Vitamin D – how much is too much?

There has been much talk recently, particularly during the current global pandemic, of the wonders of this incredible, far reaching vitamin, so much so that it is beginning to sound like the miracle cure/preventative that we are all looking for, and sales of vitamin D supplements have been flying off the shelves.

Vitamin D deficiency can cause many symptoms in the body – both physically and emotionally. It is linked to osteoporosis, convulsion, heart failure, high blood pressure, arthritis, depression, muscular weakness, sleep difficulties and auto immune conditions. Thus its role in the body is vital – but in the right amounts.

However, we must remember that Vitamin D increases our absorption of calcium, and this can result in calcification in the body – be it in the form of kidney and gallbladder stones, or calcification of the arteries which can lead to heart disease, arteriosclerosis and narrowing of the blood vessels. Therefore it’s essential that we don’t take vitamin D supplements excessively, and in fact only supplement if we are actually deficient. Vitamin D is one of the fat soluble vitamins (the others being A, K and E). This means that it will be stored in the body, rather than excreted if we have excess amounts, leading to toxicity. This isn’t the risk with water soluble vitamins like vitamin C where our body will excrete it if we have too much.

Sunlight doesn’t “contain” vitamin D. The sunlight converts 7 dehydrocholesterol in the skin to vitamin D3. The liver will then convert the D3 to 25-hydroxyvitamin D3 calcdiol (storage form) and then the kidneys go on to convert it to 1,25 dihydroxivitamin D3 Calcitriol.. So it is clear that having a healthy liver and kidneys is essential in synthesising vitamin D in our body.

Moreover, vitamin D doesn’t work in isolation. It needs two other ‘partners in crime’ – namely vitamin A and vitamin K2. The vitamin A will help with the absorption of vitamin D and will protect against toxicity. The vitamin K2 will guide the vitamin D in the body to the places where it is required. So if you are taking a synthetic vitamin D supplement, make sure it also contains vitamin A and K2.

Finding vitamin D in food form and conversion from sunlight will always be safer forms than synthetic supplements since the opportunity for toxicity is far reduced. Fatty fish, cod liver oil, shiitake or button mushrooms, butter and eggs are some of the foods which contain vitamin D, and again this will be safer than taking foods such as cereals and breads which are “fortified” with vitamin D which again will be the synthetic form. This is because in clever mother nature, the vitamin D already comes with its partners in crime – vitamins A and K2!

Sunlight will always be the safest way to get out vitamin D, and the body has a very clever way of letting us know that it has sufficient levels of vitamin D – our skin will start to burn in the sun.

If you are taking statins, you will be at increased risk of vitamin D deficiency, since this vitamin is made from cholesterol and statins block cholesterol production (they block an enzyme called HMG-CoA reductase which lowers the production of 7-dehydrocholesterol from which vitamin D3 is derived).

If you are taking a vitamin D supplement then it’s always best to have your levels tested first to see if you are indeed deficient and require supplementation. Blood tests should be measuring your levels of the active form – 1,25 hydroxyvitamin D, as well as the storage form – 25 hydroxyvitamin D.

It’s also important to note that if you are taking vitamin D supplementation and your levels are not increasing, then it may be due to poor assimilation, or poor liver or kidney function.

So there is certainly more to vitamin D supplementation that meets the eye, and taking supplements should be under the guidance of a trained nutritional therapist. Please feel free to be in touch if you would like to learn more.