Calcium and vitamin D: do they have a synergy?

Vitamin D is a fat-soluble substance that is formed in the skin due to the sun's ultraviolet rays. There are two types of vitamin D: D2, found in mushrooms exposed to the sun, and D3, produced by our bodies when we are exposed to UVB rays, and found mainly in foods such as oily fish. Whether it comes from the skin or from food, the vitamin D we absorb is transformed biologically. It passes through a preliminary stage in the liver and a second in the kidneys to become its active form, called 1,25(OH)2D.

Vitamin D plays a crucial role in regulating the absorption of calcium in the intestine, thereby promoting its assimilation in the body. The active form of vitamin D, known as 1,25(OH)2D (or calcitriol), has various biological effects on a number of body tissues. This active form is key part of bone health, but also has an effect on healthy metabolic function and immunity.

Calcium is a metallic element on the periodic table. It is present in our bodies and is mainly stored in the bones, of which it is an integral part. It contributes to the formation of bones and teeth, and to keeping them healthy. Calcium is essential for the proper functioning of the human body.

Calcium (Ca) is essential for many vital functions, mainly in the form of Ca²⁺ ions. Its ability to lose two electrons allows it to bind easily to other molecules and play a structural role in the body. In the body, calcium is mostly present in the form of calcium phosphate and the majority of our reserves are found in our bones. When calcium levels in the blood fall, it can be released from this reserve to make up the deficit. A prolonged calcium deficiency can therefore have a detrimental effect on bone strength and health.

Vitamin D exerts a significant influence on the formation of the 208 bones in the human body as it is part of your calcium metabolism. Its main role is to increase the absorption of calcium from the digestive tract, while also contributing to it being stored in your bone cells in the form of calcium phosphate.

A lack of vitamin D can have a number of consequences for your health, so it may be worth taking a vitamin D supplement if you notice a bone-related issue (as it is co-dependent on the effectiveness of calcium), muscle weakness or a weakening of the immune system, leading to general tiredness and weakness.

It is also important to note that the symptoms of vitamin D deficiency can vary according to individual circumstances. If you think you may be at risk of vitamin D deficiency, it is advisable to consult a healthcare professional to assess your vitamin D status and discuss the measures to be taken to prevent or halt a deficiency.

Bone problems are one of the first signs. As calcium is a major component of bone, a deficiency can lead to weakening of the bones, increasing disorders such as osteoporosis. In the most serious cases of deficiency, there may be an increased risk of bone fractures.

Dental problems are another warning sign. Calcium is essential for dental health. A lack of calcium can increase the risk of tooth decay and other dental problems.

Lastly, muscle cramps may indicate a calcium deficiency. This mineral plays a crucial role in muscle contraction, and a lack of it can lead to cramps and muscle weakness.

Vitamin D improves calcium absorption in the intestines, which is crucial for bone formation and strength. Without a sufficient intake of vitamin D, only 10-15% of dietary calcium is absorbed, which can lead to bone weakness and increase the risk of fractures. The importance of vitamin D supplementation in people at risk of osteoporosis has been demonstrated in the 2019 journal of rheumatism (9).

This product is not a substitute for a varied and balanced diet. Do not exceed the recommended daily dose and it must not be taken by children under 3 years of age. In addition, pregnant or breast-feeding women should consult a health professional before taking any supplements. We also recommend that you seek the advice of a health professional before you give children any supplements.

Magnesium plays a crucial role in regulating the concentration of calcium in bones and soft tissue. According to a 2022 study, it helps to convert vitamin D into its active form, which improves calcium absorption. This food supplement combines 3 forms of magnesium for optimum effectiveness and guaranteed high bioavailability. Magnesium also helps to reduce fatigue and ensure the nervous system functions properly, promotes muscle function and normal protein synthesis, and contributes to bone health.

Zinc is essential for immune health, but it also influences bone metabolism. It supports the activity of osteoblasts (bone-making cells), and its combination with vitamin D has been shown to improve bone mineral density. A study in the Journal of Bone and Mineral Research confirmed that zinc combined with vitamin D reinforced the latter's effect on improving bone health (10).

There are no harmful effects from a small one-off overdose of vitamin D3. In this case, simply reduce the dose for the following day or skip a dose to rebalance the overall dosage. It is important, however, to avoid chronic overdosing. Always follow the recommended doses for food supplements.