Understanding Gamma Linolenic Acid (GLA)
Gamma linolenic acid (GLA) is a type of omega-6 fatty acid, a polyunsaturated fat that is essential for human health. While a typical Western diet is often high in other omega-6 fatty acids, GLA is less common and is primarily sourced from specific plant oils. The body can convert linoleic acid (another omega-6) into GLA, but this process can be inefficient in some individuals due to age, genetics, or health conditions. Therefore, many people turn to supplements derived from sources like evening primrose oil, borage seed oil, and black currant seed oil to ensure adequate intake.
GLA's Role in Metabolism and Weight Management
Contrary to the fear that all dietary fats lead to weight gain, GLA plays a unique and often beneficial role in metabolism. It is converted in the body into dihomo-gamma-linolenic acid (DGLA), which can be further metabolized into anti-inflammatory compounds. Research points to several mechanisms by which GLA may influence body weight:
- Enhancing fat metabolism: Studies have suggested that GLA can promote fatty acid oxidation (the process of breaking down fat for energy). In animal studies, diets rich in GLA reduced body fat content and increased the activity of enzymes involved in fat metabolism.
- Influencing adipose tissue: Adipose tissue, or body fat, exists in different forms, including white and brown fat. White fat stores energy, while brown fat burns energy to produce heat. Research suggests that GLA may increase the gene expression of proteins that promote the function of brown adipose tissue, leading to more calorie-burning activity.
- Preventing weight regain: A key human study conducted on formerly obese individuals found that supplementing with GLA significantly reduced the amount of weight regained over a 12-month period compared to a placebo group. This suggests a potential role for GLA in long-term weight maintenance.
- Balancing the omega-6 to omega-3 ratio: A high ratio of overall omega-6 to omega-3 fatty acids in the diet is associated with an increased risk of obesity. While GLA is an omega-6, maintaining a balanced intake is crucial. Supplements containing GLA may help regulate the metabolism of other fatty acids, helping to restore a healthier balance.
Clinical Evidence: What the Studies Say
While the theoretical mechanisms for GLA's positive effects on weight management are strong, human clinical evidence is mixed and complex. It's important to consider various study outcomes.
- Positive findings: A 2007 study on formerly obese individuals showed that 890 mg of daily GLA supplementation helped reduce weight regain over nine months. Another double-blind study on overweight individuals with a family history of obesity found a small but significant weight loss with evening primrose oil, a source of GLA. Short-term studies in postmenopausal women with hypertension have also indicated positive results regarding body fat.
- Conflicting findings: Some studies have failed to find a significant effect of GLA on weight loss. A twelve-week study on overweight women found no difference between evening primrose oil and a placebo. A 2021 study on overweight young adults found no effect of borage oil (high in GLA) on metabolic rate or BMI after six weeks, though it did improve some lipid readings.
Comparison of GLA Sources
This table outlines the key differences between the most common sources of GLA for supplementation.
| Feature | Borage Oil (Starflower Oil) | Evening Primrose Oil | Black Currant Seed Oil |
|---|---|---|---|
| GLA Content | Highest (approx. 20%) | Lower (approx. 7-10%) | Medium (approx. 15-20%) |
| Dosage Required | Lower dosage needed to reach therapeutic levels of GLA. | Higher dosage required due to lower GLA concentration. | Moderate dosage needed. |
| Potential Side Effects | Mild gastrointestinal upset, soft stools, belching. | Similar to borage oil; generally well-tolerated. | Generally well-tolerated; often used with other supplements. |
| Other Active Compounds | Contains delta-6-desaturase, an enzyme that helps convert other fatty acids. | Rich in other compounds with anti-inflammatory properties. | Contains both GLA (omega-6) and alpha-linolenic acid (ALA, omega-3). |
Final Conclusion: No, it is unlikely to cause weight gain
Based on current research, gamma linolenic acid does not cause weight gain. In fact, studies suggest it may aid in weight management and fat metabolism, particularly in preventing weight regain after significant weight loss. The notion that it causes weight gain is a misconception, likely stemming from a poor understanding of how different omega-6 fatty acids function in the body. While GLA is an omega-6, its metabolic pathway and effects on body fat differ significantly from those of other, more abundant omega-6 fats. The evidence for using GLA as a standalone weight-loss supplement is mixed, but its potential benefits for metabolism and fat partitioning are noteworthy. As with any supplement, consulting a healthcare provider is recommended before starting a GLA regimen.
The Omega-6 and Omega-3 Balance
It is important to remember the context of the overall diet. While GLA can be beneficial, the modern Western diet is often skewed heavily towards other omega-6 fatty acids, leading to an imbalance. Optimizing health and body composition involves not just adding GLA, but also focusing on increasing omega-3 fatty acids (found in fish oil and flaxseed oil) and reducing an overall excessive intake of omega-6-rich vegetable oils.
- Correcting deficiencies: For those with impaired fatty acid conversion, such as individuals with diabetes or advanced age, supplementing with GLA may be more impactful.
- Lifestyle factors: GLA is not a magic bullet for weight management. Its potential benefits are best realized when combined with a healthy, whole-foods diet and regular physical activity.
Dosage and Safety Considerations
GLA is generally considered safe for most people when taken at recommended dosages. However, side effects can include mild gastrointestinal issues like soft stools, gas, and nausea. High doses may also slow blood clotting, which is a consideration for individuals with bleeding disorders or those undergoing surgery. Always consult a healthcare provider to determine the appropriate dosage and to ensure it does not interact with existing medications, particularly blood thinners.
The Long-Term Perspective
Weight management is a complex, long-term process involving multiple factors beyond a single supplement. The research on GLA's role in preventing weight regain suggests it works over an extended period as it is gradually incorporated into body tissues. This reinforces the idea that sustainable health changes come from consistent, healthy habits rather than quick fixes. Understanding how different fats, like GLA, interact with your metabolism can be a valuable part of an informed approach to overall health and weight control.
Summary of Key Findings on GLA and Weight
- GLA is an omega-6 fatty acid, not a driver of weight gain.
- Some studies show GLA can help prevent weight regain after weight loss.
- GLA may positively influence fat metabolism and brown fat activity.
- Clinical trial results on weight loss with GLA are mixed, requiring a balanced perspective.
- Correcting the overall omega-6/omega-3 ratio is critical for managing obesity risk.
