Table of ContentsView AllTable of ContentsKidney SupplementsCalciumN-Acetyl Cysteine (NAC)B VitaminsIronVitamin DFoods for Kidney HealthAvoid or Use with CautionFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Kidney Supplements
Calcium
N-Acetyl Cysteine (NAC)
B Vitamins
Iron
Vitamin D
Foods for Kidney Health
Avoid or Use with Caution
Frequently Asked Questions
If you have a kidney condition, supplements may be recommended depending on your overall health, the foods in your daily diet, and the stage of your disease. Kidney disease changes your nutritional needs, often depleting nutrients. Taking supplements may be crucial for staying healthy.
Supplements commonly used to support kidney health include B complex vitamins, iron, calcium, and vitamins C and D. However, balance is essential. Taking the wrong dose or using supplements you should avoid can aggravate kidney problems, whether you have a kidney infection, kidney stones, or chronic kidney disease (CKD).
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. Whenchoosing a supplement, look for independently tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Black female holding pills in the palm of her hand.Grace Cary / Getty Images
Grace Cary / Getty Images
What Supplements Are Used for Kidneys?
Chronic kidney disease decreases the ability of the kidneys to excretephosphorus. This can result in increased phosphorus levels in the blood.
In CKD, the kidney production of activevitamin Dis also impaired.
Vitamin D is essential for the intestinal absorption of calcium. A vitamin D deficiency also decreases calcium absorption.
The Research
Calcium levels may fluctuate (go up and down) with end-stage CKD.Phosphate binders(medications that prevent phosphorus absorption from food)in calcium supplementsseem to address both high and low calcium levels.
In people withstage 5 CKDondialysis, calcium supplements can also betaken with meals, serving as dietary phosphate binders.
Phosphate binders help reduce the amount of phosphorus available for absorption in the gut. The three calcium-based phosphate binders are as follows:
Dosage
The Kidney Disease Improving Global Outcomes (KDIGO) guidelines do not suggest limits for dietary calcium intake or any maximum level of total intake.
Side Effects
Common side effects of calcium include the following:
Excessive calcium intake can cause the following:
Interactions
Calcium supplementscan interact with some medications, such as the following:
Food:Absorption of calcium carbonate depends on an acidic environment; it should be taken with food.
Acid-reducing drugs: This class, which includesPrilosec (omeprazole), can decrease the absorption of calcium carbonate.
Please consult with your healthcare provider or pharmacist on the appropriate timing of when to take your calcium supplement and medications.
Precautions
Calcium levels that are too low increase the risk of bone fractures; calcium supplementation can correct low calcium levels.
Even thoughcalcium citrateis more easily absorbed than calcium carbonate, it isnot recommended in people with CKDdue to thepotential for citrate toincrease aluminum absorption.
However, withadvanced kidney disease, the kidneys can no longer release calcium via the urine. This increases the risk ofexcessive calcium retention. Caution should be taken with calcium supplementation in this case.
Calcium levels that are too high increase the risk ofheart and blood vessel problems.
Additionally, it is suggested that calcium levels that are too high can increase the risk ofkidney stones.
Many dietary supplement products contain NAC. However, NAC is technically an approved drug for the treatment ofTylenol (acetaminophen)overdose. It is also amucolytic(mucus-thinning) agent in certain respiratory diseases, per the FDA. However, the FDA is considering changing its stance and may allow for NAC in dietary supplements if no safety issues come up.
Chronic kidney disease is associated with an increased risk of the following:
N-acetylcysteine, a compound with antioxidant effects, had the following effects among people over 18 years old with CKD based on an analysis of a group of studies:
Further studies examining the effect of NAC supplementation on various causes of CKD and the various stages of CKD are warranted.
More rigorous studies conducted in various populations are needed to confirm the results.
Common dosages of NAC include the following:
Severe allergic reactions such as the following have been reported after the IV administration of NAC:
In people with asthma, such allergic reactions can be more severe and even fatal.Caution is advised.
Furthermore,chest tightnessandbronchoconstriction(narrowing of the airways) have been reported after using NAC.
NAC interactions include the following:
Precautions for NAC include the following:
B vitamins impact a wide variety of health conditions. Some medical treatments for CKD can disrupt the body’s uptake of certain B vitamins.
For example,dialysisis a type of treatment that helps the body remove excess fluid and waste products from the blood.Dialysiscauses aloss of water-soluble vitamins, including the following:
Folate(the natural form of vitamin B9) deficiency increaseshomocysteine, a type of amino acid associated with heart and blood vessel problems.
One study showed that takingvitamin B12 (cobalamin)withfolatesignificantly lowered homocysteine levels in people withend-stage renal disease (ESRD)orkidney failure.
High phosphate levels are common in people with ESRD.Niacin(vitamin B3)reduced phosphate levels in people undergoing dialysis. Unlike phosphate binders, such as calcium supplements, niacin does not need to be given with a meal.
Supplementation withfolatedid not reduce cardiovascular events (heart attack or stroke) in people withCKD. However, one study showed that three months of folic acid supplementation in people with CKD stages 3a and 3b reduced oxidative stress.
Vitamin B6supplementation in people with normal or high oxalate levels withkidney stonesdecreased oxalate’s excretion into the urine.
B vitamin dosages used in clinical trials include the following:
Side effects
Listed below are some of the side effects of various B vitamins.
Niacin
Symptoms of too much niacin include the following:
More severe side effects, especially with high doses, may include the following:
Vitamin B6
However, the symptoms usually stop when pyridoxine is discontinued. Other symptoms of too much vitamin B6 include the following:
Vitamin B9
The following precautions should be followed with folic acid use:
Vitamin B6 deficiency is common inpeople undergoinghemodialysisand may contribute toanemia.
However,high doses of vitamin B6may:
B vitamins lower homocysteine levels in the blood. However,high doses of B vitaminsinpeople with advanced CKD or ESRDhave been shown to be associated with worsening ofleft ventricular diastolic dysfunction.
When the kidneys are damaged, they produce lesserythropoietin, a hormone that signals the bone marrow to makered blood cells. A lower-than-normal red blood cell count can lead toanemia.
Iron is an essential component ofhemoglobin, a type of protein in red blood cells that carries oxygen from the lungs to the tissues.
Iron deficiency is also linked to anemia in CKD.Risk factors that contribute to iron deficiency in CKD include the following:
A clinical trial evaluating the effect of iron supplementation on 2,141 people with dialysis-dependent CKD showed that the group with the high-dose iron sucrose supplementation had a lower:
However, the study set a maximum safety cutoff for theferritin(a protein that stores iron) levels.
Further studies are needed to clarify the safety of iron supplementation in people with higher starting ferritin levels.
Several guidelines recommend iron supplementation in people with CKD with anemia and iron deficiency.
Moreover, the guidelines recommend intravenous or IV iron supplementation in people with CKD stage 5 on dialysis therapy.
A review of a group of studies indicated that IV iron is also the preferred treatment for people with CKD stages 3 to 5 who are not on dialysis therapy.
Below are some of the dosing regimens for various formulations ofIV ironfor end-stage CKD:
Taking iron supplements with food may reduce stomach upset.
Severe allergic reactions, such asanaphylaxisandrespiratory arrest, have been associated with certain older formulations of IV iron dextran supplements.
Less severehypersensitivity reactionsassociated with IV iron includedizzinessandhypotension (low blood pressure).
The following include iron interactions:
Please consult your pharmacist about taking iron supplements appropriately if you take any of the above medications.
The following precautions are advised with iron use:
Vitamin D deficiency is common in people with CKD due to the following:
Vitamin D supplementationis needed to increase calcium and decreaseparathyroid hormone(PTH) levels in people with CKD.
Both vitamin D3 (cholecalciferol) and D2 (ergocalciferol) have been used in studies looking at people with CKD stages 3 and 4.
Excessive amounts of vitamin Dcan cause increased calcium levels in the blood and urine. Symptoms of too much calcium include the following:
More serious side effects include the following:
Interactions with the following have been reported with vitamin D:
Vitamin D can correct low calcium levels. However, it can also increase phosphorus absorption from the gut. Therefore, it’s best to avoid vitamin D supplementation with CKD until phosphorus levels are within normal range.
In the setting of CKD, checking the levels of calcium, phosphorus, and PTH with vitamin D treatment is generally recommended.
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.
Determining the best foods for managing your kidney condition can be overwhelming at times. Your healthcare provider may refer you to a renal dietitian (a dietitian specializing in conditions of the kidneys) for guidance.
Foods for Kidney Disease
Foods and dietary patternsfor chronic kidney disease include the following:
Foods for Kidney Stones
The following may decrease the risk of kidney stone formation or manage symptoms:
Supplements to Avoid or Use With Caution
The following supplements should be avoided or used with caution in people with kidney conditions.
Creatine
Creatineis used to increase athletic performance and muscle mass. Although most of the studies indicate that creatine supplementation does not cause kidney damage in young adults and people with CKD, some anecdotal evidence suggests otherwise. Therefore, caution should still be taken.
Vitamins A, E, and K
Vitamin A supplements are not recommended in people with CKD who are on dialysis due to the risk of toxicity.Vitamins A,E, andKare fat-soluble and, therefore, are more likely to build up in the body and increase the risk of toxicity.
Phosphorus-Containing Supplements
In CKD, the body can have trouble getting rid of phosphorus, so phosphorus levels in the body tend to increase. Therefore,phosphorus-containing supplementsshould belimitedoravoided in CKD.
Some herbal supplements that have phosphorus include the following:
Potassium-Containing Supplements
Potassium-containing supplementsshould belimitedoravoided in CKD. Some herbal supplements that have potassium include the following:
Herbal Supplements That Act Like Diuretics
Supplements that act like a diuretic or water pill may cause kidney damage. These include, but aren’t limited to, the following:
Other Herbal Supplements
Certain supplements, such as the following, may be risky for people with kidney disease, those who have had a kidney transplant, or those who are on dialysis:
Always speak with your healthcare provider before taking any herbal or nutritional supplements.
Some herbal supplements can be contaminated with the following substances harmful to the kidneys and more:Aristolochic acidHeavy metals (cadmium, mercury, and lead)Chocolate and hot cocoa have also been found to be contaminated with cadmium.
Some herbal supplements can be contaminated with the following substances harmful to the kidneys and more:
Chocolate and hot cocoa have also been found to be contaminated with cadmium.
Summary
Always be sure to consult with your healthcare provider and RD before starting any supplements or making any changes to your diet if you have kidney problems or are on dialysis.
Caution should be taken with the following supplements if you have kidney problems:CreatineVitamins A,E, andKPhosphorus-containing supplementsPotassium-containing supplementsHerbal supplements that act like a diuretic or water pillSome dietary supplements are contaminated with heavy metals that may damage the kidneys.
Caution should be taken with the following supplements if you have kidney problems:
Some dietary supplements are contaminated with heavy metals that may damage the kidneys.
A review of a collection of studies suggested that IV iron is the preferred treatment for people with CKD who are not on dialysis therapy.
Hydroxyproline, one of the amino acids contained incollagen supplements, is broken down into oxalate and increased oxalate levels in the urine. When oxalate, a natural compound found in plants, binds to calcium in the urine, calcium-oxalate stone forms in the kidneys.Kidney stones increase the risk of CKD.Therefore, collagen supplements should be avoided if you have kidney stones or disease.One study suggested that the build-up of collagen in the body sped up the progression of renal fibrosis (scarring of the kidney tissues) and vascular calcification (hardening of the blood vessels).
Hydroxyproline, one of the amino acids contained incollagen supplements, is broken down into oxalate and increased oxalate levels in the urine. When oxalate, a natural compound found in plants, binds to calcium in the urine, calcium-oxalate stone forms in the kidneys.
Kidney stones increase the risk of CKD.
Therefore, collagen supplements should be avoided if you have kidney stones or disease.
One study suggested that the build-up of collagen in the body sped up the progression of renal fibrosis (scarring of the kidney tissues) and vascular calcification (hardening of the blood vessels).
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