Top 10 Best Food Sources of Glutamine
Amino acids are critical players in nearly every metabolic function within the body. One of the most critical amino acids is L-glutamine which is by far the most abundant free amino acid in the body. It accounts for over 60% of the free amino acids in blood, brain, organs, and muscle tissue (1). This article goes over the benefits of L-glutamine and the top 10 best food sources of glutamine.
This critical amino acid is necessary for a number of different functions in our body and boosting our circulating levels of L-glutamine can help a number of different health conditions and improve our overall quality of life.
Glutamine plays a very important role in cardiovascular function by supplying a key energy source for endothelial cells that line blood vessels. Additionally, glutamine regulates nitric oxide synthesis by these endothelial cells (2, 3, 4). This is critical for maintaining blood vessel tone and reducing inflammation in the blood vessel walls.
Glutamine Improves Neurological Function:
Glutamine is also a very important player in healthy neurological function and has been shown to improve mood, concentration, & memory (5, 6, 7) . Glutamine easily crosses over the blood-brain barrier where it is converted into L-glutamic acid. Glutamic acid is essential for cerebral function.
Glutamic acid is unique in that it can be converted into an energy source for neuronal cells when blood sugar is low. This characteristic is thought to be responsible for glutamine’s ability to damper sugar and alcohol cravings.
Glutamine is also a critical part of our digestive system. It is the primary nutrient for the cells of the intestinal lining where it helps regulate cellular reproduction. Through this mechanism, glutamine helps prevent and rebuild a leaky gut, which is common in people with inflammatory and auto-immune conditions (8, 9, 10) . For this reason glutamine supplementation has been shown to be very effective in individuals with ulcerative colitis, celiac disease, Crohn’s disease, & irritable bowel syndrome (11, 12).
Glutamine also helps regulate cells absorb water across the junction between the small intestine and blood stream. This is a very important part of keeping the body from losing fluid and becoming dehydrated. When water is not absorbed back into the body diarrhea is the result. Diarrhea can be disastrous because we lose both water and other vital nutrients. Glutamine has been shown to reduce the frequency and severity of diarrhea (13, 14)
Finally, glutamine plays a very important role in both cellular and systematic detoxification processes. The lymphatic system maintains fluid and protein balance in the body, carries immune cells, and filters out toxins that are stored in tissues .
Glutamine is a key energy source for lymphatic cells allowing them to better remove toxic debris (15). Additionally, glutamine acts as a transport molecule to carry ammonia out of major tissues including the brain where it is shipped to the liver for conversion into urea.
Reduces Food Sensitivity Reactions:
A 2004 study found that L-glutamine benefits the body by regulating IgA immune response (16). IgA attacks bad bacteria and viruses to keep to prevent infections. Secretory IgA (sIgA) is an anti-body that regulates the mucosal membranes of the intestines, respiratory, urinary and reproductive tracts.
Poorly regulated sIgA responses are associated with food sensitivities and allergies. Glutamine plays an important role in regulating and modulating sIgA to keep the immune system strong and reduce food sensitivity reactions.
Another study published in the journal of Clinical Immunology found that glutamine normalizes the effects of both the Th1 and TH2 immune response that stimulates inflammatory cytokines (17). This demonstrates the ability of L-glutamine to balance and modulate the immune system to reduce inflammatory activity and promote an anti-inflammatory environment.
Best Food Sources of Glutamine:
L-glutamine is synthesized by the body from glutamic acid or glutamate. It is known as a conditionally essential amino acid, because it is used by the body in large amounts. You can find it in a wide variety of both plant and animal foods, however, animal foods are the richest sources.
Individuals that have compromised digestive function and low stomach acid production, will have trouble breaking down protein they consume and absorbing amino acids from food. In these cases, it is highly advised for these individuals to not rely on food alone to support their L-glutamine needs. Easily absorbable supplements are widely available and can make a very big difference for these individuals.
1) Bone Broth and Organic Bone Broth Collagen Protein
2) Grass-fed Whey Protein
3) Grass-fed Raw Dairy
4) Grass-fed beef/Bison
10) Organic poultry
Does Glutamine Supplementation Feed Cancer
Many cancer cells use glutamine as a fuel source and so there is speculation that supplemental glutamine could feed cancer. However, this is merely myth as all the reports on glutamine show that it helps to foster an improved immune response. Studies have even shown that it helps to improve the ability to recover from various cancer treatments by reducing muscle loss and improving gut and immune barrier function (18).
Glutamine itself is the most abundant amino acid in the body and cancers that feed off of glutamine are able to get the glutamine they need without the consumption of any food at all. In fact, even doing a water fast won’t fully starve glutamine feeding cancer cells. There are certain glutamine blocking drugs that have shown effective on these forms of cancer but dietary restriction is not an effective strategy.
As a clinician, I personally use glutamine rich foods and supplements and recommend them for a wide variety of my clients due to its ability to support gut and immune system health and ability to reduce cravings. Try it out and see how your body responds to it.
Consuming These Glutamine Rich Foods
It is ideal to consume at least 2 servings from this group daily. Raw dairy products from grass-fed cows and goats are also very high in L-glutamine. This includes grass-fed, non-denatured whey protein powder which is considered the most bioavailable form from an animal source. Using an ample amount of this form of whey protein in a shake with coconut milk, berries, & cinnamon everyday is a fantastic way to naturally boost L-glutamine levels.
Some individuals, especially those with leaky gut and auto-immunity have immune reactivity to whey protein. This can include grass-fed, non-denatured whey. If you notice that you have cramping, bloating, increased pain, brain fog, skin reactions, low-energy, sleeplessness, sinusitis or lowered immunity when consuming whey than discontinue immediately.
Sauerkraut and Fermented Cabbage
Cabbage is considered the most dense vegetable form of L-glutamine and red cabbage is the most anti-oxidant rich form of cabbage. An amazing way of bringing in the high quality nutrition from red cabbage is through juicing or shredding and fermenting it.
Red cabbage sauerkraut made with apple cider vinegar may be one of the most bioavailable ways to consume L-glutamine due to the deep fermentation processes that create an abundance of enzymes and good bacteria that allow amino acids and other nutrients to be better absorbed and utilized within the body.
I recommend for most of my clients to eat fermented vegetables such as sauerkraut and kimchi daily. Even having a tablespoon of these each day can make a big difference. However, for individuals who struggle with small intestinal issues including bacterial or yeast overgrowth and histamine intolerance, it is often best to avoid fermented foods until these conditions reduce.
If you have struggled with worsening symptoms after consuming bone broth, vinegar or fermented foods you most likely have issues with your histamine metabolism. There are many things you can do to improve the histamine response and I go over those in this article.
Most people tolerate L-glutamine supplementation very well (1). However, some individuals are unable to metabolize it effectively and can have an excess build-up of glutamate in the brain. This can cause anxiety and irritablity. These individuals are typically not methylating well and often deficient in zinc, magnesium, riboflavin, B6, folate and B12. This reaction is rare but can happen if you are supplementing with heavy doses of L-glutamine while deficient in these B vitamins.
The best dosage for healing leaky gut is to start with about 3-5 grams daily and if you feel good (no increased anxiety or irritability) you can increase your dosage to 5-10+ grams. I have seen great clinical results using 20+ grams daily for certain individuals.
You want to make sure you have a purified version of L-glutamine that has been clinically tested. It is always adviseable to consult a trained functional nutritionist or functional medicine doctor before taking more than 5 grams daily. This is what I use with my clients here
Additional Info on L-Glutamine:
L-glutamine is SO POWERFUL for healing the gut as well as the endothelial lining of the arteries, urinary tract, respiratory tract, etc and stabilizing a highly reactive immune system. This is why it is one of my go to supplements with auto-immune cases and individuals suffering from damaged arteries, UTI’s, ulcers, leaky gut, painful urination, allergies and sinusitis, etc.
My favorite product to support the strength and healing of the mucousal membranes (gut lining, urinary tract lining, respiratory lining, reproductive lining) is Gut Repair. This product features four specialized ingredients including L-glutamine (in lower dosage than the product above) for enhanced gastrointestinal support.