Vitamin D is essential for maintaining bone health, supporting immune function, regulating mood, and enhancing muscle strength. Despite Singapore's abundant sunshine, many residents still face vitamin D deficiency due to indoor lifestyles, limited sun exposure, and specific dietary habits. Understanding these challenges highlights the importance of ensuring adequate vitamin D levels for the overall well-being in Singapore's population.

What is Vitamin D?

Vitamin D, also referred to as calciferol, is a fat-soluble vitamin. It is naturally present in a few foods, added to others, and is available as a dietary supplement. It is also produced endogenously when ultraviolet B (UVB) rays from sunlight strike the skin and trigger vitamin D synthesis. 

Vitamin D consists of 2 bioequivalent forms:

• Vitamin D2 (ergocalciferol), which mainly comes from plant sources, fortified foods (e.g. milk, margarine and breakfast cereals) and oral supplements 
• Vitamin D3 (cholecalciferol), which is found in animal-sourced foods (e.g. fatty fish, fish oil, liver, egg yolk, butter), oral supplements and derived from the Sun 

Functions of Vitamin D 

1. Promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal bone mineralisation and to prevent involuntary contraction of muscles, leading to cramps and spasm
2. Bone growth and remodelling by osteoblasts and osteoclasts to prevent osteoporosis and brittle bones 
3. Modulation of such processes as cell growth, neuromuscular and immune function, and glucose metabolism 
4. Reduction of inflammation through enhancement of pathogen-fighting effects of monocytes and macrophages to fight off infections and reduce risk of chronic diseases 

Benefits of Vitamin D

Vitamin D is essential for several body functions, and its benefits span across bone health, immune system support, and various other health aspects. 

Role in bone health 

Adequate vitamin D levels ensure proper calcium absorption, which is crucial for giving your bones their strength and hardness. Without sufficient vitamin D, there is an increased risk of osteoporosis, where bones become brittle and fragile, and an increased risk of fractures. A severe shortage of vitamin D can cause rickets and osteomalacia, leading to bone pain and muscle weakness.

Contribution to immune system function 

Vitamin D strengthens the immune system and plays a role in regulating both the innate and adaptive immune responses in the body. It modulates the immune system by enhancing the pathogen-fighting capabilities of monocytes and macrophages, types of white blood cells crucial for the body’s defence against infections. Additionally, it reduces chronic inflammation, which is associated with numerous autoimmune diseases and infections.

Other health benefits 

• Cardiovascular Health: Vitamin D plays a role in heart health by helping to reduce the risk of high blood pressure, arterial stiffness, and lowering the risk of cardiovascular diseases
• Mood and Mental Health: Vitamin D may influence mood and reduce the risk of depression by supporting serotonin production
• Diabetes Management: Vitamin D may improve insulin sensitivity and support insulin production, which is essential for blood sugar regulation. This is particularly beneficial for individuals with or at risk of type 2 diabetes

• Cancer Prevention: Vitamin D may reduce the risk of certain cancers, including colon, prostate, and breast cancers, by regulating cell growth, differentiation, and apoptosis (programmed cell death)

Causes of Vitamin D Deficiency

Vitamin D deficiency is a condition that occurs when the level of Vitamin D in the body is insufficient to maintain optimal health. This deficiency can be caused by: 

Limited Sun Exposure

Despite Singapore’s tropical climate with abundant sunlight, Vitamin D deficiency is prevalent. Due to high sun protection awareness, Singaporeans use sunscreen, stay indoors or in the shade, and wear long-sleeved clothing to reduce skin cancer and avoid being under the sun. However, these practices also block Vitamin D production, with studies showing that sunscreen with SPF 30 can reduce Vitamin D synthesis by about 95%.

Furthermore, urban living limits sun exposure as many of us work indoors during daylight hours and spend significant time in air-conditioned environments. After work, our modern lifestyles often involve indoor activities like watching TV, using computers, and visiting malls, further reducing opportunities for natural sun exposure.

Dietary factors 

Dietary intake is a primary source of vitamin D, making it imperative to include vitamin D-rich foods in your diet to prevent deficiency. Foods such as eggs, liver, and oily fish are natural sources of vitamin D, while fortified food products such as milk, soya milk, yoghurt, orange juice, breakfast cereals, and margarine also contribute. However, traditional Singaporean diets, which centre around rice, noodles, and vegetables, typically lack natural sources of vitamin D. Moreover, many people may not be aware of the adequate amounts needed to achieve optimal Vitamin D levels.

Symptoms of Vitamin D Deficiency

• Widespread bone pain or tenderness
• Frequent infections 
• Fatigue and Tiredness
• Depression 
• Muscle Pain and Weakness 

Chronic illnesses that affect Vitamin D absorption

1. Kidney Disease: Since the kidneys convert Vitamin D to its active form, chronic kidney disease can impair this conversion, leading to deficiency.
2. Liver Disease: The liver also plays a crucial role in the metabolism and synthesis of Vitamin D. Liver diseases can hinder this process, causing low levels of Vitamin D.
3. Celiac Disease: This autoimmune disorder damages the small intestine, reducing the absorption of nutrients, including Vitamin D.
4. Cystic Fibrosis: This genetic disorder affects the pancreas and other organs, leading to poor fat absorption, which is essential for Vitamin D absorption.

Medications That Can Lead to Vitamin D Deficiency

Certain medications can interfere with Vitamin D metabolism, leading to deficiency:

1. Glucocorticoids: Used to treat inflammatory conditions, these medications can impair Vitamin D metabolism and reduce calcium absorption.
2. Anticonvulsants: Medications for epilepsy, such as phenytoin and phenobarbital, can accelerate the breakdown of Vitamin D, reducing its levels.
3. Weight Loss Drugs: Orlistat, used for weight loss, can reduce the absorption of fat-soluble vitamins, including Vitamin D.
4. Cholesterol-Lowering Drugs: Cholestyramine and other bile acid sequestrants can also reduce the absorption of Vitamin D.
5. Antifungal Drugs: Ketoconazole can interfere with Vitamin D metabolism in the liver.

Diagnosing Vitamin D Deficiency

The primary method for diagnosing Vitamin D deficiency is through blood tests that measure the levels of 25-hydroxyvitamin D (25(OH)D), which is the main circulating form of vitamin D in the blood including vitamin D2 and D3. To maintain optimal health, various health organisations have provided guidelines for adequate vitamin D levels. 

Category		Serum 25-hydroxyvitamin D concentration
Sufficient		> 30 ng/mL (75 nmol/L)
Insufficient		20-29 ng/mL (50-74 nmol/L)
Deficient	Mild	10-19 ng/mL (25-50 nmol/L)
	Moderate	5-9 ng/mL (12-24 nmol/L)
	Severe	< 5 ng/mL (<12 nmol/L)

While blood tests are essential for diagnosing Vitamin D deficiency, certain symptoms may indicate the need for testing and medical evaluation:

• Persistent bone pain and muscle weakness
• Frequent infections
• Chronic fatigue
• Mood changes or swings
• Hair loss 
• Slow wound healing 
• Symptoms of osteomalacia: In adults, this includes diffuse bone pain, muscle weakness, and difficulty walking. Inmchildren, look for signs of rickets, such as delayed growth and skeletal deformities.

Treating and Preventing Vitamin D Deficiency

The table below shows the daily recommended dietary allowance of vitamin D, according to the Health Promotion Board Singapore:

Age group	Daily recommended Dietary Allowance of Vitamin D
18 years and above	2.5 mcg (100 IU)
Children, 7 to 18 years
Girls, 5 to < 7 years	10.5 mcg (420 IU)
Boys, 5 to <7 years	10 mcg (400 IU)
Children, 3 months to < 7 years
Pregnant and lactating women

As Singapore is a tropical country with strong sunlight exposure all year round, the daily recommended dietary allowance of vitamin D in Singapore is lower as compared to international guidelines. 

Dietary changes 

Incorporating Vitamin D-rich foods into your daily meals is essential. Fatty fish such as salmon, mackerel, and sardines, along with egg yolks, provide natural sources of Vitamin D. Additionally, many foods are fortified with Vitamin D, such as milk, cereals, and orange juice.

Below are some examples of these foods with Vitamin D values: 

Food source	Vitamin D
Cooked salmon, 3oz (90g)	14.2 mcg (570 IU)
Scrambled eggs, 1 large	1.1 mcg (44 IU)
Fortified milk, 1 cup (250ml)	2.9 mcg (120 IU)
Fortified cereal, 1 cup	2 mcg (80 IU)

Source: National Institutes of Health USA 

Sun exposure 

Sun exposure is another critical factor in maintaining Vitamin D levels as UVB radiation penetrates uncovered skin and converts cutaneous 7-dehydrocholesterol to previtamin D3, then vitamin D3. Safe sun exposure practices involve letting the sun shine on your arms and legs twice a week without sunscreen—approximately 5 to 30 minutes, between 10am and 3pm. For those with darker skin, a longer exposure might be needed to make the same amount of vitamin D as those with paler skin as the melanin pigment in dark skin provides natural protection against the absorption of UVB rays.

Vitamin D supplements 

In cases where you are unable to obtain sufficient vitamin D from food and sun exposure, supplements can be a valuable solution.

Ocean Health D-Vita Vitamin D3 Oral Spray 8ml

As Singapore’s 1st Vitamin D oral spray, Ocean Health D-Vita Vitamin D3 Oral Spray is designed for better absorption and it delivers 500 IU Vitamin D3 (Cholecalciferol) in one spray. 

Benefits: 

• Supports normal body function by binding to target cells found in our intestine, kidney, pancreas and immune system, beyond just bone and muscle
• 2X more superior absorption as compared to soft gel
• Reduces patient’s daily pill burden
• 0% taste rejection

Dosing: 

For adults, spray 2 times directly into the mouth or as prescribed by your doctor.

Cholecalciferol (Vitamin D3) 1000 IU Tablets 100’s 

These vitamin D3 tablets aid in the regulation of calcium and phosphorus in our body, which aids in the maintenance of bone structure. It also plays a vital role in supporting a healthy immune system. Suitable for people who want to maintain a healthy level of circulating Vitamin D levels.

Benefits: 

• Contains 1000 IU Cholecalciferol in 1 tablet
• Supports immune system and bone health

Dosing: 

For adults, take 1 tablet daily.

Heliocare ULTRA-D Oral Capsules 30’s 

Heliocare Ultra-D Capsules contain a high concentration of Fernblock, with 5 mcg (200 IU) of Vitamin D, making it ideal for individuals concerned about their Vitamin D levels. It is effective from the first dose, providing immediate and safe protection. 

Fernblock® has excellent antioxidant properties to reduce free radicals by up to 50%, preventing formation of hyperpigmentation caused by UV rays. It also slows down skin ageing by up to 55% through the inhibition of collagen depletion caused by UVA. Other than protecting your skin from harmful UV rays, Fernblock repairs existing damage in the cellular level, preventing cell mutation and premature skin ageing. 

Benefits: 

• Additional free radical protection from within PLUS vitamin D (5 mcg)
• Boosts skin health
• Contains green tea extract and beta-carotene as antioxidants, effectively reducing free radicals by up to 50%
• Gluten-free
• Suitable for daily consumption for intense sun protection and post-dermatological procedural care
  

Dosing: 

For adults, take 1 capsule daily before sun exposure. Do not exceed the recommended daily dose.

Combat Vitamin D Deficiency Today!

Are you getting enough vitamin D? Maintaining adequate vitamin D levels is crucial for overall health and well-being, especially in a sun-rich country like Singapore where paradoxically, vitamin D deficiency is highly prevalent. By understanding the importance of vitamin D and taking proactive but simple steps – such as incorporating vitamin D-rich foods into your diet, getting safe sun exposure, and considering supplements – you can ensure your body functions optimally. 

If you suspect a deficiency, seek professional advice and remember that our team of friendly pharmacists at Glovida-Rx is here to provide you with personalised advice and guide you through selecting the most suitable vitamin D supplement. Visit our website, www.glovida-rx.com.sg, for more information, and feel free to contact us at +65 8101 5555 if you have any queries.