Re: Arsenic and cattle

Dear Bob:

"Bob" <bbx107@xxxxxxxxxxxxxxx> wrote in message
news:jbnev1dirk6vajaiq5oakg1me8u324senk@xxxxxxxxxx
On Wed, 15 Feb 2006 06:13:44 -0700, "N:dlzc D:aol T:com
\(dlzc\)" <N:
dlzc1 D:cox T:net@xxxxxxxxxx> wrote:


I had made an unsupported statement about a year
and a half ago that cattle required a small amount
of arsenic in their diets to survive. I was asked for
any sort of literature support and found very little at
the time.

http://www.ead.anl.gov/pub/doc/arsenic.pdf
"Depending on the amount ingested, arsenic can
be beneficial (animal studies suggest that low
levels of arsenic in the diet are essential) or
adverse (high levels can be toxic)."

http://horse.purinamills.com/bulletins/poison/lamenessinducing.html

"The toxic effects of selenium in ruminants
varies, depending on the amount and rate of
its absorption, the individual animal's
susceptibility, the type of selenium present in
the plant, and the interaction of selenium with
other elements, such as sulfur, arsenic, or
copper, in the diet. These minerals, and
possibly others, competitively interfere with
selenium absorption by ruminants. If this
also occurs in horses, adequate amounts of
these minerals in their diet may help reduce
selenium poisoning for them, although
currently this hasn't been demonstrated."


I did a little more looking, and the situation does
not become clearer. The common statements are
that As is not essential for plants, seems to be
essential for some animals, and it is not known
for sure with humans. There is nothing particularly
wrong with this ambiguity. Demonstrating that a
micronutrient is truly essential, at levels
commonly encountered, is not easy -- especially
for humans. The possibility that it might act to
counter something else is a possible confounder,
that can make something non-essential appear
essential under the tested conditions. It helps if
a reason for essentiality is found, and apparently
that bar has not been reached for As. Someone
noted a relationship to methionine metabolism.
Yes, but the essentiality of that is not at all clear.


Here are a few more links, for those who want to look:


American Chemical Society:
http://pubs.acs.org/cen/80th/arsenic.html
The status of arsenic changed in 1987 when
inorganic arsenic present in drinking water was
classified as carcinogenic. Arsenic is known to
be nonessential for plants but an essential
trace element in several animal species, while
its presence in humans is an issue of debate.


EPA (US):
http://www.epa.gov/ttn/atw/hlthef/arsenic.html
Some studies have suggested that inorganic
arsenic is an essential dietary nutrient in goats,
chicks, and rats. However, no comparable data
are available for humans. EPA has concluded
that essentiality, although not rigorously
established, is plausible. (1,6)


Journal article on determining trace element needs. This one
does
accept As as beneficial. Link here is to PubMed. I have
included the
abstract below.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8811801&query_hl=10&itool=pubmed_docsum

J Nutr. 1996 Sep;126(9 Suppl):2377S-2385S. Related
Articles, Links

How should dietary guidance be given for mineral
elements with beneficial actions or suspected of
being essential?

Nielsen FH.

U.S. Department of Agriculture, Agricultural
Research Service, Grand Forks Human Nutrition
Research Center, North Dakota 58202, USA.

The term ultratrace elements, often used to
indicate elements with an established,
estimated or suspected requirement generally
indicated by microgram/, could be applied to at
least 20 elements. The quality of experimental
evidence for nutritional essentiality varies widely
for the ultratrace elements. Thus, although
differing dietary guidance is appropriate for
these elements, most need increased attention
in future editions of the Recommended Dietary
Allowances (RDAs) for the following reasons:
(1) Increased interest in these elements by the
public has been stimulated by the mass media;
thus, responsible information about the
usefulness of the ultratrace elements for health
and well being is needed. (2) Risk assessments
and toxicological standards are influenced by
the RDAs. Authorative advice is required to
prevent standards that obstruct the achievement
of beneficial intakes of ultratrace elements.
(3) An emerging new paradigm is that the
determination of nutritional requirements should
include consideration of the total health effects
of nutrients, not just their roles in preventing
deficiency pathology; some of the ultratrace
elements have identified health benefits. Six
ultratrace elements, iodine, selenium,
manganese, molybdenum, chromium and boron
(and cobalt as vitamin B12), merit specific
RDAs. The term "estimated safe and adequate
daily dietary intakes (ESADDI)" should not be
used for any of the other ultratrace elements
because of the misleading words "adequate"
and "safe". "Apparent beneficial intake (ABI)"
seems more appropriate for the elements with
beneficial, if not essential, actions that can be
extrapolated from animals to humans; these
elements include arsenic, fluoride, lithium,
nickel, silicon and vanadium. The evidence is
too limited or controversial for the remaining
ultratrace elements to even provide an
ambiguous ABI. The amount found in a
healthful diet probably should be a value
provided for an appropriate intake for
aluminum, bromide, cadmium, germanium,
lead, rubidium, and tin.



More recent journal article. Seems to make
no mention of possible benefit of As --
though that may have been outside their purview.

PubMed link:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12730460&query_hl=6&itool=pubmed_docsum

1: J Nutr. 2003 May;133(5 Suppl 1):1536S-8S.
Related Articles, Links

Health effects and risk assessment of arsenic.

Abernathy CO, Thomas DJ, Calderon RL.


Fun. Maybe there will be an answer someday.

Thanks for a very full response. As always. I think all the
bases are covered now.

David A. Smith


.

Relevant Pages

  • Re: Arsenic and cattle
    ... "Depending on the amount ingested, ... copper, in the diet. ... is not easy -- especially for humans. ... the ultratrace elements. ...
    (sci.chem)
  • Re: The critics agree: you dont need to supplement with "essential fatty acids."
    ... Let's get back to the point of this post: do you need to supplement ... acid in my cells replaced with the Mead acid), ... If something is "essential," there must be an amount that is needed ... my diet should not supply enough ...
    (sci.med.nutrition)
  • Re: Cinnamon, again
    ... Is it an amount that a person could consume without going ... The highly processed, calorie-dense, nutrient-depleted diet favored in the ... types of foods and beverages reduce inflammation and cardiovascular risk. ... A poor lore is preconceived notions when ...
    (alt.support.diabetes)
  • Re: Arsenic and cattle
    ... "Depending on the amount ingested, ... "The toxic effects of selenium in ruminants varies, ... arsenic, or copper, in the diet. ... considered toxic is also required at low levels. ...
    (sci.chem)