It is difficult to determine how much vitamin D an individual needs
According to Dr. Vieth - May 2011 (see charts below) the body starts dumping calcium via the urine long before serum levels of calcium become elevated.
Hypothesis: The body starts exponentially dumping calcium via the urine would at the top of the personal optimal serum vitamin D range.
Thus we can interpret the urine dump of calcium as a precursor to the optimal D range.
Urinary calcium response to high dose vitamin D3 with calcium supplementation in patients with multiple sclerosis.
Clin Biochem. 2011 Jul;44(10-11):930-2. Epub 2011 May 5.
Kimball SM, Burton JM, O'Connor PG, Vieth R.
University of Toronto, Department of Nutritional Sciences and Mount Sinai Hospital, Department of Pathology & Laboratory Medicine, Toronto, ON, Canada M5G 1X5. samantha.kimball at utoronto.ca
OBJECTIVE:To characterize the effect of vitamin D(3) intake on urinary calcium:creatinine ratios across predefined ranges of serum 25(OH)D.
DESIGN:Patients with multiple sclerosis (n=25) received escalating doses of vitamin D(3) (4000-40,000IU/d) with calcium (1200mg/d).
RESULTS: Urinary calcium:creatinine was driven by increased 25(OH)D when concentrations were <75nmol/L (r=0.424, p=0.009) and >200nmol/L (r=0.281, p=0.01), but no relationship existed when 25(OH)D concentrations were 76-200nmol/L.
CONCLUSIONS: A "safe", physiological range of 25(OH)D concentrations is 75-200nmol/L.
Copyright © 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. PMID: 21570386
Sulkowitch Urine (Calcium) Test – see attached PDF – very low cost ($1.30 per test) and can do at home
10 tests for $10 + shipping most anywhere in the world
Test is very simple - but will have to guess conversion between units on the graph and turbidity