Health Benefits of Conjugated Linoleic Acid

If you've ever been on a weight-loss or muscle-building journey, you may have come across conjugated linoleic acid. That's because it's most commonly marketed as a weight-loss supplement that increases fat-burning and supports lean muscle. If it sounds too good to be true, it may be.

Conjugated linoleic acid (commonly known as CLA) is an omega-6 fatty acid found naturally in dairy products and beef, especially those on a grass-fed diet. The amount of CLA in today's beef and dairy products has greatly declined due to changes in cattle farming and their diet. Because of this, scientists explored ways to synthesize CLA from other sources in the lab such as sunflower or safflower oil.

Conjugated linoleic acid is popular in the athletic and bodybuilding communities as a supplement that may reduce fat, build muscle, and increase energy and endurance.

Despite its popularity, CLA is not supported by clear evidence to determine if it can deliver on its promises.

Conjugated Linoleic Acid: Health Benefits

A quick Google search will bring about an endless supply of research proposing the benefits of conjugated linoleic acid. Navigating through that research can be tedious and confusing. The most encouraging health benefits of CLA include weight loss, blood sugar control, and immune system health.

The way conjugated linoleic acid benefits body composition and weight loss is through a few mechanisms—increasing fat-burning while limiting the amount of body fat that can be stored, all while preserving muscle. That's what makes it so intriguing to athletes and bodybuilders. The problem is much of the research contradicts one another.

A review of studies published in the American Journal of Clinical Nutrition concluded that conjugated linoleic acid, taken at a dose of 3.2 grams per day, produced only a minor loss in body fat (average 0.05kg) compared to a placebo.

Another review published in Public Health Nutrition reported no difference between the body weight or composition of those who took conjugated linoleic acid versus those who took a placebo.

Recently, this study revealed that participants who took CLA for 3 months saw a significant decrease in body fat and leptin secretion (a hormone released by body fat that helps control body weight), which means it could be helpful for weight loss.

Another review compared the effects of conjugated linoleic acid on animals versus the effects on humans and found CLA does offer some degree of fat loss on both animals and humans. However, more research is needed.

Keeping your blood sugar within normal limits is important to prevent and treat type 2 diabetes. conjugated linoleic acid's benefits on blood sugar have been studied extensively with some promise.

In mice, CLA reduced fasting blood glucose, increased glucose tolerance, and improved glycolipid metabolism.

Other older studies in humans found supplementing with conjugated linoleic acid had a beneficial effect on blood glucose and type 2 diabetes.

What's confusing though is that some research produced opposite findings. For instance, this study following 116 overweight or obese adults resulted in no improvements in insulin resistance or glucose metabolism after supplementing with conjugated linoleic acid for 6 months. Another study had similar findings.

While conjugated linoleic acid is not a treatment for type 2 diabetes, it may offer benefits for improving blood sugar levels. But with conflicting evidence, you can see how this may be confusing.

Maximizing immune health is on almost everyone's to-do list, and conjugated linoleic acid may fit into your supplement routine. Not only has conjugated linoleic acid been shown to enhance the body's immune system response, it's also been shown to provide anti-inflammatory properties that reduce inflammation.

On the other hand, this review outlines several studies that found conjugated linoleic acid does not affect immune system function.

It's difficult to determine whether CLA can offer any health benefits. Because there are so many inconclusive studies, more research is needed.

Possible Side Effects

Conjugated linoleic acid supplements are generally considered safe if taken as prescribed. Some people may experience mild side effects, including an upset stomach, diarrhea, nausea, fatigue, headache, and backache.

Conjugated linoleic acid may also slow blood clotting. Taking a CLA supplement along with an anticoagulant ("blood thinners") or nonsteroidal anti-inflammatory drug (NSAID) can further enhance this effect, leading to easy bruising and bleeding.

Possible drug interactions include:

• Advil (ibuprofen)
• Aleve (naproxen)
• Aspirin
• Advil (ibuprofen)
• Coumadin (warfarin)
• Fragmin (dalteparin)
• Heparin
• Lovenox (enoxaparin)
• Plavix (clopidogrel)
• Voltaren (diclofenac)

Dosage and Preparation

Conjugated linoleic acid supplements are typically produced as a gel cap and filled with either sunflower or safflower oil. CLA is classified by the U.S. Food and Drug Administration as GRAS ("generally regarded as safe") and typically prescribed between 3 grams and 6 grams daily. Doses up to 6 grams per day have no reported serious side effects.

What to Look For

Conjugated linoleic acid is found naturally in grass-fed beef and lamb, as well as milk and other milk products. You can also find eggs fortified with CLA at some grocery stores. Portobello mushrooms and acorn mushrooms are good plant-based sources of conjugated linoleic acid.

When choosing a CLA supplement, look for brands that put their products through independent verification and testing by certifying bodies, including U.S. Pharmacopeia (USP), NSF International, or ConsumerLab, to ensure quality and safety standards are met.

Conjugated linoleic acid is not considered an essential nutrient like vitamins and minerals. Taking or not taking it will likely have little tangible impact on your health.

If you use conjugated linoleic acid, talk with a medical professional to understand the potential risks and benefits. This is especially true if you have diabetes or are on blood thinners. In these cases, conjugated linoleic acid may cause more harm than good.