Sugary Holiday Season Food May Trigger Depression: Study

High sugar consumption, which is common during the holiday season, may trigger depression, according to a study which suggests that people prone to the mental illness should control their year-round sugar intake. Along with dwindling light in wintertime, and corresponding changes in sleep patterns, high sugar consumption may lead to a ‘perfect storm’ that adversely affects mental health, the researchers, including those from the University of Kansas (KU) in the US, said.

For many people, reduced sunlight exposure during the winter will throw off circadian rhythms, disrupting healthy sleep and pushing five to 10 per cent of the population into a full-blown episode of clinical depression,? said study co-author Stephen Ilardi, who is also KU associate professor of clinical psychology.

The study, published in the journal Medical Hypothesis, noted that these symptoms of winter-onset depression could prompt people to consume more sweets.

One common characteristic of winter-onset depression is craving sugar, Ilardi said.

So, we've got up to 30 per cent of the population suffering from at least some symptoms of winter-onset depression, causing them to crave carbs ? and now they're constantly confronted with holiday sweets,? he added.

According to the researchers, avoidance of added dietary sugar might be particularly challenging as sugar provides an initial mood boost, leading some with depressive illness to seek it for its temporary emotional lift.

They have an immediate mood-elevating effect, but in high doses they can also have a paradoxical, pernicious longer-term consequence of making mood worse, reducing well-being, elevating inflammation and causing weight gain, the KU researcher said.

He added that when it comes to depression, people who optimize their diet should provide all the nutrients the brain needs, and mostly avoid these potential toxins.

The study also revealed that inflammation is the most important physiological effect of dietary sugar related to mental health and depressive disorder.

A large subset of people with depression have high levels of systemic inflammation, said Ilardi.

"We also know that inflammatory hormones can directly push the brain into a state of severe depression. So, an inflamed brain is typically a depressed brain. And added sugars have a pro-inflammatory effect on the body and brain, he added.

The researchers also identified sugar's impact on the community of bacteria living in the human intestines, or the microbiome, as a potential contributor to depression.

Our bodies host over 10 trillion microbes and many of them know how to hack into the brain, Ilardi said.

The KU scientist said the beneficial microbes hack the brain to enhance our well-being.

But he added that there are also some opportunistic microbes that have a near parasitic relationship with their human hosts.

"Many of those parasitic microbes thrive on added sugars, and they can produce chemicals that push the brain in a state of anxiety and stress and depression. They are also highly inflammatory,? Ilardi cautioned.

 The study recommends a minimally processed diet, rich in plant-based foods and Omega-3 fatty acids, for optimal psychological benefit.

Ilardi explained this diet is recommended not just during the holidays, but year-round.

There's no one-size-fits-all approach to predicting exactly how any person's body will react to any given food at any given dose, he said.

The researchers said there could be some risk associated with high-dose sugar intake -- probably anything above 25 grams of added sugars per day.