Food and the Brain: Good Fats, Bad Fats

Omega-3 essential fatty acids have an important role in the mammalian nervous system.  They seem to be crucial for healthy neuronal structure and function.  And the healthy structure and function in our brains is what allows for healthy behavior.  Plenty of research has been conducted on the role of diets and behavior, particularly in children, with a lot of interest in the ever-controversial role of sugar.  But let’s turn our attention to fats, for a moment.

Essential fatty acids comprise parts of phospholipids and cholesterol esters, which are imperative in the structure and development of synaptic and dendritic cell membrane structures in the brain.  When lacking in essential fatty acids, such as omega-3s, our brain uses non-essential fatty acids to do its job instead.  Or, at least, it attempts to do its job… when we don’t feed our brains well, and the only fats we consume are bad fats, the brain resorts to using what is available.  And this leads to changes in membrane-bound receptors and certain neurotransmitters.  Which leads to psychological and behavioral changes.  Bad fats = bad news.

Researchers have noticed that the tremendous shift in the Western diet away from omega-3 essential fatty acids parallels the large rise in psychiatric disorders, including ADHD and depression.  For this reason, a wide array of studies have found that essential fatty acids might have a significant effect on the neurotransmission of serotonin and associated behavioral disorders.  Here is a cursory review of a few of these findings:

One study found that fatty acid plasma levels were lower in children with ADHD than other children of the same age and sex.  The same thing was found in studies of rats and monkeys with behavioral hyperactivity.  In other studies, children with dyspraxia, dyslexia, and ADHD showed behavioral improvement due to the addition of essential fatty acids in their diets.  Another study looked at violent male subjects with antisocial personality and found low omega-3 plasma concentrations.  This agrees with yet another study that found lower hostility and depression scores in those of hundreds of subjects who consume a diet high in fish.  A study of prison inmates found a significant reduction in aggressive and violent behaviors after supplementation with essential fatty acids.  The same result was found in another study of clinical populations of subjects suffering from various personality disorders.  The list goes on and on.

So how might essential fatty acids affect behavior?  Because they affect our physiology, and the physiology of our brains especially.  Physiological studies of lab animals (rats, pigs, etc.) found that diets deficient in essential fatty acids result in more serotonin receptors in the frontal cortex.  This might sound like a good thing, but actually, more of these types of serotonin receptors means less free-floating serotonin: a condition thought to contribute significantly to depression.  Other studies show that frontal cortex concentrations of serotonin, tryptophan, dopamine, homovanillic acid, and noradrenaline––stuff we want to have at healthy levels in our brains––are nearly doubled in animals supplemented with daily essential fatty acids compared to animals fed substandard diets.

In sum, a number of clinical disorders and behavioral problems have demonstrated an association with decreased levels of omega-3 fats.  Even more, correcting this deficiency by supplementation leads to clinical improvement, probably by way of the transmission of serotonin and other neurotransmitters.  Unfortunately, science is not ready to make a statement that good fats will calm a hyperactive child or make a depressed person happy.  But hey, they can’t hurt!

Information in part from “Essential fatty acids and their role in the treatment of impulsivity disorders,” Prostaglandins, Leukotrienes and Essential Fatty Acids 71 (2004) 211-16.