Chia

Chia is an annual herb in the mint family that grows to about a metre, with serrated leaves and spikes of small purple or white flowers. The seeds are tiny, oval and about two millimetres long, with a glossy, mottled coat of grey, black, brown and white. A pale-seeded variety, sometimes sold under the name salba, is also grown.

Dry chia seeds are crunchy and nearly flavourless. When soaked, each seed develops a clear mucilaginous coating and can absorb many times its weight in water, forming a soft gel. Chia is sold whole, milled into meal, pressed into oil, and added to cereals, bars and drinks.

Chia is native to central and southern Mexico and Guatemala, where it grew in the highlands and was domesticated by Mesoamerican peoples. It is now cultivated commercially in Mexico, Bolivia, Argentina, Paraguay, Australia and elsewhere.

The name comes from the Nahuatl word chian, meaning oily, a reference to the seeds. Several Mexican place names, including the state of Chiapas, are thought to derive from the same root. The botanical species name hispanica, meaning Spanish, is a mistake of early European botanists, who assumed the plant came from Spain.

Chia was a major food crop of the Aztec and earlier Mesoamerican civilizations, rivalling maize and beans in importance. Seeds were ground into flour, pressed for oil, mixed into drinks and offered to the gods, and large quantities were paid in tribute to Aztec rulers. Runners are said to have carried chia on long journeys for endurance.

After the Spanish conquest the crop declined sharply, in part because chia was bound up with Aztec religion and colonial authorities discouraged its cultivation in favour of European crops. It survived in small areas of Mexico and Guatemala, where chia drinks such as chia fresca continued to be made.

The modern revival began in the late twentieth century, when researchers rediscovered the seed's oil and fibre. In the United States, chia sprouts became familiar through the novelty Chia Pet, and from the 2000s onward chia seeds were sold as a health food. The European Union authorised chia seed as a novel food in 2009. Today, large-scale farms in Latin America and Australia supply a global market.

Chia seeds can be stirred into water and juice, soaked overnight in milk or plant milk for pudding, mixed into porridge and smoothies, sprinkled over yoghurt, and baked into breads and crackers. Ground seeds blend more readily into batters. The gel they form can partly replace eggs in some vegan baking and also thickens jams.

In Mexico and Central America, chia fresca, a drink of seeds soaked in water with lime and sugar, is traditional. Chia oil is used in nutritional supplements and cosmetics, and the sprouts are eaten in salads. Seeds can be stored for a long time without going rancid, due to their natural antioxidants.

Chia is notable for its fibre and for alpha-linolenic acid, a plant omega-3 fat, as well as calcium, magnesium, phosphorus and protein. A tablespoon or two a day can help contribute to fibre intake.

Clinical trials have looked at chia for blood sugar, cholesterol, blood pressure and weight, and results have been modest or inconsistent, with several trials finding little effect. The body converts plant omega-3 to the marine forms EPA and DHA only to a limited degree. Chia is a useful nutritious food but is not a proven treatment for any condition.