Gluten-free diet

A 'gluten-free diet' is recommended amongst other things in the treatment of coeliac disease and wheat allergy. It is a diet completely free of ingredients derived from gluten-containing cereals: wheat (including kamut and spelt), barley, rye, and triticale, as well as the use of gluten as a food additive in the form of a flavoring, stabilizing or thickening agent. Additionally, the diet may exclude oats. Some people for whom the diet is recommended can tolerate oat products and some medical practitioners say they may be permitted,^[1] but there is controversy about including them in a gluten-free diet because studies on the subject are incomplete.^[2]

Gluten-free food

Although gluten is commonly associated with wheat, not all wheat products contain gluten. For instance highly processed wheat glucose has been found to contain no detectable gluten (ie less than 5 parts per million gluten).^{citation needed}

Several grains and starch sources are considered acceptable for a gluten-free diet. The most frequently used are maize, potatoes, rice, and tapioca (derived from cassava). Other grains and starch sources generally considered suitable for gluten-free diets include amaranth, arrowroot, millet, montina, lupine, quinoa, sorghum (jowar), sweet potato, taro, teff, chia seed, and yam. Various types of bean, soybean, and nut flours are sometimes used in gluten-free products to add protein and dietary fiber. In spite of its name, buckwheat is not related to wheat; pure buckwheat is considered acceptable for a gluten-free diet, although many commercial buckwheat products are actually mixtures of wheat and buckwheat flours, and thus not acceptable. Gram flour, derived from chickpeas, is also gluten-free.

People wishing to follow a completely gluten free diet must also take into consideration the ingredients of any over-the-counter or prescription medications and vitamins. Also, cosmetics such as lipstick, lip balms, and lip gloss may contain gluten and need to be investigated before use.

Cross-contamination issues

Special care must be taken when checking ingredients lists as gluten may come in forms such as vegetable proteins and starch, modified food starch (when derived from wheat instead of maize), malt flavoring, and glucose syrup. Many ingredients contain wheat or barley derivatives. Maltodextrin, formerly thought to contain gluten, is generally considered gluten free. [1]

Many foods contain gluten, but do not indicate it in their ingredients list, because they are not in the formulation of the product, but in the preparation (or manufacturing) of some of the listed ingredients. One example of this is the dusting of the conveyor belts in the production facilities to prevent the foods from sticking during processing. The food itself might not contain gluten, but there is gluten in the ingested product.

Controversy over oats

The suitability of oats in the gluten-free diet is still somewhat controversial. Some research suggests that oats in themselves are gluten free, but that they are virtually always contaminated by other grains during distribution or processing. However, recent research^[5] indicated that a protein naturally found in oats (avenin) possessed peptide sequences closely resembling wheat gluten and caused mucosal inflammation in significant numbers of celiac disease sufferers. Some examination results show that even oats, which are not contaminated with wheat particles, are nonetheless dangerous to about 10 percent of celiacs, while not very harmful to the majority. Such oats are generally considered risky for celiac children to eat, but two studies show that they are completely safe for celiac adults to eat, ^[6] even over a period of five years.^[7] Given this conflicting information, excluding oats appears to be the only risk free practice for celiac disease sufferers of all ages.^[8] However, medically approved guidelines exist for those celiacs who do wish to introduce oats into their diet.^[9]

Unless manufactured in a dedicated facility and under gluten-free practices, all cereal grains, including oats, can be cross-contaminated with gluten. Grains become contaminated with gluten by sharing the same farm, truck, mill, or bagging facility as wheat and other gluten-containing grains. Therefore, removing all flours and grains from the diet may be the only way to guarantee a complete absence of gluten in the diet.

Accuracy of "gluten-free" labels

The "Codex Alimentarius" set of international standards for food labelling has a standard relating to the labelling of products as "gluten free", however this standard does not apply to "foods which in their normal form do not contain gluten".^[10]

The legal definition of the phrase "gluten-free" varies from country to country. Current research suggests that for persons with celiac disease the maximum safe level of gluten in a finished product is probably less than 0.02% (200 parts per million) and possibly as little as 0.002% (20 parts per million).

Australian standards reserve the "gluten free" label for foods with less than 5 parts per million of gluten, as this is the smallest amount currently detectable. As gluten-containing grains are processed, more and more of the gluten is removed from them, as shown in this simple processing flow:

Since ordinary wheat flour contains approximately 12% gluten, even a tiny amount of wheat flour can cross-contaminate a gluten-free product. Therefore, considerable care must be taken to prevent cross-contamination in both commercial and home food preparation.

This diet rules out all ordinary breads, pastas, and many convenience foods; it also excludes gravies, custards, soups and sauces thickened with wheat, rye, barley or other gluten-containing flour. Many countries do not require labelling of gluten containing products, but in several countries (especially Australia and the European Union) new product labelling standards are enforcing the labelling of gluten-containing ingredients. Various gluten-free bakery and pasta products are available from speciality retailers.

In the United States, gluten may not be listed on the labels of certain foods because the U.S. Food and Drug Administration has classified gluten as GRAS (Generally recognized as safe).^[11] Requirements for proper labelling are being formulated by the USDA. It is currently up to the manufacturers of "gluten free" food items to guarantee such a claim. "A final rule that defines the term gluten-free and identifies the criteria that would enable the food industry to use that term" is scheduled to be released by the FDA on August 2nd, 2008 ^[12]. Many so-called gluten free products have been found to have been contaminated with gluten (such as chicken bouillon, corn cereal, caramel ice cream topping, ^[13] and Pamela's cookies^[14], etc.).

In the United Kingdom, only cereals currently need to be labelled, while other products are voluntary.^[15] For example, sausages commonly contain Butcher's Rusk, a grain-derived food additive.^[16] Furthermore, while UK companies selling food prepared on their own premises are given guidance by the Food Standards Agency, they are not required to meet any labeling requirements.^[17]

Lastly, some non-foodstuffs such as medications and vitamin supplements, especially those in tablet form, may contain gluten as an excipient or binding agent.^[18]^[19] People with gluten intolerances may therefore require specialist compounding of their medication.

Alcoholic beverages

Most specialists^who? now consider all distilled forms of alcohol safe to drink, provided no colourings or other additives have been added as these ingredients may contain gluten. Although Straight Bourbon is made from maize and wheat, rye or barley, the gluten in these grains is removed by the process of distillation. Whiskey on the other hand will likely contain gluten as the malted barley or rye is often added after the grain mash has been distilled. Spirits made without any grain such as wine, sherry, port, cider, rum, tequila and vermouth do not contain gluten. Liqueurs and pre-mixed drinks should be examined carefully for gluten-derived ingredients.

Almost all beers are brewed with malted barley or wheat and will contain gluten. Sorghum and buckwheat-based gluten-free beers are available, but remain very much a specialty product. Some low-gluten beers are also available, however there is disagreement over the use of gluten products in brewed beverages: Some brewers argue that the proteins from such grains as barley or wheat are converted into amino acids during the brewing process and are therefore gluten-free,^[20] however there is evidence that this claim is false.^[21]

Medical benefits

The scientific literature on the link between gluten and autism is mixed and there is no substantial research on in utero causality. There have been too few adequately designed, large-scale controlled studies and clinical trials to state whether the diet is effective.^[24] A small single blind study has documented fewer autistic behaviors in children fed a gluten-free, casein-free diet, but noted no change in cognitive skills, linguistic ability, or motor ability.^[25] This study has been criticized for its small sample size, single-blind design which may have skewed results on the basis of a "parent placebo effect".^[26] A 2006 double-blind short-term study found no significant differences in behavior between children on a gluten-free, casein-free diet and those on regular diets.^[27] A long term double-blind clinical trial sponsored by the National Institute of Mental Health is scheduled for completion in April 2008; preliminary results are not yet available.^{citation needed}

Contents

Gluten-free food

Cross-contamination issues

Controversy over oats

Accuracy of "gluten-free" labels

Alcoholic beverages

Medical benefits

See also

References

External links