Gamma-Linolenic Acid (GLA) Supplementation: Evidence and Recommendations
GLA supplements are not recommended for general consumption as there is insufficient evidence supporting their routine use for health benefits. Current dietary guidelines do not support the use of GLA supplements for improving health outcomes related to mortality, morbidity, or quality of life 1.
What is GLA?
Gamma-linolenic acid (GLA) is an omega-6 polyunsaturated fatty acid found in certain plant seed oils. It serves as a precursor to various eicosanoids that can influence inflammatory processes in the body 2.
Evidence on GLA Supplementation
Cardiovascular Health
- The American Heart Association does not recommend GLA supplements for heart disease risk reduction 1
- Instead of supplements, the guidelines emphasize consuming foods containing long-chain omega-3 fatty acids (EPA and DHA) from fatty fish 1
- One small study showed borage oil (containing GLA) may improve HDL cholesterol and lower triglycerides in overweight young adults, but did not affect total cholesterol, LDL, or glucose levels 3
Inflammatory Conditions
- Some evidence suggests GLA may have anti-inflammatory properties:
- A randomized controlled trial showed GLA supplementation (2.8 g/day) improved symptoms in rheumatoid arthritis patients 4
- GLA can be metabolized to dihommo-gamma linolenic acid (DGLA), which may have anti-inflammatory effects 2, 5
- However, GLA can also be converted to arachidonic acid (AA), which may promote inflammation 2, 6
Metabolic Effects
- Despite some theoretical potential, GLA supplementation showed no effect on resting metabolic rate in overweight young adults with a family history of obesity 3
Potential Concerns with GLA Supplementation
- Increased Arachidonic Acid: GLA supplementation alone can increase serum arachidonic acid levels, which may potentially promote inflammation 6
- Variability in Response: Individual genetic variations in fatty acid desaturase (FADS) genes affect how GLA is metabolized, leading to unpredictable responses 2
- Limited Clinical Evidence: Most positive findings come from in vitro or animal studies, while human clinical trials show inconsistent results 2
Expert Recommendations
Current dietary guidelines from major health organizations do not support GLA supplementation:
- The American Diabetes Association states there is "insufficient evidence to support the use of cinnamon or other herbs/supplements for the treatment of diabetes" 1
- The American Heart Association does not recommend supplements like GLA for heart disease risk reduction 1
- No major clinical guidelines recommend GLA for improving health outcomes
Practical Considerations
If you're still considering GLA supplementation:
- Combining GLA with EPA (an omega-3 fatty acid) may prevent the unwanted increase in arachidonic acid levels 6
- Dosages used in clinical studies (e.g., 2.8 g/day for rheumatoid arthritis) are much higher than typically found in over-the-counter supplements 4
- Individual responses may vary significantly due to genetic factors affecting metabolism 2
Bottom Line
Based on the most recent and highest quality evidence, GLA supplements are not recommended for routine consumption. If you have a specific medical condition like rheumatoid arthritis, consult with your healthcare provider about whether GLA might be appropriate as part of your treatment plan, as some limited evidence suggests potential benefits for inflammatory conditions.