The areca nut (/ˈærɪkə/ or /əˈriːkə/) is the seed of the areca palm (Areca catechu), which grows in much of the tropical Pacific (Melanesia and Micronesia), Southeast and South Asia, and parts of east Africa. It is commonly referred to as betel nut, not to be confused with betel (Piper betle) leaves that are often used to wrap it (a preparation known as paan). The term areca originated from the Kannada word adike (ಅಡಿಕೆ) and dates from the 16th century, when Dutch and Portuguese sailors took the nut from Kerala to Europe. Consumption has many harmful effects on health and is carcinogenic to humans. Various compounds present in the nut, including arecoline (the primary psychoactive ingredient which is similar to nicotine), contribute to histologic changes in the oral mucosa. It is known to be a major risk factor for cancers (squamous cell carcinoma) of the mouth and esophagus. As with chewing tobacco, its use is discouraged by preventive efforts. Consumption by hundreds of millions of people worldwide – mainly with southern and eastern Asian origins – has been described as a "neglected global public health emergency".