There’s a wide net of research that can advance the dialogue, and structure-function claims, on how nutrition can improve outcomes related to global cognitive function, mood, and mental health.
 
At SupplySide West, Douglas Kalman, PhD, RD, clinical associate professor at Nova Southeastern University, discussed the breadth and scope of key findings on both macronutrients and an assortment of vitamins and minerals.
 
“Nutritional neuroscience is a discipline that centers on the impact that dietary components have on neurochemistry and neurobiology, and how that can shape memory, executive function, behavior, and cognition, while also influencing feelings of wellbeing and mood,” Kalman said. “In resting energy expenditure, 20-25% of calories are needed just for the brain. But there are also many factors to consider when eating for optimal brain support 40 years down the road.”
 
It wasn’t until recently that researchers within the interdisciplinary field of neuroscience even considered nutrition. But “we’re now unpacking the very strong physiologic and metabolic connections,” Kalman said. 

The Macros

In the Western Diet, there’s plenty of room for improvement when eating for optimal brain function by beginning with the kinds of carbs, proteins, and fats in the diet.
 
With carbohydrates, evidence is mounting that excessive intake of simple carbohydrates over the long-term leads to an increased risk of cognitive decline and Alzheimer’s, Kalman noted, pointing to a 2018 review.
 
In more immediate terms, however, having the right type of carbohydrate trumps a low-carbohydrate diet when it comes to returns for mood and cognitive function.
 
“While there’s no such thing as an essential carbohydrate and you won’t die without them, you’ll be moody,” Kalman said. In a study on 106 people with obesity who were prescribed either a low-fat or low-carbohydrate diet for weight loss, the reductions in weight were comparable between the two groups, “but those people on the low-carb diet were miserable—their mood states were negative, and they had a negative affect.”
 
Protein, Kalman said, is arguably the most important macronutrient for optimal cognitive function, all of the nine essential and 11 non-essential amino acids play fundamental roles in neurotransmitter synthesis. In addition to the fact that the amino acids GABA, glutamic acid, aspartic acid, and glycine are direct neurotransmitters, modified amino acids are involved in the synaptic transmission of noradrenaline, adrenaline, dopamine, serotonin, and histamine, noted Kalman.
 
“One of the things the supplement industry can do is make structure-function claims. When you understand the mechanisms of action behind how an agent works in the body you can understand which claims you can use. There are several direct roles by which adequate intakes of essential amino acids supports cognitive function,” Kalman said.
 
Research on downstream effects of these mechanisms will be increasingly important. For instance, Kalman pointed to a 2016 study which provided evidence that high-protein dieting, defined as 1.5 grams of protein per kilogram of bodyweight, improved sleep quality and cognitive function markers across two clinical studies.
 
Lastly, the types of lipids and their proportions within the diet have a profound role on neurological health, especially over the long-term, noted Kalman.
 
The overall ratio of saturated to polyunsaturated fats affects both cognition and mood disorder risk, and the breakdown of fat into fatty acyls, eicosanoids, docosanoids, and fatty alcohols—all compounds with heavy involvements in neurological processes—is of great importance.

Micronutrients

There are plenty of emerging topics examining the interplay between micronutrients and the structure and function of both the central and peripheral nervous systems.
 
For instance, while biotin is primarily marketed for hair and nail benefits, it’s much less often marketed for cognition, despite that neurons and glial cells need it to metabolize energy. And thiamin, riboflavin, niacin, pantothenic acid, lipoic acid, magnesium, iron, and manganese are all directly involved with glucose metabolism in the brain.
 
The synthesis of neurotransmitters requires the sum of thiamin, riboflavin, niacin, vitamins B6, B12, and C, zinc, folate, and choline; and the B vitamins folate and B12 are used to preserve the integrity of the myelin sheath which encases neurons.
 
For neurocognitive development, iron is extremely under-emphasized, Kalman said. “Over 50 studies demonstrate that iron deficiency which takes place in utero and up to 24 months of age leads to behavioral abnormalities, electrophysiologic abnormalities, and cognitive delays which persisted until between 19 and 23 years old.”
 
“People aren’t necessarily getting their 5-9 fruits and vegetables per day,” Kalman said. “There’s this cognitive dissonance when people go to their physician’s office and are told they look healthy because there’s no overt signs of malnutrition like scurvy.”

Gut Health

Americans have quite the hurdle to overcome in order to optimize the activity of their gut-brain axis.
 
Before exploring ingredients like pre-, pro-, and postbiotics, many people can take simpler steps to improve how their gastrointestinal tract absorbs nutrients. “A difference in absorption abilities of the small intestine effects the body’s ability to produce neurotransmitters and do many other things involved in the neurological system,” Kalman said.
 
“Many people have to normalize inflammation levels in the gut through a diverse diet. The more colorful your plate, the more of a diverse range of phytochemicals you’re getting. We’re supposed to have fiber intakes between 25 and 30 grams, and people are often getting less than half of that, so before getting into the microbiome it’s important to be able to tolerate all-bran cereal.”