Study reveals increased risk of depression linked to consumption of unhealthy foods

Indulging in that bag of chips or savoring a slice of frozen pizza may bring temporary joy while you're eating it. However, a recent study published in the journal JAMA Open Network reveals that these 'ultraprocessed' foods could leave you more vulnerable to feelings of sadness long after the last bite. Researchers from Brigham and Women's Hospital and the Harvard T.H. Chan School of Public Health conducted an extensive analysis of the dietary choices and mental health of over 31,000 women aged between 42 and 62, according to the journal article. The data was sourced from the Nurses' Health Study II, spanning from 2003 to 2017. Participants completed a food questionnaire every four years, detailing their consumption of ultraprocessed foods (UPFs) or otherwise. These UPFs were categorized into nine groups, encompassing ultraprocessed grain foods, sweet snacks, ready-to-eat meals, fats and sauces, ultraprocessed dairy products, savory snacks, processed meat, beverages, and artificial sweeteners. Tanya Freirich, a registered dietitian nutritionist based in Charlotte, North Carolina, who practices as The Lupus Dietitian and was not involved in the study, explained, 'Ultraprocessed foods are those containing numerous preservatives, stabilizers, bulking or gelling agents, as well as artificial colors and flavors.' She went on to clarify, 'These are typically the types of foods with extended shelf lives, including items like chips, candies, frozen 'TV dinners,' chicken nuggets, sodas, sugar-laden breakfast cereals, and packaged soups of the 'just-add-hot-water' variety.' To assess the participants' mental health, the researchers employed two definitions: a strict one necessitating self-reported, clinician-diagnosed depression and regular antidepressant usage, and a broader definition involving clinical diagnosis and/or antidepressant use, as per the journal article. The researchers adjusted for various factors that might influence depression risk, including age, body mass index, physical activity, smoking status, sleep quality, chronic pain, alcohol consumption, income, and any pre-existing medical conditions. Upon analyzing the results, the researchers discovered that individuals who consumed higher quantities of ultraprocessed foods, particularly artificial sweeteners and artificially sweetened beverages, were more susceptible to depression. One potential explanation they put forth is that artificial sweeteners could induce chemical changes in the brain that trigger the development of depression. Tanya Freirich noted, 'It is known that artificial sweeteners affect the brain through a different pathway than natural sweeteners like sugar or honey,' emphasizing the need for further research in this area. The study found that those with the highest UPF intake had a 34% to 49% increased risk of depression. Freirich expressed that she was not surprised by these overall findings, stating, 'Numerous studies have documented associations between certain food additives and cancer, hormonal changes, weight gain, and our mental health.' She added, 'With that in mind, it is not surprising to me that there may be a link between ultraprocessed foods and depression.' She also emphasized, 'Our brain is just as, if not more, vulnerable than other parts of our body to the negative effects of non-nutritive food additives.' Study Limitations: Although the study boasted a large sample size, a high follow-up rate, and advanced dietary assessment tools, the researchers acknowledged several limitations. The participants were predominantly non-Hispanic White females. Moreover, the study was observational and lacked structured clinical interviews. Tanya Freirich suggested, 'Greater diversity in the sample size may reveal differences among races and ethnicities in the association between UPF consumption and depression.' She highlighted that 'High UPF intake correlated with higher BMI, increased smoking rates, decreased likelihood of regular exercise, and an elevated incidence of diabetes, hypertension, and dyslipidemia.' However, she stressed, 'While we cannot definitively determine whether depression or UPF consumption came first, it is crucial to note that reducing UPF intake resulted in a corresponding reduction in depression.' She concluded, 'The association is more than mere coincidence. ' Lauren Harris-Pincus, a registered dietitian nutritionist with over 25 years of experience in the New York/New Jersey area, emphasized the importance of considering social determinants of health and access. Harris-Pincus also recommended opting for honey, sugar, or agave nectar instead of artificial sweeteners. For beverages, she suggested choosing lightly sweetened or unsweetened tea, coffee, or seltzer water over diet sodas. She also proposed using maple syrup, fruit juice-based popsicles, and 100% fruit juice as alternatives to sugar-free options. She cautioned, 'Artificial sweeteners can present another issue. Since we perceive them to be hundreds to thousands of times sweeter than natural sugars, frequent use may lead to an accustomed preference for this ultra-sweet flavor.' Furthermore, because this was an observational study rather than a controlled one, it cannot definitively establish that ultraprocessed foods were the sole determinants of depression. Tanya Freirich observed, 'A prospective study like this one solely examines the association between UPF and mental state. ' She continued, 'Were people experiencing greater depression and subsequently turning to UPF for comfort or convenience? Depressed individuals may lack the energy for grocery shopping, meal preparation, or cooking from scratch.' Harris-Pincus pointed out, 'Perhaps someone who primarily consumes UPFs lacks access to fresh foods in their neighborhood. They might work multiple jobs and have little time to cook, or they may be caregivers, sacrificing their own self-care.' She underlined that 'When treating clients, Frierich recommends considering their diets as an important aspect of the puzzle for mental health.' She advised, 'Dietary changes do not have to be dramatic or expensive. Start small by swapping out one processed snack for a piece of fruit, nuts, seeds, or raw vegetables. An apple, baby carrots, or a handful of nuts can be just as quick as a processed snack, while reducing UPF intake by at least one serving.' Harris-Pincus also recommended opting for honey, sugar, or agave nectar instead of artificial sweeteners. For beverages, she suggested choosing lightly sweetened or unsweetened tea, coffee, or seltzer water over diet sodas. She also proposed using maple syrup, fruit juice-based popsicles, and 100% fruit juice as alternatives to sugar-free options. She cautioned, 'Artificial sweeteners can present another issue. Since we perceive them to be hundreds to thousands of times sweeter than natural sugars, frequent use may lead to an accustomed preference for this ultra-sweet flavor. Harris-Pincus warned, 'Transitioning to natural sugars may initially taste less sweet, but your taste buds can and will adapt over time.' She emphasized moderation in consuming all types of sugar, with the World Health Organization recommending a limit of 25 grams or less (six teaspoons) of added sugars per day for adults. Freirich added, 'Decreasing your intake of both artificially and naturally sweetened beverages and foods is a sound strategy for your physical and mental well-being.' Harris-Pincus also underscored that not all UPFs are equal. She stated, 'When discussing the limitation of ultraprocessed foods, there is nuance—they are not all the same.' For example, even peeling a vegetable is a form of processing, and soy milk, classified as an ultraprocessed food in databases, is essentially a nutrient-dense whole food. Harris-Pincus concluded, 'Our ultimate goal is to strive for a diet rich in fruits, vegetables, nuts, beans, seeds, whole grains, and lean proteins. Some ultraprocessed foods can be acceptable, particularly when combining processed and fresh foods makes family meals more convenient.'