How does sugar drain your brain? Science explains

It’s no secret that too much sugar is bad for cardiometabolic health. From triggering insulin resistance to increasing the risk of heart attack and stroke, eating a high-sugar diet can pose serious consequences.

Recent research published in the journal Nature Communications adds another sugar-related consequence: rapid metabolic shifts. In fruit flies fed a high-sugar diet, important metabolites in the brain that modulate brain function became depleted, according to a team of researchers from the University of Michigan.

These findings suggest that understanding these metabolic shifts is the first step to shedding light on their potential effects on the brain and on the risk of brain conditions linked to diet and nutrition, including neurodegeneration and depression.

Sugar depletes the brain

To understand the effects of a high-sugar diet on the brains and bodies of fruit flies, the team compared a group of fasting flies to a group of fed flies. The team did not feed the other group of flies dinner but fed them a high-sugar breakfast of glucose jelly the next day.

The researchers then froze both groups of flies inside separate tubes to halt their metabolic processes in preparation for the collection of metabolites. To help them refine the list of metabolites, researcher Alla Karnovsky created a tool called FlyScape. According to Karnovsky, FlyScape can also help the team look for patterns in the metabolic data. The tool also helps them understand the biological processes happening as a consequence of these patterns and shifting conditions.

Using this tool, the team identified 20 metabolites that had been affected as a result of sugar consumption. In particular, the team found decreased amounts of the metabolites N-acetyl aspartate (NAA) and kynurenine. Both metabolites are indicators of optimal brain health. For instance, inadequate amounts of kynurenine are linked to a higher risk of depression. Prior to this research, the depletion of kynurenine had been thought to be the consequence of just either chronic stress and trauma.

On the other hand, recent studies found that the amount of NAA, the second most abundant human brain metabolite, is decreased in people that had brain disorders and neurological conditions, including depression, schizophrenia, dementia and stroke.

It also appeared that fasting increased the amount of NAA in the brain of fruit flies, thus confirming that levels of this metabolite rose and fell depending on sugar consumption. Changing the amount of these metabolites also made the fruit flies eat more.

Senior author Monica Dus notes that the high-sugar diet led to a metabolic remodeling, a concept that has been studied in both stem cells and cancer research. Metabolic remodeling has also been found to influence disease progression.

Moreover, their trials did not demonstrate a gradual metabolic shift, Dus adds, explaining that by the seventh day of feeding the flies a high-sugar diet, they had a completely different metabolic profile altogether.

Taken together, these findings suggest that more research is needed to understand the metabolic shifts that occur due to sugar consumption. Doing so might shed light on the effects of sugar on the brain and its influence on the risk of brain conditions linked to diet.

Dopamine spikes from eating sugar

Besides triggering rapid metabolic shifts, sugar has also been found to affect the area of the brain that controls pleasure and addiction. Recent research in pigs found that sugar intake affects the hippocampus, the so-called pleasure center of the brain. In particular, sugar intake caused dopamine levels to spike. Dopamine is a hormone and a neurotransmitter involved in pleasure and motivation.

Using imaging techniques, a group of scientists from Aarhus University in Denmark found that sugar altered numerous areas of the brain, including the striatum, nucleus accumbens, thalamus, amygdala, cingulate cortex and prefrontal cortex.

Just 12 days of daily sugar intake also caused significant changes to the brain’s pleasure center, similar to those induced by drugs like cocaine. Taken together, recent studies and ongoing research indicate that the regular consumption of sugar or high-sugar diets can affect more than just cardiometabolic markers of health; it can also pose serious consequences for brain health.

yogaesoteric
November 15, 2020