Role of Environmental Chemicals in Obesity: A Systematic Review on the Current Evidence

Table 1

Summary of main obesogen chemicals and their health effects.

Chemicals	1st author	St.yr	Ge.Loc	Sample size	Study population	Characteristics	Uses	Mechanisms	Human effects	Animal effects
Phytoestrogens; (genistein and daidzein)	Miriam J. J. de Kleijn [21] 2002	1971	USA	5209	30–59 y		Included in various food and food supplements, in particular soy product	High doses inhibited adipose deposition but at low doses similar to those found in Western and Eastern diets, in soy milk, or in food supplements containing soy, it induced adipose tissue deposition especially in males
Perfluorooctanoic acid (PFOA)	Frank D. Gilliland [24]	1985–1989	USA	115				Perfluorooctanoic acid (PFOA) increases PPAR-dependent lipid mobilization, fatty acid oxidation, and adipose tissue atrophy during periods of experimental exposure. PFOA probably exerts anorexigenic effects through a central hypothalamic mechanism that triggers a decrease in food intake in adult rodents
Perfluoroalkyl compounds (PFCs)	Sakr,CarineJ [23] 2007	2007		1025				Agonists for one or more of the PPARs, providing a mechanistic link to disturbed lipid and steroid metabolism
Phtalates	Elizabeth E Hatch [22] 2008	1999–2002	USA	4369 participants	6–80 y		As plasticizers and stabilizers in a variety of plastics. They are found in industrial paints and solvents but also in cosmetics, perfumes, and medicines	PPARα, PPARγ, ER, and peptidergic hormones
Nonylphenol	Mei-Lien Chen [19] 2009	2008	Taiwan	960	Primary and junior high schools
Organotins, as tributyltin chloride (TBT) and bis (triphenyltin) oxide	Zhenghong Zuo [17] 2011	2009	China	32 mice	Mice, aged 21 days and weighing 10.5–13.5 g	Tetravalent tin compounds with a variety of mono-, di-, tri-, or tetrasubstituted organic functional groups	Antifouling agents in paints for marine shipping and for a variety of other uses	PPARg and RXR have been shown to disrupt normal development and homeostatic controls over adipogenesis and energy balance. suggested an inhibition of adipogenesis in the 3T3-L1 cells(1) TBT stimulates adipocytes differentiation in vitro and increases adipose mass in vivo in the 3T3-L1 cells		In-utero studies, showed TBT to accumulate lipids in adipose, testis, and liver tissues in neonate mice. and increasing epididymal adipose mass in adult mice
Bisphenol A (BPA)	He-xing Wang1 [15] 2012	2011	China	360	8–15 y	BPA is a small (228 Da) molecule which is used as a monomer in polymerization reaction to produce polycarbonate plastics	Used in food and water containers baby bottles, lining of food and beverage metal cans, medical tubing, epoxy resins, and dental fillings	BPA mimics the actions of E2 on blood glucose homeostasis via two pathways: a rapid pathway involving ncmER and a prolonged pathway involving ER. It inhibits adiponectin release and stimulates release of IL-6 and TNFα. mouse triggers 3T3-L1 cells (fibroblasts that can differentiate into adipocytes) to differentiate into adipocytes. Suppression of adiponectin and increased IL-6 and TNFα	There has been no information on BPA effects on human adipocytes	Mice treated with low doses of E2 or BPA showed rapid increases in insulin release and reduced plasma glucose. High dose for 15 d reduction in body weight. 3 m did not alter body weight and fat depot