The Primary Alternative: Conjugated Linoleic Acid
For those wondering what is another name for CLA, the answer is Conjugated Linoleic Acid. CLA is a descriptive acronym that represents a group of fatty acids, or isomers, derived from linoleic acid. The term "conjugated" refers to the unique chemical structure of these fatty acids, where the double bonds are arranged adjacently, a rare feature in naturally occurring polyunsaturated fats. This structural difference is what distinguishes CLA from its parent compound, linoleic acid, and contributes to its distinct biological properties.
The Science Behind the Name
Linoleic acid is the most common omega-6 fatty acid and is widely found in vegetable oils. In ruminant animals like cows, sheep, and goats, bacteria in the rumen convert dietary linoleic acid into various CLA isomers through a process called biohydrogenation. This conversion is why meat and dairy products from these animals are the primary natural dietary sources of CLA for humans. The CLA in supplements, however, is typically created by chemically altering linoleic acid, often sourced from safflower oil.
The Rumenic Acid Isomer
Beyond the general name, specific isomers of CLA have their own identifiers. The most common and abundant natural form of CLA, cis-9,trans-11, is often referred to as rumenic acid. This isomer makes up a significant majority (85-90%) of the CLA found in food from ruminant animals. Rumenic acid is the subject of much research, particularly regarding its potential anti-carcinogenic properties. The existence of these distinct isomers, each with potentially different physiological effects, is why discussing CLA as a single entity can be misleading.
Distinct Isomers: More Than One CLA
CLA is not a single compound but a family of at least 28 different isomers. While rumenic acid is the most prevalent in nature, others are important, particularly in supplements. The two most studied isomers are:
- cis-9,trans-11 (c9,t11) CLA: Also known as rumenic acid, this is the most abundant natural isomer found in ruminant products.
- trans-10,cis-12 (t10,c12) CLA: This isomer is more common in synthetically produced CLA supplements and is particularly noted for its fat-reducing properties in animal studies.
The different ratios and types of these isomers in products from various sources are critical to understanding their potential effects on the human body.
Natural Sources Versus Supplements
An important distinction exists between the CLA obtained from natural dietary sources and the CLA in commercially available supplements. The composition, and therefore the potential effects, can differ significantly.
| Feature | Natural Food Sources (Meat/Dairy) | Supplemental CLA (Safflower Oil) |
|---|---|---|
| Primary Source | Ruminant animals (cows, sheep) | Chemically altered safflower oil |
| Main Isomer | Mostly cis-9,trans-11 (Rumenic Acid) | Approximately 1:1 mix of cis-9,trans-11 and trans-10,cis-12 |
| Isomer Ratio | Dominated by rumenic acid | Mixed isomers; may not be a natural ratio |
| Average Intake | Relatively low (e.g., 15-212 mg/day) | High, often 3-6 grams per day |
| Form | Part of a whole food matrix | Concentrated and isolated |
| Metabolic Effects | Generally associated with health benefits | Mixed results; potential for adverse effects at high doses |
Dietary Sources of CLA
For those looking to increase their CLA intake through diet, focusing on products from grazing animals is key, as their diet impacts the CLA content. Here are some common dietary sources:
- Dairy Products: Milk, yogurt, butter, and cheese from grass-fed animals tend to have higher concentrations of CLA.
- Meat: Beef and lamb from grass-fed ruminants are excellent sources. Grass-fed beef can have up to 300-500% more CLA than grain-fed.
- Other Meats: While lower than ruminant meat, ground turkey and some other poultry products also contain smaller amounts of CLA.
- Seafood: Certain fish, like salmon and trout, contain low levels of CLA.
Beyond the Name: Potential Effects and Considerations
While the search for a simple name for CLA points to conjugated linoleic acid, understanding its potential health effects requires looking deeper at its isomers and source. Early animal studies on CLA, particularly the t10,c12 isomer, suggested benefits for reducing body fat and increasing lean muscle mass, leading to its popularity as a weight loss supplement. However, human studies have yielded mixed and often modest results, with some trials showing little effect on body weight or composition.
Furthermore, at the high doses often found in supplements, some studies suggest potential negative side effects, including increased liver fat accumulation, insulin resistance, and a decrease in beneficial HDL cholesterol. These adverse outcomes appear more tied to the specific isomer profile found in many supplements (high in t10,c12) compared to the natural, rumenic acid-rich food sources.
For most people, the amount of CLA from a natural diet is considered safe and is associated with a lower risk of certain diseases. The risks seem more pronounced with high-dose, synthetic supplementation. Therefore, understanding that "CLA" represents more than one compound is crucial for interpreting research and making informed choices. The best approach for health and nutrition remains a balanced diet that includes natural sources of this fatty acid.
Conclusion: The Many Names of a Complex Nutrient
So, what is another name for CLA? The most comprehensive and correct answer is conjugated linoleic acid. Yet, this simple translation only scratches the surface. Depending on the context, other names are used, from the common natural isomer, rumenic acid, to brand names like Tonalin®. The diversity of CLA's isomers, with their different biological activities, underscores the complexity of this nutrient. Whether sourced naturally through a healthy diet or taken as a supplement, the specific isomer makeup and dose can drastically influence its impact on the body. Recognizing that different CLA variants exist and affect the body differently is key to navigating the world of nutrition and supplements effectively.
For more detailed information on natural sources of CLA, you can consult research from institutions like Penn State Extension.
