Introduction
CLA is believed to influence body composition by encouraging fat reduction while maintaining lean muscle mass. Research suggests that CLA may aid in reducing body fat, particularly in the abdominal region. As a dietary supplement, it has been studied for its ability to improve metabolism and support weight management.
What is CLA?
CLA falls within the omega-6 fatty acid family, constituting a subtype of polyunsaturated fatty acids. It is found naturally in certain animal products, particularly in the meat and dairy of ruminant animals such as cows, goats, and sheep. CLA is also available in supplement form, derived from sources like safflower oil.
Does CLA Help Lose Weight?
Since its discovery in 1997, CLA has been widely studied for its potential anti-obesity effects. While animal studies have shown stronger results than human studies, some clinical trials indicate positive associations between CLA supplementation and improvements in body weight, body fat, abdominal fat, and lean body mass.
Studies about CLA for weight loss include the following:
-
While some human studies have suggested a positive association between CLA supplements and weight loss, the results could be more consistent. Variations in study design, CLA dosage, and participant characteristics contribute to the mixed findings.
-
Studies suggested the potential benefits of CLA consumption (3.4 to 6.8 g/d) in reducing body fat mass for overweight and obese individuals. Even at lower doses (1.7 g/d), CLA supplements showed positive results without adverse effects.
-
Animal studies, particularly those conducted on rodents, have provided more consistent evidence supporting the role of CLA in reducing body fat and preserving lean muscle mass. However, translating these findings directly to humans requires caution due to species-specific differences.
-
Several meta-analyses and systematic reviews have attempted to consolidate the available evidence on CLA for weight loss. Meta-analyses suggest that supplementing with 3.2–3.4 g/d of CLA for at least six months can cause a notable reduction in fat mass and body weight. While some have reported modest effects of CLA on body composition, others have highlighted the need for more rigorous and standardized research methodologies.
What Are the Different Mechanisms of Action of CLA for Weight Loss?
CLA's effects on weight loss are thought to work through various mechanisms, including reduced energy intake, increased energy expenditure, and modulation of metabolism in lipids, adipocytes, and skeletal muscle. CLA supplementation consistently reduces adiposity in animal models but shows varied results in human studies.
CLA’s Effect on Energy Intake and Expenditure:
CLA may reduce body fat mass by decreasing energy intake. Studies in mice showed reduced food intake with CLA supplementation. The mechanism involves the modulation of appetite-regulating genes in the hypothalamus. CLA can also influence energy expenditure by increasing basal metabolic rate (BMR), thermogenesis, and physical activity. Animal studies indicate increased total energy expenditure, but results in humans are mixed.
Appetite Regulation:
Some studies propose that CLA might play a role in appetite regulation. By influencing certain signaling pathways in the brain, CLA could help individuals control their food intake and make healthier dietary choices. CLA's impact on caloric intake in humans remains controversial.
CLA and Fat Metabolism:
CLA is believed to influence body composition by affecting the metabolism of fat. Research suggests that CLA may enhance the breakdown of fat (lipolysis) and inhibit the storage of fat cells, ultimately reducing body fat mass. CLA stimulates lipolysis, releasing free fatty acids and glycerol, possibly through pro-inflammatory pathways.
CLA-Induced Apoptosis:
CLA may induce apoptosis (programmed cell death) in adipocytes through various pathways, including ER stress (endoplasmic reticulum) and the integrated stress response. Studies in mice and cultured adipocytes (fat cells) suggest increased apoptotic cell death with CLA supplementation.
Muscle Mass Preservation:
In addition to its potential impact on fat loss, CLA has been associated with preserving lean muscle mass. This is pivotal for individuals aiming for weight loss, as maintaining muscle mass is linked to a better body composition and an elevated metabolic rate.
What Are the Other Benefits of CLA?
Along with the effects on weight loss and obesity, CLA also has other benefits, like:
-
CLA exhibits antioxidant properties, which means it may help combat oxidative stress in the body. Antioxidants have an important role in counteracting the effects of free radicals, which can contribute to various chronic diseases and aging.
-
CLA has been investigated for its potential to improve insulin sensitivity. Enhanced insulin sensitivity is beneficial for blood sugar control and may reduce the risk of type 2 diabetes.
-
Preliminary studies have explored the impact of CLA on cardiovascular health. While more research is needed, there is some evidence to suggest that CLA may have a positive influence on lipid profiles, potentially contributing to heart health.
-
Some studies, primarily in animal models, have explored the role of CLA in cancer prevention. CLA's potential anticancer properties are thought to be linked to its ability to modulate cell growth and apoptosis (programmed cell death).
What Are the Adverse Effects of CLA Supplement Consumption?
Gastrointestinal Distress - One of the most commonly reported side effects of CLA supplementation is gastrointestinal distress. Users may experience symptoms such as nausea, diarrhea, or indigestion. These symptoms are often dose-dependent and may improve with a lower dosage.
Insulin Resistance in Diabetes - While some studies suggest that CLA may improve insulin sensitivity, there is concern that it could lead to insulin resistance in individuals with diabetes. As such, individuals with diabetes should exercise caution and consult their doctor before using CLA supplements.
Potential Impact on Blood Lipids - The effects of CLA on blood lipid profiles are only partially consistent across studies. While some research indicates a positive influence on lipid levels, other studies have reported increases in LDL cholesterol.
Liver Health - Limited evidence suggests that high doses of CLA may have adverse effects on liver health. Individuals with pre-existing liver conditions should consult the doctor before using CLA.
Effect on Blood Sugar Levels - CLA's impact on blood sugar levels is an area of ongoing research. Some studies have suggested potential benefits for individuals with insulin resistance. People taking CLA supplements need to observe their blood sugar levels.
Conclusion
CLA is generally considered safe for most people when consumed in amounts found in food. The optimal dosage and duration of CLA supplementation for weight loss are still areas of ongoing research. Results may vary based on these factors. Responses to CLA can vary among individuals, and factors such as age, sex, diet, and baseline body composition may influence outcomes.
