LISTSERV mailing list manager LISTSERV 16.0

Help for PALEODIET Archives

   

PALEODIET Archives

PALEODIET Archives


PALEODIET@LISTSERV.ICORS.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

PALEODIET Home

PALEODIET Home

PALEODIET  June 1997

PALEODIET June 1997

Subject:

Re: Cereal grains

From:

Staffan Lindeberg <[log in to unmask]>

Date:

Sun, 8 Jun 1997 14:55:35 +0100

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (138 lines)

Dean asked for references to the notion that phytic acid in cereal grains
causes calcium depletion. In 1992 Professor Harold H. Sandsted, who is
Interim Editor-in-Chief of the American Journal of Clinical Nutrition, the
most important journal of nutrition, noted that "the evidence seems
overwhelming that high intakes of fiber sources that are also rich in
phytate can have adverse effects on mineral nutrition of humans" and that,
"in view of the [reviewed] data, it appears that some health promoters who
suggest that U.S. adults should consume 30-35 g dietary fiber daily either
have not done their homework or have simply ignored carefully done research
on this topic" [1]. My own opinion is that authorities who advocate cereals
in a prudent western diet largely do so for practical reasons [2].

So let's look do the homework. Whole meal cereals and other seeds have in
their shells phytic acid which strongly binds to minerals like calcium,
iron, zinc and magnesium to form insoluble salts, phytates [1, 3-7]. It is
well known that whole meal cereals by this mechanism decrease the
absorption of such minerals [1, 3-7]. There is apparently no adaptation to
a habitual high intake of phytic acid [8] which is an important
contributing cause of iron deficiency in third world countries and possibly
in the western world [9]. It is also an important cause of mineral
deficiency in vegetarians [10-12]. The most commonly studied minerals are
bound to phytic acid possibly in the following decreasing order: calcium >
iron > zinc > magnesium (Fredlund K, personal communication).

Mellanby found back in the 30s that young dogs got rickets when they were
fed oatmeal [13]. He was made aware of the calcium-binding effect of
phytate [14] and showed that phytate was the dietary factor responsible for
inhibition of calcium absorption by oatmeal as well as the induction of
rickets in dogs [15]. McCance and Widdowson found adverse effects of bread
prepared from high-extraction wheat flour on retention of essential metals
by humans [16]. They also showed that destruction of phytate improved
retention of calcium [17]. Substantial evidence have later firmly
established this negative impact of phytate [1, 3-7]. Not even rats seem to
be fully adapted to graminivorous diets since phytate adversely affects
mineral absorption in them as well [18].

In the archaeological record, rickets is rare or absent in preagricultural
human skeletons, while the prevalence increases during medieval
urbanization and then explodes during industrialism [19]. In the year 1900,
an estimated 80-90 per cent of Northern European children were affected
[20, 21]. This can hardly be explained only in terms of decreasing exposure
to sunlight and descreased length of breast-feeding. An additional possible
cause is a secular trend of increasing intake of phytate since cereal
intake increased during the Middle Ages (Morell M, personal communication)
and since old methods of reducing the phytate content such as malting,
soaking, scalding, fermentation, germination and sourdough baking may have
been lost during the agrarian revolution and industrialism by the emergence
of large-scale cereal processing. The mentioned methods reduce the amount
of phytic acid by use of phytases, enzymes which are also present in
cereals [22-26]. These enzymes are easily destroyed during industrial
cereal processing [27, 28].

It should be noted that dietary fiber alone has no impact on mineral
absorption [5, 29] why a high intake of fiber from fruits and tubers can
safely be recommended, at least from this point of view.

Best regards to all of you,

Staffan

1.      Sandstead HH. Fiber, phytates, and mineral nutrition. Nutr Rev
1992; 50: 30-1.
2.      Walker ARP, Walker BF I. I. Fiber, phytic acid, and mineral
metabolism. Nutr Rev 1992; 50: 246-7.
3.      Spivey Fox MR, Tao S-H. Antinutritive effects of phytate and other
phosphorylated derivatives. In: Hathcock JN, ed.  Nutritional Toxicology.
New York: Academic Press, 1989: 59-96. vol 3).
4.      Harland BF. Dietary fibre and mineral bioavailability. Nutr Res Rev
1989; 2: 133-47.
5.      Rossander L, Sandberg A-S, Sandstr=F6m B. The influence of dietary
fibre on mineral absorption and utilisation. In: Schweizer TF, Edwards CA,
ed.  Dietary fibre - a component of food. Nutritional function in health
and disease.  London: 1992:
6.      Sandberg AS, Hasselblad C, Hasselblad K, Hulten L. The effect of
wheat bran on the absorption of minerals in the small intestine. Br J Nutr
1982; 48: 185-91.
7.      Morris ER. Phytate and dietary mineral bioavailability. In: Graf E,
ed.  Phytic acid: Chemistry and applications.  Minneapolis: Pilatus Press,
1986: 57-76. vol 4).
8.      Brune M, Rossander L, Hallberg L. Iron absorption: no intestinal
adaptation to a high-phytate diet. Am J Clin Nutr 1989; 49: 542-5.
9.      Hallberg L, Rossander L, Skanberg AB. Phytates and the inhibitory
effect of bran on iron absorption in man. Am J Clin Nutr 1987; 45: 988-96.
10.     Harland BF, Smith SA, Howard MP, Ellis R, Smith JJ. Nutritional
status and phytate:zinc and phytate x calcium:zinc dietary molar ratios of
lacto-ovo vegetarian Trappist monks: 10 years later. J Am Diet Assoc 1988;
88: 1562-6.
11.     Ellis R, Kelsay JL, Reynolds RD, Morris ER, Moser PB, Frazier CW.
Phytate:zinc and phytate X calcium:zinc millimolar ratios in self-selected
diets of Americans, Asian Indians, and Nepalese. J Am Diet Assoc 1987; 87:
1043-7.
12.     Gibson RS. Content and bioavailability of trace elements in
vegetarian diets. Am J Clin Nutr 1994; 59(5 Suppl): 1223S-1232S.
13.     Mellanby E. A story of nutrition research.Baltimore: Williams &
Wilkins Co, 1950
14.     Bruce H, Callow R. Cereals and rickets. The role of
inositolhexaphosphoric acid. Biochem J 1934; 28: 517-28.
15.     Harrison D, Mellanby E. Phytic acid and the rickets-producing
action of cereals. Biochem J 1934; 28: 517-28.
16.     McCance R, Widdowsos E. Mineral metabolism of healthy adults on
white and brown bread dietaries. j Physiol 1942; 101: 44-85.
17.     McCance R, Edgecombe C, Widdowson E. Mineral metabolism of
dephytinized bread. J Physiol 1942; 101:
18.     Fairweather TS, Wright AJ. The effects of sugar-beet fibre and
wheat bran on iron and zinc absorption in rats. Br J Nutr 1990; 64: 547-52.
19.     Stuart-Macadam PL. Nutritional deficiency diseases: a survey of
scurvy, rickets, and iron-deficiency anemia. In: Is=E7an MY, Kennedy KAR, ed=
.
Reconstruction of life from the human skeleton.  New York: Wiley-Liss,
1989: 201-22.
20.     Gibbs D. Rickets and the crippled child: an historical perspective
[see comments]. J R Soc Med 1994; 87: 729-32.
21.     Hernigou P. Historical overview of rickets, osteomalacia, and
vitamin D. Rev Rhum Engl Ed 1995; 62: 261-70.
22.     Sandberg AS. The effect of food processing on phytate hydrolysis
and availability of iron and zinc. Adv Exp Med Biol 1991; 289: 499-508.
23.     Svanberg U, Sandberg A-S. Improved iron availability in weaning
foods using germination and fermentation. In: Southgate DAT, Johnson IT,
=46enwick GR, ed.  Nutrient Availability: Chemical and biological aspects.
Cambridge: Cambridge University press, 1989: 179-81.
24.     Larsson M, Sandberg A-S. Phytate reduction in bread containing oat
flour, oat bran or rye bran. J Cereal Sci 1991; 14: 141-9.
25.     Navert B, Sandstrom B, Cederblad A. Reduction of the phytate
content of bran by leavening in bread and its effect on zinc absorption in
man. Br J Nutr 1985; 53: 47-53.
26.     Caprez A, Fairweather TS. The effect of heat treatment and particle
size of bran on mineral absorption in rats. Br J Nutr 1982; 48: 467-75.
27.     Sandberg A-S. Food processing influencing iron bioavailability. In:
Hallberg L, Asp N-G, ed.  Iron Nutrition in Health and Disease.  London:
John Libbey, 1996: 349-58.
28.     Sandstrom B. Food processing and trace element supply. In: Somogyi
JC, Muller HR, ed.  Nutritional Impact of Food Processing. Bibl Nutr Dieta.
Basel: Karger, 1989: 165-72.
29.     Andersson H, Navert B, Bingham SA, Englyst HN, Cummings JH. The
effects of breads containing similar amounts of phytate but different
amounts of wheat bran on calcium, zinc and iron balance in man. Br J Nutr
1983; 50: 503-10.

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

November 2005
October 2005
July 2004
May 2004
March 2004
February 2004
October 2003
September 2003
August 2003
September 2002
August 2002
September 2001
September 2000
August 2000
July 2000
June 2000
May 2000
April 2000
March 2000
February 2000
October 1999
September 1999
August 1999
July 1999
June 1999
May 1999
April 1999
March 1999
February 1999
January 1999
December 1998
November 1998
October 1998
September 1998
August 1998
July 1998
June 1998
May 1998
April 1998
March 1998
February 1998
January 1998
December 1997
November 1997
October 1997
September 1997
August 1997
July 1997
June 1997
May 1997
April 1997
March 1997

ATOM RSS1 RSS2



LISTSERV.ICORS.ORG

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager