You've heard about omega-3s and omega-6s. Eating too much omega-6 containing food can lead to cancer, cardiovascular disease, and excess inflammation. And eating omega-3s is important because it can keep that inflammation under control. But there's one exception to omega-6s, and that's gamma-linolenic acid (GLA).
It's considered an essential fatty acid (EFA). Whenever a nutrient is called "essential" it means you need to eat it to get it. Your body can't produce its own, the way it can with many other things. The two EFAs that you need to eat are omega-3s and 6s. However, you can't go hog-wild and eat a ton of omega-6 fatty acids. That's what most Americans do and it's caused some problems.
GLA is a omega-6 fatty acid, but it's a special one. If you're familiar with the omega-3s, you know about their ability to modulate inflammation. And because of that you might be taking fish oil. Well, what sets GLA apart is that it's an omega-6 fatty acid that doesn't increase inflammation. In fact, it decreases it.
There are a lot of claims about GLA, including its ability to burn fat. Some go so far as saying that "GLA is the dietary fat that burns fat." Why? Because they believe it activates brown adipose tissue (BAT).
The body has two different types of fat: brown and white. BAT is the brown fat that's considered a metabolically active tissue, which means that it contributes to thermoregulation and energy expenditure. Sounds pretty cool, eh?
But wait. Before you start doing all the things on Google that might increase BAT, first realize that you probably won't get that far.
Mammals that hibernate have more BAT than humans since it's used for thermoregulation during a long winter's nap. Humans do have BAT, but it's mainly a phenomenon of infancy. It's a protective mechanism to keep babies warm since they don't have the musculature to shiver for heat production. As you become older, BAT will decrease and vary from person to person. So you still have it, but not to the extent that you used to and you might not be able to increase it.
A study out of the Journal of Obesity showed that BAT was identified in adults that were exposed to cold for two hours at a temperature of 66 degrees Fahrenheit by intermittently putting the subjects' legs on an ice block. Once the they underwent this process, subjects showed that there was activation of BAT in the supraclavicular and paraspinal regions.
The caveat though, is that there were only thirteen subjects and only six showed BAT activity. That's less than fifty percent. Unless you want to expose yourself to an ice block for two hours and spend a ton of money for an evaluation, you'll never know how much BAT you have or how much you increased it. And there's probably a fifty percent chance you don't have much BAT now.
Let's say you are that special person that does have a bit of BAT. Then you'd be the type who could burn a ton of fat using GLA, right? Kind of.
The study that most refer to out of Japan is in the Journal of Comparative Biochemistry and Physiology. It has shown that the experimental group fed GLA activated BAT and accumulated less body fat than the other group. So is this is proof that GLA works? Not quite. There are a few things you need to know.
First off, the study was done in vivo, meaning that rats were used as subjects. Animal research is used as a preliminary step to find out if there's reason to believe that a nutrient has a therapeutic effect on humans. If so, then a study is set up to use people as subjects. And sometimes, rats get the results and gym rats don't. This is an extrapolation of data from a rat to a human.
But it turns out there are some studies showing GLA can contribute to fat loss in humans. Thing is, there are some issues with the studies. The biggest issue is the type of subject they used.
For instance, a study out of the Journal of Nutrition demonstrated that GLA reduces weight gain in formerly obese subjects. If you're a former obese person, then this may apply to you. But if you're a regular lifter who's never been obese, this doesn't apply to you.
GLA has shown that it may help prevent weight gain but that doesn't mean it'll help an already lean-ish person drop from twelve percent body fat to six percent body fat. That's just good old hard work and smart eating.
Conclusion: Unless future research is performed with a human, don't bother using GLA for fat loss.
Let's dig into some science. Your body's end goal is to have dihomo gamma-linoleic acid (DGLA) which is a derivative of GLA. And DGLA can reduce inflammation two ways. One, it's converted to PGE1, that's anti-inflammatory. Two, it can convert to 15- HETrE via the 15-lipoxygenase pathway. It has the ability of inhibiting the formation of 5-lipoxygenase that can lead to the formation of proflammatory metabolites.
If you look at the diagram, linoleic acid (LA) can convert to GLA then to DGLA. At that point, DGLA can have a direct anti-inflammatory effect by producing PGE1 or an indirect effect by producing 15-HEtrE. You might be thinking that all you have to do is take more LA (omega-6's) and voila, more GLA is produced and eventually DGLA.
But what looks good on paper doesn't always pan out in real life. When it comes to the conversion of certain nutrients, enzymes run the show. In this case the body needs an enzyme called delta-6-desaturase (D6D). This enzyme converts LA to GLA. This must occur to eventually produce DGLA. The problem is, the D6D decreases with:
- Trans fats
So we can safely assume that many of us have a diminishing D6D. You may not eat sugar or drink alcohol, but you probably have some stress, exposure to radiation, and you're aging. So the body's ability to produce GLA diminishes. That's why supplementing with GLA bypasses the rate limiting D6D pathway and is quickly converted to DGLA.
I would consider GLA if I were an older lifter. It's another pathway to help keep inflammation at bay and improve recovery. For those lifters out there who struggle with the use of NSAIDS for joint pain, GLA may be a worthwhile approach. A study out of the Journal of Rheumatic Disease showed the benefits of GLA for subjects with rheumatoid arthritis. There were three groups:
- Control group
- Evening primrose oil (EPO)
- Evening primrose oil and fish oil
GLA is found in plant seed oils such as evening primrose oil, black currant oil and borage oil. After twelve months of supplementation, eleven out of fifteen of the EPO group and twelve out of the fifteen EPO/fish oil group reduced or stopping taking NSAIDS.
Only five out of the fifteen of the control group reduced NSAID usage. Pretty damn good for a plant oil! You may not have arthritis, but the common issue with rheumatoid arthritis, osteoarthritis, and joint pain is inflammation. GLA is one way to create an anti-inflammatory effect.
Depending on what oil you choose, the GLA levels will vary. The dosage used in most studies is about 540 mg of GLA per day. You don't have to take a ton of it to benefit from GLA supplementation.
The bottom line is, GLA isn't super promising for fat loss, but if you've got quite a bit of stress, drink a lot of coffee, or are getting up there in age, then GLA is a good choice to deal and manage inflammation.