Limited sunlight exposure, constant skin coverage, dark skin pigmentation, ageing, and certain medical conditions or medications can contribute to vitamin D deficiency. Early signs of deficiency may include fatigue, muscle weakness, bone pain, changes in mood, and impaired wound healing.
It’s important to consult with a healthcare professional for proper evaluation and management of vitamin D deficiency, including appropriate supplementation if necessary.
What is Vitamin D?
Vitamin D is a fat-soluble vitamin that is essential for maintaining strong bones, supporting immune function, regulating cell growth and combatting mood disorders. We synthesise vitamin D3 when our skin is exposed to sunlight. Vitamin D3 can also be obtained from dietary sources, mainly fatty fish, eggs and dairy. Vitamin D2 is commonly found in fortified foods and dietary supplements.
Although both forms of vitamin D can be beneficial in addressing vitamin D deficiency, studies have shown that vitamin D3 is more effective at raising and maintaining blood levels of vitamin D than vitamin D2. It has been suggested that vitamin D3 may have a longer half-life and higher potency in promoting calcium absorption and supporting bone health, immune function, and overall well-being.
What Causes Vitamin D Deficiency?
There are various causes of vitamin D deficiency. It is crucial to know and understand the causes to treat the deficiency appropriately.
Limited Sunlight
Limited exposure to sunlight can reduce the synthesis of vitamin D in the skin. This is particularly common for people living in regions farther from the equator, where sunlight is less intense, or during winter months when sunlight exposure is reduced. In these low sunlight conditions, wearing clothing that covers most of the skin can inhibit the synthesis of vitamin D.
Melanin
Melanin, the pigment responsible for skin colour, can reduce the skin’s ability to produce vitamin D in response to sunlight. Individuals with darker skin pigmentation may require longer sun exposure to generate adequate amounts of vitamin D in low sun conditions.
Aging
As we age, the skin’s ability to produce vitamin D decreases. Older adults may also spend less time outdoors, further exacerbating the risk of deficiency.
High Body Fat
Excess body fat can decrease the bioavailability of vitamin D and its utilisation by the body. Vitamin D may become sequestered in fat cells, making it less available for use.
Medical conditions
Certain medical conditions, such as celiac disease, inflammatory bowel disease, or gastrointestinal surgeries, can impair the absorption of dietary vitamin D in the intestines. Conditions affecting the kidneys or liver can disrupt the conversion of vitamin D into its active form or affect its transportation and metabolism in the body.
Medications
Some medications, such as certain anticonvulsants, glucocorticoids, and antiretroviral drugs, can interfere with vitamin D metabolism and increase the risk of deficiency.
Diet
A diet low in foods that are good sources of vitamin D can also contribute to deficiency. Natural dietary sources of vitamin D include fatty fish (such as salmon and mackerel), egg yolks, cheese, and fortified foods like milk, cereal, and orange juice.
Early Signs Of A Vitamin D Deficiency
Early signs of vitamin D deficiency can be subtle and easily overlooked. All of the early signs of a vitamin D deficiency can be attributed to other lifestyle factors or medical conditions as well, and it’s therefore important to consult your doctor for a definitive diagnosis of vitamin D deficiency.
- One of the most common signs is feeling unusually tired, even after getting enough rest.
- Vitamin D deficiency also causes weakness in the muscles, especially in the legs. You may notice difficulty in climbing stairs, getting up from a chair, or performing everyday activities that involve muscle strength.
- Vitamin D is essential for maintaining strong bones. Early on, vitamin D deficiency can also manifest as bone pain or joint discomfort, particularly in the lower back, hips, or legs.
- Low levels of vitamin D have been associated with changes in mood, including feeling down, irritable, or having a general sense of unease. Although mood changes can be caused by various factors, vitamin D deficiency is one potential contributor.
- Vitamin D plays a role in supporting the healing process and slow wound healing or delayed recovery from injuries can be an early sign of vitamin D deficiency.
If you experience any of these early signs or suspect a deficiency, it’s recommended to consult with a healthcare professional for evaluation and appropriate management.
Tests To Diagnose A Vitamin D Deficiency
Several medical tests can help diagnose a vitamin D deficiency. The most common is a blood test known as a 25-hydroxyvitamin D test or simply a vitamin D test. The test results are typically categorised as follows:
- Normal: A level of 30 nanograms per millilitre (ng/mL) or higher is considered normal.
- Insufficient: A level between 20 and 29 ng/mL indicates insufficient vitamin D levels.
- Deficient: A level below 20 ng/mL indicates a deficiency.
Other tests may also be conducted to diagnose vitamin D deficiency:
- A parathyroid hormone (PTH) test measures the level of PTH in the blood, which is involved in regulating calcium and vitamin D metabolism. Elevated PTH levels can indicate a vitamin D deficiency.
- A calcium test measures the level of calcium in the blood. Low calcium levels, along with low vitamin D levels, can suggest a deficiency.
- An alkaline phosphatase (ALP) test measures ALP, which is an enzyme found in the liver and bones. Elevated ALP levels can be a sign of bone disorders associated with vitamin D deficiency.
Your doctor will interpret the test results and provide appropriate guidance on treatment and supplementation of Vitamin D if necessary.
How To Prevent A Vitamin D Deficiency
Many people struggle to get enough of this vital nutrient, leading to a deficiency that can cause various health issues. Fortunately, preventing a vitamin D deficiency is simple with a few lifestyle adjustments.
Get Sunlight
Spend time outdoors to let your skin produce vitamin D. Aim for around 10-30 minutes of sunlight a few times a week, depending on your skin type and location. Be mindful of sun exposure to avoid the risk of skin damage or cancer, and use sunscreen if you stay out longer.
Eat Vitamin D-Rich Foods
Include foods that naturally contain or are fortified with vitamin D, such as:
- Fatty fish (salmon, tuna, mackerel, sardines)
- Rainbow trout
- Beef liver
- Mushrooms
- Egg yolks
- Cod liver oil
- Fortified products like cow’s milk, plant-based milk (soy, almond, oat), breakfast cereals, orange juice, and yoghourt.
Supplement
If you’re not getting enough vitamin D from sunlight or food, supplements can help. Many multivitamins also include vitamin D.
Keeping a healthy body weight
Activities like cycling or walking not only offer good exercise but also allow you to get sunlight, which can help with vitamin D production.
Managing medical conditions
Individuals with conditions that impact nutrient absorption may see an improvement in their vitamin D levels by addressing the root cause of the health issue.
Check with Your Healthcare Provider
If you’re unsure about your vitamin D intake or suspect a deficiency, consult with a healthcare professional who may recommend that you complete a test to help guide you on the right path.
