New research finds surprising links between popular beverages, from coffee and energy drinks to bubble tea, and mental health.
While most studies concur that sugar-sweetened drinks can increase the risk of conditions like depression and anxiety, research has consistently found multiple health benefits for one beverage — coffee.
Researchers believe coffee’s protective effect on mood and mental health is based on multiple mechanisms, including high levels of antioxidants and flavanols.
Could your morning coffee or daily energy drink habit be affecting your mood? New research has revealed that our daily drink choices may be negatively affecting our mental health — bar one particular beverage.
A meta-analysis published in August in the journal Depression and Anxiety found that drinking nonalcoholic beverages was associated with an 18% increased risk of depression, but that coffee appeared to have a protective effect.
It goes without saying that this benefit was only observed with plain coffee with minimal or no added sugar, and that heavily sweetened coffees have been linked to health risks.
The paper analyzed data from 59 studies, involving over 2 million participants across 22 countries. People who drank higher amounts of coffee had approximately a 13% lower likelihood (an odds ratio of 0.87) of experiencing depressive symptoms compared to people who drank little to no coffee.
However, this protective effect was only observed in the case of depression, and drinking more coffee did not seem to have the same effect on anxiety or stress.
Medical News Today looks at what evidence so far shows about how different beverages can affect mental health and speaks to two experts — Andrew Odegaard, MD, PhD, associate professor of epidemiology and biostatistics with the UCI Program in Public Health, and Jennifer Pallian, RD, BSc in Food, Nutrition and Health, both uninvolved in the study — on how sugar and coffee can vastly affect mental health.
How sugar-sweetened beverages affect mood
Several pieces of research have linked artificially-sweetened and sugary drinks to a higher risk of mental health conditions and disorders, and more symptoms.
Pallian went on to discuss the biological mechanisms behind high sugar intake and anxiety levels, saying: “One [mechanism] is inflammation. Chronic consumption of a sugar-rich diet may increase neuroinflammatory activity in brain regions involved in the anxiety response, including increases in inflammatory markers such as IL-6 and TNF-α.”
“Sugar-sweetened beverages may also contribute to blood-glucose fluctuations and insulin resistance, which can affect brain-derived neurotrophic factor, or BDNF, and neuroplasticity,” she continued.
Brain-derived neurotrophic factor (BDNF) is a crucial protein that promotes the growth and maintenance of neurons, and low levels have been linked to an increased risk of depression.
Another mechanism by which sugar may affect anxiety levels is through cortisol.
“High-sugar diets may also disrupt normal cortisol rhythms and affect the hypothalamic-pituitary-adrenal, or HPA, axis, which regulates the body’s response to stress. Oxidative stress may be involved as well. High-glycemic-load diets have been associated with higher levels of C-reactive protein, a marker of inflammation and oxidative stress,” she explained.
High-sugar diets and poor fructose absorption can also lower serotonin levels in the body, which can negatively impact mood regulation, Pallian added.
Is there a ‘safe sugar’ limit for mental health?
“From a cursory [literature] search, it appears essentially all the research on the topic is observational and cross-sectional, so it’s difficult to make this conclusion – perhaps people who are feeling stressed or anxious seek sugar or sweet foods. This is well studied in animal models, and similar behavior in humans is considered a phenomenon,” Odegaard explained.
“There is currently no established ‘safe’ sugar limit specifically for mental health. One study found that adolescents consuming more than 25 g [grams] of sugar per day from soft drinks had significantly higher anxiety and depression scores, but this does not mean 25 g or less is a safe threshold,” Pallian chimed in.
Coffee may help reduce depression risk
Past research has found that drinking coffee can have a protective effect on mental health. One particular study found that drinking 4 cups of coffee daily can reduce depression risk in women as much as 20%. The recent meta-analysis adds to the growing evidence that coffee may have depression-reducing effects.
But how exactly does coffee achieve this protective effect? One way researchers think coffee has this effect is through caffeine and its influence on neurotransmitters in the brain.
Caffeine blocks adenosine, a neurotransmitter involved in us feeling sleepy and sluggish brain, which naturally triggers higher levels of dopamine and serotonin — two neurotransmitters essential for motivation, pleasure, and happiness.
Another possible working mechanism is the high antioxidant content in coffee. Antioxidants like chlorogenic acid can help calm down inflammation in the brain, which is a major trigger for depression.
“Coffee has a whole host of bioactive components and people who drink it habitually are doing so for a reason – to stay alert, enjoyment, social aspects etc. All things which are actually useful for thinking about preventing/mitigating depressive symptoms,” Odegaard said.
Can coffee help protect against depression?
Although this study found that drinking coffee was inversely associated with depression, Pallian said evidence so far on coffee’s depression risk-reducing effects has largely been observational, and no definitive causal links have been established regarding coffee drinking’s potential to prevent depression.
“A meta-analysis of 29 studies involving 422,586 participants found a similar association. Higher coffee intake was linked with a lower risk of depressive symptoms, and each additional 240 mL [milliliters] of coffee per day was associated with an approximately 4% reduction in depression risk,” she said.
“This evidence is more consistent, but we don’t have trials to make the conclusion that drinking/initiating coffee drinking is a mode to treat or prevent depression,” Odegaard said.
“[The study] could identify an association but not establish cause and effect. Overall, the evidence is still too limited and inconsistent to define a specific cutoff, although higher added-sugar intake may be associated with poorer mental health outcomes, particularly in younger people,” Pallian added.
Do other caffeinated drinks have mental health benefits?
A question that comes to mind when looking at such data is whether other caffeine-containing drinks may have similar effects. Pallian said caffeine alone is not enough to explain coffee’s mental health benefits.
“[Coffee includes] phenolic compounds, alkaloids and melanoidins, as well as chlorogenic acid and trigonelline, which have antioxidant and anti-inflammatory properties,” she said.
“Caffeine may account for part of the association as well. As a central nervous system stimulant, caffeine affects dopamine activity through adenosine receptors and, at moderate intakes, may improve psychomotor activity, alertness, and feelings of energy. Higher dietary caffeine intake has also been associated with a lower risk of depressive symptoms.”
– Jennifer Pallian, RD, BSc
However, Pallian underscored that the findings are not the same for every caffeinated drink.
“Some studies have linked black tea and other types of tea with a lower risk of depression, while others have found no significant association. Energy drinks, on the other hand, have been positively associated with depression. Caffeine may therefore be one factor, but the other ingredients and bioactive compounds in a beverage may matter as well,” she said.
Does caffeine amount matter?
Although this particular meta-analysis did not address this question, prior research has examined this link.
“In one study, intake of 450–600 mg [milligrams] per day was associated with a substantially lower risk of depression than intake of 0–300 mg, while higher intakes did not show the same apparent benefit,” Pallian said.
“Research also shows that although caffeine may reduce depression risk and improve general mental health at some levels of intake, high doses may increase anxiety and stress,” she said, adding that the health benefits seem to depend on both the source of caffeine and the amount consumed.
Are sugar-free versions of drinks healthier?
On the topic of replacing sugary drinks with sugar-free or artificially sweetened alternatives, experts agree that they aren’t necessarily better for mental health.
“In [this study], artificially sweetened beverages were positively associated with depression, with an odds ratio of 1.30. Similar associations were found for sugar-sweetened beverages (1.29), bubble tea (2.62), soft drinks (1.39), and energy drinks (1.30). In other words, replacing sugar with artificial sweeteners did not eliminate the observed association with depression,” Pallian told us.
Overall, the study adds to evidence that unsweetened coffee may help protect mental health and that sugar-sweetened drinks may increase risk. As with anything, different individuals may experience different effects, and moderation is key.
It is also important to note that mental health is affected by multiple factors, including genetics and lifestyle, and beverage choices are just one part of the puzzle.
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