Vitamin D Deficiency: Symptoms, Causes & Food Sources
Contents
Dubai gets roughly 10 hours of sunshine a day for most of the year, yet the UAE Ministry of Health and Prevention's National Health and Nutrition Survey found vitamin D deficiency in 49.3% of adults aged 18 and older. Some studies of specific population groups in the UAE and wider Gulf region have reported rates as high as 70 to 90%. Living somewhere sunny turns out to matter far less than how much of that sunlight actually reaches your skin.
This guide covers what vitamin D deficiency actually is, the symptoms worth paying attention to, why it's so common even in a climate like Dubai's, and which foods genuinely help close the gap.
What Is Vitamin D Deficiency?
Vitamin D helps your body absorb calcium and phosphorus, both essential for bone strength, and also supports immune function and muscle health. Doctors classify vitamin D status using a blood test that measures 25-hydroxyvitamin D, usually reported in nmol/L or ng/mL. A level below 50 nmol/L (20 ng/mL) is considered deficient, 50 to 75 nmol/L (20 to 30 ng/mL) is considered insufficient, and above 75 nmol/L (30 ng/mL) is generally considered adequate.
Most people with low vitamin D have no obvious symptoms at all, which is part of why the condition is so widespread and so often missed. Doctors typically don't test for it routinely; testing usually happens after someone reports symptoms or has a known risk factor.
Why Vitamin D Deficiency Is So Common, Even in Sunny Places
Vitamin D synthesis depends on ultraviolet B (UVB) rays reaching bare skin directly, and modern life in a hot climate works against that in several ways. Long hours in air-conditioned offices, homes, and malls, combined with sun avoidance during summer months when temperatures regularly exceed 40°C, mean many residents get very little direct outdoor exposure despite living somewhere sunny year-round. Car windows and building glass filter out most UVB rays, so sitting near a sunny window or driving with the windows up doesn't help. Clothing that covers most of the skin also reduces the surface area available for synthesis.
Sunscreen gets blamed too, but the evidence here is more nuanced. Laboratory studies using artificial UV sources show that sunscreen can block vitamin D synthesis, but real-world research tells a different story: most people apply far less sunscreen than a product needs for its rated SPF, and reapply less often than instructed, so enough UVB still gets through. A systematic review of both experimental and observational studies concluded that everyday sunscreen use is not consistently linked to lower vitamin D levels. The bigger factor, especially in places like Dubai, is simply spending very little time outdoors in the first place.
Symptoms of Vitamin D Deficiency
Often No Symptoms at All
Mild to moderate deficiency frequently produces no noticeable symptoms, which is exactly why it's easy to overlook for years. Anyone with risk factors for low vitamin D is generally better off getting tested rather than waiting for symptoms to appear.
Common Signs Worth Noticing
When symptoms do show up, they tend to be vague and easy to attribute to something else:
Persistent fatigue that doesn't improve with rest
Muscle weakness, aches, or cramps
Bone pain, often in the lower back, hips, or legs
Mood changes, including low mood
Frequent colds or infections
Slow wound healing
Severe or Long-Term Deficiency
Left uncorrected for a long time, deficiency reduces how much calcium and phosphorus the body absorbs from food. This can lead to bone demineralization, osteomalacia (softened bones) in adults, and rickets in children, along with a higher risk of fractures and falls.
What Causes Vitamin D Deficiency
Limited sun exposure. Indoor lifestyles, desk jobs, and heavy reliance on air conditioning all reduce direct UVB exposure.
Darker skin pigmentation. Melanin reduces the skin's efficiency at producing vitamin D from sunlight, so people with darker skin generally need more sun exposure to make the same amount.
Age. Skin becomes less efficient at synthesizing vitamin D as people get older, and older adults often spend less time outdoors.
Body weight. Vitamin D is fat-soluble, and higher body fat can sequester more of it away from the bloodstream, lowering measured blood levels.
Malabsorption conditions. Crohn's disease, celiac disease, and prior weight-loss surgery can all reduce how much vitamin D the gut absorbs from food.
Certain medications. Some steroids and anti-seizure medications interfere with vitamin D metabolism.
Limited dietary intake. Few foods naturally contain meaningful amounts, so a diet low in fatty fish, eggs, or fortified products makes a bigger difference than most people expect. Exclusively breastfed infants are also at risk without a supplement, since breast milk is naturally low in vitamin D.
How Much Vitamin D Do You Actually Need?
These figures are general population targets rather than treatment doses. Someone with a confirmed deficiency often needs a much higher dose for a limited period, prescribed and monitored by a doctor, before dropping back to a standard maintenance amount.
Best Food Sources of Vitamin D
Very few whole foods are naturally rich in vitamin D, which is why fortified products and supplements play such a large role in most people's intake.
Fatty fish sits well ahead of everything else on this list, which is one reason dishes built around salmon or mackerel are worth having on repeat rather than as an occasional treat; the grilled salmon on Lifter Life's restaurant menu is one straightforward way to get a serving without cooking it yourself. Eggs contribute a smaller amount per serving but add up quickly if you're eating them regularly, and our egg diet breakdown covers how eggs fit into a broader eating pattern beyond just vitamin D. Fortified foods are worth checking labels for too, since not every brand of milk, plant milk, or orange juice is fortified by default.
Diagnosing and Treating Vitamin D Deficiency
A simple blood test measuring 25-hydroxyvitamin D confirms deficiency. Doctors usually order it when someone reports relevant symptoms or has a known risk factor, such as limited sun exposure, darker skin, obesity, a malabsorption condition, or age over 65, rather than as a routine test for everyone.
Treatment depends on how low the level is. Mild cases often respond to increased sun exposure, dietary changes, and a standard daily supplement. Confirmed deficiency is frequently treated with a higher weekly dose for six to eight weeks, followed by a lower maintenance dose, always under medical guidance since long-term intake above roughly 4,000 IU a day without supervision can raise blood calcium to unsafe levels.
Frequently Asked Questions
Can I get enough vitamin D from Dubai's sunshine alone?
Not reliably, even though the sunlight is there. What matters is direct skin exposure to midday sun for roughly 10 to 15 minutes several times a week, and most people's actual daily routine, spent mostly indoors or in a car, doesn't provide that no matter how sunny it is outside.
Does sunscreen cause vitamin D deficiency?
Real-world evidence suggests it's not a major factor, since most people don't apply sunscreen thickly or often enough to block UVB completely. The bigger issue is spending very little time outdoors in the first place, not the sunscreen itself.
Does sunlight through a window help?
No. Window glass filters out most UVB radiation, so sitting near a sunny window or driving with the windows up doesn't meaningfully contribute to vitamin D production.
Can you take too much vitamin D?
Yes. Vitamin D is fat-soluble and builds up in the body, and long-term intake above the general safe upper limit can lead to high blood calcium, nausea, and kidney problems. High-dose supplementation should only be taken under a doctor's guidance.
The Bottom Line
Vitamin D deficiency is common, often silent, and easy to miss precisely because a sunny climate feels like it should rule it out. A blood test is the only reliable way to know where you stand, and correcting a deficiency usually just means a combination of sensible sun exposure, more vitamin D-rich foods, and a supplement if a doctor recommends one based on your actual results.
