According to the NOVA food classification system (Monteiro et al., 2018a, b), ultra-processed foods (UPF) (e.g., soft drinks, sweets, cookies, snacks, etc.) are those to which refined sugar and salt, fats, and food additives are added through industrial processes to improve their organoleptic properties, enhancing their attractiveness and increasing their consumption (Monteiro et al., 2019). These processes result in foods with high energy content and low nutritional density, i.e., rich in fats and sugar and poor in protein, fiber, minerals, and vitamins (Louzada et al., 2015; Monteiro et al., 2019).

In recent decades, an increase in UPF consumption has been observed in both developed and developing countries (Juul & Hemmingsson, 2015; Monteiro et al., 2010; L. Wang et al., 2021). For instance, a study including data from US youths from the National Health and Nutrition Examination Survey (NHANES) found a significant increase (from 61.4% to 67.0%) in the percentage of total energy from UPF consumption from 1999 to 2018 (L. Wang et al., 2021). Another time trend study including 11 metropolitan Brazilian areas observed an increase from 19.2% to 28.0% of total energy available in household food between 1987 and 2002 (Monteiro et al., 2010). This rise in UPF consumption is independent of socioeconomic status (i.e., this has been found in adolescents in both the upper and lower socioeconomic levels) (Machado et al., 2017; Rocha et al., 2021a, b) and has been connected not only with the direct costs of purchasing UPF but also with indirect social and health costs. In particular, UPF consumption has been associated with lower diet quality (Costa Louzada et al., 2015; Martini et al., 2021) and health problems such as obesity, cardiovascular disease, metabolic syndrome, and total mortality, in addition to mental health disorders such as depression (Cascaes et al., 2022; Chen et al., 2020; Elizabeth et al., 2020; Mesas et al., 2022; Morriss et al., 1997; Passos et al., 2020; Rico-Campà et al., 2019).

The recent debate on the existence of addiction to specific foods has focused on UPF because of their potential addictive effect, possibly due to being simultaneously rich in sugars and fats (Schulte et al., 2015; Whatnall et al., 2022). A systematic review reported a 12% prevalence of food addiction in community samples of children and adolescents (Yekaninejad et al., 2021), which could possibly be associated with UPF consumption. Concretely, frequent consumption of UPF could chronically stimulate brain reward mechanisms, such as dopaminergic sensitization, leading to feelings and behaviors similar to those seen in other addictions, such as withdrawal, craving, and excessive consumption (LaFata & Gearhardt, 2022; Schulte et al., 2015; Volkow et al., 2012). The similarities in the biological and behavioral effects of using UPF and other addictive psychoactive substances such as alcohol, nicotine, and cannabidiol may be particularly worrying for two main reasons. First, unlike alcohol, tobacco and other drugs whose use is commonly prohibited for those under 18 years of age, UPF are freely promoted and sold to all ages, particularly to the very young (Potvin Kent et al., 2019; Torres-Schiaffino & Saavedra-Garcia, 2020). This is of special relevance because early-onset substance use is a significant predictor of drug abuse and dependence (Grant & Dawson, 1998). Second, individuals who are addicted to one substance are more likely to develop addiction to other substances (Witek et al., 2022; Zawertailo et al., 2020).

Adolescence is a critical period of physical and emotional development in which decision-making, planning, and inhibitory control processes are not yet fully developed because, among other reasons, some brain areas, such as the prefrontal cortex, are still immature (Branje et al., 2021; Windle et al., 2018; Wray-Lake et al., 2010). Due to the adaptive challenges that this entails, added to some social aspects such as the progressively greater independence of their parents, adolescents are more vulnerable to risky behaviors that have a significant impact on the family and society (Kieling et al., 2011). Globally, adolescent diets are characterized by low consumption of fruits and vegetables and high consumption of energy-dense, nutrient-poor foods (Beal et al., 2019). Similarly, a population-based study in Brazil found that nearly one in three adolescents had an unhealthy dietary pattern characterized by an almost daily average frequency of consumption of candies, cookies, crackers and soft drinks (Tavares et al., 2014). On the other hand, the prevalence of substance use, such as alcohol (34.9%) and tobacco (9.3%), in this age group is a public health concern in Brazil (Barbosa Filho et al., 2012) and many other countries (Erskine et al., 2015). In addition to being frequent problems in adolescence, both the consumption of psychoactive substances and UPF have been associated with negative effects on mental health in this age group due to biological and behavioral reasons (Lane et al., 2022a, b; Marx et al., 2021; Patel et al., 2016). For instance, adolescents using alcohol, tobacco and/or illicit drugs are more likely to have depressive symptoms, aggression, self-injury, and suicide ideation and attempts (Klassen et al., 2018; Malta et al., 2018; Moodie et al., 2013). Furthermore, drug use disorders have been ranked among the top twenty leading causes of global disability-adjusted life-years for ages 10 to 24 (Abbafati et al., 2020). Moreover, previous studies linked UPF consumption with elevated symptoms of common mental disorders (Mesas et al., 2022; Werneck et al., 2022).

The cooccurrence of unhealthy lifestyle habits such as the consumption of UPF and psychoactive substances in adolescence is a crucial issue because this cluster effect may result in a synergism that enhances the severity of their separate harmful effects on health (Alzahrani et al., 2014; Ricardo et al., 2019; Whitaker et al., 2021). Most of the evidence on the association between UPF and substance use is based on preclinical studies with animals (Witek et al., 2022), a few epidemiological studies with adults (Amadieu et al., 2021; Schulte et al., 2015) and adolescents (Cummings et al., 2020; M. Wang et al., 2017), mostly focusing on specific UPF such as soft drinks (Atorkey et al., 2021; Fagan et al., 2021; Pengpid & Peltzer, 2019; Shih et al., 2020; Terry-McElrath et al., 2014). Moreover, these studies reported mixed results, and it remains unclear whether and to what extent these behaviors (i.e., UPF consumption and the use of psychoactive substances) are associated among adolescents.

Therefore, the objective of this study was to analyze the association between UPF consumption and alcoholic beverage drinking, tobacco smoking, and illicit drug use in Brazilian adolescents aged 13 to 17 years.

Methods

Study Design and Participants

This cross-sectional study analyzed publicly accessible data from the National School Health Survey (PeNSE), conducted in Brazil in 2019 by a partnership between the Ministry of Health and the Brazilian Institute of Geography and Statistics (IBGE), with support from the Ministry of Education (MEC) (IBGE, 2021). The PeNSE 2019 had a complex sample design that included students from public and private schools between the ages of 13 and 17 from all over the national territory. The student sample size was generated using simple random sampling in each size stratum, taking into account the school's administrative dependence (public or private) and geographic location in Brazil. The classrooms of the enrolled students who regularly attended were selected in each school. As inclusion criteria, all students present on the day of data collection who agreed to participate in the survey and provided information on sex and age were automatically included in the PeNSE database (IBGE, 2021).

Data were collected at schools by applying an electronic questionnaire available on a Personal Digital Assistant device without the assistance of the researcher. Other details of the PeNSE methodology can be found elsewhere (IBGE, 2021; Oliveira et al., 2017).

From the total initial population of 119,670 participants aged > 13 and < 17 years, we excluded those without complete information for socioeconomic condition (n = 19,257), UPF consumption (n = 670), use of alcohol (n = 198), tobacco (n = 66) or illicit drug use (n = 110) and others without information for any of the other covariates included in the analyses (n = 4,295) (Fig. 1). Thus, the sample of adolescents included in the present analyses was 95,074 participants (79.4%). Because many individuals had to be excluded due to missing data, a comparative descriptive analysis of the characteristics of the total initial population and the included sample of participants was performed (Supplementary Material, Table S1). In general, the characteristics of both samples were similar, and no difference that could affect the interpretation of the present results was found.

Fig. 1
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Flow diagram for study participants

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Data Acquisition

The consumption of ultra-processed foods (independent variable) was assessed with a questionnaire that asked adolescents about their consumption (yes or no) in the last 24 h of 13 foods classified as UPF according to the NOVA classification system (Monteiro et al., 2018a, b). A list was presented including the following UPF: soft drinks, industrialized fruit juice, powdered soft drink, chocolate drink, flavored yogurt, salty snacks (e.g., packaged chips or crackers), sweet snacks (e.g., sweet cookies, cream cookies, or packet cake), industrialized desserts (e.g., chocolate, ice cream, gelatin, flan), meat products (e.g., sausage, mortadella or ham), industrialized bread (e.g., flatbread, hot dog bun or hamburger bun), margarine, industrialized sauces (e.g., mayonnaise, ketchup), and industrialized ready meals (e.g., instant noodles, packaged soups, frozen lasagna). For the present analysis, after summing the number of UPF reported as consumed (ranging from zero to 13), the adolescents were classified according to the distribution in the sample by tertiles into low (1st tertile, from zero to three UPF), intermediate (2nd tercile, from four to five UPF) and high (3rd tercile, from six to 13 UPF) UPF consumption. In addition, the frequency of consumption in the last seven days was asked for soft drinks and sweets exclusively (the corresponding data for the other UPF are unavailable in the PeNSE database). For these questions, answers were admitted from zero (no consumption) to seven (daily consumption) days.

The use of three psychoactive substances (i.e., alcohol, tobacco and illicit drugs) was reported by the adolescent in response to two questions for each substance. For the consumption of alcoholic beverages, the first question asked was "Have you ever had a glass or a drink of alcohol in your life?". When the answer was negative, the questionnaire omitted further questions on alcohol consumption. When the answer was affirmative, they were asked "In the last 30 days, how many days have you had at least one drink or one dose (i.e., a can or a long neck bottle of beer or vodka-ice or a glass of draft beer or a glass of wine or a dose of “cachaça/pinga”, vodka, whiskey, etc.) of alcoholic beverages?", with the following response options: "no day in the last 30 days", "1 or 2 days", "3 to 5 days", "6 to 9 days", "10 to 19 days", "20 to 29 days" or "all days". Considering the response to both questions, the adolescents were classified into the following four categories: "never has drunk", "drank at least once in life but not in the last 30 days", "drank 1 or 2 days in the last 30 days", and "drank 3 days or more in the last 30 days".

Similarly, two sequential questions were also asked to collect data on tobacco smoking and illicit drug use. On tobacco smoking, they were first asked "Have you ever smoked a cigarette, even one or two puffs in your life?" and then "In the last 30 days, how many days did you smoke cigarettes?". On illicit drug use, the first question was "Have you ever used a drug such as marijuana (cannabis), cocaine, crack, solvent-based glue, general ether-based inhalants, popper, ecstasy, oxy, MD, skank, and others in your life?", and the second was "In the last 30 days, how many days did you use any drug?". The same method described for classifying adolescents according to alcoholic beverage consumption was used for tobacco smoking and illicit drug use, also generating four categories ranging from "never in life" to "3 days or more in the last 30 days".

Based on previous evidence of their relationship with both UPF (Ricardo et al., 2019; J. B. Silva et al., 2021a, b; Whitaker et al., 2021) and the psychoactive substances examined (Azeredo et al., 2016; Malta et al., 2014; Moodie et al., 2013; R. M. A. Silva et al., 2021a, b), the following covariates were considered potential confounders of the study associations: gender (boys vs. girls); age (13–15 vs. > 15 years, as pre-categorized in the PeNSE database); self-reported race (white/Caucasian vs. nonwhite, i.e., black, "pardo", Asian, or indigenous); school location (urban vs. rural); school administration (public vs. private); educational level (secondary vs. primary); parental living (both parents vs. one or no parent); having meals with parents (always or almost always vs. lower frequency); the number of close friends (≥ 3 vs. < 3); free-time physical activity (> 3 vs. ≤ 3 h/week); sedentary time (> 5 vs. ≤ 5 h/day); eating fruit every day (yes vs. no); eating other vegetables every day (yes vs. no); body image satisfaction (unsatisfied vs. satisfied); and bullying victimization at school in the last 30 days (yes vs. no). The socioeconomic condition was evaluated according to the combination of maternal schooling, possession of material goods (e.g., cell phone, computer, car), and availability of services (e.g., internet, maid) in the household. Then, a principal component analysis was applied to this set of items, and a weighted score was calculated considering the specific load of each item. Finally, the socioeconomic level score was categorized into quartiles, and those in the first quartile were designated as having "lower socioeconomic status" (lower or 1st quartile vs. moderate or higher, i.e., 2nd to 4th quartiles). In addition, the following questions assessed mental health symptoms in the last 30 days: "How often have you felt very concerned about the ordinary things in your daily life such as school activities, sports competitions, homework, etc.?" (worry), "How often have you felt irritated, nervous or bad-tempered by anything?" (irritability), "How often have you felt that no one cares about you?" (loneliness), "How often did you feel sad?" (sadness), and "How often have you felt that life is not worth living?" (helplessness). Considering the response options "1-never", "2-rarely", "3-sometimes", "4-most of the time", and "5-always", each symptom was considered frequent when they answered the last two responses (i.e., "4-most of the time" or "5-always"). We then summed the number of frequent mental symptoms reported for each individual (ranging from one to five).

Statistical Analysis

Descriptive statistics were performed by calculating the relative frequency (%) of the categorical variables and the mean ± standard error of the continuous variables analyzed. To analyze the differences in UPF consumption according to the frequency of psychoactive substance use, the chi-square test was used for categorical variables, and analysis of variance was used for continuous variables.

Multinomial logistic regression models were used to analyze the association between the tertile of UPF consumed (independent variable) and the use of alcohol, tobacco, and illicit drugs (dependent variables). As the dependent variable, each psychoactive substance was studied separately in four categories (ranging from "never in life" to "3 days or more in the last 30 days"). A first unadjusted model was performed to calculate the relative risk ratio (RRR) and the related 95% confidence interval (95% CI) for the 2nd and 3rd tertiles of UPF consumption compared to the 1st tertile (reference category). Next, three models were progressively adjusted as follows (Fig. 2): model 1, adjusted for age, self-reported race, socioeconomic status, school location, school administration, and educational level; model 2, previous model adjusted for parental cohabitation, eating with parents, number of close friends, free-time physical activity, sedentary time, eating fruit every day, and eating other vegetables every day; the variables alcohol consumption, tobacco smoking and illicit drug use in the last 30 days were also included except when they were the dependent variable under analysis; and model 3, previous model adjusted for bullying victimization in the past 30 days, satisfaction with body image and frequency of mental health symptoms.

Fig. 2
figure 2

Graphical representation of the multinomial regression analyses strategy

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Finally, the mean weekly frequency (in days) of consumption of soft drinks and sweets was compared with the analysis of variance according to the frequency of use of each psychoactive substance. Bonferroni’s post hoc test was used to detect differences between the frequency of use categories for each psychoactive substance.

All statistical operations were conducted with STATA software version 15.0 (Stata Corporation, College Station, TX, USA) considering the parameters of a complex survey design (svy commands in Stata).

Results

Baseline Participant Characteristics

Among the 95,074 adolescents included, approximately half were girls (52.3%) and attended secondary school (46.5%), and most of them studied in public schools (85.9%) located in urban areas (93.0%) (Table 1). The mean ± standard error number of UPF consumed in the last 24 h was 4.37 ± 0.02. Regarding the use of psychoactive substances, the proportion of adolescents who reported never having tried these substances was 36.5% for alcohol, 77.8% for tobacco, and 87.4% for illicit drugs. On the other hand, frequent use (three or more days in the last 30 days) was reported by 11.7% for alcohol, 3.3% for tobacco, and 2.3% for illicit drugs (Table 1).

Table 1 Characteristics of adolescent students aged 13–17 years, Brazil, 2019
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Salty snacks (49.6%) and sweet snacks (47.1%) were the most consumed UPF in the last 24 h, followed by industrialized breads (42.3%), margarine (41.4%), soft drinks (40.9%) and meat products (39.7%) (Table 2). When each UPF was analyzed separately, it was observed that the more frequent the consumption of alcohol, tobacco and illicit drugs, the greater the probability of reporting consumption of 10 of the 13 foods analyzed (p < 0.05) (Table 2).

Table 2 Consumption of ultra-processed food (UPF) in adolescent students aged 13–17 years by the use of alcohol, tobacco and illicit drugs, Brazil, 2019
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Relationship Between UPF and Use of Alcohol, Tobacco and Illicit Drugs

The results of the multivariate associations between the number of UPF consumed and the psychoactive substances are presented in tables for the use of alcohol (Table 3), tobacco (Table 4) and illicit drug use (Table 5). Overall, in the unadjusted models, those who consumed six or more UPF (3rd tertile) were more likely to report using each psychoactive substance than those consuming up to three UPF (1st tertile) in the last 24 h. These associations remained after the adjustment for all covariates considered. Specifically, higher consumption of UPF was associated with frequent (≥ 3 days in the last 30 days) drinking of alcoholic beverages (RRR = 2.19; 95% CI: 1.87, 2.56) (Table 3) and illicit drugs (RRR = 2.22; 95% CI: 1.72, 2.85) (Table 5). A similar finding was found in the complete adjusted analysis for occasional smoking (one or two days in the last 30 days) (RRR = 1.30; 95% CI: 1.05, 1.60) (Table 4).

Table 3 Association between ultra-processed food (UPF) consumption and alcoholic beverage drinking in adolescent students aged 13–17 years, Brazil, 2019
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Table 4 Association between ultra-processed food (UPF) consumption and tobacco smoking in adolescent students aged 13–17 years, Brazil, 2019
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Table 5 Association between ultra-processed food (UPF) consumption and illicit drug use in adolescent students aged 13–17 years, Brazil, 2019
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As depicted in Fig. 3, the weekly frequency of consumption of soft drinks and sweets was higher among adolescents who frequently used alcohol, tobacco, and illicit drugs than among their counterparts who never consumed them. Specifically, the mean frequency of soft drink consumption was 2.05 days in the last week, which was higher among those who used alcohol (3.10 days/week), tobacco (3.17 days/week) and drugs (3.45 days/week) more frequently (i.e., three or more days in the last month). The corresponding values considering the frequency of sweet consumption were a minimum of 3.03 days/week among never substance users and 4.13 (alcohol), 3.81 (tobacco) and 4.01 (illicit drugs) days/week among those who used them three or more days in the last month (Fig. 3).

Fig. 3
figure 3

Mean frequency (days/week) of dietary consumption of soft drinks and sweets according to the frequency of psychoactive substance use

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Discussion

Main Findings

Overall, our findings showed that UPF consumption was associated with the use of psychoactive substances (i.e., alcohol, tobacco, and illicit drugs) in a national sample of Brazilian adolescent students. The associations found were robust and independent of sociodemographic, lifestyle, and other health conditions, such as body image satisfaction, bullying victimization, and frequency of mental health symptoms. These results, along with those of other studies in children and adolescents, support the need for public policies to regulate the production and marketing of UPF (Popkin et al., 2021) placed not only in the framework of anti-obesity policies (Khandpur et al., 2020; Monteiro et al., 2010) but also immersed in the prevention of alcohol, tobacco and illicit drugs at early ages.

Comparison with the Available Evidence

These results depicted the association between alcohol, tobacco, or illicit drug consumption and both the number of types of UPF consumed and the frequency of weekly consumption of soft drinks and sweets. Consistently, a study with Israeli adolescents found that those following a "junk-food" dietary pattern (i.e., frequent consumption of soft drinks, salty snacks, cream cakes, and ice cream) were more likely to drink alcoholic beverages and smoke cigarettes (Sinai et al., 2021). The following studies have found similar results with respect to the frequency of consumption of specific UPF and substance use. Soft drink was undoubtedly the most studied UPF in this regard. For instance, the consumption of sugar-sweetened beverages was higher among adolescents reporting more days of alcoholic beverage consumption and a smoking habit (Rocha, Pessoa, et al., 2021). Other studies corroborated these associations considering sugar-sweetened (Shih et al., 2020), carbonated (Atorkey et al., 2021; Pengpid & Peltzer, 2019), and regular (Terry-McElrath et al., 2014) soft drinks. Likewise, in another study with school-aged adolescents, cigarette smoking was associated with soft drinks and fast food consumption (M. Wang et al., 2017). It is noteworthy the consistency observed between our findings and those of studies conducted in adolescents from countries of varied levels of development, employing specific UPF and methodological approaches, particularly on the associations of UPF, alcohol and tobacco. This might suggest that while in adolescence the use of psychoactive substances differs according to economic condition and social vulnerability (Halladay et al., 2020), the consumption of UPF is widespread and associated with substance use in this age group regardless of social class or cultural background.

Conversely, a study with adolescent girls found an inverse longitudinal association between the tendency to consume processed or sweet high-fat foods and the tendency to drink alcohol (Cummings et al., 2017). Another study did not find an association between sugar-sweetened beverages and tobacco smoking (Fagan et al., 2021). It is necessary to consider that discrepancies between studies are possibly due to the characteristics of the samples studied (e.g., sample size, proportion of boys and girls, age range, socioeconomic and cultural aspects, etc.), as well as to methodological aspects that may vary greatly, such as the instrument used to assess diet (e.g., 24-h recall, frequency food questionnaires), the use of psychoactive substances (e.g., validated questionnaires, single questions), and adjustment for confounding factors (among others).

Potential Mechanisms Relating UPF Consumption and Substance Use

Some possible biological and behavioral mechanisms have been suggested to explain the association between UPF consumption and the use of the psychoactive substances studied. For instance, eating foods rich in sugar and with a high glycemic load, such as UPF (Schulte et al., 2015), generates a blood glucose spike that activates brain reward mechanisms similar to what occurs in other addictive processes (Volkow et al., 2012). Moreover, foods high in fat and carbohydrate, which are common in UPF, have more hedonic value than foods containing only fat or carbohydrate, and this effect is associated with greater recruitment of central reward circuits (DiFeliceantonio et al., 2018). This fat-carbohydrate interaction potentiating food reward was observed in healthy weight but not in individuals with excess weight (Perszyk et al., 2021), which could suggest that when such consumption is frequent and long-lasting in time, sensitization of this neurological pathway may occur (Temple, 2016), which in turn could lead to increased craving (i.e., the sensation of the need to consume) of substances with similar effects, such as alcohol, nicotine, and cannabidiol, among others (Bollen et al., 2020; Chao et al., 2017). In this line, preliminary evidence suggests that tolerance and withdrawal may occur in response to UPF (Parnarouskis & Gearhardt, 2022).

In addition, it should also be considered that by providing a low density of essential nutrients, especially protein, unsaturated fats and fiber, and a high density of energy, sugars, fats, salt and food additives, the low diet quality of UPF (Martínez Steele et al., 2017) favors microbiota dysfunction (Cuevas-Sierra et al., 2021) and increases DNA oxidative damage (Edalati et al., 2021) and inflammatory markers (Lane et al., 2022a, b; Martins et al., 2022). Consequently, consuming more UPF increases the risk of nutritional, cardiometabolic and mental health disorders and symptoms (Elizabeth et al., 2020; Louzada et al., 2022; Mesas et al., 2022). Therefore, apart from sharing brain pathways related to addiction to other psychoactive substances, UPF consumption can trigger pathophysiological processes that may increase the incidence of elevated symptoms of common mental disorders (Werneck et al., 2022) and adolescents’ vulnerability to other self-destructive behaviors, such as illicit drug use (Temple, 2016; Volkow et al., 2012; Zawertailo et al., 2020). Furthermore, it could be possible that those adolescents who eat more UPF, do this as a coping strategy for emotional relief, tension-reduction, or to deal with stress (Manzoni et al., 2009), which could also be associated with other drugs consumption (Powers & Kutash, 1985). In this sense, it has been previously found that individuals who have higher perceived stress or low ability to manage stress also have a higher energy intake and consumed more sweets and fat foods (Errisuriz et al., 2016; Zellner et al., 2006), which could increase stress levels (Abrams et al., 2022; Tariq et al., 2019) and enhance addiction vulnerability (Sinha, 2008).

From a behavioral perspective, the sale of UPF to minors is not only liberalized but also stimulated by ostensive marketing and specifically directed at this public (Moodie et al., 2013; Torres-Schiaffino & Saavedra-Garcia, 2020), contrary to what happens with alcoholic beverages, cigarettes and illicit drugs such as cannabis, crack, or cocaine. UPF are palatable foods commonly consumed in out-of-home gatherings and stimulated by social motives (Onita et al., 2021), circumstances that also favor the consumption of psychoactive substances, particularly alcohol drinking (Fazzino et al., 2018). However, other psychological reasons besides socialization may also justify the consumption of tasty foods such as UPF by adolescents, such as coping, increasing reward, or conformity (Boggiano et al., 2017). In the family context, eating with family while watching TV was associated with greater intake of UPF, and household availability has increased in recent years (Monteiro et al., 2018a, b). In this regard, it was reported that parental nicotine dependence and frequent alcohol use were associated with increased reward-driven eating behavior by their children, indicating that parental use of psychoactive substances and UPF consumption are also associated in the family context (Cummings et al., 2020).

Limitations

This study has some limitations that should be considered when interpreting its results. The first is the cross-sectional design, which prevents us from stating the existence of a causal relationship between consuming UPF and consequently increasing the frequency of alcohol, tobacco or illicit drug use. Indeed, a previous study reported that appetite and snack urge increased more after alcohol consumption (Rose et al., 2015), which suggests that the association between UPF and alcohol intake could be bidirectional. The second limitation refers to the possible recall and desirability biases resulting from self-reported information on both UPF consumption and substance use. The third limitation is that possible information bias cannot be ruled out because, as alcohol and tobacco consumption are prohibited for those under 18 years of age and drug use is illegal, some adolescents could have omitted or misreported these behaviors. Last, although the large sample size allowed us to adjust the analyses for potential confounding factors, residual confounding is still possible because we did not adjust for body mass index and energy intake, which were unavailable in the PeNSE 2019 database. Our results support the hypothesis that adolescents with a dietary pattern rich in UPF are more likely to consume other addictive substances. However, because of the cross-sectional design of our study, prospective observational studies are essential to further investigate whether UPF consumption increases the risk of other addictions (i.e., alcohol, tobacco and illicit drugs) or whether these behaviors are merely concurrent. Importantly, the concomitant occurrence of UPF consumption and substance use in early stages of life, such as adolescence, may lead to unhealthy lifestyle habits in the beginning of adulthood (Chassin et al., 1996; Mikkilä et al., 2005; Spear & Swartzwelder, 2014).

Conclusion and Future Directions

In summary, in a large-scale sample of Brazilian adolescents, a higher number of UPF consumed was associated with alcohol, tobacco, and illicit drug use regardless of several confounding factors, including self-perceived body image and bullying victimization. Therefore, future research should consider the increased risk of use of these psychoactive substances and the possible addiction to them resulting from frequent use, among the various adverse health effects of UPF use.

According to our findings, reducing the number of UPF consumed is an important target not only in terms of promoting public health nutrition but also in terms of the prevention of substance abuse and dependence. In addition, our results draw attention to specific UPF consumed very frequently by adolescents and consistently associated with the use of alcohol, tobacco and illicit drugs, such as sweet and salty snacks, industrialized breads and soft drinks. It is important to highlight that high consumption of UPF by adolescents is not a novel problem in Brazil. In the 2009 edition of the PeNSE, some of these UPF topped the list of the most consumed in the unhealthy dietary pattern (Tavares et al., 2014). Similarly, the increasing prevalence of regular alcohol and tobacco use and illicit drug experimentation in adolescence is also a persistent concern in this country (Malta et al., 2014).

Therefore, considering our results and the evidence that supports the association between UPF consumption and the use of other psychoactive substances, it cannot be ruled out that the joint confrontation of both problems through combined intersectoral actions could be more effective than if done in isolation. Because eventually consuming these UPF might increase the risk of using other substances, this study adds to the body of evidence that supports the need for measures to regulate their production (e.g., reducing energy density and increasing nutritional value), distribution (e.g., preventing sales inside or near schools) and commercialization (e.g., increasing taxes and warning on labeling about the risks associated with frequent consumption).