Author: Jonine Moller
Calcium is probably best known for its occurrence in milk and its importance for bone health. From a young age, most children know that milk makes their bones and teeth strong. It is, however, a little more complicated than purely drinking milk.
Your DNA and genetic makeup can play a massive role in how well calcium is absorbed into your system.
Research on calcium has mainly focused on bone health. This mineral, though, has many other crucial functions in the human body [1, 2]. We are first staying on the topic of bone health, though. Calcium and vitamin D are as thick as thieves; their roles go hand in hand. A deficiency in either will stunt bone growth and remodeling .
Calcium is essential for bone strength as it is the main structural mineral. The blood also needs a calcium concentration to be maintained, and bone serves as a backup store in case of insufficient levels for other functions .
Vitamin D, on the other hand, is crucial for calcium absorption. Without enough vitamin D, it doesn’t help you take in enough calcium. You’ll still suffer the same effects and symptoms as if you were deficient . (*also see the article on vitamin D)
Calcium deficiency symptoms include [2, 4, 5]:
- Osteoporosis, weak bone, frequent bone fractures
- Muscle cramping
- Numbness and tingling in the fingers
- Heart rhythm problems
- Brittle nails and dry skin
- “Worse than usual” PMS and menstrual symptoms
Not only the bones are so dependent on calcium. The soft tissues also need it. It is involved in muscle contraction and relaxation, the functioning of nerves, and the activity of enzymes and hormones. The heart also needs calcium for proper contraction. 
Regarding ideal blood calcium levels, measurement of the ionized form is the most accurate and should be between 1.12 and 1.45 mmol/L. Nonetheless, total calcium can also be measured and should be between 2.2 and 2.6 mmol/L . The recommended daily amount of calcium that adults should take is between 700 mg and 1200 mg [2, 6].
Food sources of calcium include dairy products, fortified cereals or other foods, and nuts and seeds (almonds, sesame, and chia seeds are best). Broccoli, kale, and watercress are the vegetables that have the highest calcium content . Generally, calcium is increased in leafy and green vegetables. Seafood is another good source .
Full cream milk typically contains 116 mg of calcium per 100 ml. With a liter of milk per day, you should, therefore, roughly reach your recommended daily amount.
Too little nor too much calcium is good. We already mentioned some of the effects too little calcium might have. Too much calcium in the blood (hypercalcemia) is estimated to occur in 1 in 500 adults . Hypercalcemia is most commonly caused by an overactive thyroid. It can also result from excessive vitamin D intake, genetic factors, or sarcoidosis. It may otherwise be concomitant with various cancers .
Symptoms of hypercalcemia include :
- Nausea and vomiting
- Constipation and abdominal pain
- General body aches and pains
- Constant thirst and frequent urination
Furthermore, although calcium is crucial for cardiovascular health, taking a too high dose via a dietary supplement can place you at a higher risk of developing a heart attack [1, 5, 6, 7].
Too much and too little calcium may withhold adverse effects regarding osteoporosis, cardiovascular disease, gastrointestinal diseases, and kidney stones .
Due to the possible dangerous effects of over-supplementation, it is important to know whether you have any risk factors for calcium deficiency. Supplementation must, in other words, be necessitated by deficiency.
Various factors may contribute to hindered calcium absorption. Post-menopausal women are at a higher risk for calcium deficiency since their estrogen production is less. Lower levels of estrogen negatively impact calcium absorption .
Vitamin D deficiency, which may occur due to various factors, will significantly impact calcium absorption and usage. So will too much phosphorus, magnesium, and phytic acid (found in unleavened grains) . Several gene variations have been associated with calcium levels [8, 9, 10]. You may thus have a genetic predisposition for either increased or decreased calcium levels.
Amongst the calcium levels influencing genes is the CASR gene. The product of this gene codes for proteins that bind to calcium molecules in the blood. These proteins are for monitoring and regulating the blood’s calcium levels .
Other genes that are associated with calcium levels are also associated with bone mineral density. Some of these genes may be involved in the handling of calcium by the kidneys .
Taking everything into consideration - imagine you have a genetic tendency towards higher calcium. You don’t know this though, read about the importance of adequate levels and assume may be at risk for deficiency. You then unknowingly, with the best intentions for your health, take supplements. Instead of helping yourself, this could increase your chances of a heart attack later in life.
Knowing your genetic predisposition towards calcium deficiency or hypercalcemia could make it much easier to ensure your body’s bone strength and proper functioning. This without placing yourself at unnecessary risk.
Blindly taking supplements could do more harm than good. Supplements are, however, needed for some. Find out in which camp you are by taking a simple genetic test. Your genetic likelihood of being calcium-deficient is tested as a part of BioCertica’s nutrition and wellbeing toolkit.
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