Effects of ginger on metabolic syndrome : a review of evidence

The use of plants for the treatment of various ailments has been documented since antiquity. People rely on these plants not only for their nutritional values but also for maintenance of health and protection from various pathological threats to the body. Ginger (Zingiber officinale) belongs to the Zingiberaceae family, which also includes cardamom (Elettaria cardamomum) and turmeric (Curcuma longa). It originates in Southeast Asia and has become widespread across numerous ecological zones. Historically, ginger has been highly regarded for both its medicinal and its mercantile value. Ginger is commonly known as a condiment or spice used for its aroma and flavor in culinary arts; however, it is also widely used as herbal medicine to treat ailments in China, India, and Europe for centuries (Ali et al. 2008). In Ayurveda and Unani-Tibb medicine, ginger is predominantly used for digestive imbalance and gastric upset, such as nausea (Butt and Sultan 2011), whereas in traditional Chinese medicine (TCM), in addition to digestive complaints, ginger is also used for common cold as well as pain symptoms (Bensky 2004). Over the past few decades, tremendous efforts have been made in the discovery of pharmaceutical medicine from herbal sources for the management of chronic illnesses. Ginger has a long history of medicinal use. An extensive preclinical research has demonstrated that ginger possesses a broad range of pharmacological properties such as antiemetic, anti-inflammatory, antioxidant, antihyperglycemic, and antihyperlipidemic effects. Clinical research into ginger has been predominately conducted on its antiemetic effects in pregnancy or motion sickness and anti-inflammatory effects for pain management in osteoarthritis. There is a general lack of clinical evidence for ginger to be used outside of these conditions (White 2007). The metabolic syndrome is a group of risk factors that include high blood sugar (hyperglycemia), abnormal blood fat (dyslipidemia), high blood pressure (hypertension), and obesity (Alberti et al. 2005). There is preponderance of laboratory-based research supporting the application of ginger for the metabolic syndrome even though the relevant clinical evidence is generally lacking. This chapter aims to provide an overview of the clinical and preclinical evidence regarding ginger, emphasizing its effect on the metabolic syndrome.