Understanding vitamin D deficiency: are you getting enough?

Understanding vitamin D

Vitamin D, lovingly nicknamed the 'sunshine vitamin', is produced in your skin when you have direct contact with sunlight. But what exactly is vitamin D? And are you getting enough of it?

Your body creates vitamin D when sunlight hits your skin when outdoors. It is a fat-soluble nutrient that can also be found in several foods, including oily fish, red meat, egg yolks, and some fat spreads and cereals.

Fat-soluble nutrients can dissolve in fats and oils and are stored in your body's fatty tissue and liver. If you don't like a lot of the food types containing vitamin D, or you struggle to get enough direct exposure to sunlight, you can take vitamin D supplements to experience the many benefits of this vitamin.

In this blog, we take a closer look at vitamin D, how it fuels your body, and the dangers of getting too much.

How does vitamin D help fuel your body? 

Most people get vitamin D from the sun, as most food doesn't contain it naturally.

Vitamin D protects your bones from disease

The main purpose of vitamin D is to help regulate the amount of calcium and phosphate in your body, which is needed to keep your bones, teeth, and muscles as healthy as possible.

According to The National Institute of Health, getting the recommended amount of vitamin D helps protect you from bone disease such as osteoporosis, which causes your bones to become fragile and brittle and far more likely to break. Osteoporosis typically occurs in older people, but it can happen when you're younger if you don't get the right balance of calcium, vitamin D, and physical activity.

Learn more about osteoporosis from two of our leading rheumatologists

There are many benefits to having strong, healthy bones. Having healthy bones reduces your risk of experiencing falls and fractures. It also improves your coordination and balance and keeps you generally fit and healthy. Your bones are always changing - new bone is made of old bone that has been broken down, so it's important to have healthy bone density to prevent your bones from becoming fractured. They also provide structure to your body, anchoring your muscles and protecting your organs.

Vitamin D could improve your heart health

There are many studies exploring how higher vitamin D intake could improve your heart health. Although it is unclear whether vitamin D directly improves your heart health by preventing issues such as strokes and heart attacks, it is known that the nutrient supports the function of your body more generally, powering the body and helping your heart function as a result.

Vitamin D can reduce inflammation in your body

Studies show that healthy levels of vitamin D play an important role in your immune system regulation and could contribute to its ability to fight off inflammatory disease. This includes conditions such as asthma, chronic kidney disease, and inflammatory bowel disease. More research needs to be done to understand this, but an increasing number of studies have established that an insufficient amount of vitamin D can lead to several diseases. Many studies also indicate that vitamin D can regulate your body's adaptive immune response in various inflammatory and autoimmune diseases.

Frequently asked questions about vitamin D’s impact on the body

Does vitamin D help with testosterone?

According to some studies, vitamin D can play a small supporting role in testosterone, mainly when someone is genuinely deficient in vitamin D. 
Research shows that correcting low vitamin D levels can lead to a modest rise in testosterone in some men. However, this change is usually small and not reliable enough to use vitamin D as a ‘testosterone booster’.

Does vitamin D help with hypoglycaemia (low blood sugar) or hyperglycaemia (high blood sugar)?

Vitamin D is believed to help improve the body’s sensitivity to insulin (the hormone responsible for regulating blood sugar levels). This means it can help reduce the risk of insulin resistance, which is often a precursor to type 2 diabetes.

Some researchers also believe vitamin D may help regulate the production of insulin in the pancreas, but further study is needed to confirm this.

Does vitamin D help your skin?

Vitamin D helps skin cells stay strong and able to repair themselves easier, which encourages smoother, less inflamed skin and better protection against everyday damage.

If you are deficient, ensuring vitamin D is back to your normal range can benefit your skin as part of wider positive impact on the body. Ensuring your vitamin D levels are optimal may also ease certain conditions like eczema in some people.

However, taking extra vitamin D supplements when your levels are already normal will not clear acne, eczema, or other skin problems. Very high doses of vitamin D can be harmful, so it should not replace regular skincare, sun protection, or dermatologist‑recommended treatments.

Does vitamin D help with GERD and IBS?

A handful of studies have shown vitamin D may help some people with IBS symptoms, but there is no evidence yet that it directly improves GERD.

The supplement should not replace standard treatment for either condition. More research is needed to explore the connection between vitamin D and these gastrointestinal conditions.

Does vitamin D help improve your mood?

Vitamin D can provide a small improvement in mood, especially in people who are low in vitamin D or who already have depression. However, it is not a stand‑alone cure for low mood or clinical depression.

What is the recommended amount of vitamin D?

According to the NHS, adults, and children from the age of one need 10 micrograms (mcg) of vitamin D per day. This includes pregnant and breastfeeding women, and people at risk of vitamin D deficiency. Babies up to the age of one year need eight and a half to 10 micrograms of vitamin D per day.

You may be more familiar with a gram, which is a standard unit of mass measurement. A common comparison for the weight of one gram is a paper clip, which is already relatively small. A microgram is one millionth of a gram and one thousandth of a milligram (meaning 1000 micrograms is equal to one milligram). It is very small in comparison to other common mass measurements.

Getting vitamin D from the sun versus supplements

During autumn and winter in the UK, you need to get vitamin D from your diet because the sun is not strong enough for your body to make vitamin D through direct exposure. It isn't always easy to get enough vitamin D from food alone, so it is recommended that you take supplements containing 10 micrograms of vitamin D during this period.

From late March to the end of September, most people can make all the vitamin D they need through direct sunlight on their skin and a balanced diet containing plenty of nutrients.

You may choose not to take a vitamin D supplement during these months, which is okay, because you might not even be deficient in the nutrient. You should only consider supplements or changing your diet to a more vitamin D focused diet if you know that you are lacking in vitamin D.

What time of day should you take vitamin D?

Generally, there is no ‘best’ time to take vitamin D. It’s best to take the supplement when you find it most convenient to do.

Vitamin D is fat soluble, meaning it needs fat and oil to dissolve it. This means you absorb vitamin D easier when taking with a full meal, so it may be best to have the supplement when eating.

Vitamin D deficiency symptoms

So, what are the signs you might be vitamin D deficient? And at what point should you take action? Common symptoms to look out for are:

• Fatigue
• Bone pain
• Mood chances
• Muscle weakness and aches
• Muscle twitches and tremors
• Pins and needles in your hands and feet
• A history of broken bones
  
  

Studies have also shown that there is a link between low vitamin D levels and symptoms of depression and anxiety, such as low mood, irritability, and lethargy.

The symptoms listed above could indicate a broad range of conditions, which is why it is important to speak with your doctor before deciding you are vitamin D deficient. Your doctor might arrange for you to have a blood test, which can determine whether you are lacking in certain vitamins, such as vitamin D. You can decide a course of action and whether you need supplements following your results.

Vitamin D overdose: when to know you have taken too much

It is possible to take too much vitamin D, also known as overdosing. This is mostly achieved through supplements, as food doesn't usually have enough vitamin D in it, and you can't get too much from the sun. Very high levels of vitamin D in your blood can be harmful, causing an array of distressing symptoms such as nausea, dehydration, vomiting, muscles weakness, and even confusion and pain.

This is also known as vitamin D toxicity. It is rare to experience this, but it is important to be mindful of the dosage of vitamin D you are taking if you use supplements.

The dose at which vitamin D supplements become toxic isn't known. It would need to be remarkably high and way above the amount most doctors usually prescribe, or the dosage you can buy over the counter at a shop for supplements.

Get a blood test at Circle Health Group today

If you are experiencing symptoms of vitamin D deficiency and would like a blood test to know whether you need to up your intake, book a health assessment with us today.

Clinical sources and further reading

1. The National Institute of Health, fact sheets
2. The NHS, vitamin D
3. Alzheimer's Research UK, alcohol related brain damage
4. The National Institute of Health, vitamin D and inflammatory disease