Technoquest: Inuit diet/ Nerves/ Population/ Seagulls

Questions for this column may be submitted via e-mail to sci.net@campus.bt.com

Q Citrus fruit does not grow in the Arctic, so how do the Inuit [Eskimos] avoid scurvy?

Earlier this century, Vilhjalmur Stefansson argued that it was possible for people of European stock to live for long periods on a traditional and entirely carnivorous Inuit diet, and that many Arctic explorers had developed scurvy (caused by lack of vitamin C) because they would not follow the Inuit and trust their instinct and experience.

He and a colleague volunteered to subsist on nothing but meat, under medical supervision in New York, for one year starting in February 1928. They each consumed between 100gm and 140gm of protein a day, with the remaining calories coming from fat. Both men remained in good health and showed no sign of scurvy.

It has been estimated that a traditional, daily Inuit diet, even without any plant material, would contain 40mg of vitamin C, enough to avoid scurvy. But some flora - including rose hips, a good source of the vitamin - grow in areas where the Inuit live.

Q What is in a nerve besides nerve cells?

Packed between the neurones are the glial cells. These make up the neuroglia, tissue which supports the neurone network, protecting it and providing the neurones with nutrients. Glial supporting cells make up about half the weight of the human brain, outnumbering neurones by 50 to 1. In other parts of the nervous system the proportion is much lower, about 10 to 1.

Q What will the world's population be in 2050?

In mid-1997 the world's population was estimated at 5.8 billion. By the year 2050, it could have decreased to 4 billion because of falling birth rates. But most calculations suggest it could be anything up to 15 billion.

Q Why don't you see seagulls in the Mediterranean?

Actually, you do. But the Mediterranean has a lack of fish compared with places such as the North Sea. This means the number of all sea birds is lower. But there is one gull species called the Mediterranean gull, which looks like our black-headed gull, and one called Audouin's gulls, whose breeding area is confined to the Mediterranean.

You can also visit the technoquest World Wide Web site at http://www.sciencenet.org.uk

Questions and answers provided by Science Line's Dial-a-Scientist on 0345 600444.