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What is CLA?

Conjugated linoleic acids (CLA) are poly-unsaturated fatty acids containing both cis- and trans- bonds as well as double bonds.

These molecules are categorized into a family of 28 different types of linoleic acids.

The fatty acids are found primarily in meat and dairy products but are also found in supplement form.

The CLA cis-9,trans-11 is mostly found in foods, whereas trans-10,cis-12 is found in supplements (R). 

CLAs are often marketed and sold as dietary supplements because of their ability to help with weight loss (R).

However, human studies have been somewhat unreliable and have had mixed results. More research needs to be done investigating CLAs so that we can truly understand their benefits.

Health Benefits of Conjugated Linoleic Acid

1) CLA Supplementation Helps with Weight Loss

A study done in overweight Chinese subjects found that CLA supplementation (twice daily dissolved in milk) helped with weight loss over a 12-week period (R).

The supplementation was found to reduce body weight, reduce BMI, reduce total fat mass, and reduce fat percentage (R).

The treatment also reduced waist to hip ratio and reduced subcutaneous fat mass (R).

Studies have shown that CLAs decrease lipid storage by increasing the rate of fat breakdown in fat tissue (R).

The fatty acids also increase fatty acid oxidation and reduce glucose uptake in cultured fat cells (R).

It should be noted, though, that in a similar study, CLA supplementation did not prevent weight or fat regain in obese peoples after initial weight loss (R, R2).

It should also be noted that some studies have found no association between CLA and weight loss (R, R2, R3).

2) CLA Supplementation Helps Treat Fatty Liver Disease

The fatty liver disease is often an issue in overweight subjects.

The disease causes high levels of oxidative stress in the liver, which eventually leads to liver failure.

An eight-week study performed using fatty liver disease subjects found that CLA supplementation helped reduce oxidative stress in the liver (R).

CLA treatment also helped decrease cholesterol levels and improve the fats profile in the liver (R).

Through these means, supplementation is beneficial in treating fatty liver disease.

3) CLA and Omega-3 Increase Muscle Efficiency

The combination of CLA and omega-3 have been found to increase mitochondrial efficiency in muscle (R).

This causes an increased amount of energy production from glucose and fat in muscle (R).

An increased efficiency in energy production may lead to an increased athletic ability.

4) CLA Treats Type 2 Diabetes

It has been shown that weight loss helps to manage the symptoms of type 2 diabetes.

A study done in postmenopausal type 2 diabetic women found that CLA supplementation reduced BMI and improved diabetic symptoms in the subjects (R).

Decreased insulin sensitivity is a major symptom of type 2 diabetes.

In mice, it was found that CLA supplementation led to a decreased fat gain.

It was also found that while CLA supplementation decreases fat gain, the fatty acids also maintain fat tissue function and maintain insulin sensitivity (R).

5) CLA and Fish Oil Supplementation Increase Bone Mass

Increased fat deposits in bone marrow reduce bone mass in aging subjects (R).

This increases the subject’s risk for developing osteoporosis and bone breaking.

A study done in aged mice found that CLA and fish oil work to reduce fat deposits in the bone marrow and increase bone mass (R).

This reduces the risk of osteoporosis.

6) Conjugated Linoleic Acid Promote Heart Health

High levels of glucose result in major heart damage and heart disease.

A study in rat cells found that cells pre-treated with CLA and then exposed to high glucose levels had reduced heart damage and a decreased risk of heart disease than cells not pre-treated in the same conditions (R).

In another study, mice with heart disease who were treated with a combination of nitrate and CLA prior to a heart attack had improved heart function post-heart attack (R).

Hardening of the arteries is a heart disease that is caused by the buildup of fat in arteries.

This eventually leads to hypertension and strokes.

Cis-9,trans-11 conjugated linoleic acid stops fat from building up in the arteries, reducing the risk of disease development (R).

7) CLA Intake Reduces Cholesterol levels

A study found that high intakes of both cis-9,trans-11 and trans-10,cis-12 CLA raised the level of HDL cholesterol in healthy women.

HDL cholesterol promotes low cholesterol levels and healthy heart function (R).

8) CLA Helps in Treating Breast Cancer

Breast cancer is a devastating disease that affects many lives.

One of the reasons that breast cancer is so devastating is that it spreads to other parts of the body both easily and quickly.

One study performed in women with lipogenic phenotype breast cancer found that treatment with CLA over the course of 12 days reduced breast cancer tissue production (R).

Additionally, studies in rat breast cancer tumor cells have found that Gemcitabine (a drug designed to prevent the spreading of tumors) was more effective when used in combination with CLA (R).

9) CLA Helps Treat Rectal Cancer

A study in patients with rectal cancer who were currently undergoing chemoradiotherapy was conducted.

In the study, CLA supplementation was found to reduce tumor angiogenesis and decrease tumor resistance (R).

CLA was shown to improve the efficacy of chemoradiotherapy treatment (R).

In human colorectal cancer cells, CLA has been shown to promote growth arrest by inhibiting energy production in cancer cells (R). 

10) CLA Helps in Treating Bladder Cancer

In human bladder cancer cells, Trans-10,cis-12 CLA has been shown to stop growth factor receptor transmission, decreasing rapid cell production and increased cell death (R).

Side Effects

In obese rats suffering from kidney disease, intake of CLA resulted in worsened renal function and increased kidney damage due to kidney enlargement (R).

Large doses of supplemental CLC (high in trans-10,cis-12 CLC’s) in rats caused abnormal fat accumulation in the liver (R, R2).

This was also seen in hamsters, mice, and humans who took high doses of CLC. The fat accumulation led to fatty liver disease and decreased liver functionality (R, R2).

Men with metabolic syndrome taking Trans-10,cis-12 CLA had increased insulin resistance and oxidative stress.

These complications led to increased inflammation and diabetes (R).

Less serious side effects of CLA supplementation include excessive flatulence, bloating, nausea, and diarrhea. 


The majority of the studies outlined in research revolve around 5 grams of CLA daily for positive effects without harmful side effects.

Any greater amount per day could lead to serious side effects.

Supplements sold in the store are low in grams per pill. This limits the chance that somebody could overdose on CLA.

Technical Section 

  • CLA and metformin supplementation leads to increased AMPK levels. AMPK then increases levels of phosphorylated acetyl-CoA activity in fat cells. Phosphorylated acetyl-CoA decreases triglyceride levels in fat tissue (R).
  • The combination of nitrate and CLA controls a microRNA pathway responsible for preventing heart damage. This is especially true following a heart attack (R).
  • Cis-9,trans-11 conjugated linoleic acid controls the production of the anti-inflammatory macrophage Mphi2, which inhibits the deposition of fat by foam cells, limiting the development of hardening of the arteries (R).
  • Gemcitabine is a nucleoside agent that is responsible for preventing the spread of tumors of various cancer types. It is rapidly metabolized by the body. This reduces the drug’s efficacy (R).

Buy Conjugated Linoleic Acid

Natural sources of CLA are dairy products and meat from animals.

However, supplements sold in stores are derived from industrially hydrogenated vegetable products and other synthetic products.

CLA coming from animal products consist primarily of cis-9,trans-11 CLA whereas industrially hydrogenated vegetable supplements contain primarily trans-10,cis-12 CLA (R).

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