Vitamin D, the ”Sunshine Vitamin” Throughout time before known up to 2023, vitamin D is popularly called as sunshine vitamin as it can be produced by our skin when exposed to sun. But does this mean time attendance is very important? Specifically, can vitamin D be acquired from the sun after 4 PM? Well, this blog tries to investigate and penetrate the science, seasonal effects, geography, and expert opinions about this very hot question.
What Is Vitamin D and Why Is It Important?
Vitamin D is a fat-soluble vitamin that serves several important roles in the body:
• Strengthening bones by enabling calcium absorption
• Supporting immune system function
• Reducing inflammation
• Supporting muscle function and brain health
People who do not have sufficient amounts of vitamin D may suffer from fatigue, bone pain, compromised immunity, and even depression.
How the Body Makes Vitamin D from Sunlight
When ultraviolet-sunlight rays hit the skin, they induce a reaction to convert one derivative of cholesterol (7-dehydrocholesterol) to vitamin D3 (cholecalciferol) through the dermis, and the next step involves both the liver and kidneys, which will act and make activate the form of vitamin D.
But the snag is that without these rays of UVB, the reaction will not go through, and their availability is heavily dependent upon time of the day, place, and season.
Can You Actually Get Some Vitamin D After 4 PM?
Very Short Answer: In Most Cases, No.
NIH that belongs to the USA claims and assured dermatological journals about that the strongest UVB rays appear from 10 AM to 3 PM. Then later at 4 PM, due to especially in the places that are far away from the equator, the angle will become so low that UVB rays will be filtered by the atmosphere.
Scientific Evidence:
According to a study reported in the Journal of Investigative Dermatology (2008), the production of vitamin D decreased significantly after 4 PM due to greatly reduced intensity and angles of UVB radiation.
Factors Affecting Vitamin D Synthesis
While it’s technically possible to acquire some vitamin D as there is a few light getting in after 4 PM-conditions will affect how much of that light makes it into your body:
- Location (Latitude)
India and countries near the equator tend to have UVB rays coming into the atmosphere directly enough so that some synthesis could even occur till 4:30–5 PM.
Here, UVB rays are very weak even at peak hours during winter. - Season
Summer-the higher up the sun is, the longer your vitamin D window.
At some places in winter, even noon sun might not suffice for proper vitamin D synthesis. - Skin Type
More melanin in a darker skin tone reduces the ability of skin to produce vitamin D quickly.
Lighter skin synthesizes vitamin D faster but also burns more easily. - Air Pollution and Cloud Cover
UVB rays are blocked by smog, haze, and thick clouds, further leading to reduced chances of vitamin D synthesis even during daylight. - Clothing and Sunscreen
Your body isn’t making enough vitamin D, regardless of time, if you’ve covered up or applied sunscreen with SPF 30+.
What Doctors and Health Organizations Have to Say
- Taking the sun is most effective between 10 a.m. and 3 p.m. Midday rays are most efficacious for vitamin D accession. Harvard Health
- WHO: Sun exposure of 5-30 minutes between 10 AM to 3 PM, at least twice a week, among face, hands, and arms.
- ICMR recommends sunshine near midday for optimal vitamin D production, especially for Indian skin types.
What Happend After 4 PM?
Thus after 4 PM:
- Sunlight is shifting more into the UVA spectrum.
- Because of tilt from earth and angle of sun, UVB rays become weaker.
- Your body is practically not capable of making vitamin D just from exposure to sunlight.
- In conclusion, yes, sun is there. But no, it does not make vitamin D efficiently.
What Can You Do when You Cannot Get Morning Sun?
If for some reason your routine doesn’t permit the absorption of sunlight during peak hours, here are some clever alternatives:
- Take Vitamin D-Rich Foods:
• Fish oily (salmon, tuna, mackerel)
• Fortified milk, orange juice, cereals
• Yolk of an egg
• Mushrooms (especially those exposed to UV) - Use Vitamin D Supplements
• Human preference is always to take Vitamin D3 (cholecalciferol) compared to D2
• Before taking vitamin D, one must consult a physician especially for individuals having poor levels - UVB Lamp or Sunlamp
• Used with the supervision of a medic especially in very cold countries - Shift Outdoor Activities Earlier
• Aim for 20 minutes outside between 10 AM to 2 PM when possible
Recent Studies on Vitamin D Timing
- Study (2023-Dermato-Endocrinology Journal):
Confirmed that the cutaneous synthesis of vitamin D is highest at solar noon and falls sharply in late afternoon. Most people would not generate enough vitamin D after 4 PM even with an hour of exposure. - Lancet Review (2022):
showed that more than half of the urban Indian population is vitamin D deficient, despite the sunlight being abundant, which is primarily due to an indoor lifestyle and wrong timings of exposure.
Pros and Cons of Sun Exposure After 4 PM
- Lower chances of sunburn Very low UVB = almost little vitamin D
- Temperature is comfortable Not effective for skin synthesis
- Safer for sensitive skin types Doesn’t help much with D levels
Conclusion:
Can you get vitamin D from the sun after 4 PM? Not effectively. The scientific data strongly supports that your body assimilates the greatest amount of vitamin D from sunlight between the hours of 10 AM and 3 PM. After 4 PM, the levels in most locations are too low in UVB for any meaningful production of vitamin D to begin.
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