**3.1 Polyunsaturated fatty acids (PUFAs)**

The major sources of PUFAs, mostly Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) are found in fatty fish such as salmon and anchovies as

### **Figure 2.**

*Food components involved in the induction of WAT browning. Here, PUFAs- polyunsaturated fatty acids, WAT- white adipose tissue, TRPM8- transient receptor potential cation channel melastatin 8, UCP1- uncoupling protein 1, TRPV1-transient receptor potential vanilloid 1, SNA- sympathetic nerve activity; AMPK- adenosine monophosphate-activated protein kinase, SIRT1- sirtuin-1, PGC-1α-peroxisome proliferator-activated receptor gamma coactivator 1-alpha, COMT- catechol-O-methyl-transferase, cAMP- cyclic adenosine monophosphate, PDEs- phosphodiesterases. The figure was modified from the following research paper by El Hadi et al., 2019. The images used in drawing the figure were extracted from the following links as described below: 1. PUFAs- Walnuthttps://5.imimg.com/data5/JR/AK/VJ/SELLER-2793878/walnut-500x500.jpg, fish- https://www.bigbasket.com/ media/uploads/p/xxl/40186851\_1-fresho-atlantic-salmon.jpg, soyabean oil- https://image.shutterstock.com/imagephoto/soybean-oil-bottle-green-pods-260nw-310996568.jpg, sunflower seeds- https://zonefresh.com.au/wp-content /uploads/SUNFLOWER-KERNELS.jpg, 2. Curcumin- https://5.imimg.com/data5/SELLER/Default/2020/9/VE/ PK/ZA/24380440/curcumin-extract-500x500.jpg, 3. Resveratrol- https://news.mit.edu/sites/default/files/styles /news\_article\_\_image\_gallery/public/images/201303/20130307093438-0\_0.jpg?itok=xnIFxN6G, 4. Menthol- https:// smhttp-ssl-61936.nexcesscdn.net/media/catalog/product/optimized/7/5/75ea61bf1685045cff4a80f864b6472f/flavorwest-natural-menthol.jpg, 5. Capsaicin/capsinoids- https://article.innovadatabase.com/articleimgs/article\_images/ flavors8.jpg, 6. Green tea- https://femina.wwmindia.com/content/2018/nov/thumbnail1541742051.jpg.*

well as fish oil supplements [6]. Previous studies reported that EPA activates white adipocytes to beige-like adipocytes in overweight human subjects by stimulating the activation of the adenosine monophosphate-activated protein kinase (AMPK)/ sirtuin-1 (SIRT1) /peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1- α axis) [6, 8]. Furthermore, many researchers also reported that fish oil contributes to brown adipogenesis by acting as a ligand of transient receptor potential vanilloid 1(TRPV1) in the digestive tract that triggers through the brain, a β 2-adrenergical sympathetic response in adipose depots [6].
