Vitamin D3 is a truly remarkable vitamin. Scientists are finding out that it is involved in more and more key biological functions that are crucial for the healthy functioning of our bodies and for our well-being. Though the regulation of calcium absorption is the most widely known role of vitamin D3, it is by no means the most important one. There is a unique feature of vitamin D3 that allows it to be incredibly versatile: it is a hormone. According to the Vitamin D Council, vitamin D3 deficiency has been associated in the pathology of at least 17 varieties of cancer, heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.
The Discovery of Vitamin D3 and Rickets
The discovery of vitamin D3 came about as a result of the research on the disease rickets. This research was conducted by the British physician and pharmacologist Edward Mellanby in the early 1900s. Rickets is a childhood disease characterized by a softening of bones leading to bowed legs, knock knees and other deformities, and today we know it is caused by a vitamin D3 deficiency.
Mellanby had a group of dogs which he kept indoors without any exposure to sunlight and fed them a diet that consisted of four types of meals, all having oats as the main ingredient. When the dogs came down with rickets, he concluded that the restrictive diet was causing the disease. Mellanby then began giving the dogs cod-liver oil in addition to their oats diet; the dogs were cured. He then concluded that it was a component in cod-liver oil (vitamin D3), which the meals did not have, that was essential to curing the disease.
Forms of Vitamin D: Vitamin D2 is a Vitamin and Vitamin D3 is a Hormone
In order to understand vitamin D well, you need to know that it is present in two different forms: vitamin D2 and vitamin D3. Vitamin D2 is synthesized by plants, yeast, and fungi. This means that when ultraviolet light from the sun hits the leaves of plants, for example, it will convert a substance called ergosterol into vitamin D2 (ergocalciferol). This "ergocalciferol vitamin D2" product can accomplish everything it is supposed to in the life of the plant; it does not have to be converted into any other substances in order to be active.
Vitamin D2 can be found in juices, milk, and cereals that have been fortified with it. Though vitamin D2 can help to fulfill our bodies’ requirements for vitamin D, it is 30 to 50% less effective than vitamin D3 in maintaining our blood levels of this vitamin. Furthermore, when we take in vitamin D2, it will be broken down into several substances; some of these substances can be toxic to the body.
On the other hand, vitamin D3 is the form of the vitamin that is made inside the human body and it is also the most effective in maintaining our health and preventing many diseases. When ultraviolet light from the sun hits our skin, it uses cholesterol to start the process that will synthesize a form of vitamin D3 that our bodies can use, namely, calcitriol.
Vitamin D3 is a Hormone
Hormones are very powerful substances. Once they are made, they travel in the bloodstream to target cells that affect processes such as growth and development, metabolism, sexual function, reproduction, mood, and as I mentioned above in the case of vitamin D3, many diseases. Hormones are only needed in small quantities but they exert a huge effect in your body. Active vitamin D3 falls into the steroid hormone category. Steroid hormones are made from cholesterol, are very potent, and their job is to turn your genes on and off.
Once vitamin D3 enters the bloodstream, it will go through several biochemical reactions to reach the point when it becomes the most powerful steroid hormone inside your body; this hormone is called calcitriol. Calcitriol is the active form of vitamin D3 and it is absolutely remarkable in its action to protect the body from many diseases. Calcitriol is truly an amazing hormone; it can bind to more than 2,700 sites on the human genome. According to John Cannell M.D. from the Vitamin D Council, these binding sites are near genes that are involved in just about every known major disease of humans.
When you have sufficient vitamin D3 inside your body, calcitriol will:
- strengthen your bones and teeth and help prevent muscle weakness
- help reduce the risk of asthma exacerbation in asthmatic people
- reduce depression and emotional disorders
- prevent chronic fatigue
- protect you from at least 17 types of cancer
- prevent the development and progression of various autoimmune diseases
- significantly strengthen your immune system
- support your brain’s cognitive functions
- decrease the risk of pre-eclampsia and insulin resistance during pregnancy
- help prevent type-2 diabetes and insulin resistance
- prevent high blood pressure, heart attack, congestive heart failure, and stroke
- lower the risk of excessive inflammation and some bacterial infections
Learn More about Vitamin D3
Most people still don’t know what a versatile and important “vitamin” vitamin D3 is. Its most popular function still is that of the regulation of calcium and phosphorus metabolism. Vitamin D3 is activated into a very powerful steroid hormone that has the capability of turning on and off genes associated with most of the major diseases. There are many resources out there that can help you understand what a marvelous tool vitamin D3 is to keep yourself in tip top shape in both body and mind. You can start by checking out my article: "The Path of Vitamin D3 Inside Your Body," and the Vitamin D Council website, where you can find tons of great information and more resources about vitamin D3.
Sources:
Lange, E. Lange et al., “Vitamin D, the immune system and asthma.” Expert Review of Clinical Immunology. 5(6) (Nov 2009): 693-702
MedicineNet.com: “The Wonder Vitamin: Vitamin D”
Silva, J. Martins, “Breve Historia Do Raquitismo e da Descoberta da Vitamina D.” Acta Reum Port. 32(2007): 205-229
The World’s Healthiest Foods: “Vitamin D”
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