RE: [pronut-hiv] Intake level for vitamin B6 for people living withHIV/AIDS (4)

["Kraak, Vivica" <VKraak@nas.edu>]

Dear George,

The website I sent is based on the 1998 IOM report, Dietary Reference
Intakes (DRIs) for B vitamins, published by the National Academy Press
of the National Academy of Sciences.
You can order the 564-page book at:
http://books.nap.edu/catalog/6015.html 

IOM reports are expert committee consensus reports. An 11-member
appointed committee with diverse expertise in nutrition worked for more
than 2 years to review the scientific data before recommending
Recommended Dietary Intake (RDA) levels for individuals, Estimated
Average Requirement (EAR) levels for populations, and Tolerable Upper
Intake (UL) levels for individuals and populations where published data
were available. This has been done for other vitamins and minerals as
well in a series of DRI reports.

Your point is well taken that research supports that most PLWHAs can
benefit from a supplemental daily MVI at reasonable doses, in addition
to a nutrient-dense and diverse diet adequate in calories, protein and
micronutrients to sustain increased nutritional demands during active
infection and symptomatic HIV disease.

But you need to be cautious about making generalized statements about
high-level doses of micronutrients where the data are very clear about
adverse effects - even for water-soluble vitamins like B6.  I don't
believe that either you or Dr. Kaiser could come up with any literature
review beyond what an 11-member expert committee has concluded that
chronically high doses of vitamin B6 (e.g., 240 mg/d) may actually cause
neuropathy.

Vivica 

----- George M. Carter wrote:

   Hi Vivica and all--
   First,  let me reiterate that a good, potent multi is what I
recommend
   and  I  hope we can look at that issue as well--and Subha, I'd love
to
   hear your thoughts on it.
   Re  B6:  are  there scientific data to support the 100 mg upper
limit?
   The  table  you  provide  below merely lists the suggested upper
limit
   without  any  supporting  data.  It  also  notes  only  that
"Sensory
   neuropathy  has  occurred  from  high  intakes  of supplemental
forms"
   without stating what those higher doses are.
   In  an  email  from Dr. Kaiser, he noted that yes, there are 260 mg
of
   B6,  which  he  feels  is  a critical part of it. And indeed, I
recall
   having  seen safe upper limit levels of at least 600 mg before
there's
   any  risk  of  neuropathy; Jon mentioned 1,000 mg. And I believe
there
   ARE data that support that contention.
   I will try to review the literature later.
   George M. Carter
  

---Vivica Kraak wrote:

     George,
     Rachel has made an excellent and defensible point.
     The  tolerable upper intake level (UL) for Vitamin B6 for adults is
     100
     mg/d according to the Food and Nutrition Board of the Institute of
     Medicine. Please see:
     [1]http://www.iom.edu/Object.File/Master/7/296/0.pdf
     The  most  observable  adverse effect from a chronic high intake of
     vitamin
     B6 - ironically - is sensory neuropathy. Even if an HIV+ person was
     taking INH, the therapeutic dose of B6 prescribed is 10-25 mg
     pyridoxine/d.
     There are so many forms of HIV-associated neuropathy that you can't
     conclude it is always nutritionally related.

References

   1. http://www.iom.edu/Object.File/Master/7/296/0.pdf