Vitamin D (otherwise – calciferol) is vital for the functioning of all organs and systems of the body. It is formed under the influence of ultraviolet rays and comes from the outside with food. What foods contain vitamin D – mainly in seafood, animal and dairy foods, less in plant foods. Its deficiency causes serious illness. You can fill this gap with products, pharmacy products.
The role of vitamin D in the body
Vitamin D is a fat-soluble compound that is essential for the functioning of the entire body. At the same time, it performs the functions of a hormone. Its main sources are the sun’s rays and animal products (mainly seafood).
Synthetically, it was obtained in 1936 from fish oil. Then pharmaceutical preparations and dietary supplements were developed to quickly compensate for vitamin D deficiency. There are several varieties of it:
- Ergocalciferol (D2) is synthesized under the influence of sunlight on some types of fungi. It is obtained artificially, then added to bread, baby cereals and milk formulas.
- Cholecalciferol (D3) is a natural vitamin found in animal foods.
- Dehydrocholesterol (D4, otherwise provitamin D3) is found in the human epidermis. Under the influence of sunlight it is transformed into cholecalciferol.
- Sitocalciferol (D5) is found only in wheat grains.
- Stigmacalciferol (D6) is found in small amounts in plants.
Previously, calciferol was considered as a compound for the regulation of phosphorus-calcium metabolism. Then it began to be attributed to hormonal elements, because of the wide spectrum of action. Calciferol freely penetrates the plasma membrane, which separates the extra- and intracellular contents.
Passing through a reinforced layer of proteins and phospholipids, it ends up in the cytoplasm, and then in the nucleus, where it interacts with receptors that activate specific genes. Vitamin D is important for maintaining fertility and the functioning of the reproductive system. It activates a specific gene that regulates the process of embryo fixation. Therefore, vitamin D can cause miscarriages and premature births.
Calciferol is of great importance for the immune system. It activates macrophages (cleaner cells) that destroy pathogens. Participates in the transmission of nerve impulses, lipid and carbohydrate metabolism, the process of bone formation, muscle development, stops inflammatory processes, affects cognitive functions. Also foods rich in vitamin D:
- reduce the risk of developing osteoporosis, Parkinson’s and Alzheimer’s disease, senile dementia, neurological disorders and depression;
- increase the flow of calciferol to the bones, tooth enamel, strengthening them;
- prevent the formation of oncological diseases, therefore they are included in the complex therapy of cancer;
- strengthen immunity;
- prevent the occurrence of atherosclerosis, heart disease, multiple sclerosis, arthritis;
- stabilize blood pressure;
- regulate the production of insulin, normalize blood glucose levels;
- prevent the development of diabetes;
- stabilize the work of the thyroid gland;
- necessary for blood clotting;
- used to treat psoriasis;
- prevent muscle weakness;
- improve mood, increase efficiency;
- eliminate chronic fatigue;
- protect against various infections.
Thanks to vitamin D, phosphorus and calcium are absorbed, the strength of teeth and bone tissues is maintained, which is especially important for older people who develop diseases due to age-related changes. Calciferol helps to absorb zinc, magnesium and iron. Pharmaceutical preparations and dietary supplements are used to treat certain diseases:
- multiple sclerosis;
- rheumatoid arthritis;
- chronic obstructive pulmonary disease;
- kidney failure and osteodystrophy.
Products with vitamin D are recommended to be included in the menu for pathologies that are accompanied by a deficiency of phosphorus or calcium – Fanconi syndrome, pseudo- and hypoparathyroidism, familial hypophosphoatemia. Calciferol helps prevent rickets, accelerates tissue repair in case of bruises, injuries and fractures.
Deficiency and excess of vitamin D in the body
To eliminate vitamin D deficiency in the body, it is enough to spend several hours a day in the sun. A lack of calciferol often occurs due to a deficiency in ultraviolet radiation. It promotes the natural production of vitamin D in the epidermis. Therefore, insufficient exposure to the sun provokes the formation of a deficiency of calciferol. Also, its concentration in the body decreases in breast milk for a number of other reasons:
- the menu lacks products containing calciferol;
- pathology of the kidneys, liver;
- frequent and prolonged use of certain drugs – hormonal, anticonvulsant;
- malabsorption of vitamins and nutrients;
- glomerulonephritis, in which the output of calciferol in the urine increases;
- endocrine and cancer diseases;
- pathologies that lead to intestinal damage – cystic fibrosis, Crohn’s disease, ulcerative colitis, celiac disease.
In the body, calciferol reserves are stored for no longer than 60 days. For humans, the most useful are two types. Cholecalciferol is synthesized by the body under the influence of ultraviolet radiation. Ergocalciferol comes from plant and animal foods. But according to research, it is vitamin D3 that works best.
To determine the concentration of calciferol, the values \u200b\u200bobtained by the laboratory are compared with the table of the daily intake. It depends on age, activity, health status, but the maximum allowable dose is 15 mcg / day.
|Up to a year||1 to 9 years old||9 to 60 years old||Over 60 years old|
During pregnancy and breastfeeding, women are advised to consume 15 mcg / 600 IU per day. But residents of the northern regions do not have enough sunlight, so for them the dosage is increased to the maximum. Also, an increased dosage is recommended for obesity, bedridden patients living in areas with poor ecology, who often work night shifts, people with diseases of the gallbladder, liver and intestines.
Formula-fed children should not be given additional calciferol. In the mixture, it is already added in the right amount for the normal growth and development of the child. In adolescence and pregnant women, it is recommended to supplement the diet with fish oil, dairy products and animal origin.
Deficiency of calciferol can provoke the development of serious diseases or malfunctions. Vitamin D deficiency can be caused by sunscreens and sprays that protect the skin from ultraviolet radiation, or bad habits (smoking, excessive alcohol consumption). Hypovitaminosis occurs mainly from November to March, when solar activity is low.
People with dark skin are at risk for vitamin D deficiency. Melanin protects it from ultraviolet radiation and prevents the natural production of calciferol. After 60 years, the intestine absorbs fat worse and this worsens the absorption of the vitamin.
With obesity, calciferol dissolves in tissues, not having time to participate in biochemical processes. Vegetarians do not eat animal products, which are the highest concentrations of vitamin D.
|Age||Vitamin D deficiency symptoms|
|Children||Calciferol is necessary for the normal formation and development of the fetus, innate immunity. Therefore, it is included in infant formulas. It is necessary for the formation of the skeleton, muscles, nails, teeth. Vitamin D deficiency is indicated by:slow tightening of the fontanel;growth retardation;sudden weight loss;excessive excitability, tearfulness;strong sweating;sleep disturbance.Also, the symptomatology is manifested in a change in the bone skeleton – a disproportionately large head, a flat nape, crooked legs, a convex forehead. Children are often diagnosed with rickets.|
|adults||Vitamin deficiency is determined using laboratory tests. The symptoms of a lack of calciferol are:sleep disturbance;frequent infectious diseases of the respiratory tract;chronic fatigue;caries;nervousness, irritability;obesity;pulling and aching pains in muscles, joints, bones;constipation or diarrhea;alopecia;blurred vision;fragility of bones, frequent injuries, fractures;muscle cramps;decreased appetite, up to anorexia;peeling and dry skin.|
Since most symptoms accompany many health problems and diseases, focusing only on them is not a diagnosis. But this is a reason to see a doctor to check the level of vitamin D. The norm is 30-100 ng / ml, a slight deficiency is less than 20-30 ng / ml, a value of less than 10 ng / ml indicates a deficiency.
An excess of the vitamin (hypervitaminosis) in countries where there is little solar activity is rarely diagnosed. But the cause can be excessive consumption of animal food. With an excess of vitamin, its indicator increases to 100 ng / ml and above.
Then calcium salts begin to be deposited on the internal organs, muscles and skin, which impairs the functioning of the body and provokes health problems. The most common options are stone formation, kidney failure, and visual impairment. Symptoms of excess calciferol:
- muscle cramps;
- the appearance of a rash;
- stool disorder (diarrhea);
- frequent urination.
Also, an excess of vitamin D increases the severity of disease symptoms. Reactions similar to allergic manifestations may occur.
Seafood rich in vitamin D
The main category of foods containing vitamin D is seafood. Fatty fish are the best – 100 g of canned salmon will provide an adult with a daily dose of calciferol. Its highest content is in fish oil, which is enough to add to food in a small amount to eliminate the deficiency of calciferol.
According to the data, in wild fish it is contained in a higher concentration than in those that live in artificial reservoirs. The temperature of the water also affects its quantity. It is recommended to choose fish that live in cold waters. It contains five times more calciferol than warm water. Which foods have the most vitamin D (per 100 g, in IU):
- cod liver – 4000;
- salmon: wild – 1000, from cages – 600;
- mackerel and snapper (or reef perch) – 400;
- Atlantic herring – 310;
- sardine in canned food – 270-300;
- mackerel – 250;
- tuna – from 120-236;
- caviar (black, red) – 230;
- halibut and shrimp – from 150;
- oysters – 70.
What other fish have vitamin D – pink salmon, salmon, trout, chum salmon, eel. But its greatest content is in cod liver, from which oil is made, packed in capsules. In addition to calciferol, they additionally contain retinol and fatty acids.
Meat and eggs
Meat also contains calciferol, but in a small amount. To meet the daily requirement of vitamin D, you can choose from only two foods. In 100 g of beef liver – 50 IU of calciferol, in pork – up to 60 IU. It is also found in small amounts in chicken egg yolks. A pair of eggs contains 80-90 IU of vitamin D, while quail eggs contain 2 times less.
Calciferol is present in dairy products. But you need to choose them with a high fat content, otherwise it leads to a loss of the vitamin. It is bad if calciferol is added to them additionally, then it is poorly absorbed. One glass of milk (from 2.5%) fills 20% of the daily requirement for it. Hard cheese, natural yogurt, cottage cheese, sour cream and butter also help to eliminate the deficiency.
Plant sources of vitamin D
There is little calciferol in plant products. This option is more suitable for vegetarians. The plant foods with the highest concentrations of vitamin D are wild mushrooms, which get enough sunlight.
Although champignons are grown on purpose, they are illuminated with quartz lamps 3-4 hours before harvesting. Up to this point, they contain 30-40 IU of calciferol, after treatment, its concentration increases to 400 IU. A lot of vitamin D in 100 g of mushrooms:
- vulture – 2500;
- chanterelles – 340;
- morels – 250;
- oyster mushrooms – 110;
- shiitake – 50-100 IU.
In grains, nuts, vitamin D – a small amount. In 100 g of corn oil, it is only 7-9 IU. But in cereals and baby food, the level of calciferol is higher, it is enough to prevent deficiency. Manufacturers add the necessary vitamins and minerals to them. Therefore, a serving of oatmeal contains up to 160 IU of calciferol.
Vitamin D is also found in dark green vegetables – squash, cabbage, zucchini, spinach. From fruits, store-bought juices will be useful, in which vitamins and nutrients are additionally added. Orange juice would be ideal.
Vitamin D is vital for the body. With its deficiency, health problems arise, up to the development of serious diseases. The content of vitamin D in foods helps to prevent and compensate for its deficiency. People who are in a zone of low solar activity and at risk can take cod liver oil,…