A majority of Americans lack important nutritional foundations in their everyday diet and turn to supplements to fill the voids that have been left. One particular supplement, conjugated linoleic acid (CLA), has gained notoriety for claims of it being a weight loss supplement. These claims also extend the benefits of CLA to increasing the metabolism, supporting muscle tissue and increasing lean body mass. Increasing lean body mass (building muscle) is one of the most important things a person can do in order to raise the metabolism and improve overall body composition.
Ironically, CLA is a naturally occurring trans-fatty acid made from the omega-6 class of essential fatty acids. The construction of healthy fats found in CLA has also been shown to benefit those looking to improve other areas of their health such as cancer, asthma, cardiovascular performance, high blood pressure and cholesterol, and osteoporosis.
Linoleic acid is a naturally occurring fatty acid on its own and is the base for omega-6 fatty acids which are popular health supplements. Omega-6 is found in the form of vegetable and other plant based oils such as flaxseed and olive oil. The digestion process in cows changes the arrangement of bond in the linoleic fatty acid chains and produces CLA. It has been discovered that there are up to 28 different forms of CLA but the most common ones used in dietary supplementation are c9,t11 and t10,c12.
As with any nutritional supplement, it is not meant to replace or substitute for an area of a healthy diet. CLA can be found in foods that we are already consuming on a normal basis. The most readily available source of CLA comes for beef products, including meat and dairy. Sources of CLA coming from grass fed beef are significantly higher than the CLA content of grain fed beef. The modernization of beef production in the United States can be viewed as a culprit to why many Americans are looking to supplement CLA into their diet. Milk and dairy produced from grass fed beef will also yield much higher levels of CLA. The problem with obtaining grass fed beef products is that it is not always readily available in all areas and can be cost restrictive to some as a regular source. These limitations bring on the need for supplementation.
In the last decade, numerous studies have been conducted to test the validity of the claims about CLA. Initial studies that were done on lab rats revealed that it acted as a powerful cancer fighting and immune boosting agent. However, the results of the human trials have been mixed and have not produced the same concrete results as the trials on the lab animals as far as cancer research in concerned. Long term trials that have been conducted to review the effects of CLA on the metabolism and lean body mass have yielded more positive results.
The American Journal of Clinical Nutrition conducted a study that was monitored over the course of 1 year and included a control group that was given a placebo along with a group that was supplementing CLA into a healthy diet. After the extended period, this study revealed that the subjects placed on CLA showed an increase of 1.8-4.3% greater in their lean body mass than the subjects on placebo. The conclusion of this study was that long term supplementation of CLA reduced body fat in healthy adults.
The recommended daily intake for this supplement is between 2.8-3.2 grams per day and the average dose found in most products on the market is 1 gram per serving or capsule. The suggestion would be to including one dose of this supplement to each major meal of the day.
With so many claims attached to CLA, it may become a little confusing to a person on why and for what reasons this supplement should be taken. Other questions may be, is this safe product, what are the side effects and are there any alternatives.
If strict weight loss is a goal, the reduction of overall mass on the body, CLA may not provide the results that the user may be expecting. With CLA supplementation, a healthy metabolism is supported by the maintenance and building of lean mass, this means muscle growth. Additional muscle mass on the body will result in a more active metabolism and you will burn more calories throughout the day. Body composition changes as a result of fat loss which means a smaller percentage of body fat on an individual, some weight loss may occur here but the lost weight may be found with the addition of new muscle. This is sometimes hard for most people to understand when they are only focused on the number that the scale provides them on a daily basis.
The majority of the studies conducted will cite that the subjects were healthy adults, possibly slightly overweight. A supplement should not be used as a type of self prescribed “medication” to those who may be obese or have more severe medical issues such as diabetes. In studies, it was shown that CLA can reduce the insulin sensitivity of individuals allowing the body to utilize and certain sugars more efficiently and store less fat. This can contribute to the goals of fat loss and help prevent the onset of diabetes. Insulin levels are controlled as a function of the liver when these functions are disrupted the liver may begin to store fatty acids, this a dangerous condition and a properly functioning metabolism is one way that this condition can be avoided. A person may already be storing fat in the liver but is not diabetic, returning the liver to normal function is another way one can reduce body fat.
Trying to achieve the recommended dose of CLA through diet alone may not be the best option for those with weight loss as a goal. It is estimated that you would have to ingest up to 4,500 calories worth of beef and dairy alone in order to fulfill the recommended 3 grams of CLA daily. Along with the excessive caloric intake, there would also be a significant amount of fat associated with those calories. This is where supplementation can provide benefit in addition to a healthy diet.
Its is known that grass fed beef and dairy products produce healthier products with higher levels of CLA. When possible your diet should include those products along with the recommended supplementation.
Reduction of body fat will also have an impact on the function of the cardiovascular system and your blood lipid profile. Researchers also concluded from studies that CLA reduce the levels of cholesterol and triglycerides in the blood. Healthy diet and changes in activity levels have also been know to provide the same benefits in this area.
When it comes to the safety of this product, CLA is available for purchase in retail settings such as health food stores and supplement shops and is not labeled as banned or unsafe for consumption. It is already naturally occurring in some of the food products that we eat and has not been proven to cause any major or negative side effects. Every person is different and may have unique reactions to certain foods or product so it is important to know what those reactions may be and be attentive to any changes that you may observe in yourself if you begin a new supplementation routine.
Users of CLA have reported nausea, upset stomach, headaches, diarrhea, and lightheadedness. There have also been studies that have shown CLA to have the opposite effect on humans than what was intended, which includes weight gain and some cardiac dysfunction. Despite some of those reports CLA is generally accepted as a safe product to consume. There are however many different products on the market and knowing what you are consuming is important. CLA is not regulated by the FDA in the U.S. and packaging can be misleading when it comes to products.
In many cases, CLA will be combined with other substances that may enhance weight loss or appetite suppression. Be sure to read the labels on whatever purchases you decide to make. The products that are offered as oil or soft gel tablets and labeled as CLA tend to have the purest content while some of the powdered tablets tend to be mixed product often promoting weight loss as its primary function. The majority of these products were generally inexpensive, ranging from 10-20 dollars.
Taking purity a step further, the c9,t11 and t10,c12 isomers were the most readily available forms of CLA. The c9,t11 is generally considered to be the safer of the two isomers, yielding the least amount of negative side effects. One study conducted in Denmark established three test groups and gave one group a placebo of olive oil, one group received CLA in the form of c9,t11 and the third group received a mix of 40% c9,t11 and 40% t10,c12. The group that received the mix performed better that the other two groups but only on average of 1.5 lbs of fat loss. This particular example will allow you to weigh the pros and cons if there is any reservation as to what formula would be a better fit. A slighter less decrease in body fat may be worth forgoing side effects like nausea, and diarrhea.
Many of the studies reviewed only examined the effect of CLA strictly as a dietary supplement and in some cases on untrained or overweight individuals. It is well known and generally acceptable that strength training is an extremely effective way to increase lean muscle mass on the body. In some forms, CLA is presented as a supplement to weight training and bodybuilding. Athletes and certainly bodybuilders have an interest in maintaining as much lean muscle mass as possible. Performance in athletes have been shown to be directly impacted by their body composition and in bodybuilding, the goal is to produce a physique with as much lean mass and as little body fat as possible for competition. Individuals already participating in strength training or bodybuilding may have slightly more positive results if deciding to supplement CLA into their diets. Their metabolisms are often better conditioned to utilize energy sources that are provided. Dietary habits of this population tend to contain a higher level of CLA already since protein sources already rich in the supplement are an important part of maintaining lean mass.
A group was tested to determine whether the addition of CLA would improve lean mass as well as improve strength. The participants were already involved in strength training programs and were asked to document their dietary habits as well as their training before and during the time CLA was added as a supplement. The purpose was to see if strength would improve as a result of the testing. Participants were measured for lean mass as well as tested for strength before the study. When lean mass is added to the body strength will improve in most cases. The research was conducted over the course of 6 months and the participants did not increase their volume of training during this period or significantly change their dietary habit from what it had been prior to the start of the study. At the conclusion of the six month period, the participants were then retested in the areas they had provided results for prior to the study. Positive results in both strength gains and lean mass were recorded as a result of the study. There was also minimal negative side effects report by the participants. Additional testing was done that revealed the participants remained healthy in other areas such as their blood lipid profiles and kidney functions.
Deficiencies of CLA from the naturally occurring sources in the diet (grass fed beef as opposed to grain fed beef) have led many to look at the supplementation of this important fatty acid as a way to increase lean mass and assist the metabolism in weight control. The recommended dosage in order for a user to realize the results of the product is much higher than what would normally be ingested if the naturally occurring sources of CLA in the diet were unaltered. Before taking a supplement your goals and reasoning should be clear and an awareness of the effects should be present. CLA has been present in the human diets since humans began ingesting the animal and plant based sources of it without major concern for the health effects. One should consider the natural options and sources first and add supplementation where needed to support a normal weight and healthy lifestyle.
References:
Gaullier J, Halse J, Hoye K, Kristiansen K, Fagertun H, Vik H, Gudmundensen O,/Supplementation With Linoleic Acid for 24 Months Reduces Bodyfat in Healthy Overweight Humans./ J. Nutr. Apr. 2005 V. 135 no.4 778-784
Smedman A, Vessby B,/Conjugated Linoleic Acid Supplementation in Humans -- Metabolic Effects./ 2001 Aug, 36(8) 773-781
Tarnopolsky, Zimmer, Paikin ,Safdar , Aboud ,Pearce ,Roy ,Doherty/Creatine Monohydrate and Conjugated Linoleic Acid Improve Strength and Body Composition Following Resistance Exercise in Older Adults/ (2007) PLoS ONE 2(10): e991. doi:10.1371/journal.pone.0000991
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