What is CLA and Why Are Ruminants a Richer Source?
Conjugated linoleic acid (CLA) is a type of polyunsaturated omega-6 fatty acid known for various potential health benefits, including supporting weight management and immune function. However, not all meat sources are created equal when it comes to CLA content. The primary reason for this difference lies in the digestive system of the animal.
Ruminant animals, such as cattle, sheep, and goats, have a specialized digestive system that includes the rumen, where bacteria convert linoleic acid from grass and other forage into CLA. This process, called biohydrogenation, allows these animals to produce significant amounts of CLA, which is then stored in their meat and dairy fat.
The Role of Diet in CLA Content
The animal's diet is a critical factor influencing its CLA content. For instance, meat and dairy products from grass-fed ruminants contain 300–500% more CLA than those from grain-fed animals. This highlights why simply relying on meat without considering its origin can be misleading when assessing CLA intake.
The Lowdown on CLA in Chicken
While chicken does contain CLA, it is classified as a monogastric animal, meaning it does not possess a rumen. This lack of a rumen-based biohydrogenation process means chickens produce and store very little natural CLA. According to research from Eat Wild and Penn State Extension, the typical CLA concentration in chicken is substantially lower than in ruminant meats.
Enriching Chicken with CLA
Because of chicken's low natural CLA content, scientific studies have explored methods to increase it. Researchers have found that by supplementing a chicken's diet with synthetic CLA, the concentration of this fatty acid in the chicken's muscle tissue and eggs can be significantly increased. This means that some specialized chicken products or eggs may have elevated CLA levels, though this is not typical for standard commercial poultry.
Pastured vs. Conventional: A Complicated Picture
Some consumers might assume that pasture-raised chickens, which have access to greens, would naturally have higher CLA levels. While pasture-raised chicken meat and eggs often boast a more beneficial fatty acid profile (like a lower omega-6 to omega-3 ratio) and higher antioxidant content, the impact on CLA specifically is less clear. A study on pastured eggs found no significant difference in CLA isomers compared to conventional eggs, suggesting that access to pasture alone might not be enough to significantly boost CLA in monogastrics.
Chicken vs. Other Foods: A CLA Comparison
The following table provides a quick comparison of representative CLA concentrations per gram of fat in various foods, based on published data.
| Food Source | Total CLA (mg/g fat) |
|---|---|
| Lamb | 5.6 |
| Butter | 6.0 |
| Fresh Ground Beef | 4.3 |
| Fresh Ground Turkey | 2.5 |
| Chicken | 0.9 |
| Pork | 0.6 |
| Salmon | 0.3 |
Natural CLA vs. Supplements: A Key Distinction
It's important to differentiate between CLA from natural food sources and that found in supplements. The CLA in natural foods, particularly from ruminants, primarily consists of the cis-9, trans-11 isomer, which observational studies link to potential health benefits. In contrast, CLA supplements are typically manufactured by chemically altering linoleic acid from vegetable oils, resulting in a different isomer profile, often a 50:50 mix of cis-9, trans-11 and trans-10, cis-12.
Potential Risks of High-Dose CLA Supplements
Unlike natural food sources, high doses of supplemental CLA have been associated with potential side effects and health risks, including increased fat accumulation in the liver, reduced insulin sensitivity, and lowered 'good' HDL cholesterol. While supplements may deliver higher concentrations, these distinctions mean they may not offer the same health benefits as dietary CLA and could carry additional risks. For more information on the nuances of natural vs. supplemental CLA, consult an authoritative source like Healthline: CLA (Conjugated Linoleic Acid): A Detailed Review.
Conclusion
While chicken does technically contain conjugated linoleic acid, it is not a significant source compared to meat and dairy products from ruminant animals like beef and lamb. A chicken's diet can be supplemented to increase its CLA content, but typical store-bought chicken contains very limited amounts. For those looking to increase their dietary CLA intake, focusing on grass-fed beef and dairy products is a much more effective strategy than relying on poultry. It is also crucial to remember the distinction between natural, food-derived CLA and the chemically altered versions found in supplements, which may have different physiological effects.
