A body of evidence suggests that the most used flavor enhancer, glutamate, which can be found in almost every processed food, is causing adverse effects within normal dietary ranges.
The study published in the Journal of Headache Pain reveals that a single dose of monosodium glutamate (MSG) causes headache in the majority of healthy individuals tested.
The researchers conducted a double-blinded, placebo- controlled, crossover study to examine the effect of repeated intake of glutamate on spontaneous pain, mechanical sensitivity of the masticatory muscles, side effects and blood pressure.
Fourteen healthy subjects participated in 5 daily sessions and received 150 mg/kg of glutamate the first week, and placebo the second week (25 mg / kg of common salt). After 15, 30 and 50 minutes spontaneous pain, pain threshold of masticatory muscles and blood pressure was assessed. Saliva samples were taken 30 minutes after MSG intake to determine its concentration.
The results were as follows:
-headache occurred in 8 of 14 subjects on MSG and only in 2 patients on placebo
-salivary glutamate concentrations on day 5 were elevated significantly elevated
-pain increased in the masticatory muscles on day 2 and 5 after taking glutamate
-blood pressure was significantly elevated
A wide range of side effect were reported in the MSG group including: sore jaw, nausea, fatigue, headache, stomach ache, dizziness and chest pressure
What You Should Know?
This study shows a number of negative effects of the widely used food additive glutamate. Checking the food label will help in recognising this additive, designed by E numbers from E620 to E625, monosodium glutamate or other ingredients that are rich in glutamate such as hydrolyzed soy protein, yeast extract, etc. It is nearly impossible to avoid glutamate if packaged food makes the biggest part of food consumed. An effort should be made to eat a whole food based diet or one where food is prepared at home from scratch.
For those suffering from health issues listed above, MSG avoidance should be of vital importance.
The doses used in this study (150 mg/kg per day) are within the daily dietary ranges (from 50 to 200 mg/kg per day) which sows that “normal” intake is linked to negative health conditions.
Glutamate is neurotoxic and an endocrine disruptor which has been linked with dozens of adverse health effects. As a “flavor enhancer” it acts in a drug-like fashion and contributes to metabolic syndrome (a group of pathologies including insulin resistance, weight gain, blood lipid disorders and hypertension).
Shimada A et all: Headache and mechanical sensitization of human pericranial muscles after repeated intake of monosodium glutamate (MSG), J Headache Pain. 2013; 14(1):2