Glutamine is the most abundant amino acid in the human body. L-Glutamine is commonly used in the fitness industry with the plan to improve performance, support the immune system, preserve muscle and build muscle as it is the fundamental building block for protein synthesis / building things. Many people may not know this but the thing it builds first is your gut wall. Glutamine is stored and utilised first and foremost by our gut to toughen it up.
Glutamine supplementation is essential for correcting “Leaky Gut”
Intestinal Permeability is also known as ‘leaky gut’. Leaky gut has been linked to many seemingly unrelated health concerns and chronic diseases such as obesity, autoimmune disease, allergies / intolerances and diseases related to chronic inflammation. Intestinal permeability is arguably the western world’s biggest undiagnosed disease.
Factors such as stress, anxiety, high intake sugar and refined carbohydrates and grains, alcohol and tobacco use, low intake of fibre, fruits and vegetables, over use of antibiotics and pharmaceutical drugs and food intolerances are all contributors to leaky gut. It may take years for our gut to become permeable and we may start to see the following signs and symptoms:
• Digestive issues such as bloating, gas, diarrhoea, constipation.
• Hormonal Imbalances such as PMS or PCOS.
• Food allergies and intolerances.
• Chronic fatigue or fibromyalgia.
• Anxiety and difficulty concentrating.
• Autoimmune disease (type 1 diabetes, Hashimoto’s, rheumatoid arthritis).
• Candida Overgrowth.
• Seasonal allergies or asthma.
• Skin issues such as acne, rosacea or eczema.
• Inability to build muscle.
• Inability to move stubborn fat.
• Poor / inconsistent athletic performance.
So, what is leaky gut?
Naturally, the gut is permeable to allow the uptake of water, macro- and micro-nutrients. These compounds can cross the gut wall either through the cells or between the cells using active transport pumps or passive diffusion. The gut wall can also dump toxins and use this mucous membrane to flush waste. When the gaps between the cells become too open and too permeable; all sorts of things can slip through triggering immune and inflammatory activity. This is what is referred to as “leaky gut wall”.
The gaps between the cells are controlled by “tight junction proteins” and they can open these channels between cells in response to stimuli such as gluten / gliadin, infection, allergy / intolerance, inflammatory mediators, toxic exposure and stress.
Once the gut is too permeable, endotoxins leak through the gut wall and trigger an immune response, causing local inflammation disrupting digestion, absorption mechanisms and making the gut wall leakier and also a systemic inflammatory cascade which effects the whole body contributing to many disease states. Repairing gut permeability through supporting integrity of tight gap junctions can be the most fundamental healing protocol you can ever do to your body to avoid serious illnesses.
Glutamine Supplementation for Tight Gap Junction Proteins
A recent human study looked at the effects of oral glutamine on exercise-induced GI permeability. The stress of high-intensity exercise has been shown to increase intestinal permeability, stimulate a proinflammatory cascade of events, eventually causing GI distress. Participants underwent 60 minutes of high-intensity running (70% Vo2max) with a supplementation of glutamine or a placebo. The study demonstrated that 7 days of oral glutamine supplementation protected the gut during high-intensity endurance exercise by reducing intestinal permeability. It was found that glutamine had two mechanisms of actions; one through preserving the intestinal tight junction barrier and reducing permeability and the second via modulation of the inflammatory response through activation of stress markers Heat Shock Protein (HSP70) and inhibition of NF-ĸβ (reduction of inflammation makers). This study shows significant benefits of glutamine supplementation given around exercise to prevent gut permeability, improve tight junction and reduce intestinal inflammation.
The gut-brain axis is a complexed relationship between the nervous system and gastro intestinal tract. When you listen to your intuition is commonly means that you listen to your gut instinct because it is said to have a brain of its own. Being exposed to acute and chronic stress can significantly impact our gastrointestinal tract causing irritability, decreased nutrient absorption and permeability. It has recently been discovered in a human study that acute psychological stress increases small intestinal permeability via corticotropin-releasing hormone (CRH) from mast cell activation (an inflammatory response). Another study showed that stress seen in weaning piglets increased intestinal permeability by 40% by elevating corticotropin-releasing hormone (CRH) concentrations. The study went further and supplemented L-glutamine 1% for 7 days. The study showed significant improvement in intestinal permeability and villus height, while reducing jejunal MRNA and protein levels for CRF proving beneficial anti-inflammatory effects. Interestingly the study also found L-glutamine regulated expression of tight junction proteins and CRF in the jejunum of weanling piglets to further emphasis glutamines protective and anti-inflammatory properties.
Furthermore, another study on weaning piglets observed the effects 1% L-glutamine had on growth performance, antioxidant ability, immunity and expression of genes related to intestinal health. The study concluded that 1% L-glutamine administration improved performance, digestibility of nutrients and the activity of jejunum disaccharide enzyme, and regulate the relative expression of intestinal PParᵧ, mTOR and PK. Possible mechanism bay be due to the improved digestion and absorption of nutrients through increasing the related disaccharide enzyme activity and mRNA relative expressions levels of genes related to intestinal health.
How do I supplement with Glutamine?
L-Glutamine shows to have immune supporting, anti-inflammatory actions and improves intestinal tight gap junction to reverse ‘leaky gut’ and improve gut wall integrity. Supplementing will significantly benefit those in high stress jobs, using HIIT training, fasted cardio, athletes or anyone that show signs and symptoms of the mentioned intestinal permeability.
L-Glutamine is synthesised by the body from glutamic acid or glutamate. If the body is unable to produce enough it needs to get it directly from your diet. The foods with most L-glutamine benefits are bone broth, grass-fed beef, Chinese cabbage, broccoli, wild caught fish (tuna and salmon) and turkey.
Most athletes will supplement with between 2-5 grams twice per day and for athletes, this may increase to 5- 10 grams per dose once or twice daily.
As Glutamine is mainly going into your gut wall you can take it any time and with meals. The best time to take L-glutamine is post workout to restore levels that were used up during the workout.
Felice et al. 2016, Review article: Microbiota-gut-brain signalling in Parkinson’s disease: Implications for non-motor symptoms, Parkinsonism and Related Disorders, no.27, pp.1-8.
Vanuytsel, T et al. 2014, Psychological stress and corticotropin-releasing hormone increase intestinal permeability in humans by a mast cell-dependent mechanism, Neurogastroenterology, no..63, pp.1293-1299.
Zuhl, M et al 2014, effects of oral glutamine supplementation on exercise-induced gastrointestinal permeability and tight junction protein expression, Journal of Applied Physiology, no.116, pp.183-191.
Wang et al 2014, Glutamine enhances tight Junction protein expression and modulates corticotropin-releasing factor signalling in the jejunum of weanling piglets, The journal of nutrition, no145, p.25-31.
He, J 2016, Effects of L-glutamine on growth performance, antioxidant ability, immunity and expression of genes related to intestinal health in weanling pigs, Livestock Science, no.189, pp.102-109,