Friday, 6 March 2015
Dr Jason Fung: Wheat – How to Lose Weight VII
Wheat is one of the most vilified foods in the nutritional world. From gluten concerns to obesity, the poor fellow doesn’t have a friend to call his own. Yet wheat, along with rice and corn, is one of the most ancient domesticated foods in existence. The original Paleo – if you will. How can wheat possibly be so bad?
Somewhere around 3000 BC the people around the area of modern day Syria began to cultivate the ancestors of wheat – the emmer and einkorn varieties. Having a semi-stable source of food improved survival odds tremendously. Soon, the farmers had spread across the globe bringing wheat along with, later, domesticated animals.
The next major improvement in agriculture came with the application of fertilizers to increase yield. First, guano, the nitrogen and phosphorus rich droppings of penguins and seabirds were applied with great effect. With the advent of nitrogen processing, chemical fertilizers were soon making their mark. This kept agricultural production high enough to feed the world. For a time.
Nevertheless, by the 1950s there were Malthusian concerns of worldwide famine. In Mexico, Norman Borlaug, who would later win the Nobel Peace Prize in 1970, began to experiment with higher yielding varieties of wheat. One of his accomplishments was to increase the seed head size. However, there was a problem. The large head would tend to flop over on the stalk.
The solution was to shorten the stalk of the wheat. This became known as dwarf and semi-dwarf wheat and had the advantage that it would not buckle as well as faster maturation. No time was wasted growing the stalk which was not edible anyway. Within years, 95% of wheat was of the Borlaug variety and the yield increased by 6 fold. India, facing mass starvation in 1965, ordered tonnes of the new seed and farmers began to plant dwarf wheat. Wheat harvests quickly tripled and India became self-sufficient in food. This was the Green Revolution and Norman Borlaug was the Father.
But where Dr. Borlaug bred naturally occurring strains, successors quickly turned to new technology to enhance mutations. This was the atomic age after all. Using X-rays and thermal neutrons, these new Genetically Modified (GMO) crops were born. Later, scientists would discover how to target specific genes for inclusion into new genomes. Wheat is a relative laggard, with corn, rice and soybeans taking the lead.
The wheat varieties of today are not the same as those 50 years ago. The new varieties of wheat were not tested in any safety lab. They were merely assumed to be safe. But the Broadbalk Wheat Experiment is clear evidence that the nutritional content has changed significantly as documented in the paper “Evidence of decreasing mineral density in wheat grain over the last 160 years“.
The red line depicts the introduction of dwarf wheat. Even as grain yields skyrocket, the micronutrients contained in the wheat grain plummet. Does this matter? I don’t actually know, but it sure can’t be good.
Has the wheat changed over the last 50 years? Hard to say but there has certainly been an increase in celiac disease. Gluten causes damage to the small intestine in susceptible patients. Dr. Murray of the Mayo Clinic compared blood samples from Air Force men 50 years and found that the prevalence of celiac disease has quadrupled. Could this be a result of the changes in wheat itself? Hard to say, but interesting to think about.
The other major change in wheat is the method of processing. Wheat berries were traditionally ground by large millstones powered by animals or humans. This has been replaced by the modern flour mill which is better at removing everything. The bran, middlings, germ and oils are removed leaving the pure white starch. Most of the vitamins, proteins and fats are removed. This is modern white flour in all its evil beauty. Modern milling is able to grind flour to such a fine dust that absorption into the body is extremely rapid.
Starches are composed of hundred of units of sugars all linked together. 75% of the starch is organized in occasionally branched chains called amylopectin. The rest comes as unbranched chains called amylose. There are several classes of amylopectin. Legumes are particularly rich in amylopectin C. This is very poorly digested. As the undigested carbohydrate moves towards the colon, gut flora produces gas causing the familiar ‘tooting’ of the bean eater. While beans and legumes are very high in carbohydrates, much of it is not absorbed, Beano notwithstanding.
Amylopectin B is found in bananas and potatoes. This is intermediate in absorption. The most easily digested is Amylopectin A found in – you guessed it – wheat. The upshot is that wheat is converted to glucose more efficiently than virtually any other food. This is recognized in the Glycemic Index where the effects of the different amylopectins is evident.
There are also persistent concerns that the gluten in wheat produces exorphins. While other foods may have gluten, wheat is the the major source in our diets by a factor of 100. Digestion of this gluten may yield morphine like substances that can cross the blood brain barrier that many are concerned are addictive. While evidence in the medical literature is sparse, anecdotal evidence is not. Many people admit to being ‘addicted’ to bread and pasta. Comfort foods are also typically flour based – cookies, cakes, macaroni and cheese. While this does not prove anything, it is certainly worth noting.
China provides an interesting insight into a traditional rice based diet that has introduced wheat. Exhaustive data were compiled by T. Colin Campbell in The China Study. Wheat is the strongest positive predictor of body weight. As wheat intake increases, so does Body Mass Index. There was also a strong association with coronary disease and wheat intake.
So let’s see. Modern wheat is a problem because
Lower nutritional value
Processing removes most of fibre and vitamins
Modern milling speeds digestion therefore increasing glycemic effect
High in amylopectin A
May be addictive.
Please, sir, can I have some more?
Not all carbohydrates lead to obesity. However, refined grains such as flour clearly do. This has been known since the time of William Banting.
The next step in weight loss?
Reduce refined grains, particularly wheat.