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Home » Vitamin B12 & Kidney Function: 4 Facts From Research.

Vitamin B12 & Kidney Function: 4 Facts From Research.

Vitamin B12 & Kidney Function: 4 Facts from research.

Our content is not intended nor recommended as a substitute for medical advice by your doctor. Use for informational purposes only.

Summary: Does vitamin B12 affect kidney function?

  • According to research, neither vitamin b12 deficiency nor excess has significant effects on kidney function.
  • Vitamin B12 deficiency may be found in some patients with kidney disease (as a result of the kidney disease).
  • Vitamin B12 is excreted mainly through bile. So, Vitamin B12 excess is unlikely with kidney disease.
  • Some patients may benefit from vitamin B12 supplementation to improve anemia and other conditions related to chronic kidney disease.
  • Vitamin B12 deficiency or excess are not liked to kidney stones.

1. Does vitamin B12 supplementation improve kidney function?

Vitamin D supplementation is not found to improve kidney function directly.  However, people with chronic kidney disease may have a vitamin B12 deficiency and need supplementation.

Although vitamin B12 supplementation doesn’t directly improve your kidney function, It may improve other kidney disease-related problems such as anemia.

Moreover, Vitamin B supplementation may improve the response to other anemia treatments (such as Erythropiotein) in patients with ESRD and resistant anemia (reference).

However, The need for vitamin B12 supplementation may not be for everyone. People with adequate vitamin B12 will not benefit from vitamin B supplementation.


Vitamin B12 is not bad for your kidneys. It causes no significant damage or side effects when taken in patients with chronic kidney disease. And It may improve some related conditions such as anemia.

2. Can vitamin B12 deficiency cause kidney problems?

In healthy people, Vitamin B12 deficiency can cause significant blood and nervous system affection such as:

  • Megaloblastic anemia (anemia with abnormally large-sized red blood cells).
  • Neurological symptoms include nerve damage, dementia, depression, abnormal gait, and behavioral changes.
  • May increase the risk of heart failure, gastric cancer, and autoimmune diseases.
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Some studies found a higher prevalence of vitamin B12 deficiency in patients with chronic kidney disease (reference). However, vitamin B12 deficiency appears to be a result rather than a cause of kidney problems.

No significant link suggests that vitamin B12 deficiency can cause kidney problems (especially in people without kidney diseases).

3. Can too much vitamin D damage your kidneys?

The Food and Nutrition Board (FNB) hasn’t established a maximum dose for vitamin B12. However, even large doses of vitamin B2 are considered to be safe.

Excess doses of vitamin B12 are not stored inside your body as your body eliminates the extra amounts (reference).

So, in general, no need to worry about excess vitamin b12 even if you have kidney disease. This is because 90% of vitamin B12 is eliminated through the liver and biliary system; only 10% of vitamin B12 is eliminated through the kidneys.

  • One study found that high concentrations of vitamin B12 (above the normal limits) are associated with slightly higher mortality rates among people with End-stage renal disease (reference).
  • Another study found that supplementation with high-dose vitamin B12 (1mg) accelerated the deterioration of kidney function in patients with diabetic kidney disease (reference).
    After 2.6 years of follow-up, The glomerular filtration rate (a measure of kidney function) decreased by 16.5 mL/Min in patients taking vitamin B12 compared to a decrease by about 10.7 mL/Min in patients who didn’t receive vitamin B12.
  • Multiple other studies found no association between too much vitamin B12 levels and renal damage. So, The data is still unclear, and the results are marginal.
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Too much vitamin B12 is unlikely to occur even with high doses. The research evidence about the link between too much vitamin B12 and kidney damage is mixed. No clear evidence that excess vitamin B12 leads to significant Kidney damage.

4. Can vitamin B12 cause kidney stones?

No evidence supports that vitamin B12 can cause kidney stones. Vitamin B12 is excreted mainly through the bile, not the urine. Therefore, if you take Vitamin B12 supplements, there is no need to stop it.

In addition, Some Vitamins of the B family (such as Vitamin B6) may help prevent Kidney stones. This study concluded that large doses of vitamin B6 might reduce the risk of kidney stone formation.