Product Information

Most of us have heard of Vitamin D. We also probably know that Vitamin D is important for the health of our bones and that we need to be exposed to sunlight for our bodies to be able to generate it. But, in reality, that’s probably just about all that many of us know about it. And this lack of knowledge is hardly surprising. For many years, Vitamin D has languished in the shadows of its more well-known vitamin cousins and not that much notice has been taken of it. But things are changing. It is now becoming increasingly apparent that we should not under-estimate the importance of Vitamin D and that to do so is to put our own health at very real risk - not just in terms of bone health but for our overall health and well being.

And, as our understanding of just how crucial Vitamin D is begins to mature, it is also becoming increasingly clear that many of us simply aren’t getting enough Vitamin D. This should be of major concern to all of us. Given that scientists have now been able to show that Vitamin D deficiency plays a role in almost every major disease, including heart disease, high blood pressure, Parkinson’s Disease, Alzheimer’s Disease and some types of cancer, if we don’t address this situation and seek to increase our Vitamin D levels, the consequences could be very grave indeed.

So how do we increase our Vitamin D levels? Well, in order to do this, we either need increased UV exposure from sunlight (but, of course, there may be significant problems with this approach in terms of increased skin cancer risks) or via diet and supplementation. And this is where Vitamin D3 supplement comes into its own - a high strength Vitamin D3 supplement can help to significantly boost your Vitamin D levels.

But before we look at the benefits of Vitamin D (and, in particular, Vitamin D3) supplementation, it is useful to understand a little bit more about Vitamin D itself.

First and foremost Vitamin D is not actually a vitamin at all - rather it is a fat-soluble prohormone (a precursor to a hormone). Vitamins are not produced by the body. Instead we get the vitamins that we need from external sources. Hormones, on the other hand, like Vitamin D are actually made in your body.

As a prohormone, Vitamin D is biologically inert and possesses no hormonal activity at all. To become active, it must be transformed via a tightly regulated synthesis mechanism. This is a two stage process requiring Vitamin D to undergo two hydroxylations within the body. The first occurs in the liver and converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol. Through this conversion process, Vitamin D in the form of calcitriol becomes the most potent steroid hormone in the body. And yet, despite how important calcitriol is to the maintenance of a healthy body, Vitamin D is its only source.

There are two major forms of Vitamin D - Vitamin D2 (or ergocalciferol) and Vitamin D3 (or cholecalciferol). Collectively they are known as calciferol. The distinction between these two forms of Vitamin D is crucial when it comes to Vitamin D supplementation.

It is most important that you only take Vitamin D3 because Vitamin D2 is simply not as biologically active, effective or as safe as Vitamin D3.

As we have mentioned above, Vitamin D is produced within the body (endogenously). Its production requires a certain amount of UV light exposure. Even the Vitamin D that you acquire via your diet will ultimately have been derived from organisms that were only able to create their own Vitamin D through the presence of sunlight at some stage. This is perhaps best explained via an example. It’s well documented that fatty fish such as mackerel and salmon are good dietary sources of Vitamin D and yet these fish only contain Vitamin D because they have eaten ocean algae that have synthesized Vitamin D in shallow waters from the action of solar UV.

Our skin synthesises Vitamin D in response to exposure to UV sunlight. This system works so efficiently that around 20,000 IU’s (international units) of Vitamin D are produced in only around 20 minutes of summer sun exposure provided, of course, that the skin is uncovered and sunscreen free. This is far in excess of current recommended daily amounts (which stands at 200 IU for those up to the age of 50 - we discuss this in more detail below).

In order to generate Vitamin D the UV index must be greater than 3. In areas such as the tropics this level of UV index occurs daily throughout the year. In temperate regions, a UV index of 3 is usually recorded daily throughout spring and summer daily. This means that if, for example, you live in Boston, Massachusetts, sunlight exposure during the winter months (November to February) is insufficient to produce significant vitamin D synthesis in the skin. Apart from geographic location and season, time of day, cloud cover, skin colour, and smog all affect the skin’s ability to absorb UV sunlight. Sunscreen, even a low factor one, also prevents virtually all UV rays from reaching the skin. And sitting by a window or driving along in your car on a sunny day won’t help because your skin will not be able to absorb sufficient UV rays from sunlight that has passed through glass.

Very few foods in nature contain Vitamin D which accounts for why only around 10% of our Vitamin D comes directly from our diets. Fish liver oils such as cod liver oil and fatty fish like mackerel, salmon, tuna, herring and sardines are amongst the best sources. Small amounts of Vitamin D are found in beef liver, cheese, and egg yolks. Foods fortified with Vitamin D such as milk, breakfast cereals and some brands of yogurt and orange juice, are the main source of dietary Vitamin D for most. But to get adequate amounts of Vitamin D from your diet, you would have to drink at least 20 cups of fortified milk or eat at least 5 servings of salmon a day. It is, therefore, nearly impossible to get adequate amounts of Vitamin D from our food.

So if we can’t get enough Vitamin D through sunlight, and we are hardly going to be able to make up the deficit through our diets, we have to use Vitamin D supplementation.

As we have already mentioned, Vitamin D, in its active form calcitriol, is essential for healthy bones. Not only does Vitamin D promote calcium absorption in the intestines and reabsorption of calcium in the kidneys, it also acts to maintain adequate serum calcium and phosphate concentrations. By doing this Vitamin D enables normal bone mineralization to take place and is, therefore, critical for both bone growth and bone remodelling. Remodelling is the name given to the continual process of building up new bone and breaking down old bone. It is carried out by specialist cells known as osteoblasts (that are responsible for the production of new bone) and osteoclasts (that act to break down - or reabsorb - old bone).

Osteoclasts are directly affected by the thyroid hormone calcitonin which prevents bone resorption. Vitamin D inhibits calcitonin release from the thyroid gland.

But it isn’t just our bones that require Vitamin D. Calcitriol plays an important role in the maintenance of several organ systems and, like all steroid hormones, it is involved in the production of literally hundreds of different enzymes and proteins that are vital if we are to maintain our health and prevent disease. Indeed, calcitriol is capable of interacting and affecting in excess of 2,000 genes in our bodies. Apart from helping to build bone, Vitamin D also: