Vitamin D – What is it?

posted in: Nutrition, Supplements | 0

Well, to start with, did you know that vitamin D is not actually a vitamin? By definition, is a steroidal hormone made by our bodies. But don’t let that confuse you. I will go into more information about this, how it works and what it does shortly. What is important, is that you know the facts and make sure you get enough of it to get the benefits. Here’s all you need to know.

So what is it?

Also known as the sunshine vitamin, it is an essential vitamin (or hormone) like all other vitamins. But unlike other vitamins, it is hard to get through food alone. So we must rely on a safe amount of sunshine (when we can) and supplementation. This fat-soluble vitamin is made by the body when cholesterol in the skin gets exposed to the sun’s UV rays. But this doesn’t mean you should be soaking up some rays too often, as this comes with its own set of health problems.

There are two different forms of vitamin D – D2 and D3. There used to be a vitamin D1, but this was later discovered to be a compound mix rather than a pure form. Vitamin D2 (ergocalciferol) comes from plant-based sources and is commonly used in fortified foods as it is less expensive than D3. However, Vitamin D3 (cholecalciferol), which comes from animal products, is proven twice as effective at increasing levels in the blood. So this should be your preferred choice.

vitamin D sun

What does vitamin D do?

We need Vitamin D to help regulate phosphate and calcium in the body. And these nutrients are all important to help keep teeth, bones, and muscles healthy. It also has some involvement in glucose metabolism, and immune function and plays a role in reducing inflammation. Mental health and concentration may also be affected, which some evidence suggests.

Where can it be found?

There are a few ways to get this essential vitamin, however, some ways are more effective than others.

Sunshine: Direct sunlight on the skin is the only way the body is able to make its own vitamin D. It is also the best way to get it. However, in the U.K we only tend to get enough from April through to September. So we need to rely on other sources from October to March. Not only are there limited months of sun exposure, but we have the added bonus of being harmed by too much direct sunlight. It is important to make sure you get a safe amount of direct sunlight only and remember to wear sunscreen!

Supplementation: In most cases, it is best to get your nutrients such as vitamins and minerals through food. In some cases, this is not always possible, which is the situation with vitamin D. For most of us, it is only necessary to supplement during the darker, wintery months. But for those who tend to stay indoors more, have darker skin, tend to be more covered up with clothing, or have a medical condition that may cause vitamin D deficiency, supplementation may be needed all year round.

Food sources: Although food cannot be relied upon to meet all of your vitamin D needs, it can still be beneficial to include these foods in your diet. These include:

  • egg yolks
  • oily fish such as salmon, tuna, swordfish or sardines
  • cod liver oil (*precaution for pregnant women due to high vitamin A content)
  • mushrooms grown in UV light
  • liver
  • fortified foods (such as cereals) or drink (fortified milk or orange juice)

How much vitamin D supplementation do I need?

The national recommended dose in the U.K suggests all adults and children over the age of 4 take 400 IU (10 micrograms – μg) daily throughout winter. You should be able to get enough vitamin D from the sun from April through September. People at higher risk of deficiency may need higher amounts and it is recommended to have your levels checked. Each country has its own recommended amounts, such as the USA which suggests higher doses.

My personal experience – from working at a health tech company where we tested several hundreds of people’s vitamin D levels showed that most people had insufficient or deficient levels of vitamin D during and post-winter months. Taking a maintenance dose of 400IU vitamin D only maintained levels and did not increase them. Those with low levels were recommended higher amounts of 1000 – 3000IU daily for 2-3 months to boost levels. Once levels were in the normal range, they lowered their dose to a maintenance level.

How do I know if my vitamin D levels are low?

The only way to know if your vitamin D levels are normal or low is through a blood test. This will need to be arranged through your doctor and will be free in the UK if done through your NHS GP. There are also providers online that offer blood health tests that can check this for you, but make sure they are reputable services.

What happens if I don’t get enough Vitamin D?

Low levels of vitamin D are common in the UK due to weather, our northern latitude location, lifestyle, and diet. In children, low vitamin D levels over time can lead to soft bones which causes bone malformation, known as rickets. In adulthood and adolescents, low levels can lead to a condition called osteomalacia. It can also affect our teeth and muscles. There may also be a connection between low levels and low mood, but this may be weather-related and the results and evidence are not clear.

What happens if I have too much vitamin D?

Too much vitamin D or vitamin D toxicity is more common in people with particular medical conditions. However, it is not impossible to overdose from supplementation, such as taking extremely high doses for long periods. Symptoms can include:

  • Gastrointestinal issues: loss of appetite, nausea, vomiting, stomach cramps, constipation or diarrhoea
  • High calcium levels may cause dehydration, stomach disturbances, raised blood pressure, kidney stones, muscle weakness, dizziness, and fatigue
  • An altered mental state caused by high calcium
  • Kidney issues such as kidney stones

The Final Word

Vitamin D is an essential nutrient needed for bones, teeth, muscles and more. We mostly get it from the sun, but we may need extra support through supplementation for at least part of the year. At the very least, take a maintenence dose during winter, and if you are concerned, get your levels checked at your doctor.