My vitamin D levels are always in the deficient or insufficient range ever since I came to Delhi. I hardly get to sit out in the sun. If the daily recommended vitamin D limit is 600 IU, how much daily dose should I take round the year and still get to sit out in the sun without causing toxicity.

Sodium, calcium, phosphorous levels are always borderline in kidney function tests. Plus edema in lower legs. I drink about 2 litres of water everyday (never more). Should I increase/decrease the same (nephrotic syndrome?)? Or is it just the low Vitamin D that's causing these bad values in kidney function test?

You will have to bring your questions in person to a nephrologist.

I will ill say, having a niece with nephrotic syndrome, you will have to have high protein in your urine and significant facial edema.

How old are you?

Nephrotic syndrome is usually diagnosed in early childhood. My niece was 3 years old when she was diagnosed. Another friend had a granddaughter diagnosed at 18 months of age.