A balanced diet, along with regular exercise and sleep, are important not only in preventing heart disease, diabetes and cancer; they can also help protect the brain and ward off mental disorders.
UCLA professor of neurosurgery and physiological science Fernando Gomez-Pinilla reviews a multitude of studies about food's effect on the brain in the July issue of the journal Nature Reviews Neuroscience.
In a paper titled “Brain foods: the effects of nutrients on brain function,” he makes some fascinating points:
The mere act of eating sends signals to the brain
• When we eat, the nerves in our gut signal the brain. Stimulation of these nerves has been shown to treat some types of seizures, and have potential benefits in the treatment of depression.
• Our gut secretes hormones when food is ingested. Several of these hormones have been shown to be associated with cognition. Several gut hormones or peptides (small proteins), such as leptin, ghrelin, and insulin have been found to influence emotions and learning processes as well as overall mental function.
Healthy brain food
Perhaps the best recognized nutrients that affect brain health are the omega-3 fatty acids. Omega 3 fatty acids are polyunsaturated fats that are “essential”—our body needs them, but cannot make them from scratch. Therefore, they need to be part of our diet. These fats are abundant in some fish (salmon), flax, walnuts and kiwi fruit.
Gomez-Pinilla shows there are some promising results showing improved learning and memory, less cognitive decline in the elderly, and some effect on such mental disorders as depression and mood disorders, schizophrenia, and dementia as a result of consuming omega 3 fatty acids,
Flavonoids (plant molecules with many health benefits, besides their antioxidant activity) -- found in various fruits (citrus) and vegetables, cocoa, ginkgo tree, wine many culinary herbs and green tea -- are also recognized as beneficial brain food. These food components have been shown to affect cognitive enhancement in rodents, and improve cognitive function in the elderly.
Also worth mentioning is that curcumin -- the curry spice used widely in India -- has been shown to reduce memory deficits in animal models of Alzheimer’s disease and brain trauma. It is hypothesized that the high use of curcumin in India might contribute to the low prevalence of Alzheimer’s disease in that country.
Junk food is unhealthy for the brain
Gomez-Pinilla’s paper also examines the effects of unhealthy diets on brain function, and states:
“In contrast to the healthy effects of diets that are rich in omega-3 fatty acids, epidemiological studies indicate that diets with high contents of trans and saturated fats adversely affect cognition.”It references studies on rodents, in which “junk food diets,” -- characterized by high contents of saturated fats and sugar -- have been shown to cause decline in cognitive performance, and other changes in the brain after only three weeks of treatment!
What can we learn from this study?
The author notes (emphasis is mine):
“Owing to the encouraging results of clinical and preclinical studies that showed the beneficial effects of foods on the brain, the topic has attracted substantial media attention. Some of the information that has been conveyed has been hazy or exaggerated, and has contributed to people's apprehension of taking advantage of scientific advances.
As discussed, several dietary components have been found to have positive effects on cognition; however, caution is required, as a balanced diet is still the stepping-stone for any dietary supplementation. By the same token, popular dietary prescriptions that might help to reduce weight do not necessarily benefit the physiology of the body or the mind.
The fact that dietary factors and other aspects of lifestyle have an effect on a long-term timescale contributes to an underestimation of their importance for public health. Accordingly, the slow and imperceptible cognitive decay that characterizes normal aging is within the range-of-action of brain foods, such that successful aging is an achievable goal for dietary therapies. The capacity of diet to modulate cognitive abilities might have even longer-term implications in light of recent studies that imply that nutritional effects might be transmitted over generations by influencing epigenetic events.
Research indicating that an excessive intake of calories might negate the positive effects of certain diets suggests that there is an undefined line between abundance of foods and neural health.”
To me, this paper is further confirmation (as if we needed any) that we indeed are in many ways what we eat, and what we eat has a profound effect on our health, including our brain’s health.
I also appreciate the cautious way in which we’re advised by Gomez-Pinilla to interpret new studies:
“…a balanced diet is still the stepping-stone for any dietary supplementation”
The tried and true way to eat well is a balanced diet with real food. The study of supplementation with specific nutrients is in its infancy, and many of the studies are small and on animal models. We should therefore try to incorporate real foods that are good sources of omega-3, for example, (such as walnuts), as these foods are known to be nutritious and part of a healthy diet, and not get excited by highly processed foods with omega-3 added to them as a marketing gimmick.
The long-term scale in which food affects health is what makes nutrition science so tricky. If you replace dish-washing soap for dish-washer detergent in your dishwasher, you’ll know immediately that this wasn’t a good idea (I did that once; the soap bubbles filled the kitchen, and were ready to consume me).
Not so with our bodies -- our body is incredible in its adaptability, and the effects of sub-optimal treatment will many times not be noticed for years and decades. That’s also why the study of nutrition in humans is so difficult -- you’ll need to follow study subjects sometimes for years to really test a hypothesis.
It’s also interesting to note that these nutrients that are highly valued for brain function are no new invention -- they are traditional foods, mostly plant foods, that have been eaten for centuries, and have only lately been abandoned and replaced by junk.
What is new is that we’re now starting to understand the molecular effects and added benefits of these very old foods on our brains.