Should you add vitamin D?

Vitamin D is one of the fat-soluble vitamins necessary for the normal functioning of the human body. There are two main human sources of vitamin D: sunlight exposure and food. Since there is little sun in our climate, much attention should be paid to dietary vitamin D sources and supplements. Should You Take Vitamin D Supplements? Which form is better to choose - drops, capsules, tablets? What are the standards and recommended doses of vitamin D?

Dr. N. Pharm. Maria Kaspshak

NOTE: This text is for educational purposes only, is not self-medication, and is not a substitute for individual medical advice. Please check with your doctor before deciding on supplements, especially if you suffer from a chronic medical condition.

Sources of vitamin D for the human body 

Vitamin D is a name that includes sterol derivatives: D2 or ergocalciferol is a derivative of ergosterol, and D3 or cholecalciferol is a derivative of cholesterol. Ergosterol and vit. D2 is present in some mushrooms, but they have no dietary value, and the biological activity of vit. D2 is less than vit. D3. Vitamin D3 is synthesized in the skin under the influence of UV radiation and can be obtained from food of animal origin. Its main sources are oily sea fish, fish oil, egg yolks, and full-fat dairy products, especially from cows grazing in sunny pastures.

Vitamin D3 is currently used in Poland to fortify margarines and some other food products. However, despite this, the most commonly consumed foods contain very little vitamin D compared to the requirement of at least 5 mcg (200 IU) per day.

The role of vitamin D in the human body 

The importance of adequate vitamin D intake for human life and health can be seen with the naked eye - this is illustrated by the change in skin color of people living in different regions of the world. People who come from hot regions with high levels of sun exposure have dark skin due to high amounts of melanin, a pigment that protects against ultraviolet rays. This dye, protecting the skin, also reduces the synthesis of the vitamin. D3, which occurs under the influence of ultraviolet radiation. When there is a lot of sun, it doesn't matter. However, the farther north, the lighter the skin of people - precisely so that they use less UV rays from the sun and allow them to synthesize vitamin D in the amount necessary for their survival. Interestingly, the peoples living further north, the Inuit, have rather dark skin. This is because the basis of their diet for generations has been oily sea fish with a high content of vitamins. D3, so there was no strong selection pressure in this population to favor the survival of fair-skinned individuals. 

It has been known for centuries that exposure of children to the sun helped protect them from rickets, a disease associated with insufficient mineralization and underdevelopment of bones. In Poland, rickets was once called the "English disease" because in England, a country with little sunshine, it was particularly common, especially among people who could not afford to eat fish, butter, and eggs often. An acute lack of vitamin D causes poor absorption of calcium from food and rickets in children, and in adults - the so-called. osteomalacia, or colloquially "softening of the bones" - a disease also characterized by insufficient mineralization of the skeleton. Impaired calcium economy due to vitamin D deficiency can also have a negative impact on muscle function, which needs an adequate concentration of calcium ions for contraction. Effects on bone development and muscle function are not the only role of the vitamin. D in the body. Its role in other processes and phenomena - the regulation of immunity, the functioning of the cardiovascular system, the impact on the incidence of tumor diseases - is increasingly documented. 

Vitamin D supplements are recommended for most Poles. 

For many years it has been known about the frequent occurrence of vitamin D deficiency in our latitudes. In the post-war period and during the Polish People's Republic, children in kindergartens and schools were covered by mass health care, which included the introduction of fish oil rich in vitamin D. Many people have unpleasant memories of it, because. rarely did children like to drink fish oil, thick and smelly fish oil. However, it improved the health of an entire generation.

Vitamin D3 is now also recommended for pregnant women, infants, children and the majority of the Polish population. Due to little sun exposure and low vitamin content. D in food, it is safe to assume that most Poles do not consume enough of this vitamin, especially during the period from autumn to spring. Therefore, it is worth seeking appropriate nutritional supplements that will help fill the deficiency. 

How to choose the best vitamin D supplement? 

Pharmacies and pharmacy stores have a large selection of vitamin D preparations - you can buy drops, soft capsules, hard capsules and tablets. Which to choose? It depends on who is taking them. For young children, drops or sprays are best, as the youngest patients cannot yet swallow the capsules. Drops with vitamin D are usually made on the basis of vegetable oils, because. vit. D is soluble in fats. Natural animal oil containing vit. D3 is fish oil (cod liver oil) or fish oil. To overcome the unpleasant taste and smell of fish oil, fruit flavors are currently added to most preparations or it is enclosed in capsules.

Soft capsules with vit. D is also most often filled with an oily solution of this vitamin. Preparations with vitamin D dissolved in oils ensure optimal absorption of this substance. However, if you decide to take hard capsules (oil-free) or tablets, you should always take them with a meal containing fat. This will allow the vitamin to dissolve. D of them is fat and its effective absorption in the digestive system. 

What are the standards and recommended doses of vitamin D?

Vitamin D deficiency can be diagnosed by laboratory blood tests. To do this, determine the concentration of 25(OH)D, i.e. 25-hydroxyvitamin D (calcidiol), the precursor of the active hormone calcitriol. The concentration of 25(OH)D in serum should be 30-80 mg / ml (nanograms - that is, billionths of a gram - per milliliter). A concentration below 10 ng / ml means severe beriberi. D, which requires treatment with doses of the vitamin selected by the doctor. However, most healthy people do not have these tests and would like to take vitamin supplements. D. How then to choose a dose? 

For healthy people, a safe dose is about 400 IU for infants, about 600-1000 IU for children, and 1000-2000 IU (25-50 mcg) of vitamin D3 per day for adults. In winter, this dose should be closer to the upper limit, in summer, if we spend a lot of time in the sun, to the lower one. It also depends on body weight and composition (for example, obese people may need higher doses). These recommendations are reflected in the most common doses of vitamin D3 in preparations available in Poland. For infants, it is 400 IU per day, for older children - 600-1000 IU, and for adults it is usually 2000 IU per day. Vitamin D3 can also be found in numerous multivitamin supplements for children and adults.

Is it possible to overdose on vitamin D? 

Theoretically, an overdose of vitamin D3 is possible, but in order to get poisoned, one would have to take doses many times higher than recommended. Vitamin D is safe for healthy people if you follow your doctor's instructions or the instructions on the package insert.

When should you consult your doctor before taking supplements? 

It should be remembered that people from certain sensitive groups should consult a doctor before taking it and ask him about the possibility of testing the level of 25 (OH) D in the blood. If you are pregnant, nursing, have a chronic illness, or are looking for advice for your child, always check with your doctor first.

People who especially should see a doctor to order such a test and determine the daily dose of the vitamin. D - persons with suspected vitamin D deficiency or persons at risk of this deficiency (pregnant women, the elderly, etc.) and patients with certain chronic diseases - incl. obesity, diseases of the liver, kidneys, incl. nephrotic syndrome, people with malabsorption, suspected rickets, osteomalacia, or osteoporosis, treatment with steroids, antiepileptic drugs, certain antifungal and antiviral drugs. There are also medical conditions where taking vitamin D can be dangerous, and you should always do so under the supervision of a physician, who will prescribe regular tests and determine a safe dose. These diseases include, but are not limited to: sarcoidosis, granulomas, primary hyperparathyroidism, certain cancers and calcium phosphate disorders, and some congenital metabolic disorders.

You can find more useful articles in the AvtoTachki Passions Tutorials section. 

Bibliography

1. Paweł Płudowski, Edyta Kryśkiewicz, Elżbieta Karczmarewicz, Supplementation rules and standards for assessing the body's supply of vitamin D in the light of its pleiotropic effect. Postępy Nauk Medycznych, Vol. XXV, No. 3, 2012, pp. 265-272.

2. Paweł Płudowski, Elzbieta Karchmarevich et al. Practical Guidelines for Vitamin D Supplementation and Deficiency Treatment in Central Europe - Recommended Vitamin D Intake for the General Population and Risk Groups for Vitamin D Deficiency. (Vitamin D Supplementation Guidelines for Central Europe - Recommended Vitamin D Doses D for healthy populations and risk groups for vitamin D deficiency). Endocrinology Poland 2013, 64 (4): 319-327. 

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