Sweet nothings – can sugar make you sad

Is there a connection between a high sugar diet and mental disorders? Maybe.

Despite WHO recommendations to cut added sugars in one’s diet to less than 5% of your total energy intake, people in the UK and USA double and triple this. Most added sugars come from foods such as cakes, or soft drinks and other processed foods. Simultaneously, 1 in 6 people worldwide suffers from a mood or anxiety disorder. Are these two occurrences linked?

A few studies took a look at this idea:

  • Baylor College, USA (2002) found that higher rates of refined sugar consumption were linked with higher rates of depression.

  • Spanish researchers (2011) concluded that people who ate a lot of commercial baked foods had a 38% greater chance of getting depression.

  • A US study (2014) discovered a link between depression and sweetened drinks.

  • Another study (2015) conducted on 70 000 women found a higher risk of depression with added sugar diet, compared to natural sugar.

What causes depression?

  • Biological changes – probably influenced by sugar. A study on rats showed that a high sugar diet reduces an important protein (BDNF) involved in developing depression or anxiety.

  • Inflammation – research suggests that high sugar diets can increase inflammation. This in turn is possibly linked to mood disorders.

  • Dopamine – part of the body’s reward system. Another study on rats showed sweet foods are perhaps as addictive as cocaine, because of how dopamine works.

  • Obesity – because of high sugar, which then ultimately affects mood.

Is the data being interpreted correctly, though? Could it not perhaps mean depressed people eat more sweet foods because they feel bad?

A new study tried to test this link between sugar and mood. It found that:

  • Men who didn’t suffer from a mood disorder, and who ate more than 67g of sugar daily, ran a 23% increased risk of developing a mood disorder within 5 years, in comparison to those who only ate 40g a day.

  • Men and women with a mood disorder and a high sugar diet ran an increased risk of developing depression again five years later, compared with those who ate less sweet foods.

  • Mood disorders did not trigger an increase in sugar consumption.

In spite of research, there are still a few unanswered questions about how sugar affects our mood. Reducing your sugar intake has many other health benefits, though – you’re better off having less of the sweet stuff.


Read more about this at The Conversation