Purposeful Primitive Online

The following is to be used for informational purposes only and should not be taken as medical advice.  The information below and any related correspondence does not imply a physician/patient relationship with the author.  Please consult your personal physician for your medical care and/or before beginning any exercise or nutrition program.  Dr. Hardy’s opinions are his own and do not necessarily reflect those of Johns Hopkins University or the U.S. Navy.

Whole Grains: Health hero or nutritional villain?

Q: I recently have heard that whole grains may not be good for me.  I thought we were supposed to eat whole grains because they are healthier than processed grains like flour.  Why are some people now saying they are not the best dietary choice?

A:  Whole grains have traditionally been recommended because they are less processed and have a lower glycemic index than grain-based foods such as white flour.  The glycemic index is basically a measure of how fast a carbohydrate containing food is broken down into individual glucose molecules and enters the bloodstream (i.e. how fast a food raises blood sugar).  This is important because a raise in blood glucose stimulates the pancreas to produce insulin to clear the blood of glucose and facilitate entry of it into various cells for fuel.   The larger the rate of blood sugar increase, the larger the insulin spike.  Chronic high insulin levels have significant health consequences that will be discussed at another time.

So a lower glycemic index sounds good right?  This would only be true if we ate very small amounts of whole grains, rather than the large servings usually ingested as part of current dietary recommendations.  In truth, whole grains, in the amounts eaten in most of our diets, still produce a very substantial dose of insulin that persists several hours after the meal.

Aside from the high levels of insulin produced, cereal grains have other properties that are potentially much worse for your health than the insulin response.  Cereal grains contain an “anti-nutrient” called phytate in high amounts.  Phytate is in a class of chemical called chelators.  Chelators bind to metal ions such as iron, calcium, zinc, and magnesium, and sequester them away.  In this way, phytates prevent intestinal absorption of these biologically important minerals that are crucial for various physiologic processes in our bodies. There are various ways to prepare grains (such as soaking/fermentation) to reduce the phytate concentration, but this is seldom done in modern society before ingestion.  Phytates are also resistant to heat, so cooking won’t destroy them. For an excellent technical overview on phytates, check out the paper from Dr. Schlemmer and colleagues¹.

Perhaps the most insidious component of the ever more villainous cereal grain (specifically wheat, barley, and rye), is gluten.  Gluten is a protein categorized in a larger family of plant proteins called lectins.  Lectins are found in many plants and have widely varying levels of toxicity to humans, from small amounts of irritation/inflammation to autoimmune disease and even death.  An extreme example of a toxic lectin is the biowarfare agent ricin, which is derived from the castor bean.

Gluten itself is an overall classification of many individual proteins, which are largely represented by the specific proteins gliadin and glutenin.  These proteins can be resistant to digestion in the lining of our gut where food absorption normally takes place.  They can cause reactions from low level inflammation to outright destruction of the gut lining as seen in Celiac Disease.  Celiac Disease (AKA gluten-sensitive enteropathy) is an autoimmune disease that occurs in genetically susceptible individuals in response to gluten.  It is seen clinically as a malabsorption syndrome characterized by an inability to absorb essential fat, vitamins, and other nutrients.  It has other manifestations such as dermatitis, neurological problems, liver disease, infertility, and has been associated with Type I Diabetes and thyroid disorders².

Celiac disease used to be considered a rare disorder, but now is seen in as many as 1 in 100 people in the United States and other parts of the world.  So why I am going on about a disease that affects approximately 1% of the population?  Recent research is starting to look at adverse reaction to dietary gluten as a continuum, ranging from outright Celiac disease to gluten sensitivity manifested as irritable bowel syndrome.  A recent study showed evidence of gluten-related, immune-mediated inflammation in healthy subjects without celiac disease³. More importantly, even these low (sub-clinical) levels of reactivity to gluten are known to cause “leaky gut”, characterized by the passage of undigested food particles into the bloodstream.  The gut lining usually has tight junctions that don’t allow these particles to pass.  These particles become immunogenic (cause an immune response) as they are viewed by the immune system as foreign.  It is postulated that some of these particles “look” like structures in our own body, thus triggering an autoimmune response.  Some researchers believe this process may lead to conditions such as rheumatoid arthrtitis⁴ and Type 1 diabetes⁵.

Other interesting research has been carried out that shows substantial improvement of clinical signs of autism in autistic children given a gluten-free diet⁶.  Although these small studies are hardly conclusive, they give some important initial data to a possible link to gluten and this devastating childhood condition.

Many will argue that cereal grains are an important source of dietary fiber and minerals.  Given the above discussion on phytates, the mineral argument becomes fallacious.  Furthermore, there are much better sources of fiber from vegetables that are used by our body’s micro-flora to make butyric acid (the colon’s main energy source). In fact, butyric acid (butyrate) is anti-inflammatory and protects the gut against permeability (“leaky gut”)⁷.  It makes no sense to get fiber from gluten-containing grains that may act to counter the beneficial effects of butyric acid produced from dietary fiber.  There is nothing in grains from a nutritional perspective that cannot be obtained elsewhere from better sources, and without the potential adverse health consequences discussed above.  Thanks for the great question!

Yours in Strength and Health,

Chris

Christopher G. Hardy D.O. MPH CSCS

1. Schlemmer U, et al. (2009)  Phytate in foods and significance for humans: Food sources, intake, processing , bioavailability, protective role and analysis. Mol Nutr Food Res; 53: S330-S375.
2. Briani C, et al. (2008) Celiac disease: From gluten to autoimmunity. Autoimmunity Reviews; 7: 644-650.
3. Bernardo D, et al. (2007) Is gliadin really safe for non- coeliac individuals? Production of interleukin 15 in biopsy culture from non-coeliac individuals challenged with gliadin peptides. Gut; 56:889-890.
4. Cordain L, et al. (2000) Modulation of immune function by dietary lectins in rheumatoid arthritis. British Journal of Nutrition; 83: 207-217.
5. MacFarlane AJ, et al. (2003) A Type I Diabetes-related protein from wheat: cDNA clone of a wheat storage globulin, Glb1, linked to islet damage. Journal of Biological Chemistry; 278: 54-63.
6. Elder JH. (2008) The gluten-free, casein-free diet in autism: An overview with clinical implications.  Nutrition in Clinical Practice; 23: 583-588.
7. Saemann MD, et al. (2000) Anti-inflammatory effects of sodium butyrate on human monocytes: potent inhibition of IL-12 and up-regulation of IL-10 production. FASEB Journal; 14: 2380-2382.