Vitamin D
Patients with renal disease are prone to vitamin D deficiency through inadequate intake and limited sunlight, which is exacerbated by the diseased kidney’s inability to effectively convert calcidiol to calcitriol. Vitamin D deficiency is linked to poor bone health, fatigue, muscle pain, impaired wound healing, and depression. Low vitamin D status has also been linked to poor outcomes in cancer, multiple sclerosis, cardiovascular disease, type 2 diabetes, and weight loss.
A meta-analysis of over 6000 patients with CKD found that high levels of 25-hydroxy vitamin D (25[OH]D) are associated with significantly improved survival rates regardless of CKD or ESRD status.
Kidney Disease: Improving Global Outcomes guidelines recommend supplementing with ergocalciferol or cholecalciferol to correct (OH)D deficiency. This ensures adequate supply for conversion to calcitriol, but it cannot affect bone and mineral metabolism without further intervention in the form of calcitriol supplementation. By supplementing with ergocalciferol or cholecalciferol to meet the recommended daily allowance of 15 µg (600 IU) for adults under 70 years and 20 µg (800 IU) for adults over 70 years, the primary care team can ensure that the body has all the building blocks required for the nephrology team to then address mineral and bone disorder in CKD without the fear of promoting hypercalcemia.
Safe Purchasing Practices
Patients should be reminded to purchase dietary supplements from reputable dealers, especially when purchasing online. Retailers like Amazon are increasing the barriers required to sell supplements to improve the quality of products sold on the site. But other online retailers may sell products from outside of the United States that fall outside of the Food and Drug Administration’s jurisdiction.
Patients should also be reminded that “more is not always better” and counseled on appropriate dosages for individual needs.
In Summary
Patients will probably continue to lean on dietary supplements, regardless of our approval. Transparency and education are important when working with patients with CKD, especially in regard to dietary supplements.
When recommended appropriately, however, the supplements discussed can lead to better outcomes with improvements in kidney health by addressing inflammation, serum lipids, glycemic control, and cardiovascular health.
Ms. Winfree Root is a renal dietitian in private practice in Mary Esther, Florida. She disclosed no relevant conflicts of interest.
A version of this article first appeared on Medscape.com.