Seven stunning Bioactive compounds that activate Brown Adipose Tissue

By: Fady Habib

Brown Adipose Tissue

By Thiyagarajan Sivapriya, M.Sc, M. Phil

The looming pandemic of obesity and overweight, driven by ready access to high-calorie food and an increasingly sedentary way of life, poses a severe threat to global public health. The pathological accumulation of excess dysfunctional adipose tissue that characterizes obesity is a major risk factor for many other diseases, including type 2 diabetes, cardiovascular disease, hypertension, stroke, arthritis, and various types of cancer [1].

The adipose tissue in mammals is composed of at least two functionally different types of fat: white and brown. White adipose tissue is the primary site of energy storage, modulate whole-body metabolism and insulin resistance. Excess accumulation of white adipose tissue causes obesity [2] .Brown adipose tissue, on the other hand, is important for both basal and inducible energy expenditure in the form of thermogenesis [3].

Brown adipose tissue (BAT) has been believed to be negligible or absent in adult humans but recent studies have proved the existence of metabolically active BAT in adult humans [4]. BAT in humans is located in fat tissues in the neck, thorax, and abdomen, juxtaposing deep viscera (heart, lungs, kidneys, adrenals, and intestines) and along the great vessels like carotids, aorta, pulmonary, and mesenteric vasculature [5].

The contribution of BAT to thermogenesis and its inducibility invitro has created a new paradigm in adaptive thermogenesis in humans, defining new therapeutic directions in obesity treatment through BAT enhancing strategies. The concept of managing obesity through the stimulation of thermogenesis is currently a focus of considerable attention by the pharmaceutical, nutraceutical and functional food industries [6]

Bioactive components

There are numerous bio active components in our foodstuff that have an antagonistic activity, expected to activate BAT and functional in preventing obesity. Let’s be acquainted with a few of them:

• Capsinoids, nonpungent capsaicin analogs, present in red pepper increase energy expenditure through the activation of a subtype of the transient receptor potential channels (TRP) and BAT in humans [7]
• Methylxanthines: The ability of caffeine, the most abundant dietary methyl xanthine to stimulate metabolic rate was demonstrated in humans almost a century ago both in post-absorptive and postprandial states in lean, obese and post-obese subjects[8]
• Resveratrol and quercetin, two quantitatively important grape polyphenols possess such thermogenic properties[9]
• Oleuropein, a phenolic compound in extra virgin olive oil, has been shown to enhance catecholamine secretion and to increase BAT [10]
• Lemon polyphenols (hesperidin) suppress diet-induced obesity associated with the up-regulation of gene markers of lipid oxidation in white adipose tissue[11]
• Similarly, dietary supplementation with soy isoflavones has been shown to decrease fat accumulation in several animal models of obesity [12]
• Finally, the small polyphenolic flavonol molecule kaempferol (found in broccoli, spinach, berries) increases thermogenesis in human skeletal muscle myoblast [13]

The usage of herbal preparations, nutraceuticals and functional foods in the management of body weight has generally been perceived by the medical establishment as essentially anecdotal. With research likely to generate many new candidate bioactive components, with the market likely to be overwhelmed with new products containing combinations of these components and with claims of a more effective multi-targeted approach for weight control, the challenge for regulatory agencies is to decide as to what type of safety and efficacy standards these single target or multi-target products should be subjected before being ‘approved’ as supplements or functional foods for the purpose of managing human obesity.

References

1. Bray GA, Bellanger T. Epidemiology, trends, and morbidities of obesity and the metabolic syndrome. Endocrine 2006;29:109–117
2. Ronti T, Lupattelli G, Mannarino E. The endocrine function of adipose tissue: an update. Clin Endocrinol (Oxf) 2006; 64: 355-65.
3. Almind k, Manjeri M, Sivitz WI, Cinti S, Kahn CR. Ectopic brown adipose tissue in muscle provides a mechanism for differences in risk of metabolic syndrome in mice. Proc Natl Acad Sci 2007; 104: 2366-71.
4. Virtanen KA, Nuutila P, Brown adipose tissue in humans, Curr opin lipidol 2011; 12: 44- 49
5. Lean ME, James WP, Jennings G, Trayhurn P. Brown adipose tissue uncoupling protein content in human infants, children and adults. Clin Sci (Lond). 1986;71:291–297.
6. Paul Lee, Michael M. Swarbrick, and Ken K. Y. Ho, Brown Adipose Tissue in Adult Humans: A Metabolic Renaissance, Endocrine Reviews 34: 413–438, 2013
7. Saito M, Yoneshiro T, Capsinoids and related food ingredients activating brown fat thermogenesis and reducing fat in humans, Curr Opin Lipidol 2013, 24:71–77
8. Higgins HL, Means JH. The effect of certain drugs on the respiratory and gaseous metabolism in normal human subjects. J Pharmacol Exp Ther 1915; 7: 1–9.
9. Baur JA, Pearson KJ, Price NL, Jamieson HA, Lerin C, Kalra A et al. Resveratrol improves health and survival of mice on a high-calorie diet. Nature 2006; 444: 337–342.
10. Oi-Kano Y, Kawada T, Watanabe T, Koyama F, Watanabe K, Senbongi R, Iwai K. Oleuropein, in extra virgin olive oil, increases uncoupling protein 1 content in brown adipose tissue and enhances noradrenaline and adrenaline secretions in rats. J Nutr Sci Vitaminol 2008; 54: 363–370.
11. Fukuchi Y, Hiramitsu M, Okada M, Hayashi S, Nabeno Y, Osawa T et al. Lemon polyphenols (hesperidin) suppress diet induced obesity, J Clin Biochem Nutr 2008; 43: 201–209.
12. Ørgaard A, Jensen L. The effects of soy isoflavones on obesity. Exp Biol Med (Maywood) 2008; 233: 1066–1080
13. Da-Silva WS, Harney JW, Kim BW, Li J, Bianco SD, Crescenzi A et al. The small polyphenolic molecule kaempferol increases (skeletal muscle myocyte) cellular energy expenditure and thyroid hormone activation. Diabetes 2007; 56: 767–776.