Is it safe to take supplements if you have chronic kidney disease (CKD)? On the Mayo Clinic Radio podcast, Dr. Rozalina McCoy, an endocrinologist and family physician, explained why it’s important to use supplements cautiously, particularly herbal supplements, and always with a physician’s guidance for those with CKD.

Supplements 101

Vitamins, minerals, herbs, and protein powders are used by many Americans and are all considered supplements. McCoy reports that nearly one-third of those with CKD take at least one supplement every day. Most of these people also do so without informing their doctor. 

According to McCoy, the stage of CKD a person has plays an important role in determining a supplement’s level of safety. Those with moderate to severe CKD (stages 3-5) should be more cautious and discuss any supplement use with their physician before starting to take anything. 

How do supplements damage the kidneys? 

McCoy explains supplements may injure the kidneys in two different ways. 

1. Some supplements (and medicines) are nephrotoxic, which means they cause direct damage to the kidneys. This may be immediate and lead to short-term acute kidney injury (AKI), where hospitalization may be warranted to treat the injury. Other times, nephrotoxic supplements gradually worsen CKD. 
2. Some supplements have components that are not able to filter out of the kidney properly. Some components are natural, while others are added during processing. Certain components do not filter out of the body when a person has CKD. These components eventually accumulate and lead to worsening kidney function.
   

Why do physicians typically not recommend supplements?

Even for physicians, McCoy says supplements are difficult to recommend for three key reasons: 

1. Supplements affect each person differently.
2. Research on using supplements with CKD is lacking. 
3. Nutrition labels are not required on supplements currently. Therefore, it is difficult to know what the ingredients are and how much of each ingredient is in the supplement. 

What supplements should be avoided with CKD? 

The National Kidney Foundation (NKF) provides a list of herbal supplements to limit or avoid if you have CKD. Many of these supplements contain potassium or phosphorus, which are difficult for the kidneys to filter. 

Particularly for people with kidney disease, the following herbal supplements should be avoided:

• Astragalus
• Barberry
• Cat’s Claw
• Apium Graveolens
• Creatine
• Goldenrod
• Horsetail
• Huperzinea
• Java Tea Leaf
• Licorice Root
• Nettle, Stinging Nettle
• Oregon Grape Root
• Parsley Root
• Pennyroyal
• Ruta Graveolens
• Uva Ursi
• Yohimbe

For the full list of high-risk supplements, please visit their Herbal Supplements and Kidney Disease page.

Are there any supplements recommended for people with CKD? 

According to McCoy, taking a daily multivitamin is suitable for most people. Depending on the stage of CKD, a renal multivitamin may be recommended. A renal multivitamin will contain less of certain vitamins and minerals that do not get filtered out of the kidneys well. A physician can discuss the most appropriate multivitamin for each person, whether it is a standard multivitamin, renal multivitamin, or no multivitamin at all. 

*Mayo Clinic. (2019, September 22). Supplement concerns for kidney disease patients: Mayo Clinic Radio [Video file]. Retrieved from https://www.youtube.com/watch?v=iiMs-bC7I0k.