How to Keep Your Brain Healthy

Could sudoku, drugs and a Mediterranean diet help keep our brains fit? What can the latest neuroscience research tell us?

Neuroscience research got a huge boost last week with news of Professor John O'Keefe's Nobel prize for work on the "brain's internal GPS system". It is an exciting new part of the giant jigsaw puzzle of our brain and how it functions. But how does cutting-edge neuroscience research translate into practical advice about how to pass exams, remember names, tot up household bills and find where the hell you left the car in a crowded car park?

O'Keefe's prize was awarded jointly with Swedish husband and wife team Edvard and May-Britt Moser for their discovery of "place and grid cells" that allow rats to chart where they are. When rats run through a new environment, these cells show increased activity. The same activity happens much faster while the rats are asleep, as they replay the new route.

We already knew that the part of the brain known as the hippocampus was involved in spatial awareness in birds and mammals, and this latest work on place cells sheds more light on how we know where we are and where we're going. In 2000, researchers at University College London led by Dr Eleanor Maguire showed that London taxi drivers develop a pumped-up hippocampus after years of doing the knowledge and navigating the backstreets of the city. MRI scans showed that cabbies start off with bigger hippocampuses than average, and that the area gets bigger the longer they do the job. As driver David Cohen said at the time to BBC News: "I never noticed part of my brain growing - it makes you wonder what happened to the rest of it!"

Yet great breakthroughs don't automatically translate into practical benefits. "Research may give us great insights, but we still can't cure Alzheimer's," points out neuroscientist Baroness Susan Greenfield. "And just because we know more about what parts of the brain do normally, it doesn't tell us why things go wrong. We still need to know why special cells die in dementia. How come you can have a major stroke with lots of neuronal damage, but not lose your memory? What is the link between Parkinson's disease and dementia?" In other words, why are some cells damaged but not others?

Lab-based research is key to piecing together the jigsaw of how our brains work and what goes wrong when they don't. Even scans or postmortem examinations of brains of people who had dementia are of limited value, points out Greenfied, because "degeneration starts 10-20 years before symptoms appear". So what does neuroscience tell us about keeping the brain fit?

It seems obvious that the more you train, use and test your brain, the better it will perform. There is some evidence that people with more education or skills have a lower incidence of dementia. But the picture is complicated; perhaps highly educated people eat better food. And more skilled people may be more likely to be in work, benefiting from exercise, social interaction and mental stimulation. You may build up a "cognitive reserve" while young, which gives you a headstart over less educated people once dementia sets in. Staying physically, mentally and socially active means that even if your brain scan looks as ropey as that of a less active person, you will function better. No one can confirm the benefits, but there is at least no downside to daily sudoku, crosswords, reading, walks and talks.

Nootropics are also called smart drugs or cognitive enhancers. One of the best known is modafinil, a "wakefulness-promoting" drug that stimulates the central nervous system and is only prescribable in the UK for excessive daytime sleepiness (narcolepsy). Whether it is much more effective than a strong cup of coffee remains debatable, but its effect lasts longer. Modafinil is widely used by academics and students because it makes people feel sharper and more alert. Professor Barbara Sahakian of the University of Cambridge has found that sleep-deprived surgeons perform better on modafinil, and thinks it may have a wider role in improving our memory and mental function. "We found that modafinil improves motivation and working memory in healthy people and makes doing tasks more pleasurable," she said. But long-term safety, especially for young brains, is still not established. But for a lot of students, the question isn't whether the drugs are safe or constitute cheating, but how they can get hold of some.

Our environment is full of neurotoxins that can interfere with the genes, proteins and small molecules that build and maintain our brains. The younger the brain, the more susceptible it is to neurotoxins. A paper by the US National Scientific Council on the Developing Child says there are three types of neurotoxins that can affect the developing brain: environmental chemicals such as lead, mercury and organophosphates (pesticides); recreational drugs such as alcohol, nicotine and cocaine; and prescription medications such as Roaccutane, used for severe acne. Mature brains can be quite resilient, thanks in part to a barrier of cells that restricts entry of chemicals from the bloodstream into the brain tissue. But drugs, alcohol and cigarettes will poison even the most developed of brains if you take enough of them.

The brain needs a good blood flow to deliver vital nutrients and oxygen and take away waste products. Smoking, high blood pressure, uncontrolled diabetes, obesity and high cholesterol all sludge up the arteries and impede blood flow. If you care about your brain function, sorting out these risk factors remains the most useful thing you can do.

Omega-3 fatty acids, antioxidants such as vitamins C and E, and vitamins B and D all have neuroprotective effects, but trials have failed to show that high-dose supplements of these individual nutrients will protect you from dementia. However, eating a tasty Mediterranean diet that combines most of these nutrients can't hurt.

Professor Sahakian has identified five areas of neuroscience research that will help our understanding over the next five years.

• Smart and wearable technology to monitor people's brain health - similar to wristband monitors that track heart rate.

• Brain scanning to monitor changes in mental illness and track changes during treatments such as CBT.

• Trials of neuroprotective drugs such as solanezumab to prevent further deterioration in patients with Alzheimer's disease.

• Connectomics, the study and production of connectomes - neural maps of the brain - will combine a number of techniques to map and study connectivity in the brain.

• Genetics, to understand the genetic mutations that contribute to autism and other conditions.

 A brain ready for dissection. Photograph: Graeme Robertson/Guardian