June 21, 2016
Fat-burning foods. Muscle-building foods. Superfoods. Sugar is bad. Saturated fat is bad. No wait, saturated fat is good again. The role of diet in health is complicated. Not only is it complex, but one vital system of the body is often overlooked. The brain. Dr Helen Macpherson, NHMRC-ARC Dementia Research Postdoctoral Fellow at the Institute for Physical Activity and Nutrition (IPAN) in the School of Exercise and Nutrition Sciences (SENS), shares her views on healthy eating and a healthy brain.
We can’t directly see the impact of our diet on the brain; there is no brain equivalent of the “thigh gap” or six pack abs. Nevertheless, our dietary choices can influence our mental health i.e. how we feel, but also our cognitive health, such as how we think and make decisions. A quick Internet search brings up lists of “brain-boosting” foods, but the brain requires a range of nutrients for optimum function, therefore it is the cumulative effect of our entire diet, rather than individual foods, that is key to maintaining brain health.
The optimum dietary pattern
The Mediterranean diet, as the name suggests, is based on the foods favoured by populations from the Mediterranean region. This dietary pattern gained attention after observations that inhabitants of southern Europe were less likely to die from coronary heart disease than those from Northern Europe or the United States.
The Mediterranean diet is rich in fresh fruits, vegetables, breads, cereals, nuts, and legumes. Olive oil provides the main source of dietary fat. A low to moderate consumption of dairy, fish, and poultry is included. In some definitions alcohol served with meals is also counted as beneficial (low amounts – don’t get too excited). Red meat is consumed only in low quantities.
Following this dietary pattern has the potential to benefit heart and brain health. In fact, the majority of studies have demonstrated that higher adherence to a Mediterranean diet is related to better cognitive function. In older people, this diet has been linked to a slower rate of cognitive decline and a lower number of people developing Alzheimer’s Disease. These positive findings have been shown for people living in countries around the world, including those outside of the Mediterranean region.
The good news is that some of the benefits of the Mediterranean diet may occur quite quickly. In one of my research collaborations,we found that in 24 healthy young women, following a Mediterranean style diet for only 10 days was capable of improving mood and memory recall.
These results are important for a couple of reasons. First of all they suggest that making a dietary change can improve brain function, even before a change would be noticeable in our physical appearance. If we were following a weight loss diet we would be pretty impressed to see a change in body shape in less than 2 weeks! These results also suggest that even for healthy people, making some dietary changes can help us to feel and function better.
Superfoods or super diet?
Although it is good to get away from the idea that increasing intake of a single food type or “superfood” is the best way to boost brain health, it is important to consider which aspects of the Mediterranean diet are responsible for influencing brain health. Fresh fruits and vegetables provide essential nutrients used to produce neurotransmitters, the signalling chemicals of the brain. Olive oil is another key component, as it is rich in polyphenols which can have potent benefits to heart health and reduce inflammation. Oily fish contains the omega 3 fatty acid EPA, which has anti-inflammatory properties, as well as DHA which is found in high quantities in the brain.
Another argument is that any brain benefits of a Mediterranean diet is due to the foods it doesn’t include, rather than those it does! When we consider the “Western” diet in which a high percentage of calories come from manufactured products that are highly refined, with chemical additives, added sugar, salt and refined fats. A diet of highly processed foods can increase gut inflammation. It might sound like science fiction, but we are starting to learn that the health of the bacteria that reside in the gut may be able to influence brain health and function! This is an emerging field of research but one that may help us in future to develop diets for a healthier brain.
We still have a long way to go with regards to understanding how dietary choices can impact brain health. The Mediterranean dietary pattern is only one example of a potentially ‘brain friendly’ approach. Superfoods may be all the rage at the moment, but the best way to supercharge the brain is to follow a diet which includes lots of variety and limits processed foods.
Dr Helen Macpherson
NHMRC-ARC Dementia Research Fellow
Institute for Physical Activity and Nutrition (IPAN)
School of Exercise and Nutrition Sciences