According to a review published in the journal Medical Hypotheses, consuming large amounts of added sugars are already associated with adverse health consequences, such as increased risk of cardiovascular disease, affecting gut health, creating systemic inflammation, prompting insulin resistance and disrupting hormone signaling – especially dopamine. Now the link between sugar and mental health is being investigated.
A wide range of research on the psychological and physiological effects of sugar consumption was analyzed, including several large studies, like the Women’s Health Initiative Observational Study, which followed nearly 70,000 women over three years.
Looking at sugar consumption and health, researchers observed that women who consumed the most amount of added sugar were at 23 percent greater risk of subsequent clinical depression than those who consumed the least amount.
Other studies in the review found that incidence of depression for Australian, Chinese, Latino and Iranian adolescents and adults were also higher in those who reported drinking sugar-sweetened beverages, like soda, regularly.
Although these actions can negatively affect physical health, they also increase risk of major depressive disorder, the researchers suggest. And the more one consumers sugar, the worse it gets — particularly for those who live in colder climates during the winter when sunlight is weaker and can lower intake of vitamin D. However, the depression-sugar connection was found during any season, the study suggests.
The cycle gets worse as the depression kicks in because a common characteristic of winter-onset depression is craving sugar, according to study co-author Stephen Ilardi.
Having sugar, on an occasional basis is unlikely to create the kind of mood-altering effects seen in this study. Instead, it’s chronic, long-term, high-dose sugar consumption over a span of months that starts to create this perfect storm of physical and mental changes.
That said, Ilardi added that a sugar binge can cause a blood sugar crash that affects mood and energy, thanks to a rebound effect as the pancreas releases an overly large dose of insulin in response. That can result in sugar blues, not to be confused with true clinical depression, Ilardi said.
But if those sugar binges are a regular, perhaps even daily occurrences that continue over a few months or longer? That’s a different story. And, as Ilardi pointed out, it’s a common one.
“The average American eats about 22 teaspoons worth of added sugars each day,” he said. “Consuming refined sugar in high doses like that can increase a person’s risk of becoming clinically depressed. That’s the takeaway message here.”
Given this research, perhaps it’s time food manufacturers – especially those producing high-sugar foods – become more transparent about sugar levels and find alternatives to added sugars. The US Food and Drug Administration (FDA) has taken a step in the right direction by requiring food labels to disclose added sugar content.