Genomics Blog
March 15, 2010 12:45 PM
Genomics of Gluten and Gluten Intolerance: Part I
Filed Under: Gerry Ward
It started when I read a tweet that said that the gluten content of wheat was 10 times more than it was 10 years ago. I always heard that 87% of all statistics are completely made up. At least when we are faced with statistics that are not backed up with data, we must apply our critical thinking skills. As I started trying to substantiate or refute the claim regarding gluten content, it took me on an interesting journey through the genomics of both humans and wheat. The wheat kernel is made up mostly of carbohydrates and proteins. The protein portion, collectively called gluten, makes up about 10% to 15% of the wheat seed. A little quick math tells me that if the gluten content increased 10 times, it would make up more than 100% of the kernel, so I guess the short answer to my question is that the claim is bogus. This does not however negate the fact that a significant portion of the population is gluten intolerant. In my blog over the next several entries, I will examine the genomics of both gluten in wheat and gluten intolerance in humans.
The protein content of wheat is measured as part of the grading system. On a tour of the government facilities in Ottawa, I learned that the amount and kind of flour that a baker uses depends greatly on what is being made. Apparently, the gluten content ranges from about 10% in ‘soft’ wheat to 15% in ‘hard’ wheat. The texture of cakes and pastries calls for the use of soft wheat while hard wheat is destined for making breads and pasta.
Little Bags of wheat arrive
Chemical Analysis
Little loaves made in controlled ovens
The gluten content of the wheat is a varietal characteristic, specific and hereditary, which is only partly dependent on environment. Environmental influences such as amount of rainfall, especially during the last phases of plant development, as well as soil type definitely have an effect on the gluten content of the wheat kernel.
Since the amount of gluten is important in pasta manufacture and texture of cooked food products, Agriculture and Agri-Food Canada (AAFC) in Swift Current has developed varieties that meet or exceed target levels of gluten strength. According to their statement, "In the future, growers will continue to see the development of more varieties of durum wheat in this class with stronger gluten strength”. Thus it is clear that the gluten concentration in some varieties of wheat is indeed increasing.
In my next blog I will look at how the use of genomics has changed the way wheat varieties are developed.
Since the amount of gluten is important in pasta manufacture and texture of cooked food products, Agriculture and Agri-Food Canada (AAFC) in Swift Current has developed varieties that meet or exceed target levels of gluten strength. According to their statement, "In the future, growers will continue to see the development of more varieties of durum wheat in this class with stronger gluten strength”. Thus it is clear that the gluten concentration in some varieties of wheat is indeed increasing.
In my next blog I will look at how the use of genomics has changed the way wheat varieties are developed.
Categories
Blog Roll
Archive
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
September 2007
August 2007
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
September 2007
August 2007
Comments
keith grimaldi - eurogene.blogspot.com
I look forward to your next post. What I would also find interesting is data on the increased gluten consumption through the use of gluten as an ingredient to improve the properties of many processed foods.
According to a recent paper CD is on the increase, in the USA levels are 4 fold higher than 50 years ago, and this is not because of better diagnosis as the samples were compared to actual stored blood samples, the data reflect a true increase in the prevalence of the disease (Rubio-Tapia, et. Al, Gastroenterology. 2009 Jul;137(1):88-93.)
Is there any correlation suggesting that increased gluten consumption may be a factor - if not it would be good to be able to exclude it
Gerry - www.genomealberta.ca/blogs/default.aspx
Thanks for your comment Keith, I want to answer your question from two perspectives. First, risk factors for celiac disease in Indo-European populations seem to be related to some specific genetic markers. These markers however are not found in the same frequency in Asian populations. I intend to develop this topic further in the series I am writing about gluten and gluten intolerance on this blog. With regard to the interesting study on blood, I read that with great interest when it first came out. What a find to have access to all those blood samples taken in the 1950s! It would be nice if they could now go back and look at the same blood samples to see if there is the same distribution of genetic markers that exist in our population today. I suspect the answer is yes. If that is true, then there is a good chance that the increase in gluten intolerance is indeed environmental.
Second, with regard to gluten as an ingredient, I understand that in Canada, bakers of bread prefer to purchase flour made from the more expensive ‘hard’ wheat. If the flour is from ‘soft’ wheat then additional gluten must be added to bring the levels up to make the higher rising breads. Addition of gluten as an ingredient is very expensive making the choice of ‘hard’ wheat flour economically preferable.
Clayton -
Gerry,
A great posting. I've passed it on to my wife, Carolyn, whose sister has Crohn's. My mother-in-law has periodic bouts of celiac symptoms. I'm sure that they'll want to read your posting, as will many of their friends and their families.
Cheers, Clayton
gypsy -
Don't know if you can help... I have a wheat intolerance but on a trip to New York found that I was able to eat wheat products without the symptoms I suffer here in the UK. Is that to do with the processes used in wheat production or do they use different types of wheat? Any info would be welcome.
Thankyou in advance.
gypsy
Odile Brock -
I don't think your little math is right. "The protein portion, collectively called gluten, makes up about 10% to 15% of the wheat seed. A little quick math tells me that if the gluten content increased 10 times, it would make up more than 100% of the kernel..." The conclusion to the two statements is that the gluten content WAS 1% to 1.5%, since it is now 10% to 15%. No logical contradiction.