Grains in relation to Celiac Disease

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Grains in Relation to Celiac Disease

 

Preface: The following information was supplied originally in 1991

in the form of a letter to Phyllis Brogden,

Chairperson of the Greater Philadelphia Celiac Sprue Support Group,

by Donald D. Kasarda, who was a Research

Chemist with the US Department of Agriculture at that time. Copies

were sent to four other major celiac patient groups

in the US. Dr. Kasarda retired from the USDA in 1999, but updated

the information in February of 2000. Dr. Kasarda

wishes to add the following disclaimer to the information: " These

are my opinions based on quite a few years of

research in the area of proteins as they relate to celiac disease.

They do not necessarily represent those of the

Agricultural Research Service, U. S. Department of Agriculture. " If

you have any questions or comments regarding the

piece, you can address them to Don at: kasarda

 

The only plants demonstrated to have proteins that damage the small

intestines of people with celiac disease are

those from wheat, rye, and barley (and the man-made wheat-rye cross

called triticale). Although oats had generally

been considered harmful until 1996, several high quality studies

published since then indicate that oats are not harmful

either in celiac disease or dermatitis herpetiformis. Some

physicians choose not to accept these findings or else point

out that there is some potential problem of contamination of oats

by wheat. The contamination question has not yet

been adequately researched, but may be overemphasized. The three

harmful species are members of the grass family

and are quite closely related to one another according to various

schemes of plant classification (taxonomy). However,

not all members of the grass family damage the intestines of celiac

patients. Rice and corn, for example, are

apparently harmless.

 

Many other grains have not been subjected to controlled testing or

to the same scrutiny as wheat, rye, barley, oats,

rice, and corn in relation to celiac disease. In fact, only wheat

and oats have been extensively studied in controlled

experiments with the most up-to-date methods. If we accept corn and

rice as safe, however, and this seems

reasonable to me, then members of the grass family that are more

closely related to these species (on the basis of

taxonomy) than to wheat are likely to be safe. Such grasses include

sorghum, millet, teff, ragi, and Job's tears, which

appear to be reasonably closely related to corn. In some cases,

there are protein studies in support of this conclusion,

although the studies are not sufficiently complete to provide more

than guidance. Scientifically controlled feeding

studies with celiac patients would provide a better answer.

However, such studies are not likely to be carried out in the

next few years because of high costs and the difficulty of

obtaining patient participation (such studies would likely

involve intestinal biopsy). In lieu of feeding studies, further

studies of protein (and DNA) would provide the next best

way to evaluate my suggestion that millet, sorghum, teff, ragi, and

Job's tears are not likely to be toxic in celiac

disease, although even such studies are hampered at present by a

lack of knowledge of which sequences in the wheat

gluten proteins are harmful. There is evidence that a few sequences

are harmful, but not all possibilities have yet been

tested.

 

The scientific name for bread wheat is Triticum aestivum var.

aestivum--the first part of the name defines the genus

(Triticum) and the second part, the species (aestivum). Species

falling in the genus Triticum are almost certain to be

harmful to celiac patients. Grain proteins of these species include

the various types characteristic of the gluten

proteins found in bread wheats (including the alpha-gliadins) that

cause damage to the small intestine in celiac

disease. Durum wheats (Triticum turgidum var. durum) used for pasta

are also harmful to celiac patients. Some

Triticum species of current concern include Triticum aestivum var.

spelta (common names include spelt or spelta),

Triticum turgidum var. polonicum (common names include Polish

wheat, and, recently, Kamut), and Triticum

monococcum var. monococcum (common names include einkorn and small

spelt). I recommend that celiac patients

avoid grain from these species. Also, given their very close

relationship to bread and durum wheats, I think it is

unlikely that these grains would be safe for those with classical

allergic responses to wheat.

 

Rye (Secale cereale) and barley (Hordeum vulgare) are toxic in

celiac disease even though these two species are less

closely related to bread wheat than spelta and Kamut. They belong

to different genera, Secale and Hordeum,

respectively, and lack alpha-gliadins, which may be an especially

toxic fraction.

 

There have been anecdotal reports suggesting a lack of toxicity in

celiac disease for spelta and Kamut, along with

anecdotal reports of the opposite, at least in the case of

spelta-celiac patients who have been harmed by eating it.

Controlled tests would be necessary to draw a firm conclusion,

although they hardly seem necessary insofar as spelta

and Kamut should be considered forms of wheat.

 

The diagnosis, sometimes self-diagnosis, of celiac disease is

occasionally made without benefit of reasonably

rigorous medical or clinical tests, especially intestinal biopsy.

Individuals who are " diagnosed " in this way without

rigorous testing may not actually have celiac disease. Claims that

particular foods cause this latter group no problems

in relation to their celiac disease could cause confusion.

 

Furthermore, celiac patients who report no problems in the short

run with spelta or Kamut might experience relapse

later. There is now adequate evidence that when celiac patients on

a " gluten-free " diet (that is, a diet free of any

proteins or peptides from wheat, rye,and barley) have wheat

reintroduced to their diets, times-to-relapse vary

enormously among individuals, ranging from hours to months, or even

years. And this is for wheat, presumably the

most toxic of all cereal grains to celiac patients.

 

Additionally, the relapse may not be accompanied by obvious

symptoms, but be recognized only by physicians

through observation of characteristic changes in the small

intestinal tissues obtained by biopsy. The reasons for the

enormous variability of response times are not known. It may be

speculated that the variability has something to do

with the degree of recovery of the lining of the small intestine on

a gluten-free diet, the degree of stress that the patient

had been experiencing (including infections), and individual

genetic differences.

 

As I have indicated, all known grain species that cause problems

for celiac patients are members of the grass family.

In plant taxonomy, the grass family belongs to the Plant Kingdom

Subclass known as monocotyledonous plants

(monocots). The only other grouping at the Subclass level is that

of dicotyledonous plants (dicots). Some other

species about which celiac patients have questions actually are

dicots, which places them in very distant relationship

to the grass family. Such species include buckwheat, amaranth,

quinoa, and rape. The seed of the last plant listed,

rape, is not eaten, but an oil is pressed from the seeds that is

commonly used in cooking. This oil is being marketed

as canola oil. Because of their very distant relationship to the

grass family and to wheat, it is highly unlikely that these

dicots will contain the same type of protein sequence found in

wheat proteins that causes problems for celiac patients.

Of course, some quirk of evolution could have given rise in these

dicots to proteins with the toxic amino acid sequence

found in wheat proteins. But if such concerns were carried to a

logical conclusion, celiac patients would have to

exclude all plant foods from their diets. For example, buckwheat

and rhubarb belong to the same plant family

(Polygonaceae). If buckwheat were suspect for celiac patients,

should not rhubarb, its close relation, be suspect as

well?

 

It may be in order to caution celiac patients that they may have

undesirable reactions to any of these foods--reactions

that are not related to celiac disease. Allergic reactions may

occur to almost any protein, including proteins found in

rice, but there is a great deal of individual variation in allergic

reactions. Also, buckwheat, for example, has been

claimed to contain a photosensitizing agent that will cause some

people who have just eaten it to develop a skin rash

when they are exposed to sunlight. Quinoa and amaranth may have

high oxalate contents-approaching those of

spinach and these oxalate levels may cause problems for some

people. Such reactions should be looked for, but for

most people, buckwheat, quinoa, or amaranth eaten in moderation

apparently do not cause problems. (Buckwheat is

sometimes found in mixture with wheat, which of course would cause

a problem for celiac patients.) It seems no more

necessary for all people with celiac disease to exclude buckwheat

from their diets because some celiac patients react

to it than it would be for all celiac patients to exclude milk from

their diets because some celiac patients have a

problem with milk.

 

In conclusion, scientific knowledge of celiac disease, including

knowledge of the proteins that cause the problem, and

the grains that contain these proteins, is in a continuing state of

development. There is much that remains to be done.

Nevertheless, steady progress has been made over the years. As far

as I know, the following statements are a valid

description of the state of our knowledge:

 

Spelt or spelta and Kamut are wheats. They have proteins toxic

to celiac patients and should be avoided just

as bread wheat, durum wheat, rye, barley, and triticale should

be avoided.

Rice and corn (maize) are not toxic to celiac patients.

Certain cereal grains, such as various millets, sorghum, teff,

ragi, and Job's tears are close enough in their

genetic relationship to corn to make it likely that these

grains are safe for celiac patients to eat. However,

significant scientific studies have not been carried out for

these latter grains.

There is no reason for celiac patients to avoid plant foods

that are very distantly related to wheat. These include

buckwheat, quinoa, amaranth, and rapeseed oil (canola). Some

celiac patients might suffer allergies or other

adverse reactions to these grains or foodstuffs made from

them, but there is currently no scientific basis for

saying that these allergies or adverse reactions have anything

to do with celiac disease. A celiac patient may

have an allergy to milk, but that does not mean that all

celiac patients will have an adverse reaction to milk.

Again, however, scientific studies are absent or minimal for

these dicots.

 

A list of my publications with pertinence to celiac disease

follows. Cross-references to the literature for most of the

points discussed above can be found in these publications.

 

1.Kasarda, D. D., and D'Ovidio, R. 1999. Amino acid sequence of

an alpha-gliadin gene from spelt wheat (Spelta)

includes sequences active in celiac disease. Cereal Chem.

76:548-551.

2.Kasarda, D. D. 1997. Celiac Disease. In Syllabus of the North

American Society for Pediatric Gastroenterology

& Nutrition, 4th Annual Postgraduate Course, Toronto, Ontario,

Canada, pp. 13-21.

3.Kasarda, D. D. 1997. Gluten and gliadin: precipitating factors

in coeliac disease. In Coeliac Disease:

Proceedings of the 7th International Symposium on Coeliac

Disease (September 5-7, 1996), edited by M.

Mäkki, P. Collin, and J. K. Visakorpi, Coeliac Disease Study

Group, Institute of Medical Technology, University

of Tampere,Tampere, Finland, pp. 195-212.

4.Srinivasan, U., Leonard, N., Jones, E., Kasarda, D. D., Weir,

D. G., O'Farrelly, C., and Feighery, C. 1996.

Absence of oats toxicity in coeliac disease. British Medical

Journal 313:1300-1301.

5.Tatham, A. S., Fido, R. J., Moore, C. M., Kasarda, D. D.,

Kuzmicky, D. D., Keen, J. N., and Shewry, P. R.

Characterization of the major prolamins of tef (Eragrostis

tef) and finger millet (Eleusine coracana). J. Cereal

Sci. 24:65-71. 1996.

6.Kasarda, D. D. 1994. Defining cereals toxicity in coeliac

disease. In Gastrointestinal Immunology and

Gluten-Sensitive Disease, edited by C. Feighery, and F.

O'Farrelly, Oak Tree Press, Dublin, pp. 203-220.

7.Shewry, P. R., Tatham, A. S., and Kasarda, D. D. 1992. Cereal

proteins and coeliac disease. In Coeliac

Disease, edited by M. N. Marsh, Blackwell Scientific

Publications, Oxford, U. K., pp. 305-348.

8.De Ritis, G., Auricchio, S., Jones, H. W., Lew, E. J.-L.,

Bernardin, J. E. and Kasarda, D. D. 1988. In vitro

(organ culture) studies of the toxicity of specific A-gliadin

peptides in celiac disease. Gastroenterology

94:41-49.

9.Kagnoff, M. F., Patterson, Y. J., Kumar, P. J., Kasarda, D.

D., Carbone, F. R., Unsworth, D. J. and Austin, R.

K. 1987. Evidence for the role of a human intestinal

adenovirus in the pathogenesis of celiac disease. Gut

28:995-1001.

10.Levenson, S. D., Austin, R. K., Dietler, M. D., Kasarda, D. D.

and Kagnoff, M. F. 1985. Specificity of antigliadin

antibody in celiac disease. Gastroenterology 89: 1-5.

11.Kagnoff, M. F., Austin, R. K., Hubert, J. J., Bernardin, J. E.

and Kasarda, D. D. 1984. Possible role for a human

adenovirus in the pathogenesis of celiac disease. J. Exp. Med.

160: 1544-1557.

 

Grains in Relation to Celiac (Coeliac) Disease by Donald D.

Kasarda.

An annotated copy: http://wheat.pw.usda.gov/topics/