This blog tracks updates to the Blood Sugar 101 Web site.

Tuesday, April 27, 2010

Vitamin B Supplementation Hastens Kidney Damage Raises Incidence of Stroke

Page Changed: Worthless or Dangerous Supplements

Added the following:

B Vitamin Supplementation Increases Stroke and Kidney Damage

A study published in JAMA in April 2010 asked whether giving supplemental B vitamins to people with diabetes would improve their kidneys because they were known to have low levels of homocysteine. What the study found was very disturbing: people with diabetes who were given a single daily tablet of B vitamins containing folic acid (2.5 mg/d), vitamin B6 (25 mg/d), and vitamin B12 (1 mg/d) ended up with significantly worse kidney function as measured by GFR and also in a higher incidence of stroke. This suggests B Vitamin supplementation is harmful to people with kidney problems.

Effect of B-Vitamin Therapy on Progression of Diabetic Nephropathy. A Randomized Controlled Trial. Andrew A. House et al. JAMA Vol. 303 No. 16, April 28, 2010.


country mouse said...

>gack< and here I was looking at b1 help for kidneys

Anne said...

The article did not say what form of the B vitamins were used in this study. Were they the bioavailable forms? Methylcobalamin, methylfolate and P-5-P or were they the forms the body has to convert to a usable vitamin? There may be a big difference.

Another thing to remember is metformin depletes B12. Some people who have diabetic neuropathy may truly have neuropathy from B12 deficiency.

Jenny said...


The people in this study had documented vitamin deficiencies, too. This is only the last of a long list of studies finding problems with vitamin supplementation. My guess is that this is yet another case of altering only one factor when there is a complex involved, and that the artificial supplementation of only one elements puts something else important out of balance. I have yet to see a single major study that finds health benefits from vitamin pill supplementation.

In the case of B-12 deficiency caused by Metformin (over time--it may take as long as 15 years to develop), injections are needed, not pills.

michael plunkett said...

Rock and a Hard place with the vit supps.
First- If you are diabetic and really haven't reduced your Carb intake in your diet changes are it IS the diabetes and not some B12 deficiency causing ones Neuropathy- don't fool yourself.
Second- Studies I'm sure have shown the importance certain vits in doses greater than one can get in a diet, certainly a diet a LC or IF style diet. And not all vits are made the same. Could it be the 'pill' form and maybe not a powder or liquid version. I have little faith in most studies that find anything other than a pharmaceutical as benefical.