Vitamin D: Is it a natural sunlight remedy or just a myth?

Today, researchers, doctors and professors engage themselves in numerous studies to explore the effects of Vitamin D. Renowned scientists and the entire progressive world, at the suggestion of Linus Pauling, were astonished by vitamin C theory proving the benefits that vitamin C has for our body. Today, some people claim that all this is also true for Vitamin D, and many years ago scientists began to investigate.

Research showed that Vitamin D deficiency can cause heart and blood vessel disorders, psoriasis, cancer, and sclerosis. However, as there’s no scientifically proven data, healthcare specialists say that they can’t recommend vitamin D as a preventive measure.

It’s a known fact that to replenish Vitamin D in our body, we need to spend several minutes a day outside in the sun. This is especially true for children. Specialists are reluctant to extensively study the effects of vitamin D because it could undermine many of the big pharmaceutical companies. What benefits does it have? The sun isn’t going to provide them with huge profits so they prefer not to invest in any vitamin D studies.

Vitamin D and its effects on the body

Prohormones or fat soluble inert substances are another name for vitamin D. It produces D3, which is cholecalciferol, and this is released when we’re exposed to the sunlight. The body can also absorb it from food of animal origin, fish and some types of edible mushroom.

Vitamin DVitamin D is synthesized in the human skin from cholesterol when it’s exposed to UVB light. It then transforms into D3 and is delivered to our blood and liver. The D2 and D3 absorbed from food are also delivered to our blood and liver. In the liver it’s transformed into calcidiol and that then changes into the hormone calcitriol. How can we observe that there’s a vitamin D deficiency? When vitamin D deficiency is suspected, a blood lab test is required to measure the body’s calcidiol level.

The most important function of Vitamin D is that it keeps our bones strong and healthy, and without this vitamin our body can’t absorb calcium and phosphorus. This miracle-working vitamin can also control the multiplication of cells and immune reactions in the body. It can also differentiate cells and influence the secretion of hormones.

Some cells and tissues contain calcitriol receptors that can regulate protein synthesis. We have receptors for this vitamin in our brain, heart, skin, intestine, and genitals – about 40 different tissues and organs in total. We also have evidence for 3 percent of the genome regulating hormone 1,25(OH)2D, which is formed from calcidiol.

Calcitriol can bind to receptors and change the activity of enzymes inside the cells. It accelerates regulation and, unlike the gene-based method, it takes only a few dozen minutes. This fact was first recorded in 2012 by researchers who studied G-protein-coupled receptors and were eventually awarded the Nobel Prize for this discovery.

Vitamins and oncology

Specialists in this sphere as well as scientists have been puzzling over whether vitamin D deficiency can increase the risk of developing diseases such as cancer, osteoporosis and diabetes. The first assumption that sun rays were associated with cancer was made in 1937, and in 1941 it was explained that cancer development depends on the region in which patients live – the closer they are to the equator, the less people die from cancer.Vitamins and oncology

In 1980, Cedric and Frank Garland published the results of their studies in the International Journal of Epidemiology, showing that a sufficient amount of vitamin D reduces the risk of intestinal cancer. We also have evidence that people who live in villages or rural areas have the lowest cancer rates.

Some researchers believe that about 25 (OH)D (or, at least, 75 nmol/L) reduces the risk of breast cancer, ovarian and intestinal cancer. However, this data isn’t currently scientifically supported, as it’s a huge challenge to find people who will give their consent to participate in such an experiment.

Oncological diseases develop over time as cancer cells are gradually accumulating. So we can’t speak about any direct correlation between vitamin deficiency at any given moment and the development of disease. Cancer develops slowly over several years and it’s very difficult to monitor the levels of vitamin in our body for many years.

Several studies have been conducted to assess the role of calcium and vitamin D in our overall health. Not only men but also women of a certain age are at risk of developing osteoporosis. For this reason, several studies explored the role of vitamin D in preventing brittle bones.

The results of the studies by the Garland Brothers are astonishing. They proved that people who regularly walk outside or take a multivitamin complex have 50 percent lower rate for cancer development.

Specialists proved that a rise of 25(OH)D in the blood to 25 nmol/L reduces the risk of developing oncological diseases by 17 percent. They also showed that an adequate amount of vitamins in the body of a cancer patient helped to fight the disease more effectively. More than 300 studies have since been conducted to explore the relationship between this substance and cancer.

Grandfather and grandmother in the sun

As a result of this, specialists suggested that we should increase our daily intake of vitamin D to 2000-4000 IU a day (IU is a dosage of a mineral, hormone or vitamin).

Interestingly, in northern regions the rate of disease is higher than in southern regions. We haven’t been able to establish a link between these two factors during different seasons when the sun is more active.

For example, cancer cases in Norway are typically common in winter and in the north of the country. However, the death rate from cancer doesn’t increase during winter. Scientists explain that living in the north, people eat more oily fish which can be a substitute for the sun’s rays.

How does Vitamin D work?

Vitamins and oncology

Scientists reported on dozens of defense mechanisms associated with vitamin D. It can promote cells and vascular growth and also has an anti-inflammatory effect. Results of the studies showed that it may also inhibit the growth of cancer cells.

Some scientists have already taken advantage of this new data and doctors have made attempts to treat or, at least, to inhibit the growth of malignant tumors in patients using the vitamin. Many experiments are being conducted at the moment to study the role of vitamin D in the management of multiple sclerosis. Such studies have been carried out in the Charité Clinic in Berlin, for example.

The amount of vitamins absorbed from sunlight

It’s important that the recommended daily intake is different in different countries and sometimes these differences are significant. It largely depends on the geographical position of the country with respect to the Earth’s equator.

In the USA, in 2010 the following guidelines were developed for the sunlight vitamin: less than 50 nmol/L is deficiency; 50-74 nmol/L is an inadequate amount; 75 or more is a sufficient amount of vitamin D in the blood. Rickets is diagnosed at 25 nmol/L.


Vitamin D recommended daily intake (IU)

Vitamin D safe upper limit (IU)

0-12 months 400 1000-1500
1-13 years old 600 2500-4000
14-18 years old 600 4000
19-70 years old 600 4000
71 years old and over 800 4000
Pregnant and breastfeeding women 600 4000

Please note that if a person has a healthy lifestyle, i.e. healthy eating and spending enough time outside, then a blood test will often show an inadequate amount of this vitamin. How can it be? It’s not as simple as it may seem. The pace of life today is too fast, which means that people have to eat fast, they don’t spend enough time outside and, consequently, they’re advised to take vitamin D supplements. Many people today have a low level of calcidiol in their bloodstream.

As statistics shows, in the USA, a third of the population is in the risk group, as these people don’t have a sufficient amount of vitamin D. In India and China, nearly half of the population fail to meet their recommended daily intake (75 nmol/L). The reasons vary: a lack of sunlight, dark skin, no fish in the diet. In spite of these various reasons, the outcome is the same.

Foods that are rich in Vitamin D include mushrooms such as porcini and shiitake (but not the white button and oyster mushrooms sold in supermarkets). Fish liver, fish, milk and butter also contain D3.


Vitamin D per 100 g (IU)

Oily fish 200-400
Liver Up to 50
Butter Up to 35
Egg yolk 25-60
Meat 13
Corn oil 9
Milk 0.3-4

To maintain a normal level of this vitamin, you should include about 600 IU of it per day in your diet. To receive this amount you need to eat only oily fish during the day. It’s virtually impossible of course, but through other food we can only receive about 10 percent of the recommended dosage. So, we come to the logical conclusion that humans can’t do without sunlight.

The girl is sunbathing

Our body needs at least 30 minutes of sunlight exposure per day. In California and Spain, 12 minutes is enough, and during this time a person receives around 3,000 IU. Do not use any creams before sunbathing. If you were to sunbathe until your skin was burnt red, then that would equal around 10,000-20,000 IU of the vitamin.

You’ll probably remember from childhood that you shouldn’t sunbathe for a long time, in order to avoid getting skin cancer. For this reason, we recommend you combine sunbathing with a proper diet. Eat more oily fish and take vitamin D supplements during the cold season. You should replenish vitamin D during summer then in winter you’ll have an adequate amount of it in your blood.

By the way, if you’re a regular visitor of sun-tanning salons, this doesn’t replenish vitamin D, because only natural sunlight can provide our body with this vitamin.

Who needs vitamin D in particular?

There are certain groups of people who need additional vitamin D in particular:

  • the elderly, if they rarely go outside;
  • babies and new moms should try to take their babies outside on sunny days;
  • people living in the north.

Many of us try to avoid exposure to ultraviolet rays by applying a cream before sunbathing. UV protection creams protect the skin from sun rays, but they also prevent the body from producing D3. Dark-skinned people also need more sun to receive a sufficient amount of this vitamin.

Medical testOverweight people also need more D3. You can calculate your body mass index (BMI) by dividing your height in meters by 2. If the result is 25-30 kilograms per meter or higher then you have excess weight. If the result is more than 30 than this is a sign of obesity. It’s been shown that the higher your BMI, the fewer useful elements there are in your blood cells. A BMI increase by one reduces the level of calcidiol by 0.7-1.3 nmol per liter.

Analyzing statistical data, researchers identified that about 19 percent of males and 27 percent of females have normal BMI and their total amount of D3 is about 100 nmol/L. 75 percent of overweight males and 40 percent of overweight females have a deficiency in this vitamin during the winter.

Vitamin D is fat soluble and in overweight people it’s stored in fat cells. In women a with normal body, one third of the vitamin is stored in fat, one third is stored in blood vessels and the rest in other parts of the body.

It seems logical to conclude that obesity is associated with cancer development. Men and women have different predisposition to diseases, but the mechanism of disease development is practically the same. Obesity causes insulin resistance, then inflammation occurs and the amount of globulins decreases.

Evidently, obesity and vitamin D deficiency are associated with cancer development. This hypothesis is supported by statistics: overweight people with a BMI of 45 are twice as likely to develop cancer than people with a normal weight. 20 percent of cancer patients have vitamin D deficiency. Interestingly, the level of the vitamin in breast cancer patients is 40 percent and in intestinal cancer it’s 70 percent.

It seems we need to reassess our recommended daily intake of this sun vitamin. Scientists in many countries have not yet reached a consensus, but Canadian specialists suggest that the daily allowance for vitamin D should be 2000 to 6000 IU.

However, there is a flipside to the coin: Don’t overdo it, as an excess of this vitamin can be as harmful as a deficiency.

Slow down to the rhythm of life, eat wisely, take vitamins, and it won’t be long until you see a result. Listen to your body and everything will be fine!