Today we are going to evaluate glutamine- an amino acid for its effect on body weight. It is the most abundant amino acid in the body but in times of stress like injury or burns, the body requires more glutamine.
It is useful in wound healing and helping patients to recover from illness. Glutamine can increase immunity and improve gastrointestinal health.
Cancer and AIDS patients tend to experience severe weight loss and loss of immune function which is why they are generally started on glutamine supplements.
What does research have to say about role of glutamine in weight loss?
Here are a few research studies which have evaluated the effect of glutamine on body composition.
Animal studies investigating role of glutamine in body weight regulation
Results of an animal study show that mice fed with high fat diet but supplemented with glutamine show reduced body fat, reduced insulin resistance, improved glucose metabolism in muscles and liver as well as reduction in inflammatory parameters.
Both glutamine and L-alanine are found to reduce body weight in animals genetically predisposed to obesity. Additionally glutamine also proved to improve glucose metabolism and insulin activity.
What does this mean?
There are not many animal studies available that suggest that glutamine helps in regulating body weight, though available studies show a positive effect.
Does glutamine improve exercise performance and weight loss in athletes?
Glutamine supplementation is very popular among athletes and bodybuilders as it is believed that glutamine helps build muscle mass, decreases body fat and increases exercise performance.
However a few studies don’t seem to support this idea.
Short term glutamine supplementation is not found to increase exercise performance in trained individuals. A study was conducted to verify whether glutamine supplementation prevents loss of muscle mass in athletes enrolled in weight loss programs.
Subjects exercised and ate a low calorie diet to create a calorie deficit. They received glutamine or a placebo. Interestingly both groups lost significant amount of body mass, lean body mass and fat mass.
What does this mean?
Glutamine is an amino acid and therefore its supplementation is believed to increase muscle mass and improve exercise performance. We came across studies that do not seem to agree with this idea which kind of makes this concept doubtful.
How can glutamine help obese individuals?
We found a few studies that show that glutamine can regulate body weight but still there is a lack of scientific evidence that confirms that glutamine is effective for weight loss.
Glutamine causes weight loss without change in diet
One of the best studies or rather the only study favouring glutamine for weight loss is the clinical trial conducted in Sapienza University, Rome. In this 6 overweight and obese individuals were randomized to receive glutamine or another protein supplement for four weeks after which their treatments were interchanged.
No changes in lifestyle or diet were made. The glutamine group lost around 3kg body weight and waist circumference reduced approximately by 4cm. They concluded that glutamine is safe and effective for weight loss.
Glutamine can affect satiety and glucose metabolism
When we consume food, there are instant changes in blood sugar. Insulin prevents rise in blood sugar by promoting its effective utilisation. Sharp rises in insulin can lead to sharp decreases in blood sugar which can in turn affect appetite.
A study conducted in Australia showed that glutamine at 15 and 30g stimulated GLP-1 secretion and prevented post meal blood sugar rise in diabetic patients. Glucagon like peptide-1 (GLP-1) is a hormone that is secreted in the intestines and affects satiety and gastric emptying.
Researchers at University of Cambridge found that a single oral dose of glutamine increases secretion of GLP-1 in healthy volunteers but the effect is extremely small to be clinically useful.
Researchers from the same institute have also proven that glutamine supplementation increases GLP-1 secretion in obese, lean and diabetic obese individuals. They say that this finding can help in treatment of obesity and diabetes.
It improves gut bacteria in obese
L-glutamine supplementation is proven to modify gut microflora of obese individuals. 14 days of glutamine supplementation brought about changes in type of bacteria that grow in the intestine.
Ratio of Firmicutes to Bacteroidetes (2 types of bacteria) is a good indicator of obesity. This ratio decreased with glutamine supplementation.
It increases metabolism and fat oxidation
In a clinical trial 10 healthy young adults received a mixed meal with either glutamine supplementation or an amino acid mixture. Increase in energy expenditure was observed in glutamine group and was observed within 3 hours of meal consumption and even beyond that.
Carbohydrate oxidation was 38% higher in glutamine group and glutamine also enhanced fat oxidation by 42 Calories.
What does this mean?
Few research studies show that glutamine indeed can help treat obesity by acting through different mechanisms. However they are very limited in number to conclude that glutamine can help in weight loss.
Glutamine is available as powders, capsules, tablets, or liquids. Standard preparations are typically available in 500 mg tablets or capsules.
There are no side effects associated with glutamine supplementation. However people with kidney disease or liver disease or history of seizures should avoid glutamine.
It is preferable to consult a doctor before starting on glutamine supplements.
Glutamine shows decent potential into being developed as an anti-obesity agent but as of now we need good long clinical trials to prove glutamine’s efficacy in weight loss. So I wouldn’t really suggest taking glutamine for weight loss.