Vitamin D and its dosage: more or less?

October 3, 2019December 17, 2020

Vitamins and minerals are primarily involved in regulating metabolic processes in the body. Depending on age, gender, health status, weight, height, physical activity, and physiological needs, a person needs different amounts of these substances. Therefore, there are standards that help prevent vitamin deficiency and its consequences associated with the development of diseases. Prevention of vitamin D deficiency is an important public health goal. Among the vitamins valuable for a woman’s health, of course, vitamin D (calciferol) plays a special role, existing in two forms - D2 and D3, the activation of which occurs in the liver and kidneys.

Types of vitamin D - D2 and D3

D3 (cholecalciferol) is called “solar” because it is formed in the skin due to exposure to ultraviolet radiation. To do this, children and adults should spend about 15–30 minutes in the sun several times a week. However, intensive production of vitamin D occurs during hours that are harmful to health - from 11:00 to 14:00, when the skin needs protection.

In addition, the natural absorption of the vitamin decreases over time, and people with dark skin absorb it more slowly. Negative factors for the perception of beneficial sunlight are sunscreens and unfavorable ecology, such as air pollution. Therefore, even in the summer months, not always and not everyone can stock up on cholecalciferol.

D2 (ergocalciferol) enters the body along with the usual food. However, not many foods of animal origin are known to be enriched with vitamin D: fatty fish (herring, sardines, salmon, mackerel, tuna, halibut), lamb, eggs (yolk), butter, cream, sour cream, hard cheese, beef liver , seafood, cod liver, red caviar, fish oil. The vitamin is present in limited quantities in plant foods: chanterelle mushrooms, oatmeal, potatoes, oranges, parsley, broccoli, nuts, vegetable oils.

It is important to follow the cooking rules so that the beneficial vitamin is not destroyed. It has also been proven that food cannot provide the body with a sufficient dose of D2, since this requires eating too many foods rich in it, some of which also contain cholesterol. In addition, this list contains things that are advised to be consumed with caution or are not allowed at all for pregnant women and in the first 6 months of lactation.

Release form

There are several main forms of vitamin D3: tablets and capsules, softgel capsules filled with fish oil or oil (most often soybean), chewable candies or lozenges, and solution.

Tablets and gelatin capsules are the most common format for any vitamins, but they are absorbed more slowly, and if we talk about tablet forms, they can lose some of the active substances while they go through all stages of complex digestive processes.

The advantage of softgel capsules is that fat-soluble vitamin D is placed in an oil environment, making it better absorbed in the body. In addition, softgel capsules are easier to swallow.

Vitamin D3 in liquid form, as well as in the form of lozenges and candies, is best absorbed. The solution can be diluted in water or in a non-hot drink, and chewing candies are suitable for those who have difficulty swallowing regular capsules or tablets, and it should be noted that there is a pleasant bonus in the form of fruit or berry flavors.

Sources of Vitamin D

Vitamin D was discovered about 100 years ago during the search for foods needed to combat deficiencies in calcium and phosphorus in bones and teeth. The benefits of taking fish oil, which contains large amounts of vitamin A, have been proven. However, when this vitamin was neutralized, fish oil retained its properties, which led researchers to the conclusion that it also contains other vital substances. Subsequently, the discovered vitamin received the name of the fourth letter of the Latin alphabet - D. But fish in sufficient quantities was not available everywhere, and organizing the industrial production of fish oil took time. Therefore, the research continued. It was soon discovered that the beneficial properties of certain types of food are enhanced by irradiation with ultraviolet rays. Further, it was possible to prove that vitamin D can be synthesized by living cells under the influence of sunlight.

The second wave of vitamin D research began in the 1980s. Nowadays, experts primarily name fatty fish and dairy products, as well as animal by-products as its food sources [1].

If you are intolerant to the protein contained in cow's milk, dairy products made from goat's milk can be a source of vitamin D. They are especially indicated for women during pregnancy and breastfeeding [2]. Quiz: Find out how much vitamin D you get from food.

Vitamin D deficiency - symptoms and treatment

The prognosis depends on the presence or absence of complications (bone and extra-osseous), which can result from long-term vitamin D deficiency. In the absence of bone manifestations and adequate replenishment of vitamin D deficiency, the prognosis is favorable.

Vitamin D belongs to the group of fat-soluble vitamins. In nature, it is present only in a very limited number of foods.

Richest in Vitamin D:

• wild salmon (600-1000 IU per 100 g);
• herring (300-1600 IU per 100 g);
• canned sardines (300-600 IU per 100 g);
• fish oil (400-1000 IU per 1 tablespoon);
• ultraviolet irradiated mushrooms (400 IU per 100 g);
• sour cream (50 IU per 100 g);
• egg yolk (20 IU in 1 piece);
• cheese (40 IU per 100 g);
• beef liver (15-45 IU per 100 g) [1].

Population studies demonstrate that only 10-15% of people have a normal vitamin D supply, and therefore they require prophylactic doses of colecalciferol [8].

It must be remembered that vitamin D has a more effective effect on bone if the body has enough vitamin K, calcium and protein [17].

To obtain bone effects from vitamin D therapy, it is sufficient to maintain vitamin 25(OH)D levels at 20-30 ng/ml (50-75 nmol/L). For extraosseous effects, higher concentrations of 25(OH)D are required - (30-60 ng/ml (75-150 nmol/l) [3].

A toxic excess of vitamin D in the blood can cause dangerously high calcium levels, the formation of kidney stones and kidney failure. But it has not yet been precisely established which blood concentrations of 25(OH)D should be used as a threshold level. The results of modern large meta-analyses suggest that at blood concentrations of 25(OH) D below 50 ng/ml (125 nmol/l), the side effects of colecalciferol are not detected [4]. Most authors consider vitamin D levels of more than 150 ng/ml (375 nmol/l) to be hazardous to health [3][4][5].

Acute toxicity can be caused by doses of vitamin D exceeding 10,000 IU/day [22]. Potential chronic toxicity may result from administration of doses above 4000 IU/day for prolonged periods. The VITAL study, which examined the effects of vitamin D and omega-3 supplementation on morbidity and mortality in nearly 26,000 people, found no excess blood calcium, kidney stones, or kidney failure with daily supplementation of 2,000 IU (50 mcg) of vitamin D [ 4].

Recommended medications for the prevention of vitamin D deficiency are colecalciferol (D3) and ergocalciferol (D2). However, ergocalciferol has lower absorption [1][3][15][21]. The recommended dosage regimen for colecalciferol in various age and clinical groups is presented in the table below [1][2][3][5][6][18]. Taking colecalciferol in a prophylactic dosage is recommended without interruption during the summer months [2].

Recommended doses of colecalciferol for the prevention of vitamin D deficiency in various age and clinical groups:

The benefits of vitamin D and why you need it

Calciferol is considered a women's health vitamin. Indeed, it is important for women. After all, its consumption, like other vitamins in general, is much higher than in the body of men. This is due to the characteristics of the female body and its functions: the menstrual cycle, pregnancy, childbirth, breastfeeding, menopause. Therefore, at different periods of life, the need for D3 and D2 may increase. But the main thing is that women need to maintain an adequate amount of calciferol, avoiding its shortage or excess.

Thus, vitamin D is essential because it:

1. Responsible for the level in the blood of minerals such as calcium and phosphorus, which contribute to the preservation and strengthening of musculoskeletal tissue (bones, joints, muscles, teeth).
2. Important for the musculoskeletal system, including correct posture, which is formed before the age of 20.
3. Controls the functioning of the immune, cardiovascular, endocrine, hormonal, and nervous systems. In particular, it supports the level of innate immunity; acts as a hormone (D-hormone) that regulates carbohydrate metabolism, that is, it is directly related to weight loss issues. This means it is needed for proper metabolism and maintaining optimal body weight.
4. Regulates more than 200 genes.
5. It has anti-inflammatory, antitumor, immunomodulatory effectiveness, slows down the aging process, and fills with energy.
6. Promotes conception, maintenance of pregnancy and normal gestation; it is extremely necessary during pregnancy, as it affects the formation of the immunity of the fetus and its bone tissue.
7. Restores a woman’s body after childbirth, corrects the condition of PMS.
8. Good for vision, concentration and memory.

Lack of vitamin D in a woman’s body

Vitamin D deficiency affects 75% of the world's population, the majority of whom are women and children. The reasons why a woman’s body lacks this substance may be:

• insufficient production of D2 under sun exposure;
• winter-spring period of the year (from October to March);
• mono-diets, protein diets, unbalanced nutrition, vegetarianism, pregnancy;
• breastfeeding: in the first 6 months of breastfeeding, a woman’s vitamin D level drops sharply, which provokes a loss of calcium 4 times more than during pregnancy;
• mature age (after 50 years);
• the presence of diseases of the liver and kidneys, gall bladder, small intestine;
• excess weight;
• lack of physical activity;
• taking antacids (reducing high levels of acidity in the stomach) and anti-cholesterol drugs;
• chronic diseases of the endocrine system, gall bladder, pancreatitis, etc.

Interpretation of vitamin D levels based on 25(OH)D concentration

If it is necessary to evaluate the level of 25(OH)D over time, then the analysis must be taken in the same laboratory.

• 25-OH vitamin D (25-hydroxyvitamin D)

When vitamin D insufficiency or deficiency is detected, it is advisable to also check other indicators of bone health. This is the level of total calcium and calcium ionized in the blood, phosphorus, parathyroid hormone, calcium and creatinine in daily urine, and glomerular filtration rate (GFR).

• Calcium
• Calcium Ca
• Phosphorus
• Parathyroid hormone
• Creatinine, glomerular filtration rate (GFR) according to the Cockroft-Golt formula
• Creatinine, urine (daily)
• Calcium, urine (daily)

Learn more about vitamin D deficiency

The consequences of this condition lead to serious problems - the development of various pathologies of organs and systems. Main problems:

• immunity suffers;
• there is a metabolic disorder;
• malfunctions may occur in the functioning of organs such as the thyroid, parathyroid, pancreas, adrenal glands, kidneys, lungs, heart, intestines, stomach, pituitary gland, hypothalamus, etc.;
• possible complications during pregnancy;
• menstrual irregularities may occur;
• changes begin in bone tissue, which leads to osteomalacia (leaching of minerals from the bones), and then to osteoporosis, which is fraught with fractures and injuries;
• deformation of posture, weakness and muscle pain occurs;
• problems with the ovaries and uterus (endometriosis, fibroids, etc.);
• a hormonal imbalance occurs: the production of testosterone and estrogen may increase, which leads to early menopause;
• the condition of the skin deteriorates (vitamin D is involved in the process of renewal of skin cells), hair, teeth (caries), manifestations of skin diseases may occur;
• excess weight gain occurs;
• there is a feeling of anxiety, insomnia, depression;
• chronic fatigue and headaches are felt;
• hypertension, diabetes, arthritis, multiple sclerosis may occur;
• ARVI and acute respiratory infections become frequent.

Test: Check if you are at risk of vitamin D deficiency.

Excess vitamin D for women

During pregnancy or with the onset of menopause, women begin to take vitamin complexes, synthesized D3 in the form of dietary supplements and medications. However, it is worth knowing that it is fat-soluble and is difficult to eliminate from the body. Due to prolonged overdose of more than 10,000 IU over many days, vitamin D easily reaches the point of toxicity. So its elevated level is also very dangerous. Hypersensitivity to this substance can also provoke an overabundance. Interestingly, the sun usually does not cause an oversaturation of the body with vitamin D.

There are two stages to the problem of hypervitaminosis. Initially, the consequences of intoxication include symptoms such as nausea, thirst, headaches, lack of appetite, weight loss, constipation or diarrhea, frequent urination, dehydration, weakness, fever, cramps, irritability, muscle and joint pain. Then calcium deposits occur in soft tissues, and atherosclerosis may develop. Severe cases include loss of consciousness and coma.

It is worth mentioning that an increased level of calciferol is fraught with infertility and the onset of early menopause, frequent colds, arrhythmia, hypertension, and liver enlargement.

Therefore, the dosage of the vitamin should be prescribed by a doctor after receiving the results of a blood test. In case of long-term use, regular testing is necessary.

How to find out your vitamin D level?

You can get information about how saturated your body is with vitamin D by doing a blood test. Typically, this laboratory test is carried out if osteoporosis is suspected, during pregnancy, if the woman spends very little time in the sun, lives in the northern regions, has refused food of animal origin, has chronic diseases or hereditary disorders of the metabolism of this vitamin.

Vitamin D correction

Taking D3 is the prevention of diseases, treatment of pathologies of internal organs, a recipe for good health and longevity. However, its absorption directly depends on physical activity, for example, fitness classes, walking. Interestingly, swimming does not produce vitamin D, since water reduces body weight, relieving stress on it. Vitamin D can only be prescribed by a doctor: his recommendations must be strictly followed. The maximum dose for adult women, as well as pregnant and breastfeeding women, is 4,000 IU per day (100 mg). At the same time, women should pay attention to calcium, magnesium, vitamins A, C, E, B6, which improve the absorption of vitamin D, zinc, phosphorus, and calcium. That is why a vitamin complex is often prescribed for preventive purposes. A nursing young mother or postmenopausal woman can drink special complexes.

The combination of vitamins D2 and D3 has the most lasting effect. Vitamin D2 can accumulate in adipose tissue, forming a valuable reserve for the body. Vitamin D3 is used in metabolic processes faster, ensuring ongoing metabolism. One tablet of NUTRILITE Vitamin D combination product contains 15 mcg of vitamin D2+D3 from natural sources.

One of the popular dietary supplements is NUTRILITE™ calcium, magnesium, vitamin D, which contains the daily requirement of vitamin D. It is recommended to take 1 tablet 3 times a day with meals for a month. It is convenient to purchase and arrange delivery in Moscow or other cities of the country on the official Amway website. When taking such complexes or vitamin D on its own, you should avoid iron, which impairs its absorption. To achieve a more vivid effect and give the body everything it needs, you need to make changes to your diet. In addition, it should be remembered that the absorption of vitamin D is greatly harmed by drinking alcohol and smoking.

Children and the “sunshine” vitamin

The history of the discovery of vitamin D, which occurred about a century ago, was connected precisely with the search for a treatment for childhood rickets. It was found that this disease is a sign of calciferol deficiency. The level of this substance begins to affect the child in the womb, then during breastfeeding. Therefore, prevention of calciferol deficiency in pregnant and lactating mothers is so necessary. A deficiency can result in significant problems that are associated with the formation of the skeletal system and the baby’s susceptibility to diseases after birth, which often manifests itself after some time, including in adulthood. There is also a risk of having low birth weight babies. Prematurity, untimely cessation of breastfeeding, lack of sun, and poor nutrition deprive the baby of the necessary vitamin. But it is necessary not only to increase bone strength, growth, but also general development: vitamin D interacts with the level of cognitive potential and affects a child’s performance at school. Learn more about the symptoms of vitamin D deficiency in children.

Laboratory diagnostics

Mass screening to determine vitamin D levels is not recommended. First of all, blood should be donated to people at risk. And this:

• Persons with bone diseases (rickets, osteoporosis)
• People over 60 years old
• Obese people
• Pregnant and nursing
• Black faces
• Patients with kidney disease
• Patients with inflammatory bowel disease, cystic fibrosis
• Persons taking certain medications (glucocorticoids, antiretrovirals, antifungals).