It may seem paradoxical that one of the sunniest countries in the world has some of the highest rates of vitamin D deficiency globally. Studies consistently report that 75-90% of UAE residents have suboptimal vitamin D levels. Understanding why this happens and how to address it is important for maintaining bone health and overall well-being.
Why Is Vitamin D Important?
Vitamin D plays essential roles in:
- Bone health: Enables calcium absorption from the gut. Deficiency causes soft bones (osteomalacia in adults, rickets in children)
- Muscle function: Deficiency is associated with muscle weakness and increased fall risk
- Immune function: Vitamin D receptors are present on many immune cells
- Mood: Low levels are associated with depression, though evidence for supplementation improving mood is mixed
Why Is Deficiency So Common in the UAE?
Sun Avoidance
- Extreme heat (regularly exceeding 45°C in summer) drives people indoors
- Most daily activities occur in air-conditioned environments
- Cultural practices: many residents wear clothing that covers most of the skin
Inadequate Sun Exposure
- Vitamin D is produced in the skin when exposed to UVB radiation
- In the UAE, the optimal time for vitamin D synthesis is 10am-3pm, precisely when people avoid the outdoors
- Glass windows filter out UVB rays, so indoor sunlight does not produce vitamin D
- Darker skin tones require longer sun exposure to produce the same amount of vitamin D
Dietary Insufficiency
- Few foods are naturally rich in vitamin D
- Natural sources include oily fish (salmon, mackerel, sardines), egg yolks, and liver
- Food fortification is inconsistent in the UAE
Other Factors
- Obesity (vitamin D is sequestered in fat tissue, reducing bioavailability)
- Increasing age (skin becomes less efficient at producing vitamin D)
- Certain medical conditions (kidney disease, liver disease, malabsorption conditions)
Symptoms of Vitamin D Deficiency
Mild deficiency may cause no symptoms. More significant deficiency can cause:
- Tiredness and fatigue
- Bone pain or aching (often lower back, pelvis, legs)
- Muscle weakness (difficulty climbing stairs, getting up from a chair)
- Muscle cramps
- Frequent infections
- Low mood
- Delayed wound healing
In severe deficiency:
- Children: Rickets (bowed legs, delayed growth, dental problems)
- Adults: Osteomalacia (softening of bones, leading to bone pain and fractures)
Testing
A simple blood test measures 25-hydroxyvitamin D [25(OH)D]:
- Deficient: Below 25 nmol/L (10 ng/mL)
- Insufficient: 25-50 nmol/L (10-20 ng/mL)
- Sufficient: 50-125 nmol/L (20-50 ng/mL)
- Potentially harmful: Above 250 nmol/L (above 100 ng/mL)
Treatment
Supplementation
Treatment depends on the level of deficiency:
For deficiency (below 25 nmol/L):
- Loading dose: 50,000 IU weekly for 6-8 weeks (or equivalent)
- Followed by maintenance dose: 800-2,000 IU daily
For insufficiency (25-50 nmol/L):
- 800-2,000 IU daily
General maintenance:
- Most adults in the UAE should consider 1,000-2,000 IU (25-50 mcg) daily
- Vitamin D3 (cholecalciferol) is preferred over D2 (ergocalciferol)
- Take with a meal containing fat for better absorption
Safe Sun Exposure
- 10-15 minutes of sun exposure to face, arms, and hands during peak hours, several times per week
- Avoid sunburn
- Darker skin tones require longer exposure
- Use sunscreen for prolonged exposure, but brief unprotected exposure is needed for vitamin D synthesis
Dietary Sources
- Oily fish (salmon, mackerel, sardines, herring)
- Egg yolks
- Fortified dairy products and cereals
- Cod liver oil
- Mushrooms exposed to UV light
Special Populations
- Pregnant and breastfeeding women: 400-1,000 IU daily recommended. Breast milk alone does not provide adequate vitamin D for infants
- Infants and children: All breastfed infants should receive 400 IU daily from birth. Formula-fed infants may also need supplementation
- Elderly: Higher risk due to reduced skin synthesis and dietary intake. 800-2,000 IU daily
- Obese individuals: May require higher doses due to sequestration in fat tissue
- Patients with malabsorption: May need higher oral doses or intramuscular injection
Safety
Vitamin D toxicity is rare but can occur with excessive supplementation (typically above 10,000 IU daily for extended periods). Symptoms include nausea, vomiting, weakness, and dangerously high calcium levels. Always follow your doctor's recommended dose and have levels monitored.
At Jabal Sina Medical Centre, our family medicine and general practice teams routinely screen for vitamin D deficiency and provide tailored supplementation guidance for all ages.
This article is for informational purposes only and does not replace professional medical advice. Always consult your doctor for personalised guidance.