title: The slim, the fat, and the obese: guess who lives the longest?
abstract: In a modern society that is increasingly older and "heavier," it is understandable that the majority favors a slimmer body that helps to sail smoothly into the dusk of life. Given the association between obesity and many metabolic and cardiovascular disorders, there are stern criticisms over such a thought of "good fat". Ironically, a phenomenon called "obesity paradox", that is, the overweight population purportedly enjoys the lowest all-cause mortality, and baffles open-minded clinicians and scientists. Lipids are essential to all life forms. Fat, in particular, triacylglycerol, also exists in different forms and in different locations in the human body, making any simple statement that vilifies all fat invalid. Whether the phenomenon of obesity paradox, indeed, has its root in a hitherto unrealized pro-survival function of fat deserves a serious look. Indeed, a recent publication using yeast as the model showed that elevation in the cellular storage of triacylglycerol extends lifespan in an energy expenditure independent fashion. In stark contrast, lean cells devoid of triacylglycerol biosynthetic capability die upon entering the senescence phase. Together, a new cytoprotective function of fat emerges. This mini-review aims to discuss potential mechanisms for the observed lifespan preservation function of triacylglycerol.
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Li
authors.affiliation: Cell and Molecular Biology Program, Michigan State University, East Lansing, MI, USA.
authors.forename: Witawas
authors.initials: W
authors.lastname: Handee
authors.affiliation: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA. kuom@msu.edu.
authors.forename: Min-Hao
authors.initials: MH
authors.lastname: Kuo
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000375:Aging; D000818:Animals; D001835:Body Weight; D006801:Humans; D008017:Life Expectancy; D050356:Lipid Metabolism; D008136:Longevity; D009765:Obesity / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological; D014280:Triglycerides / Q000378:metabolism; D015003:Yeasts / Q000502:physiology
chemical_list: D017382:Reactive Oxygen Species; D014280:Triglycerides
keywords: Aging; Free radicals; Lifespan regulation; Obesity paradox; Triacylglycerol