Could they pass on the gingko?

25th May 2001 at 01:00
Tests show that some herbal supplements seem to enhance learning and exam-taking abilities. Phil Revell reports

Children's capacity to learn and their ability to perform to their potential in exams could be improved by a programme of food supplements. In tests, ginseng and gingko, traditional herbal remedies, have been found to have dramatic effects on performance.

"It was as if the treatment was making the arithmetic easier," said the researchers. The test findings have been published by a team led by Dr Andrew Scholey at the University of Northumbria. Gingko and ginseng apparently have the capacity to increase the supply of the glucose and oxygen which fuels the brain.

"It's a simple principle," he says. Despite the brain's small size it burns nearly 20 per cent of the body's calories, creating a huge demand for the glucose and oxygen that the body uses to deliver energy. But the brain cannot store glucose and the results of poor supply can be seen in diabetics, whose bodies are unable to use glucose efficiently.

When sufferers are "hypo" (hypoglycaemic or in a state of low blood glucose) they report difficulties with concentration and memory. A shortage of oxygen can have a similar effect. Climbers at high altitudes often report feeling "groggy". The same reactions have been reproduced in laboratory experiments.

The Northumbria team wanted to discover whether the reverse was true. Would an increased supply of oxygen and glucose improve cognitive ability?

Experiments with oxygen showed positive results, including one where players' performance in the popular computer game Tetris was enhanced by oxygen inhalation. Similar results were obtained when Northumbria undergraduate volunteers were asked to carry out arithmetic exercises after a glucose drink.

The problem was that the effect was short-lived. The impracticalities of carrying oxygen bottles around were also obvious.

A possible answer came from work that researcher David Kennedy had been carrying out with herbal extracts. Kennedy and Scholey decided to do lab tests on some well-established herbal remedies to see if they would allow the body to use existing supplies of glucose and oxygen more efficiently.

"The results were unequivocal," they said. "Single doses of gingko improved ability to sustain attention over the day."

Students who took a single dose at 9am were still showing heightened responses at 3pm. Ginseng had a different effect. Initially the results were disappointing. Memory-related activities were enhanced but alertness was reduced.

The real breakthrough came when a combination of the two herbs was used. Using a "serial sevens" test where volunteers repeatedly had to subtract seven from an initial sum, the Northumbria researchers were amazed to find a significant improvement across the range of cognitive ability.

Dr Scholey emphasises that other research teams are engaged in parallel studies and he i wary about drawing immediate practical implications from his results.

He is currently working on studies into longer-term usage of the extracts, but he argues that their effects on a wider range of people - and with different tasks - also need to be researched.

Memory, in particular, could be affected in different ways. There is the initial "laying down" of memory, retention over time and retrieval. Gingko and ginseng may have an effect, but which memory process is enhanced the most?

Scholey is optimistic that what he sees as a real marriage between modern pharmacology and traditional herbal medicine will have practical uses. But until he has seen results from more extensive studies he is not advising this year's GCSE and A-level students to rush down to their herbalist.

"At present it would be irresponsible to encourage younger people to take these things." he says. He points out that exam performance has a lot to do with hard work and motivation - and there is no evidence that herbal treatments have any effect on either.


Herbalists and nutritionists were not surprised by the Northumbria research. Ian Marber is author of The Food Doctor and is clear about the effect that food supplements can have on cognitive performance.

"I've had parents bring children to me for this precise reason," he says.

He talks about the importance of balancing glucose levels to avoid highs and lows. For brain function he would recommend B vitamins such as choline, along with essential fatty acids, which are found in oily fish such as herring and mackerel.

For just before an exam he recommends a mild stimulant such as caffeine, either in coffee or in a drink like Red Bull. But Barber points out that the effect of caffeine is lessened as usage increases and he would advise people to limit their intake.

Herbalist Trudi Norris also backs up the Northumbrian researchers, pointing out that ginseng can also help people deal with the stress of exams. She would also consider lemon balm, lavender and passion flower extract.

Silver nitrate is often recommended for exam nerves, but Lennie Marlow, a homoeopath in the Midlands, points out that he and his colleagues treat patients holistically and they would want to see a client before recommending a course of treatment.


Gingko (gingko biloba, sometimes called the Maidenhair tree) is found in China and Japan.

It is the only tree that has survived since the Jurassic Age. A single gingko in Hiroshima survived the 1945 nuclear attack on the city.

Ginseng (Panax quinquefolius) is found in East Asia and North America. It has a forked root, which is usually used for the herbal extract.

Both remedies have been used for centuries and are considered safe, although anyone taking medication would be advised to consult their doctor before attempting to treat themselves with the herbs.

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