Hi Jane,
I think I may have miscommunicated when I mentioned that we speak to the doctor before adding zinc to their regimen. What I meant by this is that we discuss the possibility of recommending a renal vitamin that contains zinc with the MD before starting this type of vitamin. We actually do not test for blood levels of zinc at our clinic. Usually a renal vitamin with zinc is given when a patient is having specific nutrition issues such as changes in how food tastes. Taste dysfunction is a common symptom of zinc deficiency. Sometimes we check blood levels of folate and vitamin B12. However, this is typically checked when a lab result called MCV is elevated and a folate or vitamin B12 deficiency is suspected. This is not common.
We do not check vitamin levels to determine which supplement to recommend. There are a couple reasons for not checking vitamin levels. The one about cost and benefit that your dietitian mentioned is one reason. Also, there is no specific science to decide on individual supplement doses based on a patient’s blood levels of vitamins. We recommend renal vitamins even when patients are not deficient in these important nutrients to maintain sufficient vitamin levels for good health. I believe that a patient with signs of vitamin deficiency would benefit from the maximum recommended dose. Otherwise, taking a common renal vitamin such as dialyvite or nephrovite seems sufficient. Renal vitamins are specifically formulated to be adequate for the needs of patients on dialysis. Although the nutrient levels may vary between brands, overall they tend to be very similar. As you know, other factors besides vitamin levels are also important. These factors include tolerability, cost, and size of pill (ability to swallow).
I hope this helps answer your question. Thank so much.
LeeAnn Smith, MPH, RD