While many hear “butter and beef” and immediately think of heart attacks and weight gain, the truth is that all types of natural fats are healthy and even beneficial when you eat high-quality versions of them and have them in moderation. Conjugated linoleic acid (or CLA) is the name given to group of chemicals found in the fatty acid called linoleic acid.
A few of the major sources of CLA in the diet include full-fat dairy products, beef and grass-fed butter. Although most people think of these foods as “unhealthy” sources of saturated fat, they also provide essential CLA, which is a type of polyunsaturated fat that we must obtain from our diets.
The body needs all three types of fats for optimum health because they all have various functions, from pregnancy to digestion to brain function. Not only is it true that eating fat doesn’t make you fat, but certain types of healthy fats are actually some of the best fat-burning foods available. But quality is very important to fats, especially the kinds that come from animal products.
What does CLA do to your body? CLA is known for fighting cancer, blocking weight gain and helping build muscle, and it’s almost exclusively found in high-quality beef and butter from healthy, grass-fed cows or other animals.
What Is CLA (Conjugated Linoleic Acid)?
Conjugated linoleic acid, or CLA, is a type of polyunsaturated fat, specifically an omega-6 fatty acid. It’s a form of linoleic acid, which is the most common omega-6 fatty acid found in foods. There are actually 28 different forms of CLA, including 16 naturally occurring CLA isomers that have been identified, but two seem to be the most important. These are called “c9, t11” and “t10, c12.”
According to research, conjugated linoleic acid benefits can include:
- helping with weight loss
- muscle-building and strength improvements
- anticancer effects
- bone-building benefits
- growth and developmental support
- reversing atherosclerosis (hardening of the arteries)
- improving digestion
- reducing food allergies and sensitivities
- helping to normalize blood sugar levels
There isn’t an established daily recommended dose of CLA, but studies show that the average daily intake is approximately 152–212 milligrams for non-vegetarian women and men. Because CLA is found in animal products, vegans and vegetarians usually have lower levels.
But Aren’t Omega-6 Fats “Inflammatory”?
CLA is found in dairy products, meat of ruminant animals, and also in industrially hydrogenated vegetable oils and other synthetic products. It’s believed that certain microbes that live in the gastrointestinal tract of ruminant animals, including cows, sheep and goats, convert linoleic acid into different forms of CLA through a biohydrogenation process. This process changes the position and configuration of the fat’s double bonds, resulting in a single bond between one or both of the two double bonds.
All types of fats (lipids) — whether from animal products, eggs, dairy, oils, nuts, seeds or coconuts — are made up of fatty acids. Some fats are considered essential, because the body cannot produce them on its own, while others are nonessential because the body can synthesize them from other nutrients. The essential fats we need to obtain from our diet include polyunsaturated omega-3 fatty acids (found in fish, seafood, eggs and some nuts or seeds) and polyunsaturated omega-6 fats (mostly found in vegetable oils, nuts and seeds).
Omega-3s are known as being anti-inflammatory while omega-6s are said to be inflammatory. The truth is that we need both types of essential fats to balance our immune, hormone, digestive and nervous system functions, which is why so many low-fat diet risks exist when someone skips out on eating enough healthy fats.
Omega-6 oils are are typically overly consumed by those eating a standard Western diet and therefore dangerous, mostly because they are found in vegetable oils used to make processed junk foods. Ideally, the diet would be equal in terms of omega-3 and omega-6 fatty acid intakes, but the standard American diet is much higher in omega-6s, which is why it’s known for being so “inflammatory.” Unfortunately, inflammation is at the root of most chronic diseases — including cancer, heart disease, diabetes, depression, autoimmune disorders and dementia.
Both types of essential fats not only need to be obtained from the foods we eat, but it’s also really important that we eat them in the right amounts. Conjugated linoleic acid is one type of omega-6 fat we can afford to eat more of because it tends to act like an omega-3 food in the body, helping lower inflammation and promote other aspects of health. It also helps turn off hunger (by controlling our hunger-hormone called ghrelin) and can improve your ability to absorb nutrients.
1. Helps with Weight Loss and Fat-Burning
You might find it hard to believe, but it turns out that butter can be a fat-burning food! CLA has been shown to help with fat loss in many animal and some human studies, which is why in its concentrated form, it’s one of the most popular weight loss supplements in the world. A number of studies have found evidence that CLA not only reduces body weight and body fat mass, but may also help increase lean mass in different species.
How does CLA help you lose weight? According to a 2009 report published in The Journal of Nutritional Biochemistry, it’s believed that CLA reduces adiposity (fat) because of its impact on 1) energy metabolism, 2) adipogenesis, 3) inflammation, 4) lipid metabolism and 5) apoptosis. In certain animal studies, CLA (specifically types 10 and 12) has also been found to lead to increased energy expenditure, increased fat oxidation and browning of subcutaneous white adipose tissue (aka white fat).
Supplementation with a CLA mixture (equal concentrations of the 10,12 and 9,11 isomers) or the 10,12 isomer alone decreases body fat mass, according to results from numerous animal studies. Of the two major isomers, 10,12 specifically seems to be responsible for the anti-obesity effects of CLA.
In human studies, the results for CLA on weight loss have been somewhat mixed, although still promising. One study found that supplementation of a CLA mixture in overweight and obese people (three to four grams a day for 24 weeks) decreased body fat mass and increased lean body mass. Other studies have shown similar results and that CLA also has no adverse effects on overall blood lipids, inflammation levels and insulin response in healthy, overweight and obese adults.
It’s believed that some people experience better results than others due to factors including: CLA isomer combination versus individual isomers, CLA dose and duration of treatment, gender, weight, age and metabolic status of the subjects. One of the possible potential mechanisms by which CLA reduces body fat mass might be that it decreases energy intake or increases energy expenditure. One study demonstrated that mice supplemented with a CLA mixture for four weeks reduced their food intake and experienced liver function improvements, although studies haven’t shown this same effect yet in humans.
Does CLA reduce belly fat? There isn’t any single type of food or supplement that will specifically target belly fat, or fat located elsewhere on the body. That being said, because CLA may help with weight loss in general and blood sugar balance, it’s possible that you can lose some belly fat if you consume more CLA.
2. Regulates Blood Sugar and Helps Improve Insulin Function
There’s strong evidence that an inverse association exists between CLA intake in someone’s diet and their risk for developing diabetes. The hypothesis is that CLA may be involved in insulin regulation. We also know that the best food sources of CLA, including healthy fats like butter or grass-fed beef, can stabilize blood sugar and help someone stick to a low-sugar, low-carb diet that’s beneficial for controlling diabetes.
3. Improves Immune Function and Might Help Fight Cancer
Conjugated lienoic acid has shown immune-enhancing effects and anticarcinogenic activities in several animal studies. The CLA present in saturated-fat foods might offset the adverse effects of the saturated fat content and benefit everything from blood sugar control, to hormone regulation, to natural cancer prevention.
Research repeatedly shows that the quality of fatty acids in someone’s diet is greatly important for reducing their overall cancer risk, and conjugated linoleic acids (especially rumenic acid) have proved to be health-promoting in several ways, especially by lowering inflammation. Lower inflammation is a sign of less free radical damage (or oxidative stress) that is linked to lower cancer risk.
CLA seems to modulate immune and inflammatory responses as well as improve bone mass. Research on the effects of conjugated linoleic acid for preventing breast cancer is somewhat conflicting, but some early research suggests that higher intake of CLA from natural foods is linked with a lower risk of developing breast cancer. Other study results suggest that it can be beneficial for fighting cancer of the digestive organs and can improve detoxification via healthier liver function, too.
4. Reduces Allergies and Asthma Symptoms
Consuming foods high in CLA or taking CLA supplements for 12 weeks seems to improve symptoms and overall well-being in people with seasonal allergy symptoms. Similarly, some research shows that for people with asthma, CLA might be a natural treatment method for asthma-related symptoms, due to its ability to help control inflammation. Twelve weeks of supplementation seems to improve airway sensitivity and ability to exercise.
5. Improves Rheumatoid Arthritis Symptoms
Early research suggests that CLA is beneficial for lowering inflammation and therefore autoimmune diseases like rheumatoid arthritis. Taking conjugated linoleic acid alone or along with other supplements like vitamin E benefits those with arthritis by reducing symptoms, including pain and morning stiffness.
Pain and inflammation markers including swelling have been improved for adults with arthritis taking CLA compared to their pre-treatment symptoms or people not taking CLA, meaning CLA can naturally treat arthritis.
6. Might Improve Muscle Strength
Although findings have also been somewhat conflicting, some research shows that taking conjugated linoleic acid alone or along with supplements like creatine and whey protein can help increase strength and improve lean tissue mass. This is why CLA is often added to some bodybuilding supplements, protein powders and weight loss formulas.
Best Food Sources
According to a report published in The Journal of Food Composition and Analysis, the top food sources of CLA include:
- Butter from grass-fed cows (ideally organic)
- Full-fat, preferably raw, dairy products like cream, milk, yogurt or cheese
- Grass-fed beef (ideally organic)
- Also found in dairy products from sheep or goats, like goat milk, in addition to cows
- Found in smaller amounts in grass-fed lamb, veal, turkey and seafood
What an animal eats and the conditions in which they are was raised highly affect how much CLA (and other fats or nutrients) their meat or milk will supply.
The proportion of CLA ranges from 0.34–1.07 percent of the total fat found in dairy products (making it the highest source) followed by about 0.12—0.68 percent of the total fat in raw or processed beef products (the second best source). However, when it comes to animal products, the breed and especially the quality of the animal’s diet and lifestyle really affect the fat that you will obtain when you eat the animal. In other words, not all beef or dairy is created equal when it comes to supplying us with healthy fats like CLA.
Even the season, quality of the soil on the farms and age of the animal affect the CLA content. One study, for example, found that the CLA content in beef and dairy from grass-fed cows is 300–500 percent higher compared to grain-fed cows!
Grass-fed beef contains higher levels of CLA (and even more omega-3 fats and vitamins too) than beef from factory farm-raised animals. The same goes for dairy products we get from cows, including cream or butter. One of the best ways to find high-quality grass-fed beef is to purchase it directly from small farms, whether visiting farmer’s markets, joining a community-sponsored agriculture group or even looking online. If you can’t find the perfect product, for example 100 percent organic and grass-fed beef, do the best you can while also focusing on limiting industrial and man-made fats from your diet.
If all of this advice about obtaining various fats seems overwhelming to you, just remember that you’re doing your body best when you eat all different types of natural fats, in their natural forms. Butter, beef and cream are nothing to be scared of, as long as you consume the highest quality you can, just like traditional populations have done for thousands of years.
Should You Take CLA Supplements?
It’s also possible to get CLA from supplements, but just like with most nutrients, CLA in supplement form won’t necessarily have the same health effects as CLA from natural, real foods.
It’s possible that the types of CLA found in supplements are not the most effective types; whole foods are made of c9, t11 CLA, while many supplements are high in t10, c12 CLA.
While CLA supplementation has shown some positive effects for managing risk and symptoms for some diseases, most might lack high levels of rumenic acid, which is the predominant form of CLA found in naturally occurring foods. This comprises approximately 90 percent of CLA found in ruminant meats and dairy products and the most biologically active forms (9,11 and 10,12 isomers).
On the other hand, in many cases the CLA found in supplements is made by chemically altering linoleic acid from unhealthy vegetable oils.
How to Take CLA:
- For certain benefits like reducing body fat in obese patients, a dose of 1.8 to 7 grams per day of CLA has been used successfully. But amounts on the smaller side of that range might be plenty, since some research shows that greater than 3.4 grams per day doesn’t always seem to offer any additional benefits. Other research suggests that a minimum CLA dosage of 3 grams daily may be necessary to see effects. It’s recommended that daily doses be split into 2–3 divided doses.
- Most studies have used CLA dosages between 3 and 6.5 grams per day. Taking 6 grams daily is considered to be generally safe for most adults.
- Most studies have tested the effects of taking CLA for durations between 8 weeks and about 7 months.
- CLA seems to work best when consumed before or during a meal.
- How fast do CLA supplements work? It may take as long as 6 to 12 weeks to see results in terms of body composition changes. Other effects like reduced hunger may be felt earlier, within several weeks of taking CLA.
Risks and Side Effects
Before beginning to take CLS, it’s important to consider what we know about both CLA benefits and dangers. CLA has been granted “Generally Recognized As Safe” status in the U.S. for use as a dietary supplement. However, not all research shows that taking high supplemental doses is safe.
What are the side effects of taking CLA? CLA is considered safe when eaten as part of whole, natural foods or taken by mouth in moderate amounts that are still larger than those found in foods. For some people, it’s possible that taking CLA supplements can cause temporary side effects like an upset stomach, diarrhea, nausea and fatigue.
There’s also some evidence that taking high doses of CLA may contribute to more serious health problems, especially those that affect the liver. In some animal and human studies, conjugated linoleic acid has been shown to increase accumulation of fat in the liver (also called hepatic steatosis) and to promote inflammation. This can potentially increase the risk for problems like insulin resistance, metabolic syndrome, type 2 diabetes and lower “good” HDL cholesterol. However, overall there have been conflicting findings about whether CLA is mostly inflammatory or not.
The liver may be most impacted by high intake of conjugated linoleic acid because it plays an important role in energy homeostasis and converting excessive dietary glucose (from carbs and sugar) into fatty acids. Research suggests that CLA’s effects on liver health depend on factors like the level of CLA in the diet and the exact type of CLA, duration of taking high doses, and someone’s overall health/physiological condition.
Regarding conjugated linoleic acid for children, it’s best to avoid giving your kids CLA supplements since at this time there isn’t enough evidence to know if long-term use is safe. However, food sources like butter and beef are definitely safe and encouraged, since these provide not only CLA, but important nutrients for growth and development, including various fat-soluble vitamins, minerals and protein.
If you are getting surgery or have a history of poor liver function or bleeding disorders, keep in mind that supplementing with CLA might not be safe. Conjugated linoleic acid might slow blood clotting and increase the risk of bruising and bleeding, but again eating foods with CLA should pose no risk.
- Conjugated linoleic acid (CLA) is a type of polyunsaturated fat, specifically an omega-6 fatty acid.
- Conjugated linoleic acid is naturally found in foods like full-fat dairy products and meat from cows, sheep and goats. CLA is also available in supplement form.
- Studies suggest that conjugated linoleic acid benefits can potentially include: reducing body fat, supporting growth of lean muscle mass, normalizing blood sugar, improving digestion and immune function, reducing allergies, and protecting against certain heart disease risk factors.
- CLA side effects can include an upset stomach, diarrhea, nausea and fatigue. More serious side effects may occur if you take high doses, such as accumulation of fat in the liver and increased inflammation.