Vitamin D

Vitamin D

Vitamin D is a fat-soluble vitamin. It is important for delivering calcium and phosphorus to the bones. It is important for the strength of bones and teeth.

A person’s body is supplied with vitamin D from exposure of the body to direct sunlight. Vitamin D is found in fish oil, sardines, herring, salmon, tuna, milk and other dairy products. The body can store some of this vitamin in the fatty tissues and thus provide for its needs during the winter.

Smog is the biggest enemy of this vitamin, and sun tanning stops its synthesis by the body.

If there is a deficiency of vitamin D in the child’s body, it develops rickets. If there is a deficiency of vitamin D in the body of an adult, his bones begin to thin. Muscle strength is also reduced and the risk of osteoporosis and fractures increases.

The active form of vitamin D is vitamin D3 (cholecalciferol).

Vitamin D is not an ordinary vitamin, but a steroid hormone that has the ability to influence about 2000 genes in the human body.

Just one example of an important gene that vitamin D regulates is the body’s ability to fight infection and chronic inflammation. It also produces over 200 antimicrobial peptides, the most important of which is cathelicidin, a naturally occurring broad-spectrum, immunity-boosting antibiotic.

This is one explanation why vitamin D is so effective against colds and flu.

Many other benefits to the human body from vitamin D“intake” are also known, including maintaining healthy bones and teeth. A large number of studies prove that it can protect against diseases such as cancer, type 1 and 2 diabetes, multiple sclerosis, and its prolonged deficiency is their catalyst.

Vitamin D has multiple roles in the body, helping to:

  • Maintaining bone and dental health;
  • Influence on processes involved in cancer development;
  • Support immune, brain and nervous system health;
  • Regulation of insulin levels and prevention of type 1 and 2 diabetes;
  • Support lung function and heart health;
  • Influence on pregnancy (reduced risk of caesarean section and pre-eclampsia);
  • Autism, Alzheimer’s disease and other brain disorders.

Vitamin D deficiency is associated with serious diseases such as breast and colon cancer, soft bones, osteomalacia and weight gain, depression, etc.

Vitamin D is believed to be a preventive agent for autoimmune diseases such as autism, cardiovascular disease, diabetes, high blood pressure, neuromuscular diseases, osteoporosis, chronic pain, colds, etc.

The main outward symptoms of vitamin D deficiency are bone pain and lack of muscle strength. In some people, however, the symptoms may be more subtle and difficult to detect. But even without noticeable signs, a small amount of vitamin D in the body can contribute to the development or increase of:

Signs of lacking Vitamin D:

  • Multiple sclerosis
  • Cognitive impairment in the elderly
  • High blood pressure
  • Cardiovascular disease
  • Type 1 and 2 diabetes
  • Cancer
  • Severe form of asthma in children

The uniqueness of vitamins lies in the fact that in minimal quantities they are absolutely necessary for the maintenance of normal activity and health of man, as well as for his proper development.

Their absence disrupts the proper course of almost all physiological processes. Vitamin D is no exception in this respect, for which there is already sufficient scientific evidence proving its preventive and curative function.

The best way to get Vitamin D

The best way to get the vitamin D we need is actually through regular exposure to sunlight.

However, modern lifestyles often prevent us from getting a healthy amount of the fat-soluble compound naturally.

A number of studies claim that between 70 and 80% of Europeans are vitamin D deficient, and that many diseases and health conditions can be complicated by prolonged vitamin D deficiency.

How much sun exposure is needed to get vitamin D?

To get enough vitamin D, it is recommended to expose your body to direct sunlight for a certain period of time every day.

  • For people with lighter skin, this period is about 15 minutes per day;
  • For those with darker – about 30 minutes;
  • For blacks – about 60 minutes.

Since ultraviolet forms vitamin D, it is good to know at which times of the day it is most present. In winter these are the hours between 11:30 and 15:00, and in summer between 9:00 and 11:00, and also between 15:00 and 18:00.

If you find it difficult or impossible to make time for sun exposure, you can get the right amount of the vitamin by taking supplements.

Fun fact: Vitamin D breaks down quickly, which means that the body’s required amounts can easily run out, especially in winter and in the absence of a varied and healthy diet.

What amounts of Vitamin D are needed?

According to endocrinologists, 30-100 ng/ml. of the vitamin are needed by man to maintain good health. More frequent exposure to sunlight and a varied and balanced healthy diet are needed to avoid deficiency of the substance.

In case one of the two factors is lacking, a tanning bed and/or vitamin D supplements can be of serious help.

Recommended daily amount of vitamin D:
  • For children up to 1 year – 400-1000 IU/day.
  • For children from 1 to 18 years – 600-1000 IU/day.
  • For adults – 1500-2000 IU/day.

IU/day – Units per day.

Risk groups of people for vitamin D deficiency

Vitamin D deficiency can also be seen in a completely healthy body, as the symptoms can be more subtle and difficult to detect. Risk groups identified as needing caution and additional vitamin awareness:

  • Breastfed babies. Breast milk is the best food for newborns, created directly from nature. However, it is good to bear in mind that through it it is difficult to transmit vitamin D from the maternal organism. For this reason, it is important to take babies for walks from a very young age. On the recommendation of a pediatrician, a dietary supplement in the form of vitamin D drops is also often prescribed;
  • Elderly people. Not only do they spend less time outdoors, but as the years go by, their skin fails to synthesize vitamin D as efficiently as a young body;
  • People with dark skin. Higher amounts of the pigment melanin in the skin lead to its reduced ability to synthesise vitamin D from sunlight, and for this reason the recommended daily sun exposure values for this group are increased;
  • People with reduced sun exposure. Those whose work prevents them from going out; those who avoid walking; those who often wear full-body covering clothes;
  • People with specific diseases. Vitamin D is a fat-soluble compound, which means that in diseases with impaired fat metabolism in the body, it fails to be effectively absorbed.
  • Overweight people. Greater amounts of subcutaneous fat require greater amounts of vitamin D.

Foods rich in vitamin D

Few foods actually contain higher amounts of vitamin D if it is not supplemented.

This is because our bodies are designed to produce the amount of vitamin they need through the skin (from sunlight), not through the mouth (with food).

3 popular foods that contain vitamin D:

  • Salmon (especially wild caught);
  • Mackerel;
  • Mushrooms (especially if exposed to UV light when growing).

Interesting fact: AquaSource Organic Vitamin D – provided by organic mushroom powder. This special type of mushroom with a white part on the underside of the cap produces a very pure and potent form of vitamin D2. In practice, these mushrooms are literally not processed and are certified organic.

Other foods contain less vitamin D or are not as popular in Bulgaria:
  • Cod liver oil (high in vitamin D);
  • Tuna;
  • Sardines preserved in butter;
  • Liver (beef or veal);
  • Egg yolks;
  • Cheese.

List of proven benefits of vitamin D

  • Lowering the risk of falls and bone fractures in the elderly. A stronger effect is noted when combining it with calcium;
  • Improving muscle and neural functionality in older adults;
  • Reduced risk of cardiovascular disease or complications of such diseases;
  • A direct link between vitamin D levels and high blood pressure has been proven. Higher concentrations of the vitamin lead to lower blood pressure;
  • Directly affects the regulation of parathyroid hormone secretion. It is used as a reference drug;
  • Dramatically lowering (50%) the risk of colon cancer;
  • Reduces asthma attacks in young individuals;
  • High vitamin D levels in children are associated with greater height growth. A similar effect in the elderly is not noted;
  • Improving insulin secretion in individuals with type II diabetes or at risk. The effect is directly associated with protective properties at the level of the pancreas;
  • Improvement in insulin sensitivity resulting from improved insulin secretion from the pancreas;
  • Reduction of inflammation in systemic lupus erythematosus (lupus erythematosus);
  • Symptom reduction in tuberculosis;
  • Slight lowering of blood triglyceride levels after long-term use;
  • Increase low testosterone by 30% in men after one year of use. Low testosterone may be the result of a vitamin deficiency;
  • High serum vitamin D levels improve calcium metabolism and absorption;
  • It drastically reduces the risk of developing multiple sclerosis, as well as reducing some of the symptoms of multiple sclerosis;
  • Vitamin D supplementation has been associated with a reduced risk of breast cancer, pancreatic cancer, prostate cancer and ovarian cancer;
  • Vitamin D deficiency is associated with low mood and depression, and a direct link has been found between vitamin D supplementation and symptom reduction in depression;
  • Optimal serum vitamin D levels positively affect seminal fluid quality.

Can you overdose on vitamin D?

Too large amounts of vitamin D can cause abnormally high levels of calcium in the blood, which in turn can lead to nausea, constipation, confusion, rapid heart rate and even kidney stones.

According to research and studies, it has been found that it is almost impossible to get a vitamin D overdose naturally (through sun exposure or through food). Almost every recorded overdose was due to excessive intake of dietary supplements.

Extensive studies conducted in 1997 have established safe limits of up to 2,000 IU daily vitamin D for adults and up to 1,000 IU daily for infants up to 12 months of age.

IU – international unit of measurement for some vitamins (e.g. vitamin D and vitamin A)

A few years later (2010) these values were adjusted and increased to:

  • 4000 IU daily for adults;
  • 3000 IU daily for children aged 4 to 8 years;
  • 2500 IU daily for children aged 1 to 3 years;
  • 1500 IU daily for infants aged 6-12 months;
  • 1000 IU daily for infants 0 to 6 months of age.

Even more recent studies show that adults can tolerate more than 10,000 IU of vitamin D from natural sources daily.

To synthesize 10,000 IU of vitamin D, in these studies it was sufficient to expose the entire body of an adult to the sun for a period of 30 minutes.

Main symptoms of vitamin D overdose:
  • Fatigue and irritability;
  • Headache, slurred speech;
  • Dehydration with subsequent constipation;
  • Decreased appetite and a sharp reduction in body weight (anorexia);
  • Vomiting;
  • Muscle weakness;
  • High levels of calcium in the blood (hypercalcemia).

Vitamin D research

An overdose or deficiency can best be detected by monitoring the blood status of the fat-soluble vitamin. In addition, the blood test would give confidence that the vitamin D level is within normal limits.

Experts recommend periodic testing (every six months) to protect you from possible toxicity caused by additional supplementation.

Treatment in these cases is usually associated with rehydration, stopping the intake of any type of supplement including vitamin D, as well as limiting calcium intake.

Diseases associated with low levels of vitamin D in the body

Optimal amounts of this vitamin in the body significantly improve the condition and function of the immune, nervous and bone systems, and deficiency is associated with a number of diseases, the most common of which are:

  • Acne, various allergic manifestations, asthma, autoimmune diseases;
  • Autism, Alzheimer’s disease, Parkinson’s disease, dementia, depression;
  • Kidney failure, arthritis;
  • Breast, colon and ovarian cancer;
  • Chronic fatigue, colds, as well as various bacterial and viral infections;
  • The formation of dental cavities and poorly coordinated teeth, the development of paradontosis;
  • Gluten intolerance;
  • Osteoporosis, osteomalacia, muscle weakness, pain, rheumatoid arthritis, rickets, frequent sports injuries;
  • Chronic obstructive pulmonary disease, tuberculosis;
  • Hypertension;
  • Diabetes (type 1 and 2), obesity;
  • Psoriasis.

Interaction of vitamin D with minerals and medications

Some elements cannot be adequately absorbed by the body without the presence of vitamin D and vitamin K2, the most prominent among them being calcium.

This is another reason why taking a stand-alone nutritional supplement is not the best solution for an established deficiency.

Corticosteroids also have a direct interaction and can contribute to creating a deficiency with their ability to leach extra calcium and vitamin D from our bodies.

Other medications that can interact with vitamin D are those prescribed for cholesterol reduction and for seizures. For this reason, if you are taking any of these, consult an adequate person to advise you on how to take vitamin D and in combination with what.


Vitamin D has versatile and indispensable functions for human health.

A nationally representative survey conducted in Bulgaria in 2012 found that 76% of Bulgarians are deficient in Vitamin D.

The most noticeable examples in deficiency are a weak immune system, pain and weakness in joints, tendons and muscles. Vitamin deficiency is also associated with some more severe diseases such as osteoporosis, diabetes and cancer.

The best way to get healthy amounts of vitamin D is through daily sun exposure.

Since overall body exposure to light is limited during the colder months, it is of the utmost importance to pay attention to a healthy and varied diet and, if necessary, to supplementation and tanning.

For most people, exposure to the sun for between 5 and 15 minutes, 2-4 times a week is enough to give the body the opportunity to produce the amounts of vitamin D it needs.

Frequent sun exposure or another method of getting the vitamin is important, as vitamin D is rapidly broken down by the body and constant replenishment is needed.

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