Areca nut

The areca palm is a medium-sized palm with a single straight trunk reaching about 20 m; the trunk is 10–20 cm in diameter, slightly wider at the base, greyish-brown when mature and greener near the top, with evenly spaced leaf scars. The pinnate leaves reach 2 m long on short stalks; each crown holds 8–10 leaves whose shaft bears 20–30 dark green leaflets per side — the middle leaflets longest at up to 70 cm, those at the base 40–50 cm and at the tip 15–25 cm. The inflorescence has several branches up to 25 cm long and spreads to 60 cm; small white flowers sit on yellowish-white axes, female flowers with petals 1.4 cm long and male flowers with petals only 0.5 cm. The fruit is a one-seeded berry up to 8 cm long and 6 cm wide, green turning yellow and then red at maturity; the seed (areca nut) is reddish brown, hard, up to 2 cm across, rounded and tapering at one end.

According to Kew POWO, the palm is native to the Philippines and has been introduced across the tropics: South Asia, Southeast Asia, southern and south-central China, Taiwan, West Africa, Madagascar, many Pacific islands and the West Indies. Betel chewing arose in Maritime Southeast Asia together with the Austronesian expansion: it reached Micronesia about 3,500–3,000 years ago, South India and Sri Lanka about 3,500 years ago, mainland Southeast Asia about 3,000–2,500 years ago, northern India about 1,500 years ago and Madagascar about 600 years ago. The oldest evidence is a burial pit in Duyong Cave (Palawan, Philippines) dated to about 4,630±250 years before present, whose teeth show the red staining typical of betel chewers. Today India produces 60% of the world crop (2023); India, Bangladesh and Myanmar together account for about 87%.

The fruit contains about 31% phenols — phenolic acids and flavonoids (isorhamnetin, chrysoeriol, luteolin, quercetin, liquiritigenin) — together with 18.7% polysaccharides, 14% fat, 10.8% fibre and about 0.5% alkaloids. The alkaloids include arecoline (the main one), arecaidine, guvacine and guvacoline; in 2019 Cao et al. isolated two new alkaloids, acatechu A and B. Tannins in the nut are proanthocyanidins (arecatannins); there are also fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic and more), amino acids (phenylalanine, arginine) and triterpenes and steroids (ursolic acid, sitosterol, isoarborinol, ergosterol and others). Arecoline is a non-selective partial agonist of muscarinic and nicotinic receptors, promoting salivation, vasodilation and contraction of the digestive smooth muscle.

The nut is chewed with betel leaf and slaked lime (calcium hydroxide), sometimes with clove, cardamom or catechu resin (kattha); it is the fourth most widely used psychoactive substance after caffeine, nicotine and alcohol. In South Asia the nut is also processed into pan masala, supari and gutka (with tobacco). Traditional medicine in India, Sri Lanka, China and Southeast Asia uses the nut to expel intestinal worms (especially tapeworms), to treat diarrhoea and in dentifrices (Peng et al., 2015; Sun et al., 2024). The husk fibre serves for cushions, ornaments and handicrafts and is studied to strengthen construction materials; pressed dry leaves make disposable plates and bowls; in Vietnam the trunk is used for posts and rafters. On classification and health, IARC (2004) ranked betel quid with or without tobacco as Group 1 — carcinogenic to humans — while arecoline alone is Group 2B; Taylor et al. (1992) recorded bronchoconstriction in asthmatic patients after chewing betel nut.

Habitual betel chewing is addictive through arecoline and raises the risk of oral submucous fibrosis, oral and oesophageal cancer, cardiovascular disease, metabolic disturbance, cirrhosis and liver cancer; use during pregnancy is linked to preterm birth and low birth weight. With some 600 million users it has been called a neglected global public-health emergency, and the habit should be limited, especially when combined with tobacco. On conservation, the palm is widely cultivated across tropical Asia–Pacific and supply comes mainly from plantations, so the species is not threatened; following the Kew/POWO update the IUCN lists it as Data Deficient (DD), while this site keeps its original Least Concern (LC) status.