After a long wet winter, finally spring arrived, followed by a hesitant summer, but the sun has shone more consistently than it has in the past few years. Fantastic, it lifts your mood and makes you feel good to be alive. It also means that I can have the top down, I hasten to add - my little sports car's not mine, and most importantly top up my Vitamin D levels. Last winter, a routine blood test revealed that I was deficient in vitamin D. Hence my doctor advised me to take vitamin D supplements.
So what are vitamins? They are a group of unrelated organic compounds basically lumped together because they are all essential and are needed in small amounts for normal growth and metabolism. We obtain most of these vitamins from the food we eat and our gut bacteria. In 1912, the English biochemist Frederick Gowland Hopkins carried out an experiment with two groups of rats. The first group of rats were fed on a diet which consisted of only proteins, carbohydrates, fats, minerals and water. This group did not grow properly and eventually became unhealthy. The second group of rats were fed the same diet but in addition, a small amount of milk was also added to the diet. This group of rats grew normally. In fact, when the first group were given a daily addition of a small amount of milk, it soon restored their health. Gowland suggested that the milk contained a ‘vital amine’ required for normal growth and hence the word ‘vitamin’ was coined. This vitamin was later named vitamin A.
If our diet lacks any particular vitamin, it leads to a disorder known as deficiency disease. For example, if we don’t eat citrus fruit or we have a diet lacking in Vitamin C, it leads to a deficiency disease known as scurvy. I don’t want to get side tracked by other vitamins because in this blog I want to talk about vitamin D.
The main job of vitamin D is to absorb calcium and phosphorus in our diet from the gut. You simply can not absorb calcium or phosphorus from the gut without the presence of vitamin D. Calcium is vital for normal bone growth and strength. Both of these are needed for strong and healthy bones and teeth. Vitamin D is also very important for muscles, the immune system and general health. It has also been implicated in helping to prevent other diseases such as cancer, heart disease and diabetes.
How do we get this important vitamin? The main source is sunlight on our skin. About 90% of our vitamin D is derived from the ultraviolet B light rays. I will give more detail of this later. We can also get small amounts of vitamin D from some foods, but not in sufficient amounts to satisfy our requirements; we would have to eat huge amounts of these. These foods include oily fish like salmon, pilchards, sardines, mackerel, herrings, trout and tuna. Although not very high in vitamin D content, they are invaluable for calcium and the essential Omega-3 fatty acids needed for many functions in the body, like maintaining brain and nerve function. Egg yolks also contain little amounts of vitamin D, as do some fortified foods like fat spreads, margarine, breakfast cereals and powdered milk.
Mild deficiency of vitamin D in adults may go unnoticed, but you may get general tiredness, vague aches and pains and basically an overall feeling of not being very well. The big worry of vitamin D deficiency is in babies and young children under the age of 5 when a huge amount of growth is taking place. A lot of the symptoms of the deficiency are related to the low levels of calcium. In babies and young children, severe vitamin D deficiency can lead to muscle spasm/cramps, breathing difficulties due to weak chest muscle and a soft rib cage, seizures, soft leg bones that look curved or bow-legged, soft skull and poor growth. The bow-legged condition is known as rickets, the main vitamin D deficiency disorder. Vitamin D deficiency affects height due to poor growth and in turn might make children reluctant to walk. It can also lead to irritability and makes them more prone to infections. Calcium is also needed for normal tooth growth and may lead to the late development of milk teeth. In older children, it can lead to tooth decay. In severe cases of rickets, the calcium levels are very low in the blood, needing urgent hospital treatment. In very rare cases, severe low levels of vitamin D can cause weakness of the heart.
In adults, severe deficiency leads to a similar condition as rickets, but it is known as osteomalacia (or soft bones) manifested in profound bone pain and muscle weakness. This muscle weakness is reflected in the person being very stiff, finding it difficult to climb stairs,walking with a waddling gait and having problem getting up from a low chair or the floor. Pain is experienced in the hips, lower back, thighs, pelvis and often a hairline fracture in the bones is not uncommon.
Although all of the above sound very alarming, the condition can be treated fairly easily if diagnosed early to reverse the situation, although it may take a few months for the bones to recover and the pain to subside.
Vitamin D is often nicknamed ’The Sunshine Vitamin’. It is slightly unique in that, unlike other vitamins, it is synthesised by our bodies on exposure to sunlight. In our skin we have a compound known as ergosterol, a family of steroid and is chemically related to cholesterol. On exposure to sunlight, the ultraviolet irradiation converts ergosterol to Vitamin D2, chemically known as ergocalciferol. Quite rightly, we have been bombarded with health advice to avoid too much sun exposure to prevent skin cancer and hence many people are taking heed of this advice. This unfortunately has led to the reduction of vitamin D levels in the body, especially in northern countries where there is little sunlight. In the past few years, in England we have had very wet and overcast summers which may be escalating the problem. A recent survey has shown that more than half the adults did not have enough vitamin D and that in the winter and spring, 1 in 6 people have severe deficiency. And if you are of South Asian or Afro-Caribbean origin, the incidence is even greater - 9 in 10 adults.
Due to these health warnings, as soon as the summer sun makes an appearance, or we fly off to sunny destinations for a holiday, we tend to plaster ourselves with sunblock creams. A lot of the makeup foundation creams and moisturising lotions also contain these sun protection factors (SPF). Although it is sensible to protect ourselves from the Ultraviolet B (UVB) rays, it is quite important to get some of these rays onto our bodies to synthesise enough Vitamin D. The trick is not to overexpose ourselves to sun and especially go red and get sun burnt. Just to put it into some perspective, it is estimated that if you are a fair-skinned person, you only need 20-30 minutes of sunlight on your face, arms and legs (best around the middle of the day) 2 to 3 times a week to make the necessary amount of Vitamin D in the summer in the UK. If you have darker skin or are elderly, you will need longer exposure to sunshine. It has to fall on bare skin and sitting in a sunny room like a conservatory is no good because glass and windows will block the UVB rays. So get out into the garden or go for a nice sunny walk to top up your Vitamin D. It is a problem during the months of October to April because there isn’t enough UVB and so supplements may be required. It is worth having a blood test to check your levels.
People most at risk are:
•pregnant and breast-feeding women
•babies and young children under age of 5
•older people over 65yrs
•if your religion or culture requires you to be covered up and use Hijab or Burkha
•housebound people or those confined indoors due to illness, or other reasons, for long periods
•darker skin people
•night shift workers
It is easy to diagnose whether one is deficient in Vitamin D by a simple blood test to measure the levels. Another way to determine changes in levels of Vitamin D is to test for calcium and phosphate level and in children X-ray of bones like wrist bone can give a good indication of the severity of the problem. It is definitely not a good idea to start taking vitamin D supplements without consulting your doctor first, especially if you are on any other medication or have any other medical conditions. Anyone with high calcium levels must definitely not take vitamin D. You can not over-dose vitamin D from UVB rays but taking too many vitamin supplements over a long period can cause a problem. You will end up with excess of calcium which can be deposited in the kidneys and damage them. In excess, it can also do the reverse and end up removing calcium from the bones and hence weaken them rather than strengthen them.
As with most biological issues the story is not always straight forward. You might think that in countries with high levels of sunshine, vitamin D deficiency would not be a problem. However, many of these countries are developing and children, in particular, have a poor diet due to high levels of malnutrition. Without a balanced diet you will not get the calcium and phosphorus needed to absorb from the gut, regardless of how much vitamin D you get.
It won’t be long before autumn is upon us, so go out there and make the most of the sunshine while you can. I am hoping for a nice Indian Summer! During the months of winter, It may be worth getting your vitamin D levels checked by your doctor.