Feeling down? Grab a chocolate pie, macarons, or chug a can of "happy soda" (a nickname for cola). Many firmly believe: though sweet treats carry weight gain risks, they deliver instant joy. Yet the truth is different. After a fleeting sweet high, people often sink back into gloom and depression. Over time, this cycle may even worsen.
A meta-analysis of observational studies found that increased consumption of sugary drinks may elevate depression risk. This doesn't mean you can't have a single sip of high-sugar beverages like cola. Data analysis indicates a significant effect only occurs when consuming more than two small servings daily—drinking three cans of cola per day increases depression risk by 25%.Analyzing sugar intake specifically, consumption below 15g showed no association with depression risk. However, between 15g and 100g, the relative risk of depression increased with higher intake.This finding suggests that consuming just one serving of yogurt is not cause for concern. Based on a 12% carbohydrate content, 100g of yogurt contains only 7.5g of added sugar, while 200g contains 15g.
Japanese researchers found in a three-year cohort study of nearly 1,000 participants that individuals who consumed more sugary drinks daily did indeed face an increased risk of depression. After controlling for factors like age, gender, and region, those who drank four or more sugary drinks per day had a 90% higher risk of developing depressive symptoms compared to those who consumed fewer than one drink per week.Even after accounting for socioeconomic status and baseline depression scores, the highest consumers still showed a 68% higher risk than the lowest consumers. When comparing those scoring over 19 on depression scales—a more severe measure—the gap widened dramatically: the highest consumers faced a 162% higher risk than the lowest consumers.
One might wonder: Doesn't drinking sugary beverages and eating sweets actually make me feel happier? Could the causal relationship be reversed? Perhaps it's the depressed individuals who crave sweets and sugary drinks more, rather than consuming them leading to depression?
First, when Japanese researchers initiated this study, they surveyed nearly a thousand participants for depressive symptoms. All were found not to be severely depressed.Over the three-year period, participants were allowed to consume foods and beverages according to their usual patterns, with researchers conducting periodic surveys and analyzing the data. After three years of observation, participants' depression symptoms and questionnaire scores were reassessed. The results showed that those who consumed the most sugary drinks also experienced the greatest increase in depression scores.
Secondly, the immediate effects of a food may not align with its long-term effects. For those with a sweet tooth, consuming sweets and sugary drinks does indeed provide instant pleasure. This is because sugar intake increases serotonin and dopamine levels, temporarily boosting mood. However, the study revealed the long-term effects of consuming sweets and sugary drinks. A food that makes you happy in the moment may not necessarily help prevent depression.Sweets can be seen as a temporary anesthetic. Over the long term, they reduce the body's ability to cope with stress and diminish the nervous system's regulatory capacity, thereby hindering depression prevention.Why do sugary drinks promote depression? Researchers suggest two mechanisms: First, animal studies show that high added sugar intake increases anxiety and depressive behaviors while elevating cortisol levels. Particularly in developing animals, excessive sugar consumption disrupts the maturation of the hypothalamic-pituitary-adrenal axis, impairing stress regulation and increasing depression risk.On the other hand, sugary drinks promote obesity, and obesity itself reduces the body's ability to regulate stress. The relationship between obesity and depression risk has been confirmed by multiple studies.
Additionally, sugary drinks can cause glucose metabolism disorders and insulin resistance. Such metabolic disorders lead to low-grade but persistent inflammatory responses, and the release of certain inflammatory factors itself increases the risk of depression.Animal studies have also revealed that long-term feeding of diets high in added sugars reduces serotonin 1A receptors on dendritic cells. This reduction disrupts the feedback control of serotonin synthesis and release in the hypothalamus, impairing stress response capabilities. This mechanism is crucial for depression prevention.
Another contributing factor is that sugary beverages deplete B vitamins in the body. Deficiencies in vitamins B1, B6, and niacin can impair nervous system function and disrupt neurotransmitter balance, thereby increasing depression risk. Therefore, maintaining a nutritionally balanced diet remains essential for avoiding depression.