Vitamin D: What is it and what does it do?

09/02/23

Sunshine, happiness, strong bones. This broadly sums up where we get Vitamin D from, and what it does for the body. It’s not a very comprehensive overview, I’ll grant you,as there are many more health benefits attributed to Vitamin D than just strong bones. This is why we’ll be taking a longer look at ‘The Sunshine Vitamin’, what it does for the body, and what it might look like if you’re not getting enough.

As someone who has had a deficiency, I want to highlight its effects so that you can identify when you might not be getting enough. Obviously, I am not a medical professional, or I might have known more about Vitamin D in the first place, but I will share what I’ve learned. With sources, of course.

In this guide, we will cover everything you need to know about Vitamin D in your day to day life, and the benefits of making sure you’re all topped up. Let’s begin!

What is Vitamin D?

Okay, I’m going to wow you with a gamechanger right off the bat… Ready? Vitamin D isn’t a vitamin, it’s a hormone.

Technically, it’s a prohormone, which means that it is converted to a hormone inside the body. A precursor to a hormone, if you will. The difference is that vitamins cannot be produced by the body, but we can produce Vitamin D. Sometimes known as ‘The Sunshine Vitamin’, it’s mainly produced by our skin in response to sunlight, more specifically UVB rays. It’s then processed by our kidneys into the active hormone, which is called calcitriol.

Calcitriol is an active form of Vitamin D3 required by the body to regulate calcium levels in our blood and build strong, healthy, bones. It does this by increasing the body’s ability to absorb calcium from foods in the stomach and gut. That’s not all, though!

What does Vitamin D do for the body?

There are multiple health benefits that come from Vitamin D, so ensuring that you’re getting an adequate supply is really important in staying healthy.

Vitamin D fights disease: That’s right! Research has shown that those with lower levels of the Sunshine Vitamin in their blood are at a greater risk of heart disease, diabetes and certain types of cancer, including breast and prostate. It’s also been shown that it could play a role in preventing Multiple Sclerosis (MS). Finally, Vitamin D has been shown to reduce the risk of flu, so getting plenty of this vital vitamin all year around is super important!
Vitamin D combats depression: As well as your physical health, it plays a role in healthy brain function, and has been shown to reduce levels of anxiety and depression. It can also help to prevent the development of mood disorders and dementia.
Vitamin D helps manage diabetes: Research has shown that higher levels of Vitamin D can aid in the prevention of both Type 1 and Type 2 diabetes and regulate insulin levels, thereby supporting diabetes management. It also decreases your risk of hypertension and glucose intolerance.
Vitamin D is vital for healthy bones: It regulates the amounts of calcium in the body, and enhances our ability to absorb it. This is vital in keeping bones, muscles and teeth healthy and strong.
Vitamin D supports body function: Immune system, nervous system, lunch function, cardiovascular health - you name a function, and Vitamin D is likely there somewhere, in the background, helping to regulate those systems and keep everything functioning as it should.

How is Vitamin D created or ingested?

Vitamin D can be ingested through food, but is mainly produced in the body via exposure to sunlight. The sun’s ultraviolet B (UVB) rays interact with a protein in our skin which creates Vitamin D3, the active form of Vitamin D. This is then processed into an active hormone by our kidneys, giving the intestines a greater ability to stimulate and absorb calcium from our food, and reclaim calcium that would otherwise be excreted.

Between April and September (in the Northern Hemisphere) most of us will get all the Vitamin D we need from sunlight. Between 10 and 30 minutes of sunlight on our legs and arms is a good amount of time for a decent dose of The Sunshine Vitamin.

However, there are certain factors which can change this - the amount of melanin in our skin can reduce the skin’s ability to absorb Vitamin D from sunlight, so people with darker complexions would need to spend longer in the great outdoors for the same amount.

Speaking of the great outdoors, you need to actually be in it. You can’t just stand near a window, as glass prevents the UVB rays from reaching your skin.

There are other factors which determine our ability to create Vitamin D. As we age, our kidneys cannot convert as much of it as they once did, meaning that older people are at a greater risk of Vitamin D deficiency.

Certain chronic illnesses also have an impact on our ability to ingest Vitamin D. Conditions such as Crohn’s Disease, Cystic Fibrosis and Coeliac Disease might make it more difficult to absorb Vitamin D from food.

Weight is also a factor. As Vitamin D is a fat-soluble vitamin, those of us with a higher percentage of body fat are at a greater risk of a deficiency. This is because the Vitamin D we create or ingest is stored in fat, rather than being processed by the kidneys.

Which foods provide Vitamin D?

There are not very many plant-based foods which are naturally high in Vitamin D. Most often, they will be fortified to contain it.

The exception here are mushrooms, which contain significant amounts of Vitamin D2 due to exposure to UVB. Some mushrooms will contain even higher levels if grown in certain conditions that provide extra UVB. The Vitamin D2 in mushrooms does not have the same level of bioavailability as the Vitamin D3 found in animal products, but does indeed raise overall levels in the blood.

Other foods that are often fortified with Vitamin D are:

Cereals
Spreads
Fortified plant milks

Is Vitamin D the same for vegans and non-vegans?

There are two commonly occurring types of Vitamin D. The first, Vitamin D2 is always suitable for vegans as it derives from plant-based sources.

Vitamin D3, on the other hand, is usually found in animal products. Non-vegan fortified products which contain Vitamin D3 usually contain lanolin, a greasy substance found in sheep’s wool.

There are vegan forms of Vitamin D3, so you don’t need sheep grease in your cereal. Vivo Life’s Vegan Liquid Vitamin D3 is derived from algae, which has one of the highest bioavailabilities of any vegan D3. This means that it is able to have more of an active effect in the body than other sources. It also includes Vitamin K2 which enhances the health benefits of D3, aids in calcium absorption, reduces calcium build up in the arteries and improves blood flow. Double win!

Can you have a Vitamin D deficiency, and what does it look like?

Yes, you can have a Vitamin D deficiency and they often look different depending on who has it. Generalised symptoms of a deficiency include fatigue, bone and back pain, low mood (and I mean really low), hair loss, and muscle pain or weakness. As Vitamin D has an impact on our immune system, people with a deficiency will often notice that it takes longer for cuts and scrapes to heal.

In children, a lack of the Sunshine Vitamin can lead to bone deformities such as rickets, high blood pressure, stiffness in the arterial walls, severe asthma, and an increased risk of allergies. A lack of Vitamin D can be problematic from birth, so making sure your levels are high is vital for a healthy pregnancy. In pregnancy itself, having a low level of Vitamin D may increase the risk of pre-eclampsia, premature birth and gestational diabetes.

In adults, a lack of Vitamin D can cause a condition called osteomalacia, which presents itself as bone pain and tenderness. In the longer term, low levels are associated with cognitive impairment in adults and an increased risk of death from heart disease.

In the longer term, a deficiency can present as osteoporosis, and cause stress fractures in the legs and pelvis. Long term deficiencies have also been linked to cardiovascular and autoimmune conditions, neurological diseases, infections and certain cancers.

How much Vitamin D do you need per day?

Vitamin D is commonly expressed in two units; micrograms and International Units (IU). In this case, 1 microgram is equal to 40IU.

Children under a year old require between 8.5 and 10 micrograms of Vitamin D every day, with everyone else needing 10 micrograms (400 IU) daily. This is the same during pregnancy and breastfeeding, and for people who are at risk of a deficiency.

The NHS recommends that adults and children take a 400 IU Vitamin D supplement in the autumn and winter months (September - March / April) due to a lack of sunlight, and being cosied up inside a lot more! However, people who are housebound or wear clothes that cover most of their skin all year, are recommended to take a daily supplement throughout the year, as they are at a greater risk of deficiency.

Vivo Life’s Vegan Liquid Vitamin D3 contains 2,000 IU of Vitamin D per dose, along with 25 micrograms of Vitamin K2, enhancing the beneficial effects to ensure that you are at a lower risk of becoming deficient.

Can you have too much Vitamin D?

There is an upper limit for taking Vitamin D, and taking too much can cause complications in the body. Taking more than 4,000 IU daily can cause a condition called hypercalcaemia. Too much calcium is absorbed and builds up in the body, damaging the kidneys, heart and weakening bone. Whilst this is a rare condition, it is always good to understand that over supplementing can have adverse effects on your health. Other adverse effects of too much Vitamin D include: loss of appetite, dry mouth, vomiting, and diarrhoea.

It is also worth noting that you cannot overdose on Vitamin D from sunlight. However, I will strongly recommend that we all continue to protect our skin against environmental damage and the risk of skin cancer.

It is always better to ensure that you are eating and supplementing in such a way that it gives you a broad spread of vitamins etc. Rather than just focusing on one as a cure-all - they all work together in order to keep up healthy, so it’s important that you’re getting everything you need. Our Vegan Multivitamin & Mineral Supplement is packed full of a range of vitamins, including Vitamin D3, Vitamin A, Vitamin B2, B12, Calcium, Iron and more, and is a great way of supporting a plant-based diet with all the essential nutrients your body needs.