Eat Your Blueberries

The British Science Festival is one of Europe’s largest science festivals, taking place each September. The Festival is in a different location in the UK each year, bringing the latest in science, technology and engineering to a wider audience. This year it has been based at the University of Surrey.

The Department was represented by Dr Jeremy Spencer and Dr Carol Wagstaff who had been invited to jointly give a presentation entitled: ‘Food for Thought: Phytochemical Rich Foods and Their Effects on Brain Ageing’.

Speaking at the British Festival of Science, Dr Jeremy described how new research has shown that drinking a smoothie made with 200 g of blueberries boosts performance in tests of attention. He said that the berries took effect within hours.

People aged between 18 and 30 were given a smoothie before doing tests of their mental acuity. Everyone’s brainpower dipped in the afternoon, but after five hours it was 15 to 20 percent higher if the smoothie had contained blueberries than if it hadn’t.

Blueberries contain high levels of plant pigments called flavonoids, which are already known to help protect against heart disease and cancer and can now add improved memory, attention and learning ability to their list of benefits.

The potency of flavonoids was originally ascribed to their anti-oxidant properties, which allows them to mop up damaging reactive molecules in the body. However, the quantities present in the brain are so low it is unlikely this can explain their effects on brain function.

Instead, they are thought to increase blood flow to the brain and interact with signal pathways that are crucial to brain cell survival and growth. The changes they evoke help at the vital stage where a fleeting nerve impulse is converted to a lasting memory. Flavonoids may even encourage the growth of new brain cells.

It is hoped the plant chemicals might have the power to repair damage that occurs in the brain as we age, combating dementia and Alzheimer’s disease. Dementia is estimated to cost the UK £17 billion per year and just a 1% decrease in this figure would cancel out the expected costs of long-term care for our ageing population.

Dr Spencer admitted to frequently eating dried blueberries himself, but was keen to avoid the term ‘superfood’. “It would not be right to single out blueberries as other plants could also be effective” he said.

Studies of grapes, tea and cocoa, all of which are rich in flavonoids, have demonstrated beneficial effects on blood flow to the brain and improve memory and learning. The chemicals are also found in many other fruits, vegetables and cereals.

Dr Carol Wagstaff emphasised the need for a balanced diet because there are many different plant chemicals that are good for our health. She advised us to eat “a varied diet that incorporates all these different things, and to choose whole foods rather than supplements”.

How much of these beneficial compounds are present in fruit and vegetables depends on how they are grown and what happens to them on the journey from farmer’s field to dinner plate.

Plants produce the chemicals to protect themselves from stresses such as insect attack and sunlight. Growing the lettuce rocket under normal light intensities rather than in the shade, as is conventionally done, enhances the levels of flavonoids in its leaves. This raises the possibility of changing the way we grow food to boost its nutritional value.

Once harvested and sitting on the shelf, levels of many plant chemicals start to decline. “A short supply chain produces healthier food” said Dr Wagstaff.

Sometimes a little bit of stress can be a good thing though. For example, being put in the fridge might be sufficient to shock your salad into producing extra protective chemicals.

Read about the science here: Flavonoids and Brain Health: Multiple Effects Underpinned by Common Mechanisms

Food and Nutritional Sciences
10 September 2009: British Science Festival addressed by Drs Spencer and Wagstaff
© University of Reading