scientists noted that high dietary calcium intake was associated with reduced atherosclerosis. On the other hand, they found that calcium supplementation increased the risk. They therefore recommend that people primarily get their calcium from dietary sources such as vegetables, almonds, nuts, dairy products and fish, also because these foods contain other nutrients. Water also contains calcium, especially “hard water”. Soup bones that have simmered for hours are particularly rich in calcium plus other minerals and trace elements.
According to the scientists behind the new study, too much calcium from supplements may result in atherosclerosis and cardiovascular disease by way of various mechanisms such as the lipid metabolism, insulin sensitivity, blood clotting, and inflammation. A very import yet overlooked factor is the interplay between calcium and magnesium

  • Many people get far too much calcium from their diets and from supplements
  • It is a good idea to read the label on your supplement(s) to find out what your total calcium intake is
  • Remember that calcium should be balanced carefully with magnesium

Magnesium’s interaction with calcium is vital for your bones and health

The way calcium and magnesium interact is fundamentally important for all living cells, and you should never take calcium on its own for bone health. You risk doing more harm than good, and it can even be life-threatening in extreme cases. Magnesium functions like a door bolt in the calcium channels of our cell membranes. By virtue of this ability to control calcium levels in all cells, magnesium makes sure to channel nearly all calcium into bones and teeth, while it only allows very little calcium into the cells of soft tissues such as nerve, muscles, blood vessels, and internal organs.
If you lack magnesium, you have no guarantee that the calcium enters the cells in your bones and teeth, and that increases the risk of osteoporosis. You also risk that too many calcium ions enter the cells of soft tissues. This calcium flooding of the cells works like a tsunami and stresses the cells, causing them to produce pro-inflammatory cytokines. It is not felt directly, but it may cause low-grade, chronic inflammation and oxidative stress that is typically seen in diseases like cancer, atherosclerosis, type 2 diabetes, depression, ADHD, Alzheimer’s disease and other neurological disorders. If too many calcium ions flood the nerve cells, it may trigger changes to the synaptic bridges, which overstimulates the cells and causes them to cramp. This may even destroy the mitochondria, which are the energy-producing powerhouses in the cells. An array of different diseases, including cancer and certain neurological disorders, are characterized by mitochondrial defects.

  • We need vitamin D to take up calcium
  • Calcium supplements can increase bone density, although studies show that calcium taken as a stand-alone supplement does not increase bone strength
  • It is bone strength that is of most importance for avoiding fractured bones as a result of falls or other types of impact
  • To boost bone strength, you also need magnesium and vitamin K2
  • Moreover, strong bones depend on exercise and a healthy diet and lifestyle without too many “magnesium robbers” such as sugar, candy, soft drinks, Coca-Cola, and other energy beverages

The essential balance between calcium and magnesium in diet and supplements

In the Western world, the diet typically contains around four times as much calcium as magnesium, which means that we get calcium and magnesium in a 4:1 ratio. This is because we eat a lot of dairy products and not so many vegetables. If people take calcium supplements in addition to this, the balance becomes even more skewed.
In countries like Japan, the calcium-magnesium ratio is closer to 1:1, which is because the typical Japanese does not consume dairy products and therefore only gets around 400-500 mg of calcium daily. On the other hand, the Japanese get far more magnesium from their vegetable consumption. It is most likely because of their diet that the Japanese have a lower rate of osteoporosis. But they also have a higher life expectancy due to a lower rate of cancer and atherosclerosis, which are two of the major killers.
The big question is therefore if we really need less calcium and more magnesium than the dietary guidelines recommend in order to stay healthy and maintain strong bones. It is also worth mentioning that cow’s milk is intended for calves and not for human consumption. After all, other mammals such as shrewmice, monkeys, blue whales etc. have strong bones and they do not consume milk from other species.
In other words, it is not just calcium that is determining for bone strength. In fact, calcium taken in the wrong amount and without being accompanied by relevant micronutrients can actually be harmful.

  • Facts about the calcium/magnesium ratio and about supplements
  • The calcium/magnesium ratio according to the guidelines should ideally be 2:1
  • The calcium/magnesium ratio in the Nordic diet is close to 4:1
  • The calcium/magnesium ratio in the Japanese diet is around 1:1
  • Milk contains nine times more calcium than magnesium
  • Solid cheese contains around 35 times more calcium than magnesium
  • Too much calcium inhibits the uptake/utilization of iron, zinc, and magnesium
  • Too much calcium increases the risk of constipation
  • Too much calcium combined with too little magnesium is very harmful
  • Never take a calcium supplement without taking magnesium, as well
  • It is not a problem if you take a stand-alone magnesium supplement
  • The quality of a supplement is determining for its bioavailability
  • Health authorities warn against taking calcium supplements if people suffer from hypercalcemia, impaired renal function, or tend to form kidney stones


Fan Chen et al. Association Among Dietary Supplements Use, Nutrient Intake, and Mortality Among U.S. Adults. Annals of Internal Medicine 2019

Tufts University, Health Sciences Campus. Nutrients from food, not supplements, linked to lower risks of death, cancer. ScienceDaily 2019

Forrest H Nielsen. Magnesium deficiency and increased inflammation; current perspectives. J Inflamm Res 2018

Helen Sauil Case. Magnesium demper hyperaktivitet blant AD/HD-barn. Helsemagasinet Vitenskap og Fornuft. N1 2017

Fujita T, Fukase M. Comparison of osteoporosis and calcium intake between Japan and the United States. Procb Soc Exp Biol Med 1992

Travis Christoffersen. Når man snubler over sandheden. Ny behandling af kræft. Hovedland 2019

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