Though it sounds similar, glutamine should not be confused with the neurotransmitter glutamate. Glutamine is a key component of proteins for humans and performs a host of functions in our bodies.
Research is pretty clear on the fact that glutamine is important, but not so clear on the amounts we need on a daily basis. It is present in many common foods in varying degrees, as well as in food supplements. In this article, you’ll find some of the best food sources for glutamine.
What Is Glutamine
Glutamine is an amino acid. That means that it plays a role in a lot of metabolic functions. It is a property it shares with most other dietary amino acids.
Let’s take a step back and look at amino acids. For the purposes of a human body, they’re compounds that form proteins. They come in two broad categories – essential and non-essential. Essential amino acids are those that we must ingest through our diet. Non-essential amino acids are those that the body can produce on its own, as well as ingested through food.
Glutamine is one of the non-essential amino acids. As the most abundant amino acid in humans, we rarely lack it. Cases of extreme starvation, injury or illness are notable exceptions.
Also like most other amino acids, glutamine comes in two forms – L-glutamine and D-glutamine.
A Tale of Two Glutamines
The difference between the two types is in their molecular arrangement. Humans only use L-glutamine. Therefore our list of best food sources for glutamine will be restricted to those that provide L-glutamine.
There has also been research into the role of glutamine in building muscle and enhancing sports performance. The research is inconclusive, but L-glutamine supplementation has gained significant traction in the sports community.
Glutamine in Sports
Most of the research about muscle building and performance hasn’t really panned out. However, some studies have concluded with a fair level of certainty that glutamine does act as a glucose precursor in humans. In this way, it does aid in exercise recovery as an agonist of carbohydrates in the metabolism.
Additionally, a link between glutamine supplementation and immune health has been suggested. It’s likely that it plays a role in immune function as well as intestinal health.
How Much and Where Do You Get It?
Now that we’re clear on what it is and what it does, you’re probably wondering how much glutamine you need on a daily basis. That’s another grey area, as a non-essential amino acid, glutamine intake can vary widely from person to person.
Reliable research has shown that around three to six grams per day is the typical daily intake. However, the actual figures depend heavily on the diet, given that some of the best food sources for glutamine are absent from some people’s daily menu.
Glutamine Rich Foods
As an amino acid, glutamine will notably be present in foods that are rich in protein. However, not all proteins are created equal. Every protein source has a different amino acid profile.
Just because a food source is protein-rich, doesn’t make it a good source of glutamine. Conversely, some foods that are low in overall protein have very high glutamine content.
Meat and Fish
The most complete source of protein in our diet is meat. Meats typically have the most well-rounded amino acid profiles.
Because glutamine is a component of protein, it isn’t present if fats. Glutamine concentration will be higher in lean cuts of meat and white fish.
Cooked red meat has the highest glutamine content in the form of glutamic acid. Up to 16.5% of the protein found in red meat is glutamine. That translates to around 1.2 grams per 100 grams of meat and even more in leaner cuts.
Most fish are also a great source of both protein and specifically glutamine. Saltwater fish has higher glutamine content on the whole, but not by much. White saltwater fish such as mahi-mahi has as much as 3.5g of glutamic acid per 100g of meat.
Eggs are another great source of complete protein. They are one of the healthiest foods in a lot of respects. They’re also one of the most versatile foods when it comes to preparation.
In terms of bang for your buck, eggs are probably the cheapest source of glutamine. 100 grams of eggs contains between 0.6 and 1.6 grams of glutamine. If you need to increase your daily glutamine consumption, eggs are a great way to do it affordably.
Roughly speaking, most eggs have similar glutamine content. However, duck eggs edge out chicken eggs by a small margin and goose eggs contain the most. If you have access to goose eggs, they rank among the best food sources for glutamine.
Cabbage is an outlier on this list in that it isn’t a good source of protein, nor is it a source of complete protein. Nonetheless, it has significant amount of glutamine.
If you’re in the market for glutamine in a low-calorie delivery system, cabbage is the food for you. 100 grams of cabbage contains 0.2 grams of glutamic acid.
That doesn’t sound like much, but consider that 100 grams of cabbage only contains around 25 calories. Compare that to 100 grams of beef with 250 calories and around one gram of glutamine. You can easily see how cabbage can provide more glutamine per calorie.
If you’re following a vegetarian or a vegan diet, you should also know that tofu and legumes have high glutamine content.
Dairy products contain two types of protein – casein and whey. Whey is a particularly good source of glutamine, but both casein and whey contain significant amounts of glutamic acid.
Whey is also commonly found in protein supplements. In dairy products, as with meats, the best sources of glutamine are those with low fat content. Skim milk is an excellent source of glutamic acid with around 0.8 grams per 100ml.
A Glut of Glutamine
Those are some of the best food sources of glutamine. This versatile amino acid is important for a lot of bodily processes. It’s conditionally essential, but it never hurts to have it in ample supply.
Meats, seafood, and dairy are your top choices for glutamine in the form of glutamic acid. But most sources of complete protein will also do the trick. For vegetarians and vegans, tofu and cabbage provide ample amounts of glutamine, as do most legumes.