Fiber and Vitamin Supplements


  1. Is there any downside to soluble fiber supplements for dialysis patients ? I have checked that the one I am considering(powder form) contains very little potassium and phosphorus.

  2. Is there any downside to multi-vitamin supplements?

Thank you.

The overall answer is … no … there are no major downsides to most of these but, I am already feeling ‘nervous’ +++ by having said that!


Well … there are just so many variants of both … both vitamins and fibre … out there on the market that to make a simple ‘blanket’ statement to you and answer that all are ‘fine’ may mislead some to try inappropriate products. And, believe me, there are some!

This is definitely an area where you should seek local help and local dietary advice. I cannot check (nor will I know) many of the products ‘out there’.

Fibre supplements vary significantly, country to country. Dietary habits and preferences do too. Vitamin and fibre preparations that are available here in Australia will be different to those in the US. Canada and Europe will be different again. Asian, Indian, Chinese and Japanese fibre and vitamin supplements are often very much different again - not only from ‘western’ options but from each other as well. The range is almost endless and, yes, there IS stuff out there that can be harmful.

You have already mentioned two to watch for - potassium and phosphorus. These can ‘sneak into stuff’ in significant quantities if you are not careful. Some of the herbals can have harmful things tucked away inside them (aristocholic acid comes to mind).

So, though broadly most are harmless and may be truly beneficial, please check what you take with your service dietician and with your physician first. Don’t buy off the shelf without due caution. Oh … and by the way … not all prescription medicines are free of risk either!

As for dialysis and vitamin supplements … yes … we routinely use an oral vitamin supplement of B, C, pyridoxine and folic acid (see my answer to the question on ‘tiredness’ at this Q&A site over the last day or two).

Vitamins and minerals (especially those that are water soluble) will be lost during dialysis. Dialysis is a non-selective process. It will remove anything that can (a) pass across the dialyser membrane and (b) which is not protein-bound and which will pass down a concentration gradient.

While dialysis removes ‘nasties’, it removes ‘goodies’ too. It is far too expensive and impractical to construct a dialysis fluid that will prevent a concentration gradient for vitamins and minerals and an obligatory loss is thus built into the process. While a good diet on dialysis will replace most of these more than adequately, it is easy to (1) recognize it will happen and (2) replace where needed. We do that. Routinely. In all patients.

Again, reading the label is important … and here I turn a little naive and say that I suppose we have to trust the label!

So … labels? … read them. As an example, vitamin D can sneak in to stuff and, although that that is not necessarily bad, if vitamin D is concurrently being given in other ways too, excess (or unaccounted for) vitamin D may end up being taken.

At the end of the day – learn to label-read and remember to always check with your team dietician and with your physician. Furthermore, if you are ON dialysis but are NOT on any vitamin replacements – perhaps you should be! If this applies to you, maybe it is something for you to discuss with your team as well.

John Agar