By Steven V. Joyal, MD
Chronic, low-level inflammation due to food sensitivity is a little-appreciated contributing factor for unwanted weight gain, along with other health conditions like fatigue, fluid retention, headache, and skin conditions.
Before we review how sensitivity to certain foods can make weight loss difficult, we need to understand the difference between food sensitivity and food allergy.
Classic food allergy occurs when certain foods trigger the immune system to release large amounts of the chemical histamine. When large amounts of histamine flood the body, a potentially life-threatening condition called anaphylaxis can occur. This potentially fatal condition causes the throat to swell, potentially cutting off the air supply to the lungs. This type of reaction is called a type I hypersensitivity reaction, mediated by Immunoglobulin E (IgE), a type of antibody.
Sensitivity to certain foods in our diet is different from classic food allergy. As opposed to the immediate surge in histamine release in classic food allergy, sensitivity to certain foods can contribute to a delayed reaction that results in chronic, low-level activation of the immune system. This chronic, low-level immune system activation is mediated through Immunoglobulin G (IgG). Inflammatory substances are produced in response to IgG antibodies at the level of the gut wall. These inflammatory factors generate free radicals that interact at the local level of the gut wall to enhance the ability of molecules in our gut to be absorbed intact through the gut wall and enter the bloodstream. These molecules can then further cause low-level inflammation at the tissue level, with fluid retention a common sign. In fact, fluid retention and the difficulty to lose weight despite dieting are often-overlooked signs of chronic, low-level immune system activation and associated inflammation due to undiagnosed food sensitivity.
Scientific research shows that food sensitivity and associated anti-food IgG antibodies play an underappreciated but important role in weight management. For example, a 2008 human clinical study in the prestigious peer-reviewed journal Experimental and Clinical Endocrinology & Diabetes compared carotid arterial IMT (measurement of arterial thickening consistent with atherosclerosis), anti-food IgG antibodies, and C-reactive protein (CRP), a pro-inflammatory factor known to be an independent risk factor for heart attack risk, in obese and normal weight study subjects.
The results of this study were incredible.
Researchers found that the level of inflammation as measured by CRP in the bodies of the obese study volunteers was 200% higher than the normal weight study volunteers, 3.6 mg/l vs. 1.2 mg/l, respectively. Furthermore, anti-food IgG antibodies were dramatically different between the two groups. The obese group’s mean anti-food IgG levels were 1451 mg/l, and the normal weight (control) group’s anti-food IgG levels were 600 mg/l, a 141% higher level of anti-food IgG antibodies in obese human test volunteers!