Why Sitting so much in Sunlight does not Benefit Dark Skin Indians?

It is said that people who receive good amount of sunlight or sit in sunlight does not suffer from vitamin D deficiency. But why this theory become opposite in case of dark skin Indians? Why dark skin Indians even after receiving good amount of sunlight yet suffer from vitamin D deficiency? Why this theory does not stand true in case of dark skin Indians?

Why vitamin D synthesis does not occur in skin of dark skin Indians even after receiving so much sunlight? Why they still suffer from vitamin D deficiency? Why sitting so much in sunlight does not benefit dark skin Indians? Why the story of vitamin D deficiency continues even after receiving so much of sunlight?

There are inhibiting factors for it, which are acting in background and are causing difficulty in synthesis of vitamin D from sunlight in skin. These inhibiting factors are not letting synthesis of vitamin D from sunlight in skin. They are blocking the channel.

But, what are these inhibiting factors? What are the inhibiting factors, which are acting as barrier and not letting vitamin D synthesis in skin from sunlight? The inhibiting factors, causing vitamin D synthesis inhibition in presence of sunlight are-

1) Number one factor responsible for such occurrence is melanin, yes, pigment melanin found in skin which acts as barrier and does not let vitamin D synthesis to occur in skin. And, this pigment melanin is found in excess in dark skin Indians which is not letting synthesis of vitamin D happen in skin from sunlight, on the opposite inhibiting it.

2) Usage of sun-blockers too much by dark skinned Indians to prevent skin darkening blocks the sunlight vitamin D synthesis channel of skin and does not let vitamin D synthesis to occur.

-Yes, these are the two factors which is preventing, inhibiting skin's vitamin D synthesis from sunlight.

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