What are the nutritional benefits and/or hazards of eating the shells
of roasted (salted and unsalted) peanut shells?

Obviously, information about the nuts is easy to find, so I'm only
interested in information about the roasted shells.

Aside from potential allergic reactions, which I understand could
develop at any age, the only health issue I've found has to do with
aflatoxin, from a mold that can grow on the shell.  I need to know
whether that is eliminated in the roasting process, and if there are
other risks, and the nutritional content of the shells, if any.

Reason: I much prefer to snack on peanuts in the shell, rather than
shelled peanuts, but like sunflower seeds they are inconvenient,
especially while driving or working.  Besides, they taste better with
the shells on.  But maybe they're unhealthy that way...

Hello stuckfly!

What an interesting way to get a little fiber into your diet!

That seems to be about all peanut shells are good for, though, and you
may end up getting more than you bargained for by eating the shells.

Searching for information about peanut shells and their nutritional
value almost exclusively turns up references to the shells being "low
value, agricultural by-products", "agricultural waste" and filler
material for pet foods that should be avoided.  I found no definitive
discussions of the merits of peanut shells and human consumption, and
neither the American Peanut Council ( http://www.peanutsusa.com ) nor
The Peanut Institute (http://www.peanut-institute.org ) discuss peanut
shells *at all*:

"Disposal of agricultural byproducts such as peanut shells has become
a serious problem in the U.S. due to the enactment of more stringent
federal and state regulation. Water contamination by heavy metals is
another serious ongoing problem in this country. Conversion of these
low-value peanut shells into adsorbent that can remove toxic metals
from wastewater would increase their market value and ultimately
benefit peanut producers."

Asdorption of selected toxic metals by modified peanut shells
http://ift.confex.com/ift/2000/techprogram/paper_3841.htm

"Agricultural waste products exceed 600 billion lbs each year in the
United States, have little monetary value and create a disposal
problem. However, some agricultural waste products, such as peanut
shells, have been reported as having a natural ability to remove
metals from water and wastewater. "

ADSORPTION OF SELECTED TOXIC METALS BY MODIFIED PEANUT SHELLS
http://www.nal.usda.gov/ttic/tektran/data/000012/02/0000120204.html

(This article was accessed from a USDA page classifying peanut shells
as "Non-Food Industrial Products" 
http://www.nal.usda.gov/ttic/tektran/categoryV3/Industrial_Products_Nonfood_.html
)

"Recently a top specialty diet was found responsible for the deaths of
highly-trained working dogs. The investigation revealed that the
company had been using peanut shells for fiber in the products.
Unfortunately, one lot of shells were contaminated with fungus that
produced a lethal toxin. peanut shells? Uh huh. They're cheap and add
volume to the product."

Natural Pet
http://naturalpet.protohype.net/naturalpet/learn_bookquotes_pelchner.html

"Peanut shells are sometimes used in dog food as a source of fiber.
Stay away from this ingredient. They can abound in aflatoxins
(Aflatoxin B1 is very toxic and can be deadly for your dog or
yourself, should you ingest it)"

Fuzzy Faces
http://www.fuzzyfaces.com/fooded1.html

"Manufacturers in the pet food industry have been pressing for label
changes to permit them to call peanut shells and corn husks "vegetable
fiber", cheese rind "cheese", and feathers "processed poultry
protein".

Obviously, manufacturers are seeking to hide the inferior quality of
their ingredients with more healthful-sounding, euphemistic terms."

WYSONG HEALTH LETTER - Dr. R. L. Wysong
Volume 6 Number 5/May 1992
http://www.wysong.net/healthletter/hl_may92.shtml

Roasting the peanuts in their shells is said to *reduce* levels of
aflatoxin, but doesn't necessarily eliminate it all together. 
Additionally, already roasted peanuts can become contaminated if
improperly stored:

"When roasting peanuts, the toxicity of aflatoxin B1 is reduced by
70%, and that of aflatoxin B2 by 45%. Thus, heat treatment cannot be
considered as a satisfactory means to eliminate mycotoxins."

Natural toxic constituents in food, and effect (or absence of effect)
of cooking
http://www.beyondveg.com/tu-j-l/raw-cooked/raw-cooked-1g.shtml


"Peanuts are susceptible to molds and fungal invasions. Of particular
concern is aflatoxin, a poison produced by a fungus called Aspergillus
flavus. Although better storage and handling methods have virtually
eliminated the risk of aflatoxin ingestion, aflatoxin is a known
carcinogen that is twenty times more toxic than DDT and has also been
linked to mental retardation and lowered intelligence. To help prevent
aflatoxin ingestion, the FDA also enforces a ruling that 20 parts per
billion is the maximum of aflatoxin permitted in all foods and animal
foods, including peanut butter and other peanut products. If
purchasing raw peanuts, it is still wise to ensure that the peanuts
have been stored in a dry, cool environment (the fungus grows when the
temperature is between 86-96°F and when the humidity is high). Roasted
peanuts are thought to offer more protection against aflatoxin, plus
roasting is also thought to improve peanuts' digestibility."

Peanuts, roasted - Safety
http://www.whfoods.com/genpage.php?tname=foodspice&dbid=101#safetyissues

"The conditions surrounding the growth and processing of the crops is
very instrumental in the extent of contamination. The problem is
greatest when the crops have been damaged by droughts, blights, or
rough handling. Likewise, contamination can occur after harvesting if
the products are not properly dried or stored. Thus, infections by the
aflatoxin producing molds is sporadic. The results of an FDA survey on
the concentration of aflatoxins in peanuts and peanut butter over
eight years shows that the contamination of aflatoxins can very from
as little as 2.5% to as high as 22.2% of the total sample of roasted
peanuts. Likewise, the percent of the sample which contains more than
20ppb of aflatoxins can very drastically, as can the concentration in
relation to the percent contaminated. Furthermore, this is only
dealing with roasted nuts, and studies have shown that the roasting
process can kill between 40 and 80% of the toxin (Pohland &Wood,
1991)."

Aflatoxins: the particular poisons of peanuts.
http://www.cnr.berkeley.edu/~reynolds/Luna/Aflatoxin.html

What about additional risks?

I placed a call to the Anderson's General Store (419-473-3232) and
spoke with John in the produce department.  John stated that peanut
shells are considered non-food, and should not be consumed because
they are not digestible.  He cautions that the sharp edges of bits of
peanut shells (as we cannot chew them well) can cause intestinal
distress, and does not recommend eating them at all.

I also made a trip to Ciolino's Farm Market in Temperance, Michigan
(about half a mile up the road from my home) to speak to the
proprieter.  The proprieter was slightly horrified by the idea of
eating peanut shells, and exclaimed "Tell him to stop!  He can get
sick!"

He went on to explain that fertilizer and pesticide residues are
absorbed by the shells, and are not removed by the washing and
roasting processes.  A nibble or two probably won't hurt, but over
time the residues might build up in your body, or you might even risk
suffering an allergic reaction to the residues.

Based on my research and the conversations noted above, I would not
recommend eating the peanut shells, either.  As inconvenient as it is,
it appears to be safer for you to just lick the salt off the shells
and discard them.

Be well!


--Missy



Search terms: [  "peanut shells" "human consumption" ], [ "peanut
shells" nutrition ], [  "peanut shells" "nutritional value" ], [
aflatoxin roasting peanuts ]

The question was specifically and entirely answered, references were
cited, and related information was provided, as well as a summary and
recommendations.  This really boosts my confidence in the Google
Answers service.  It's an excellent value.