by Bonnie Kaplan, Julia J Rucklidge, The Conversation
Emotional,
non-rational, even explosive remarks in public discourse have escalated
in recent years. Politicians endure insults during legislative discussions; scientists receive emails and tweets containing verbal abuse and threats.
What's going on? This escalation in angry rhetoric is sometimes attributed to social media. But are there other influences altering communication styles?
As researchers in the field of nutrition and mental health, and authors of The Better Brain, we recognize that many in our society experience brain hunger, impairing their cognitive function and emotion regulation.
Ultra-processed products
Obviously,
we are not deficient in macronutrients: North Americans tend to get
sufficient protein, fats (though usually not the best fats) and
carbohydrates (usually not the good complex carbs). But we are being
cheated of micronutrients (minerals and vitamins), particularly in those
whose food choices are dominated by ultra-processed products.
Ultra-processed
products include things like soft drinks, packaged snacks, sweetened
breakfast cereal and chicken nuggets. They generally contain only
trivial amounts of a few micronutrients unless they are fortified, but
even then, only a few at higher amounts.
Three
published analyses from the 2004 Canadian Community Health Survey and
the 2018 U.S. National Health and Nutrition Examination Survey revealed
these sobering statistics: in Canada, in 2004, 48 percent of the caloric intake across all ages came from ultra-processed products; in the United States 67 percent of what children aged two to 19 years consumed and 57 percent of what adults consumed in 2018 were ultra-processed products.
Most of us are aware that dietary intake is a huge issue in physical health because diet quality is associated with chronic health conditions such as obesity, diabetes and cardiovascular disease. The public is less aware of the impact of nutrition on brain health.
Micronutrients and mental health symptoms
Given
that our society's food choices have moved so strongly toward
ultra-processed products, we need to learn about the substantial
scientific evidence proving that micronutrient intake influences mental
health symptoms, especially irritability, explosive rage and unstable
mood.
The
scientific evidence base for this statement is now vast, though it is
so rarely mentioned in the media that few in the public are familiar
with it. A dozen studies from countries like Canada, Spain, Japan and Australia have shown that people who eat a healthy, whole foods diet have fewer symptoms of depression and anxiety than people who eat a poor diet (mostly ultra-processed products).
Correlational
studies cannot prove that nutritional choices are the cause of mental
health problems: for that we turn to some compelling prospective
longitudinal studies in which people with no apparent mental health problems
enter the study, are evaluated for their health and dietary patterns,
and are then followed over time. Some of the results have been
astonishing.
In a study of about 89,000 people in Japan with
10-15 years of followup, the suicide rate in those consuming a whole
foods diet was half that of those eating less healthy diets,
highlighting an important new direction not yet covered in current
suicide prevention programs.
Here in Canada, similarly powerful findings show how children's dietary patterns, as well as following other health guidelines
on exercise and screen time, predicted which children aged 10 to 11
years would be referred for diagnosis of a mental disorder in the
subsequent two years. It follows that nutrition education ought to be
one of the first lines of treatment for children in this situation.
Irritability
and unstable mood often characterize depression, so it's relevant that
multiple independent studies have found that teaching people with
depression, who were consuming relatively poor diets, how to change to a
whole foods Mediterranean-style diet resulted in significant
improvements. A Mediterranean-style diet is typically high in whole
grains, fruits, vegetables, nuts, legumes, seafood and unsaturated fats
such as olive oil.
In one such study,
about one-third of the people who changed to a whole foods diet in
addition to their regular treatment found their depression to be in
remission after 12 weeks.
The
remission rate in the control group using regular treatment but no diet
changes was fewer than one in 10. The whole foods diet group also
reported a cost savings of about 20 percent in their weekly food budget.
This final point helps to dispel the myth that eating a diet of
ultra-processed products is a way to save money.
Important
evidence that irritability, explosive rage and unstable mood can be
resolved with improved micronutrient intake comes from studies
evaluating micronutrient supplements to treat mental health problems. Most public awareness is restricted to the ill-fated search for magic bullets: studies of a single nutrient at a time. That is a common way to think about causality (for problem X, you need medication Y), but that is not how our brains work.
To support brain metabolism, our brains require at least 30 micronutrients to
ensure the production of neurotransmitters such as serotonin and
dopamine, as well as breaking down and removing metabolic byproducts.
Many studies of multi-nutrient treatments have found improved mood
regulation and reduced irritability and explosive rage, including in
placebo-controlled randomized trials of children with attention deficit hyperactivity disorder and mood dysregulation.
The
evidence is clear: a well-nourished population is better able to
withstand stress. Hidden brain hunger is one modifiable factor
contributing to emotional outbursts, aggression and even the loss of
civility in public discourse.