The Consensus: Eating Well Could Help Against Dementia

Every time a neuron in your brain sends out a message to another one down the road, substances like sodium and potassium are pumped in and out of the neuron in a wave that spreads along its membrane. Then, once the signal gets to the end of the neuron, there will be a signal to fire and the neuron will immediately release a bunch of neurotransmitters to its neighbours. This process is repeated over and over again in your brain – and for that, you need lots of energy.

The brain is a hugely demanding machine and burns about a fifth of all the glucose in our body – but even that is not enough. Like other organs, it needs a number of different nutrients in the right amount to function well. So can your diet affect cognitive function?

Good nutrition, bad nutrition

An incomplete diet (that is, one lacking certain nutrients) can indeed alter the function of our brain, as pointed out by Justin Rhodes, a neuroscience expert from the University of Illinois. Professor Sue A. Shapses, a nutrition expert from Rutgers University, agrees with this. A well-balanced diet, she says, needs to include appropriate amounts of nutrients such as vitamins D and B12 or omega-3 fatty acids. In fact, according to geriatrics expert William J Evans, from the University of California, Berkeley, a diet with plenty of omega-3 fatty acid (found in sardines or nuts) is beneficial in preventing dementia or slowing it down. Some experiments on animals have also shown that dietary intake of minerals like selenium can improve their learning, says Mohammad Naderi, a neuroscience expert from the University of Saskatchewan.

Having said that, bear in mind that there is broad consensus that superfoods are a myth and most supplements are not grounded in solid evidence. Just like eating lots of calcium won’t make your bones any stronger, no magic pills are likely to help you prevent brain disorders. What’s more, Professor Sharpses warns against the use of supplements as she points out that more recent evidence reveals that an excessive intake of micronutrients can also be damaging.

That is not to say that there aren’t healthy and unhealthy foods, though. There certainly are. So what do we really mean by a healthy diet? The traditional Mediterranean diet is usually taken as a good standard. We can take the “healthy eating plate” designed by Harvard’s School of Public Health as a more visual guide: plenty of veggies and fruits, plant oils, lean protein, whole grains and good amounts of water (note that you won’t find butter, processed meat or sugary drinks in this plate).

Several reviews (like this or this) have looked at available evidence to work out whether Mediterranean diet is associated with dementia. Such studies should be taken with a grain of salt and more long-term, thorough trials are still needed. Still, these reviews concluded that following a healthy, Mediterranean-like diet is linked to a lower risk of getting dementia and a slower progression of the disease in the patients that have it.