What Is the Link Between Sugar and Depression?

Sugar’s not the greatest thing for us; this is no secret. There’s the energy crash, the unhealthy weight gain, and yes, even links to depression and anxiety that are all associated with excessive and consistent sugar consumption. While the energy crashes and the weight gain are widely understood and expected through most of society now, how sugar connects to depression may take a little more research for the common person to understand.

"Sweet food has been found to induce positive feelings in the short-term,” says Anika Knüppel, a Ph.D. student at the Institute of Epidemiology and Public Health at University College London. “People experiencing low mood may eat sugary foods in the hope of alleviating negative feelings. Our study suggests a high intake of sugary foods is more likely to have the opposite effect on mental health in the long-term.”

Knüppel’s study is one of many that links high-sugar diets to higher risks of anxiety and depression, in which researchers found men consuming more than 67 grams of sugar per day were 23 percent more likely to develop an anxiety or depression disorder over a five-year span than men consuming less than 40 grams of sugar per day.

Another study once found links between sugar, chronic inflammation, and depression as well. That 2004 study found that dietary predictors of depression are also shared in diabetes and heart disease. In the long term, chronic inflammation which is shared amongst many people affected by all three breaks down the body’s immune system.

So while the link is evident, as has been shown time and time again, exactly why and how sugar has this effect on our emotional and mental health is equally as important to learn.

So, how does this happen exactly? For one, sugar affects dopamine, the very thing that tells your brain to feel happy, as well as contributing to insulin and leptin resistance, which impair signaling in the brain and impact our mental health. And the third way in which sugar directly impacts the brain is by suppressing the activity of what’s known as brain-derived neurotrophic factor (BDNF), a growth hormone that influences healthy brain neurons.

But it’s not just sugar’s direct impact on the brain that puts you at higher risk of depression. Sugar also damages your mitochondria, which are responsible for generating a majority of your body’s energy. When your body gets used to being field by those notorious sugar spikes and ensuing energy drops, you start generating excessive reactive oxygen species (ROS). Unsurprisingly, these are the very thing that wreaks havoc on cellular mitochondrial membranes and DNA. Over time, with your mitochondria declining thanks to excessive sugar consumption, your energy starts to decline too. The brain struggles to function properly as a result, throwing your entire body out of sorts as a result. Healthy fats like Omega-3 DHA and EPA, for example, more or less do the opposite for brain health by creating fewer free radicals and reactive oxygen species.