What are Peroxisome Proliferator-Activated Receptors (PPAR)?

PPARs are a group of nuclear receptor proteins.  They function as transcription factors and regulate your genes.  They play a major role in the metabolism of proteins, fats, and carbohydrates.  Their role in metabolism, especially metabolism of fat, is the main reason we will be discussing PPARs in detail.

Once PPAR is activated in the cells, it promotes the uptake, utilization, and catabolism of fatty acids.  It does this by upregulating genes involved in fatty acid transport, intracellular fatty acid binding, and peroxisomal and mitochondrial fatty acid β-oxidation.[10] Basically, PPAR activation results in more fat burning. 

There are three different types of PPARs that make up the PPAR family.  There is peroxisome proliferator-activated receptor alpha, peroxisome proliferator-activated receptor gamma, and peroxisome proliferator-activated receptor delta (also known as peroxisome proliferator-activated receptor beta).  


PPAR-alpha is expressed in muscle and heart tissues, but mainly in the liver. In the liver, PPAR-alpha regulates lipid metabolism.  PPAR-alpha is activated under conditions of energy deprivation such as prolonged bouts of fasting, and is necessary for the process of ketogenesis. 


PPAR-gamma acts as a master regulator of adipocyte formation and is located primarily in 

adipose tissue.  It is thought to have effects on insulin sensitivity.  For example, when the gene that encodes for PPAR-gamma is inhibited it results in insulin insensitivity and other factors that may cause diabetes.


PPAR-delta is expressed in many tissues, like muscle tissue, but only a small amount is present in the liver.In muscle PPAR-delta expression is increased by exercise, resulting in increased oxidative (fat-burning) capacity. In adipose tissue PPAR-delta increases both oxidation as well as uncoupling of oxidative phosphorylation.  Uncoupling of oxidative phosphorylation basically means that PPAR helps cells create heat rather than energy molecules(ATP) within the cells.  If more energy is dedicated to create heat, the body will expend more calories and this will accelerate weight loss.

In one study conducted on mice, researchers found that mice with upregulated PPAR-delta displayed a lean phenotype when compared to the the control mice.  During the experiment the mice were fed a normal diet AND a high fat diet.  The mice with the upregulated PPAR-delta expression displayed a lean phenotype on the standard AND the high fat diet.  Researchers went a step further and tested the effects of PPAR delta on mice that were already predisposed to obesity.  What they found was that expression of activated PPAR-delta reverses the obesity phenotype, and also that short-term treatment with a PPAR-delta agonist markedly depleted lipid accumulation in the obese mice. 

How to Activate PPAR

We’ve mentioned a few ways how PPAR gets activated in the body already, but here are a few more ways.  

Studies have shown that participating in a high fat diet, such as the ketogenic diet, is one way to activate PPARs.  Fasting is another way to increase PPAR expression in cells.  Drinking apple cider vinegar has been shown to upregulate the expression of PPAR gamma according to this study.  Exposure to the cold such as cold baths or cold showers 

Exercise.  Exercise has been shown to up-regulate PPAR-delta in muscle tissue.  This allows muscle to burn more fat for fuel during workouts.