Sun is the source of vitality: it is virtually impossible to get a vitamin D overdose

6. August 2015

In our climatic zone, sunshine is a rare commodity for most months of the year and it may well be that the scarcity of sunshine is the underlying cause of tiredness and fatigue many experience. People in Estonia are able to get the optimal dose of vitamin D from being outdoors and exposed to sun in the four months of summer.

Hippocrates, the father of modern Western medicine, said as early as around 400 BC that it is best to live on the southern face of a hill. And indeed, those who live between the 35th latitude north and the 35th latitude south get a sufficient dose of sunlight all year round. Between the 56th and 60th latitude where we live, the amount of sunshine required for vitamin D synthesis is available only in the summer season between 10 a.m. and 2 p.m.

Thus it is no wonder that some 70% of Estonians suffer from vitamin D deficiency during the winter months. Vitamin D levels in expecting mothers, infants and youngsters must be closely monitored because vitamin D deficiency in a developing organism harms mostly bones and may cause rickets. To minimize the risk, in many countries baby formulas, milk, breakfast cereals and juices are enriched with vitamin D. Luckily, in recent years Estonian supermarkets have started to sell milk, cooking oil and margarine spreads fortified with vitamin D.

Hormone produced by the human body

In fact, vitamin D is not an actual vitamin, but a hormone, because our body is able to synthesise it through interaction with UV radiation from the sun.

Kaja Osi, the coordinator of bioanalytical activities in the central laboratory of East-Tallinn Central Hospital, says that vitamin D regulates the absorption of calcium and phosphorus from the small intestine and their uptake in bones and teeth. Vitamin D maintains the proper function of the nervous system, skin, heart and muscles; strengthens the immune system; stabilises the blood sugar level, inhibits the formation of cancer cells; delays the onset and progression of several serious diseases, such as multiple sclerosis, autoimmune conditions, etc.; and plays an important role in blood coagulation. Therefore, it might be held that vitamin D is extremely vital for our bodies because it affects everything in our bodies from a runny nose to malignant tumours.

The absorption of vitamin D may be inhibited by a number of medical factors: its malabsorption in the small intestine, being overweight, age, excessive alcohol consumption and smoking, taking medication for a prolonged period, or gastric bypass surgery.

The optimal level of vitamin D in the human body

According to Kaja Osi, different types of tiredness – fatigue, muscle weakness and exhaustion – may be signalling a vitamin D deficiency in the body. In addition, it may be the cause of a sensation of heaviness in legs, aching bones, frequent infectious diseases, and depression. As a rule, it means that the level of vitamin D in the body is significantly lower than the recommended levels.

To diagnose vitamin D deficiency, a blood test has to be taken. If the blood test shows that the level is above 75 nmol/l, there is no need to worry. But one should be concerned if the level is below 50 nmol/l. In this case, vitamin D should be supplemented in the form of pills, drops or oil capsules, but consult with your doctor to find the most suitable solution.

But what should you do if vitamin D levels in the blood far exceed the recommended value? This means that, according to the blood test, vitamin D levels are over 370 nmol/l. However, Kaja Osi assures all that this problem is a rare occurrence. 

This may be the case when someone regularly supplements vitamin D in huge amounts for a prolonged period of time. But even then, it would take a long time for side effects to appear (nausea, itching, high blood pressure, stomach ache, and increased thirst). Under medical surveillance, it is possible to get vitamin D levels back to normal in a couple of days.

Sun, diet and vitamins

What are good sources of vitamin D? One of them is certainly sun. People in Estonia are able to get the optimal dose of vitamin D from being outdoors and exposed to sun in the four months of summer. For the rest of the year, the intensity of sunlight is so low that our skin is not able to produce vitamin D.

Moderate and reasonable use of a solarium is beneficial in this respect, but care should be taken not to overdo it. Also, a “highly sun-intensive” beach vacation is not a very good idea because when the skin is sunburnt – a common sight among tourists from Northern countries – it is simply unable to synthesise vitamin D. What you get is just a severe sunburn and skin that ages at an accelerated rate. What is more, severe sunburn increases the risk of skin cancer.

When on a sun holiday, a sun cream with an SPF above 15 is a must for fair-skinned Northern people. At the same time, it is recommended to be in the sun for a couple (!) of minutes before applying sun cream to give the body a chance to produce the necessary amount of vitamin D upon exposure to UV radiation.

All in all, it may be said that it is most reasonable to spend as much time as possible outdoors during times when sunlight is not very intense – it helps to get the face and hands exposed to sun, but if possible, get an all-over body tan and eat a varied diet: oily fish, eggs, milk, butter made from summer milk, liver, cheese, seeds and grains are all rich in vitamin D.

Source: Terve Pere special supplement of Eesti Ekspress newspaper