Vitamin D is an important vitamin, required by the human body for healthy teeth, bones and muscles as well as a healthily functioning immune system.
Unlike all other vitamins, we don’t generally get vitamin D from our food. Instead, it’s known as the sunshine vitamin, and for good reason…
In this Article
Why is Vitamin D Known as the Sunshine Vitamin?
Do We Need Vitamin D?
What’s the Role of Vitamin D and the Immune System?
A Fat Soluble Vitamin Can be Stored by The Body
Who Might Not Get Enough Vitamin D?
How Do We Ensure We’re Getting Enough Vitamin D?
The Importance of Vitamin D
Why is Vitamin D Known as the Sunshine Vitamin?
Although there are some food sources of vitamin D, the majority of the vitamin D in our body is actually manufactured by the body when our skin is exposed to sunlight. So unlike most other nutrients, we don’t need to think too much about getting enough vitamin D from our diet, since food isn’t our main source.
However, that’s not to say we don’t need to consider vitamin D at all - it’s still vital that we get enough. During the summer, we can produce enough vitamin D from exposing our skin to the sunlight - hence its name, the sunshine vitamin. At other times of the year, supplements are considered necessary. But more on those shortly.
Why Do We Need Vitamin D?
Vitamin D is most well known for its role in protecting the teeth and bones, helping to keep them strong and healthy. It does this by regulating the absorption of calcium and phosphorus, two minerals essential for the teeth and bones. It’s also important for the normal functioning of the muscles.
Abnormal bone formation
A lack of vitamin D can lead to rickets in children resulting in reduced or abnormal bone formation and soft, weak bones. In adults, it can cause osteomalacia. Osteomalacia can cause muscle weakness, pain in the bones and weak bones that are more susceptible to fractures.
Thyroid and parathyroid glands
This important vitamin also has a role in the health of the thyroid and parathyroid glands, and in protecting the body against any negative effects from ingesting food additives, insecticide residues and heavy metals.
What’s the Role of Vitamin D and the Immune System?
Vitamin D isn’t just necessary for our teeth, bones and muscles. It’s also vital for the healthy functioning of the immune system as it plays an important role in the growth of the cells that regulate and strengthen our immunity.A deficiency in vitamin D has been linked to poor immune function and an increased risk of developing infections and autoimmune diseases.
Since the beginning of the global Covid-19 pandemic, we’ve all become a little more aware of the importance of a healthy immune system. Never before has vitamin D been considered so important, so much so that the NHS advice on a daily 10mcg vitamin D supplement (see below for more on this topic) during the autumn and winter was extended to all year round advice during the lockdowns when we were all inside a lot more.
Studies have since shown that taking vitamin D supplements “could be beneficial in improving immunity and combatting Covid infections more effectively”.
In the future, it’s expected that vitamin D supplementation will play an important role in the management of future epidemics and pandemics.
A Fat Soluble Vitamin Can be Stored by The Body
Along with vitamins A, E and K, vitamin D is a fat soluble vitamin. This means that they dissolve into the fat globules in our bloodstream. The fat soluble vitamins can be stored by the body in the liver and fatty tissues for when we need them.
(The B vitamins and vitamin C are all water soluble vitamins, meaning that they dissolve in water and are immediately available. They cannot be stored by the body, any excess being excreted in the urine, and they therefore need to be consumed every day.)
Who Might Not Get Enough Vitamin D?
It’s thought that around 1 in 6 UK adults have a vitamin D deficiency. We’re more at risk of developing a deficiency during the autumn and winter months due to the lack of sunlight and daylight hours.
If we don’t spend much time outside, even in the summer months, due to being unwell, frail or housebound or we’re in an institution such as a care home, hospital or prison, we’re at a higher risk of developing a vitamin D deficiency.
Those of us from south Asian, Afro Caribbean or African backgrounds can also have a higher risk. This is because darker skin has more of the skin pigment melanin, which reduces the ability of the skin to manufacture vitamin D.
Covering our skin with clothing for religious, cultural or medical reasons also means that even in the summer, we can have a higher risk of not being able to produce vitamin D at healthy levels.
Also, as we age, our ability to synthesise vitamin D from sunlight becomes impaired. Those of us over 60 years old are also therefore more at risk of a deficiency.
So, what’s the answer?
How Do We Ensure We’re Getting Enough Vitamin D?
All vitamins and minerals are known as the micronutrients (as opposed to the calorie and energy giving macronutrients; carbohydrates, fats and proteins). The majority of both the micronutrients and and the macronutrients come from the food we eat. But as we’ve mentioned, vitamin D is different.
Some foods do contain some level of vitamin D, and they tend to be foods that are high in fat (both good fat and bad fat). Safely exposing our skin to sunlight and taking vitamin D supplements are the best ways to ensure we’re getting enough vitamin D.
Foods That Contain Vitamin D
Oily fish such as salmon and mackerel contain vitamin D, along with their healthy fats in the form of omega 3 fatty acids. Fish with edible bones including sardines and pilchards are also good sources, along with fish liver oils.
However, farmed fish and farmed fish supplements can contain mercury, a heavy metal, that can be detrimental to health. If you choose to eat fish, choose wild fish over farmed fish to reduce your exposure to mercury, and even then only once or twice a week.
Egg yolks, liver and red meat also contain vitamin D, but care must be taken to avoid eating too many of these foods, particularly red meat, due to the levels of saturated fats. Also, as we advocate eating alkaline foods for around 80% of the time, we also advocate minimising animal products such as these.
Mushrooms that have been exposed to UV light are also a good source of vitamin D, but how do you know if they’ve been exposed to UV light? One way is to pop them in a bowl and leave them next to an open window in direct sunlight for half an hour or so.
Some foods are also fortified with vitamin D, and these include some cereals, breads and spreads. In the UK, most dairy products are not routinely fortified with vitamin D, as they are in some countries including the US.
It is, however, not recommended to rely on your diet for your vitamin D intake, especially if you’re a vegetarian or vegan and you don’t consume animal products.
Sun Exposure
During the spring and summer, when there are more hours of daylight, we can get enough vitamin D from a 20 minute walk each day. Vitamin D is manufactured by the body when UV light from the sun hits the skin.
This process is impaired by covering our skin with clothing and sunscreen. Taking care not to burn in the sun is important, so if you’re going out for a “vitamin D walk” make sure it’s not when the sun is at its strongest, which is generally between the hours of 11am and 3pm.
Vitamin D Supplements
Unless you’re in one of the at risk groups mentioned above, 20 minutes of sun exposure per day during the months of April to September should be enough. In the autumn and winter, or if you’re in an at risk group, it’s recommended in the UK that adults take a 10mcg supplement of vitamin D each day.
If you’re a vegetarian or vegan, check that your vitamin D supplement is suitable for someone who wishes to avoid animal products. Some vitamin D supplements are produced using lanolin, the waxy substance found in the wool of sheep and lambs.
The Importance of Vitamin D
Vitamin D is crucial for our skeletal health, and for protecting our immunity. So when it’s sunny and warm, take a walk with your arms and legs exposed. During the colder months, take a daily supplement. That way, you know you’re covered.
References
https://www.nhs.uk/conditions/rickets-and-osteomalacia/symptoms/ https://pubmed.ncbi.nlm.nih.gov/23857223/ https://pubmed.ncbi.nlm.nih.gov/21527855/ https://pubmed.ncbi.nlm.nih.gov/21527855/ https://www.nutrition.org.uk/news/2021/british-nutrition-foundation-survey-reveals-49-adults-unaware-of-uk-government-guidelines-for-vitamin-d/ https://www.sciencedaily.com/releases/2020/12/201215091635.htm https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
This article is not meant to treat or diagnose. Please visit your doctor for advice about any health concerns you may have.