By Stephen Daniells

May 19, 2009; Related topics: Science & Nutrition

Following a gluten-free diet may be detrimental to gut health, which may also affect immune health, according to a new study from the Spanish National Research Council.

According to results of a small study with 10 people consuming a gluten-free diet, populations of beneficial gut bacteria, such as Bifidobacterium and Lactobacillus, decreased, while counts for Enterobacteriaceae and Escherichia coli increased.

“Thus, the gluten-free diet may constitute an environmental variable to be considered in treated coeliac disease patients for its possible effects on gut health,” wrote the authors in the British Journal of Nutrition.

Coeliac disease, a condition characterized by an intolerance to gluten in wheat, is reported to affect up to 1 per cent of children and 1.2 per cent of adults, according to a study in the BMJ's Gut journal. Coeliac disease is a permanent intolerance to cereal gluten proteins and the only therapy for the patients is to adhere to a life-long gluten-free diet (GFD),” explained the authors, led by Giada De Palma. According to a recent report from Packaged Facts, the gluten-free market has grown at an average annual rate of 28 per cent since 2004, when it was valued at $580m, to reach $1.56bn last year. Packaged Facts estimates that sales will be worth $2.6bn by 2012.

New data
The Spanish researchers analysed the gut microflora of ten healthy subjects with an average age of 30 assigned to consume a gluten-free diet for one month. Consumption of the gluten-free diet did not change significantly the normal dietary intakes for the volunteers, except for polysaccharides, which were reduced.

Analysis of the participants' faeces showed that Bifidobacterium, Clostridium lituseburense and Faecalibacterium prausnitzii populations decreased following the gluten-free diet patter, while populations of Enterobacteriaceae and Escherichia coli increased.

Markers of immune health, such TNF-alpha, interferon-gamma, interleukin-10 (IL-10) and IL-8, which would be produced when the host's immune system is challenged, were also reduced following consumption of the gluten-free diet.

“Therefore, the GFD led to reductions in beneficial gut bacteria populations and the ability of faecal samples to stimulate the host's immunity,” concluded the researchers.

Digestive health
Products aimed at gut health have traditionally been much more popular in Europe than North America, but this is changing as Americans embrace the idea of boosting gut health via foods and beverages. Europe still leads the way in terms of product launches and market value, but North America is catching up fast, due in part to the remarkable success of Danone's DanActive in North America. The gut health product was launched there in 2005 and built on its Activia presence.

Source: British Journal of Nutrition
Published online ahead of print, First View article, doi:10.1017/S0007114509371767
“Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects”
Authors: G. De Palma, I. Nadal, M.C. Collado, Y. Sanz