Conjugated linolenic acid, or CLA, is a type of fatty acid naturally found in certain foods. In supplement form, it is mainly touted as a weight loss aid, but a meta-analysis of numerous studies, published in a 2005 issue of the ‘’Asia Pacific Journal of Clinical Nutrition,’’ found it provided minimal benefit at best. While considered generally safe, some safety concerns exist. Before using Tonalin CLA or any other brand, talk to your doctor first.
Reduced Blood Sugar Control
Studies have produced mixed evidence on whether CLA raises blood sugar levels and decreases insulin sensitivity, or how well your body’s tissues respond to this hormone trying to move sugar into them and out of the bloodstream. Given these mixed findings, it is probably a good idea to talk to your doctor before using Tonalin CLA if you have diabetes or prediabetes.
A study by Irish researchers published in the October 2004 issue of ‘’The American Journal of Clinical Nutrition’’ compared the effects of taking 3 grams of CLA daily for eight weeks to a placebo on the blood sugar in individuals with type 2 diabetes 4. They found that CLA supplementation appeared to significantly increase fasting glucose levels and decrease insulin sensitivity.
**A more recent study, published in the July 2007 issue of ‘’The International Journal of Obesity,’’ found no significant differences in fasting glucose or insulin sensitivity in the treatment group compared to the placebo group 5. This study used a more accepted method of measuring insulin resistance than other studies.
- Studies have produced mixed evidence on whether CLA raises blood sugar levels and decreases insulin sensitivity, or how well your body’s tissues respond to this hormone trying to move sugar into them and out of the bloodstream.
- A study by Irish researchers published in the October 2004 issue of ‘’The American Journal of Clinical Nutrition’’ compared the effects of taking 3 grams of CLA daily for eight weeks to a placebo on the blood sugar in individuals with type 2 diabetes 4.
Increased Potassium Levels
How Long Does it Take CLA to Work?
Laboratory testing suggests CLA may increase potassium levels, according to the Memorial Sloan Kettering Cancer Center 1. In most people, this is not a cause for concern. If you have kidney disease or take medications such as potassium-sparing diuretics to treat hypertension, however, you could experience dangerously high potassium, which can pose significant health problems.
The University of Pittsburgh Medical Center reports that CLA might inhibit normal blood vessel function and that it has been linked with increasing levels of c-reactive protein, a substance that indicates inflammation is present in the body 3. High levels of this protein have been identified as a risk factor for cardiovascular disease. If you already have heart disease or have risk factors that increase it, talk to your doctor about whether to use CLA.
Effect on Breast Milk
Side Effects of Tonalin
CLA’s effect on reducing fat might affect the fat content of your milk. This can lead to your baby consuming insufficient amounts of calories and fats, which would impact proper growth and development.
Tonalin CLA is made from safflower oil, which is commonly found in foods and is used as a cooking oil. It appears generally safe, but Drugs.com reports cases of allergic reactions from the safflower itself, making an allergic reaction a possibility 2. CLA and safflower oil do not have any known medication interactions, but if you take any medications, always clear the use of supplements with your doctors; this same precaution goes if you have liver or kidney disease, two conditions that make you particularly vulnerable to what you put in your body.
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- Memorial Sloan Kettering Cancer Center: Conjugated Linoleic Acid
- Drugs.com: Complete Safflower Information
- University of Pittsburgh Medical Center: Conjugated Linoleic Acid
- ''The American Journal of Clinical Nutrition''; Conjugated Linoleic Acid Supplementation, Insulin Sensitivity, and Lipoprotein Metabolism in Patients with Type 2 Diabetes Mellitus; F. Moloney, et al.; October 2004
- ''International Journal of Obesity''; The Effect of 6 Months Supplementation with Conjugated Linoleic Acid on Insulin Resistance in Overweight and Obese; C. Syvertsen, et al.; July 2007
- Benjamin S, Prakasan P, Sreedharan S, Wright AD, Spener F. Pros and cons of CLA consumption: an insight from clinical evidences. Nutr Metab (Lond). 2015;12:4. Published 2015 Feb 3. doi:10.1186/1743-7075-12-4
- Whigham LD, Watras AC, Schoeller DA. Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans. Am J Clin Nutr. 2007;85(5):1203-11. doi:10.1093/ajcn/85.5.1203
- Silveira MB, Carraro R, Monereo S, Tébar J. Conjugated linoleic acid (CLA) and obesity. Public Health Nutr. 2007;10(10A):1181-6. doi:10.1017/S1368980007000687
- Lehnen TE, da Silva MR, Camacho A, Marcadenti A, Lehnen AM. A review on effects of conjugated linoleic fatty acid (CLA) upon body composition and energetic metabolism. J Int Soc Sports Nutr. 2015;12:36. Published 2015 Sep 17. doi:10.1186/s12970-015-0097-4
- Arab A, Akbarian SA, Ghiyasvand R, Miraghajani M. The effects of conjugated linoleic acids on breast cancer: A systematic review. Adv Biomed Res. 2016;5:115. doi:10.4103/2277-9175.185573
Kelli Cooper has been a writer since 2009, specializing in health and fitness. She holds a Bachelor of Arts in political science from Rutgers University and is a certified personal trainer with the American Council on Exercise.