Written by Lorena Ruci, MA, C. Psyc., PhD

 

Sugar has become a staple of the North American diet. Food manufacturers have included refined sugars in many products that we do not think contain any sugar at all. Refined sugar has also been dubbed as a poison for the body by medical professionals1 because it lacks the natural minerals and vitamins found it the sugar we get from eating fruit. Refined sugar, in addition to providing “empty” calories, also strips the body of vitamins and minerals in the way that it is digested and processed by the organism.

 

Food items with hidden refined sugars include, barbeque sauce, pasta sauce, fruit yoghurt, cereal, granola bars…and the list goes on. Sugar has been linked to obesity for many years now. People are now becoming aware of the strong link between sugar and diabetes, cardiovascular disease, macular degeneration and tooth decay. While the list of physical illnesses that are linked or caused by a high sugar diet is long and has become a cause for concern for health care professionals, less is known about the effects that sugar has on Mental Health. Let’s review what we know so far:

 

Refined sugar sabotages learning and memory. Body fuel is Brain fuel too! It comes as no surprise that nutrition (a.k.a. body fuel), also affects the functioning of the brain. Until recently though, the link between refined sugar and brain functioning was not as apparent as the sugar-body link. Researchers at UCLA2 looked at the relationship between a high fructose diet and memory and learning in lab rats. After feeding half of the animals a fructose solution for 6 weeks, and the other half were fed a balanced diet (including of omega-3 fatty acids, which protect against brain damage in the cellular level), they tested the animals’ ability to remember how to navigate a maze. Their findings showed that the rats on the sugar-only diet were much slower in maze navigation and their brains were less active compared to their well-fed friends.

 

Studies in humans also indicate that chronic high levels of sugar in healthy adults are associated with poor memory due to possible changes in the learning centres of the brain (the hippocampus)3. In a study where over 6,000 adults whose health was monitored for 2 years, it was found that having diabetes made it twice as likely to develop dementia (a class of brain disorders that affect learning, memory and reasoning)4. We don’t know yet how diabetes is linked to brain disorders, but we know enough to start making changes in our diets and reduce sugar, for the sake of our brain5.

 

Take home message: What you eat affects how you learn and how you think. Long-term consumption of sugar leads to disruptions in learning and memory, because of the way that sugar disrupts synaptic activity (the way that brain cells communicate with each other). If you find it challenging to completely eliminate sugar from your diet, make sure to also include foods (e.g. salmon, flax-seeds) that are high in omega-3 fatty acids, which might minimize the damaging effects of sugar. Eat for high performance and you’ll be running those mazes in no time!

 

Sugar is implicated in the development of Depression. There is no doubt that depression is a serious mental illness, the development of which implicates a number of genetic, emotional, psychological and biological factors. In the past few decades however, researchers have pinpointed a new factor in the development of depression:

 

Inflammation. Inflammation is the body’s response to harmful substances, injury and stress. When the body feels threatened, it produces chemicals (cytokines) that help it recover from the threat. However, when cytokine levels remain high, the levels of inflammation remain high and that is not good. Some studies have linked high cytokine levels with depression6. Also, studies have shown that when people with depression were given anti-inflammatory drugs (Ibuprofen) in addition to antidepressants, they recovered much faster than those on anti-depressants alone7. Sugar is a known contributor to inflammation, because people on a high sugar diet develop deficiencies in glucose and insulin regulation, which in turn causes inflammation in the body. Refined sugars are especially dangerous because they deliver empty calories to the body; disrupt glucose and insulin regulation, which in turn increases inflammation.

 

Take home message: What you eat affects your mood and emotions. While we have yet to fully understand how badly sugar affects our brain, we know that sugar has negative effects on mood. Next time that you might reach for a bowl of ice-cream or a jar of cookies when you’re feeling down, remember that you might actually make yourself feel worse in the long run. Go for a walk in nature instead, or call a friend and talk about it.

 

 

 

 

Bottom line

 

This is what we know: Sugar is bad for your heart. Sugar is linked to obesity. Sugar negatively affects the functioning of your internal organs. Sugar is bad for your eyes and your teeth. Sugar is good for…um…nothing?

 

This is what we’re finding out: Sugar negatively affects your learning. Sugar negatively affects how you remember things. Finally, sugar is a culprit when it comes to depression.

 

Moving forward, your challenge is to try to reduce sugar from your diet, and monitor any changes in your physical health and mental health. You can start by eliminating sugar in your drinks (e.g., coffee or tea) and then gradually reduce the food items with sugar in the ingredients. Try this: if you have two teaspoons of sugar in your coffee, try reducing it to one for a few weeks, then try to stop using it at all.

 

Remember: Any small step you take in your every day life is a huge step towards improving your overall health in the long run.

 

 

References:

 

 

1. Dufty W. Sugar blues. Grand Central Publishing. 1986.

2. Agrawar R & Gomez-Pinilla F. “Metabolic syndrome” in the brain: deficiency in omega-3 fatty acid exacerbates dysfunctions in insulin receptor signalling and cognition. J Physiology. 2012: 2485-99.

3. Kerti L, Witte AV, Winkler A, Grittner U, Rujescu D, Flöel A. Higher glucose levels associated with lower memory and reduced hippocampal microstructure. Neurology. 2013;81:1746–1752

4. Ott A, Stolk RP, Van Harskamp F, et al. Diabetes mellitus and the risk of dementia: The Rotterdam Study. Neurology 1999;53:1937–42.

5. Biessels GJ, Staekenborg S, Brunner E, et al. 2006. Risk of dementia in diabetes mellitus: a systematic review. Lancet Neurology, 5:64–74.

6. Raison CL, Capuron L, Miller AH. Cytokines sing the blues: inflammation and the pathogenesis of depression. Trends Immunology. 2006;27(1):24-31.

7. Müller N, Schwarz MJ, Dehning S, et al. The cyclooxygenase-2 inhibitor celecoxib has therapeutic effects in major depression: results of a double-blind, randomized, placebo controlled, add-on pilot study to reboxetine. Mol Psychiatry. 2006;11 (7):680-684.