Sugar, Ultra-Processed Foods & Mental Health

This research conducts a comprehensive umbrella review to assess the correlation between the consumption of ultra-processed foods, categorized by the Nova food classification system, and negative health impacts. Utilizing databases such as MEDLINE, PsycINFO, Embase, and the Cochrane Database of Systematic Reviews, along with manual reference checks from publications between 2009 and June 2023, the study scrutinizes systematic reviews and meta-analyses covering cohort, case-control, and cross-sectional studies. It employs a predefined set of criteria to classify the evidence into five levels ranging from convincing to no evidence. It utilizes the GRADE framework to rate the quality of the evidence from high to very low. The investigation uncovered 45 distinct pooled analyses involving over 9.8 million participants that showed a clear link between the intake of ultra-processed foods and a variety of health issues, including mortality, cancer, and various diseases affecting mental, respiratory, cardiovascular, gastrointestinal, and metabolic health. Convincing evidence revealed significant associations with an increased risk of cardiovascular mortality, type 2 diabetes, anxiety, and common mental disorders. Highly suggestive evidence linked high consumption of these foods to elevated risks of overall mortality, heart disease mortality, Type 2 diabetes, depression, adverse sleep conditions, wheezing, and obesity. Out of the analyses, 21 indicated suggestive to weak evidence, and 13 showed no significant findings. Most analyses were deemed low to very low quality, with a few rated moderate. The study underscores the association between high consumption of ultra-processed foods and severe health risks, advocating for public health strategies and policies to diminish consumption for better health outcomes. It also calls for further research into the mechanisms behind these associations. [NPID: Ultra-processed, mortality, mental health, health outcomes, public health, cancer, anxiety]

The dietary landscape of the Western world has dramatically transformed since the mid-20th century, particularly with a significant rise in the intake of refined carbohydrates, which have been linked to several negative health outcomes. This change in diet has been connected to physiological effects like increased blood sugar and insulin levels, which may also influence aspects beyond health, including facial attractiveness. This was explored in a study with 104 French participants, examining how both short-term and long-term consumption of refined carbohydrates, measured by glycemic load, affects facial attractiveness. Evaluations were made by raters of the opposite sex based on photos taken two hours post a standardized breakfast. Long-term intake was analyzed through the lens of three meals known for their high glycemic content: breakfast, afternoon snacks, and snacks eaten between meals. The study found that consuming a high-glycemic breakfast decreased attractiveness for both genders, even when accounting for variables like total calorie intake. The impact of long-term consumption of refined carbs on attractiveness varied, influenced by the type of meal and gender. Overall, consuming refined carbs during the specified meals decreased attractiveness, whereas consuming more calories tended to have the opposite effect. Interestingly, for men, this trend flipped for afternoon snacks, where more calories led to lower attractiveness, but a higher glycemic load had a positive impact. These observations held even after adjusting for potential factors that could affect attractiveness, such as age, perceived age difference, masculinity/femininity, body mass index, physical activity level, whether one's parents owned their home, smoking status, relationship status, use of hormonal birth control (in women), and facial hair (in men). The study suggests that these effects might be related to how refined carbs can make women appear older and men seem less masculine. It also delves into how the body's response to these meals can be understood from the perspective of adapting to or struggling with our modern diet. [NPID: Facial attractiveness, glycemic, refined carbohydrates, high-glycemic, Western Diet]

Addiction is becoming more and more understood scientifically. Even though the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) does not list food addiction as a disorder, study on the subject has expanded significantly over the past 20 years. The Yale Food Addiction Scale (YFAS), created to quantify food addiction by evaluating DSM-5 criteria for drug use disorder in the context of food intake, is used extensively in this research. Gearhardt et al. (2023) present a recent analysis of two systematic reviews, including 281 research from 36 countries, which revealed that 14% of adults and 8% of children worldwide have YFAS-measured food addiction. However, the degree of suggested addiction in children is unprecedented. This claimed prevalence is comparable to the levels of addiction documented for other legal drugs in adults (14% for alcohol and 18% for tobacco). YFAS found that the prevalence of food addiction approaches 32% in obese patients undergoing bariatric surgery and above 50% in patients with binge eating disorders in populations with clearly established clinical diagnoses. According to the YFAS, food addiction is linked to key elements of addiction, including mood dysregulation, impulsivity, reward-related brain dysfunction, worsened physical and mental health, and decreased quality of life. The authors conclude that convergent and consistent evidence supports the validity and clinical applicability of food addiction; nevertheless, it is less clear what kinds of foods are addictive. Despite the ambiguity, labeling certain foods as addictive may encourage study and change public perceptions of regulation. [NPID: Addiction, craving, diet, ultraprocessed food, adolescent, adult, smoking]

Food addiction (FA) is a term used to describe hedonic eating behaviors that involve consuming foods of high palatability in amounts that exceed the body's everyday energy needs (i.e., foods heavy in salt, fat, and sugar). According to current beliefs, FA and other drug addictions have shared brain underpinnings as well as behavioral parallels, and FA shares similar symptoms with other eating disorders, such as binge eating. The striatum, amygdala, insula, orbitofrontal cortex, and nucleus accumbens have all shown different activation patterns and connectivity in neuroimaging studies of brain reward circuits in people with FA responding to food cues and the consumption of highly appetizing food when compared to healthy controls. The hypothalamus, responsible for controlling eating habits and peripheral satiety networks, has shown additional impacts. Impulsivity and mood have a significant influence on FA. Chronic stress can impair the hypothalamic-pituitary-adrenal axis's capacity to operate, which in turn affects eating habits and makes highly palatable foods more appealing. Future research will need to specifically identify FA as a diagnosis that differs from other eating disorders. [NPID: Food addiction, food cues, fMRI, connectivity, eating addiction, addictive behavior, reward circuitry]

There is mounting evidence that nutrition may affect depression risk. Despite a wealth of information connecting ultra-processed foods (UPF, i.e., appealing, energy-dense, and fast food items) with human illness, there is little research exploring the relationship between UPF intake and depression. Short-term dietary data and a limited capacity to control for possible variables have hindered earlier investigations. Furthermore, no study has shown how specific UPF elements or meals may increase the risk of developing depression or how the timing of UPF consumption may do so. In this work, Samuthpongtorn et al. (2023) looked at the potential links between UPF and its components with new cases of depression. Between 2003 and 2017, the authors conducted prospective research in the Nurses' Health Research II among middle-aged females who were not depressed at baseline. Every four years, diet was evaluated using validated food frequency questionnaires (FFQs). Utilizing the NOVA classification, which divides meals into categories based on their level of processing, UPF consumption was calculated and further divided into its constituent parts in secondary studies, including savory snacks, ready-to-eat meals, ultra-processed grains, fats and sauces, sweet snacks, ultra-processed dairy products, processed meat, drinks, and artificial sweeteners. Furthermore, the authors looked at the relationship between changes in UPF consumption updated every four years and incident depression in an exploratory study. Analysis of the cohort demonstrated the following demographics: n = 31712 women, aged 42 to 62 years old (mean = 52 [4.7] years; 95.2% non-Hispanic White women). The authors noted that participants who consumed more UPF were less likely to exercise regularly, were more likely to be smokers, had higher BMIs, and had more comorbid conditions such as hypertension, diabetes, and dyslipidemia. Participants in the top percentile of UPF consumption had a higher risk of depression than those in the lowest quintile. This finding remained significant after accounting for confounders. Age, BMI, physical activity, smoking, or other categories did not reveal differential associations within subgroups. Reverse causation was refuted by a 4-year lag study that found no appreciably different relationships. The relationship between certain UPF elements and the risk of depression was then investigated, revealing that artificial sweeteners and artificially sweetened drinks were linked to a higher incidence of depression when extreme quintiles were compared. In an exploratory study, those who decreased their daily consumption of UPF by at least three servings were at a lower risk of depression than those who maintained a reasonably consistent intake throughout each four-year period. Based on their findings, the authors comment on how consuming more UPF, especially artificial sweeteners, and drinks containing artificial sweeteners, is linked to a higher chance of developing depression. Recent experimental research shows that artificial sweeteners trigger purinergic transmission in the brain, which may be implicated in the etiopathogenesis of depression, even though the mechanism linking UPF to depression remains unclear. The authors comment on the need for further research, utilizing structured clinical interviews and diverse populations to validate current findings further. [NPID: Diet, Depression risk, ultra processed food, artificial sweeteners]

Thousands of peer-reviewed papers have examined food addiction, particularly addiction to ultra-processed foods. Even though 20% of individuals fit the diagnostic criteria for this disorder, food addiction is not a recognized clinical diagnosis. Hence there are few tried-and-true treatment regimens and published result statistics. The concept of food addiction having therapeutic applications has increased the number of doctors providing their services to patients. This audit by Unwin et al. (2022) provides information on three clinical teams who offer programs that are delivered online using a shared methodology. Each team concentrated on a whole food, low-carb strategy while providing emotional support and educational resources related to recovering from food addiction. There were weekly meetings for 10–14 weeks, followed by monthly support. Data included pre- and post-program results for body weight, ICD-10 symptoms of food-related substance use disorder (CRAVED), modified Yale Food Addiction Scale 2.0 symptoms of food addiction, and the Short Warwick Edinburgh Mental Well-being Scale to evaluate mental well-being. There were 103 individuals in the included population sample. Food addiction was substantially reduced across all settings, as evident by mYFAS2 score of -1.52, CRAVED score of -1.53, and body weight reduction of 2.34 kg. Overall, there were noticeable gains in mental health. The authors further comment that, in due course, follow-up statistics will be made public. More research is necessary to evaluate and compare long-term therapies for this complicated and challenging biopsychosocial illness. [NPID: Addiction, ketogenic diets, low carbohydrate diet, processed food, sugar]

The association between drinking sugar-sweetened drinks (SSBs) and depression risk is still unclear. To assess the relationship between SSB intake and the chance of depression, Hu, Cheng & Jiang (2019) performed a meta-analysis of studies (up to June 2018) released in PubMed and Web of Science. A total of 365,289 individuals from 10 observational trials with 37,131 instances of depression were included. The results showed that the combined overall risk of depression was found to be higher for those who consumed the most SSBs compared to those who consumed the least. The results were the same in both cohort and cross-sectional investigations. The likelihood of suffering from depression may rise by 5% among SSBs consumers who consumed the equivalent of two glasses of coke per day, rising to a potential 25% increase in depression likelihood for those who consume around 3 cans of cola per day. This denotes a nonlinear dose-response association between SSB intake and the likelihood of depression. The authors conclude that consuming SSBs may be linked with a slightly increased chance of depression. Future confirmation of the findings is required, especially using cohort studies, which the authors note that only 4 of the 10 studies included in this meta-analysis were cohort studies. [NPID: Depression, meta analysis, observational study, sugar sweetened beverages]

In this study by Grech et al. (2022), the authors utilized data from the Australian National Nutrition and Physical Activity Survey to validate the predictive outcomes of the protein leverage hypothesis (PLH). PLH implies that the excessive intake of energy and resultant obesity occurs in the setting of stringent protein intake regulation with concomitant current carbohydrate and fat content of consumed diets. Hence, PLH predicts a negative relationship between total energy intake and energy produced from protein under stringent regulation, and that humans modulate their dietary consumption to maintain said regulation. Using the aforementioned dietary data, the authors discovered that PLH predictions were indeed valid, where individuals were found to be more likely to consume highly processed discretionary foods to dilute their protein intake which led to a substantial increase in energy intake. In addition, energy intake continued to decline with increasing levels of consumed proteins, where the average individual protein intake accounted for 18.4% of total consumption. The authors conclude that these findings may help explain the environmental impacts and mechanisms underlying the process of obesity, whereby a reduction in protein intake was accompanied by an increased intake of highly processed, energy-dense foods, and that this increase was due to biological drivers for protein consumption. This study highlights the role played by proteins in the domain of obesity, and its implications on health from a global level. [NPID: Obesity, protein, diet, energy intake, protein leverage hypothesis, PLH, Australia]

Ultra-processed foods (UPF) were found to play a role in the pathogenesis of several illnesses, both physical and mental, however, their involvement in the pathogenesis of dementia remains unknown. In this prospective cohort study by Li H. et al. (2022), the authors used data from 72083 adult participants of the UK biobank study (aged 55 years and above, dementia-free baseline) to investigate the impact of UPF on dementia. Participants submitted a minimum of two 24-hour dietary assessments compliant with NOVA food classification, while dementia from all causes (vascular, Alzheimer’s, etc.) was noted through reviewing medical records. Analysis of the data across a follow-up duration of 10 years revealed a substantial relationship between the likelihood of developing dementia and the increased consumption of UPF (where 287 participants suffered from Alzheimer’s disease, and 119 suffered from vascular dementia). Furthermore, the authors discovered that decreasing UPF consumption by 10% dietary weight resulted in a 19% decrease in the risk of suffering from dementia. The authors conclude that increasing UPF consumption leads to a higher likelihood of suffering from dementia while replacing UPF consumption with unprocessed or minimally processed food helps decrease the odds of suffering from dementia. [NPID: Diet, ultra processed foods, mental health, dementia, Alzheimer’s disease, vascular dementia]

A myriad of evidence demonstrates the impact of dietary composition on food perception, and that genetics play a role in shaping our dietary preferences. However, as taste is a plastic trait that changes due to nutritional composition, illness, and age, the level of evidence regarding the impact of chemosensory plasticity on dietary consumption remains insufficient. In this study by May & Dus (2021), the authors explore recent studies investigating the impact of sugar-rich diets on sweet taste in humans, rodents, and vinegar flies, attempting to understand the underlying neural and molecular mechanisms, in addition to identifying key areas for further research. Moreover, the authors seek to further the understanding behind the relationship between taste, nutrition, feeding, and how dietary chemosensory plasticity impacts the selection and intake of food or contributes to the incidence of metabolic diseases or obesity, and finally, how this knowledge can be used to improve public health interventions. [NPID: Chemosensory plasticity, diet composition, molecular mechanisms, obesity, taste]

The relationship between consuming ultra-processed foods and depression, in addition to other mental disorders, has undergone further studies beyond the scope of previously published meta-analyses, that were curtailed by the then-available body of evidence. In this systematic review and meta-analysis by Lane et al. (2022), the authors assembled the current body of evidence (comprised of 17 observational studies: 15 cross-sectional and two prospectives, total n = 382,541 participants) investigating the relationship between consuming ultra-processed food and mental disorders. Analysis of the results revealed a link between elevated consumption of ultra-processed food and a rising risk of suffering from depression and anxiety, in addition to increased risk of developing depression later in life. The authors comment that, despite initial results demonstrating a substantial risk to mental health resulting from the intake of ultra-processed foods, further research is necessary to fully understand the mechanisms underlying these observed interactions. [NPID: Major depressive disorder, anxiety, mental disorders, ultra-processed food, NOVA, meta-analysis, nutritional psychiatry, psychiatry]

Recent studies point out the negative impact of consuming ultra-processed foods (UPF) on cardiometabolic health, and subsequently, depression. Thus, it may be inferred that UPFs are linked to depression, a leading causative factor of disability and disease across the world. In this study by Gómez-Donoso et al. (2019), the authors conducted a prospective evaluation of the links between UPF intake and the odds of suffering from depression, in a Mediterranean population composed of 14,907 university graduates (mean age = 36.7 ± 11.7 years, free from depression on participation, and followed up for around 10.3 years). UPF intake was investigated using a validated, semi-quantitative 136-item food-frequency questionnaire. Analysis of the results showed a recording of 774 instances of depression during participant follow up, with a substantial relationship between the level of UPF intake and the odds of developing depression, as seen with participants in the highest quartile of UPF intake reporting more incidents of depression compared to their cohort in the lowest quartiles. The authors conclude that their results show a substantial positive relationship between dietary intake of UPF and depression risk, which was increasingly tangible in study participants who did not exercise. [NPID: SUN cohort, prospective study, food processing, ultra-processed food, depression]

Psychological disorders represent a significant health issue across the world. Adopting a healthy diet helps avert and manage mental derangements. Epidemiologic studies demonstrated key links between consuming a nutrient-rich diet and suffering from lower risks of developing symptoms of anxiety and depression. Thus, Coletro et al. (2022) aimed to investigate the links between anxiety and depression pervasiveness and the consumption of food, depending on how processed the food is, during the COVID-19 pandemic. In an epidemiological household survey, the symptoms of anxiety and depression were evaluated using the Generalized Anxiety Disorder 7-item/Patient Health Questionnaire-9, while food intake was investigated using a qualitative food frequency questionnaire which helped recall dietary consumption within the last 3 months. The foods were divided into groups according to the NOVA classification from fresh/minimally processed food up to ultra-processed food, using the average weekly consumption as the cutoff point. Interestingly, participants who consumed fresh/minimally processed foods over the weekly average frequency showed a significantly decreased pervasiveness of depressive symptoms, while, on the other hand, consuming ultra-processed foods above the weekly average resulted in experiencing more symptoms of anxiety and depression. Thus, the authors conclude that dietary intake of ultra-processed foods is linked to escalating odds of suffering from anxiety and depression, and hence advocate for enhancing the intake of fresh/minimally processed foods. [NPID: Depression, anxiety, food consumption, food processing industry, mental health, nutrition]

Ultra-processed foods (UPFs) are increasingly available in the United States. Growing interest in the health impacts of UPF gave rise to a growing body of research, and in this study by Zheng et al. (2020), the authors investigated the links between UPF intake and symptoms of depression in adults. Using data from the National Health and Nutrition Examination Survey (NHANES, 2011–2016), dietary information from 24-h dietary recall interviews, and depressive symptom assessment using a nine-item Patient Health Questionnaire, the authors discovered a positive relationship between UPF intake and symptoms of depression. Thus, the authors conclude that UPF intake may raise the odds of experiencing depressive symptoms, especially in individuals who have low levels of physical activity. [NPID: Depressive symptoms, ultra-processed food, dose-response, cross-sectional study, NHANES]

As sugar continues to become an increasing part of our available diet, it has inadvertently led to sugar overconsumption in children, teens, and adults in over 60 countries around the world, where the average consumption of sugar is >100 g/person/day - more than four times the dietary limit recommended by WHO. Current literature postulates that traits like obesity and impulsive behavior are linked to poor dietary choices, resulting in an increase in processed food and beverage intake. The extent of the chronic effects of exaggerated sugar intake on cognition and consequential hyperactivity, from the age of adolescence onwards, are not well understood. Thus, Beecher et al. (2021) conducted their experiments on a mouse model of sugar intake, observing that overconsumption of sugar (at significant levels to induce weight gain) over an extended period of time resulted in mice exhibiting aberrant hyperlocomotor activity, and suffering from derangements in episodic and spatial memory. These findings are congruent with published works investigating attention deficit and hyperactivity disorders, where pathological hippocampal neurogenesis was found to be linked to defective hippocampal-dependent learning and memory processes. Based on these facts, the authors postulate that chronic exaggerated intake of sugars (which is observed in western diets) may increase the risk of suffering from persistent hyperactivity and other neurocognitive disorders in adulthood. [NPID: Sucrose, hyperactivity, neurocognitive deficits, neurogenesis, adulthood].

This 2002 study investigated the role of sugar intake in major depression by correlating the per capita consumption of sugar with the prevalence of major depression. Depression incidence data was taken from the Cross-National Epidemiology of Major Depression and Bipolar Disorder study (1996), while the Food and Agricultural Organization of the United Nations published in 1991 showed how much sugar was consumed. When sugar intake rates (calories per day) across 6 countries were analyzed against the annual report of major depression, there was a highly significant relationship identified between the two variables. Although these results do not imply any causative relationship between the two variables examined, sugar consumption may have a direct influence on major depression occurrence. But it should be added that the data was based on a limited number of countries. The paper also discusses the potential link between sugar consumption, beta-endorphins, and oxidative stress. [NPID: sugars, diet, nutrition, depression, depressive, mental health, snacks, calories, unhealthy]

In this 2012 study, the association between consumption of fast foods (hamburgers, sausages, pizza) and processed pastries (muffins, doughnuts, croissants) with prevalence of depression was analyzed among the 8964 participants of the Seguimiento Universidad de Navarra project. A validated semi-quantitative food frequency questionnaire was completed at baseline while depression was identified at follow-up with questionnaires asking about physician diagnosis and use of antidepressant medication. After a median follow-up of 6.2 years, 493 cases of depression were documented. Compared to subjects in the first quintile for fast food eating, risk of depression was greater in those who consumed the most fast food [Q5; hazard ratio (HR) = 1.36, P trend = 0·003], even after adjustments were made for other food items. Although the intake of commercial baked goods did not linearly correlate with depression, the participants in the quintiles 2-5 for pastry consumption had an elevated risk of developing depression compared with those in Q1 (HR = 1·38). Sánchez-Villegas et al. (2012) believes eating fast food and processed pastries may enhance chances of developing depression. [NPID: sugar, processed food, fast food, pastries, depression]

This 2016 cross-sectional study assessed 3363 members of staff of Isfahan University of Medical Sciences to uncover the relationship between dietary glycaemic index (GI) and glycaemic load (GL) with psychological distress, anxiety and depression. A validated, self-administered, dish-based, semiquantitative food frequency questionnaire gathered GI and GL data, while validated Iranian versions of the Hospital Anxiety and Depression Scale and General Health Questionnaire-12 analysed anxiety, depression, and psychological distress among the sample. After potential confounders were controlled, Haghighatdoost et al. (2016) discovered that the subjects in the top tertile of GI had a 44% greater risk of depression (with a p-value of 0.03) and a 52% increase for anxiety (p-value was 0.06), relative to those in the first tertile. Whereas, the higher the glycaemic loads (GLs) of the subjects’ diets, the lower the odds were of developing mental disorders (Odds ratio: 0.66), depression (OR=0.69), and psychological distress (OR=0.67). When stratified analyses were performed by sex, a positive link was observed between GI with odds of depression (OR = 1.52) and psychological distress (OR = 1.66) in women but not in men, after potential confounders were accounted for. These findings supported a direct association between dietary GI with depression odds and inverse relationships between glycaemic load with mental disorders, depression and psychological distress. [NPID: sugar, processed food, anxiety, depression, mental disorders, depression, psychological distress]

This 2014 review presents evidence from rodent-model studies demonstrating the effects of sugars on cognitive measures such as learning, memory, reward processing, in addition to psychological aspects including anxiety and mood. Kendig (2014) explains that sugar clearly induces cognitive dysfunction, with deficits most consistently observed on tasks measuring spatial learning and memory, while younger animals appear to be especially sensitive to sugar’s impact on reward processing (although results vary according to what reward-related behaviour is assessed). Although the implications are that sugar may not have long-term effects on mood and anxiety, cognitive impairments have been found when intake approximates levels of sugar consumption in people and without changes to weight gain. The narrator warns us about the possible impact of sugar on cognition in humans, and discusses the potential underlying mechanisms, parallels between sugar consumption and addictive behaviors, as well as directions for future research. [NPID: sugar, processed food, learning, memory, reward processing, anxiety, mood, spatial learning, cognition, addiction]

Brookie and her colleagues (2018) surveyed young adults living in New Zealand and the United States to compare consuming raw fruits and vegetables with eating processed (cooked/canned) fruits and vegetables in their relationships with mental health. The 422 participants (aged 18-25) disclosed their diets, and revealed their negative and positive mental health experiences (depressive symptoms, anxiety, negative mood, positive mood, life satisfaction, and flourishing). While controlling for covariates (socio-economic status, body mass index, sleep, physical activity, smoking, and alcohol use), raw fruit and vegetable intake (FVI) was found to predict reduced depressive symptoms and higher positive mood, life satisfaction, and flourishing, while processed FVI only predicted higher positive mood. The top 10 raw foods related to better mental health were carrots, bananas, apples, dark leafy greens like spinach, grapefruit, lettuce, citrus fruits, fresh berries, cucumber, and kiwifruit. These findings support the recommendation of raw fruits and vegetables consumption in order to optimize mental health benefits. [NPID: sugar, processed food, mental health, fruit, vegetables, depression, anxiety, life satisfaction, FV intake, carrots, bananas, apples, dark leafy greens, grapefruit, lettuce, citrus, berries, cucumber, kiwi]

Machado et al. (2019) examined the consumption of ultra-processed foods in Australia using the data from the National Nutrition and Physical Activity Survey (2011-2012), with the objective of exploring its relationship with the intake of nutrients linked to non-communicable diseases (NCDs). Dietary information on 12,153 participants aged 2+ years were determined, including the dietary components classified according to the NOVA system (a classification based on the nature, extent and purpose of industrial food processing) as well as the mean nutrient content of ultra-processed food and non-ultra-processed food fractions of the diet. The primary outcomes of this study were the average dietary contents of nutrients linked to NCDs and the prevalence of intake outside levels recommended for the prevention of NCDs. The results showed ultra-processed foods contributed most (42% of the energy intake), followed by unprocessed or minimally processed foods (35.4%), processed foods (15.8%) and processed culinary ingredients (6.8%). Machado et al. (2019) also discovered a positive and statistically significant linear trend between quintiles of ultra-processed food consumption and intake levels of free sugars, 3 categories of fats (total, saturated and trans), sodium, and diet energy density, and also discovered an inverse association with dietary fiber and potassium. Moreover, a linear increase in prevalence of non-recommended consumption levels of all studied nutrients was seen across quintiles of ultra-processed food intake, most markedly for free sugars (22% to 82%), trans fats (6% to 11%), and dietary energy density (2% to 25%), from the lowest to the highest ultra-processed food quintile. The researchers concluded that the high energy contribution of ultra-processed foods had negative effects on consumption of non-ultra-processed foods and also on all nutrients linked to NCDs in Australia. The findings supported decreasing the dietary share of ultra-processed foods in order to enhance diet quality across the country and help accomplish recommended nutrient intake levels. [NPID: sugar, processed food, NOVA, saturated fat, trans fat]

Although dietary guidelines recommend restricting amounts of saturated fats in general since they were found to raise levels of total cholesterol in the blood and thus postulated to increase risk of coronary heart disease (CHD), DiNicolantonio and his team (2016) reviewed the evidence linking saturated fats and also sugars to CHD, and explains how the latter is the bigger issue. Firstly, it is explained that saturated fats are a diverse class of compounds, with different fats possibly having varying effects on low-density lipoproteins (LDLs) and on CHD risk. It is dependent on the specific saturated fatty acids (SFAs), which signifies some food sources of SFAs may pose no risk for CHD or possibly be even protective. The authors emphasize that the advice to reduce saturated fats in the diet could actually increase people's risk of CHD if the LDL, SFAs, or dietary sources are not considered also. Furthermore, the substitution of saturated fats with refined sugars and added sugars can result would not be favorable for heart health. The transition into a high sugar diet can alter LDL, HDL and triglyceride levels (possibly increasing risk of CHD), elevate levels of glucose, insulin, and uric acid, and impair glucose tolerance, insulin and leptin resistance, lead to non-alcoholic fatty liver disease, and alter platelet function. It was highlighted that a sugar-rich diet has been shown to cause a 3-fold increased risk of death due to cardiovascular disease. This paper explains that sugars are also a diverse class of compounds, indicating that monosaccharides, fructose, and fructose-containing sweeteners (e.g. sucrose) produce greater degrees of metabolic abnormalities and may present greater risk of CHD than glucose. DiNicolantonio et al. (2016) believed dietary guidelines should shift focus away from cutting down on saturated fats and consuming carbohydrates as replacements, and should guide the population to decrease their consumption of concentrated sugars (particularly the fructose-containing sugars like sucrose found in ultra-processed foods and beverages) in order to reduce the burden of chronic heart disease. [NPID: sugar, processed food, saturated fat, coronary heart disease, heart disease, LDL, HDL]

While it is known that diet can alter the gut microbiota composition by providing the microorganisms with certain nutrients, Townsend et al. (2019) provides an example of how diet can regulate the level of bacterial protein and thereby also controlling gut colonization by a beneficial gut commensal bacterium. This paper explains that fructose, a common dietary additive particularly in the Western World, reduces the number of regulators of gut colonization by the human gut commensal Bacteroides thetaiotaomicron. In mice fed a fructose-rich diet, fructose was shown to confer advantage by lowering the levels of and silencing the colonisation factor. [NPID: sugar, processed food, gut microbiota, gut-brain axis, bacterial protein, gut colonization, gut bacteria, Bacteroides thetaiotaomicron]

Since reducing intake of added sugars was one of the Healthy People 2020 objectives, Park et al. (2016) investigated the socio-demographic and behavioral characteristics associated with added sugar consumption among US adults (18 years and over). Using the 2010 National Health Interview Survey (n = 24,967) dietary screener frequency responses, the participants’ daily intake of added sugars were converted to estimated numbers of teaspoons. Among men, the median added sugars intake was estimated at 17.6 tsp/day while it was 11.7 tsp/day among the women. Considering both genders, those at significantly higher risk of being in the highest tertile of added sugars consumption (defined as ≥22.0 tsp/d for men; ≥14.6 tsp/d for women) were younger, less educated, earned less income, less physically active, current smokers, and former/current infrequent/light drinkers. Whereas, non-Hispanic other/multiracial individuals and those living in the West had significantly lower odds for being in the highest tertile of added sugars intake. Various other patterns were observed by sex: non-Hispanic black men were less likely to be in the highest tertile of added sugars intake, whereas non-Hispanic black women were at greater risk. In summary, one in three men consumed ≥22.0 tsp added sugars and one in three women had daily diets consisting of ≥14.6 tsp added sugars. The researchers hope the data can help inform efforts to design programs and policies specific to high-intake populations. [NPID: sugar, processed food, education, income, smoking, cigarettes]

Since there is evidence of sweet food, beverages, and added sugar consumption being related with depressive symptoms, this 2017 study set out to investigate the cross-sectional and prospective associations between sweet food/beverage intake, common mental disorder (CMD) and depression, as well as examine the influence of mood on intake as potential explanation for the observed link. The study analyzed 23,245 person-observations from the Whitehall II study, in which food frequency and validated questionnaires were used to obtain information on diet and mood. Cross-sectional analysis showed a positive association, while the prospective analysis revealed that men in the highest tertile of sugar intake from sweet food/beverages had a 23% increased odds of incident CMD after 5 years, independent of various factors including socio-demographics and diet-related factors. The risk of recurrent depression was elevated in the highest quartile for both sexes but was not found to be statistically significant when diet-related factors were included in the model. Although there was no indication that CMD and depression predicted intake changes, Knüppel et al. (2017) reaffirmed the adverse impact of sugar intake from sweet food/beverage on long-term psychological health, and also the results suggested that lower sugar consumption may be connected to improved mental health. [NPID: sugar, processed food, depression, mental health]

The purpose of this 2020 study was to investigate the impact of consuming locally produced foods without additives on known risk factors for non-communicable diseases (NCDs) such as hypertension, and levels of fasting glucose and visceral adipose tissue (VAT). Healthy volunteers (n = 159) were randomly selected to purchase foods from either local producers not using additives (Group 1: n = 89), or from supermarkets (Group 2: n = 70), with the focus on various types of cheese, sausages, fresh pasta, pastries, biscuits and chocolate without additives to make them palatable and convenient for traveling. Both groups underwent evaluation for weight, blood pressure, VAT, serum sodium, potassium, fasting glucose, insulin, C-peptide and creatinine levels, and were also examined using the State-Trait Anxiety Inventory (STAI) and Beck Depression Inventory (BDI-II) at baseline and at the follow-up 6 months later. At baseline, the state part of the State‐Trait Anxiety Inventory (STAI) and Wechsler Adult Intelligence Scale IV (measure of intelligence and cognitive function) were also performed, and body mass index, HOMA index and estimated glomerular filtration rate calculated. While baseline evaluations did not differ between the groups, HOMA scores, VAT, systolic blood pressure, BDI-II score, and fasting glucose levels were lower in group 1 than in group 2 after 6 months. On the other hand, fasting glucose concentrations, diastolic blood pressure, and C-peptide levels were greater in group 2. Migliaretti et al. (2020) found that eating locally produced foods resulted in the improvements of some of the major risk factors for NCDs after 6 months. [NPID: sugar, processed food, non-communicable diseases, hypertension, fasting glucose, intelligence, cognitive function]

Ye et al. (2011) analyzed the participants of the Boston Puerto Rican Health Study to determine whether consumptions of total sugars, added sugars, sugar-sweetened beverages or sweetened solid foods are associated with cognitive function. A total of 737 adults (aged 45-75) without diabetes completed food frequency questionnaires and were examined on cognitive function using several tests (Mini-Mental State Examination (MMSE), word list learning, digit span, clock drawing, figure copying, and Stroop and verbal fluency tests. After adjusting for covariates, Lower cognitive performance (indicated by lower MMSE score) was associated with higher consumptions of total sugars, added sugars and sugar-sweetened beverages, but not of sugar-sweetened solid foods. When comparing the highest to lowest intake quintiles for total sugars and added sugars, the adjusted odds ratios for cognitive impairment ((MMSE score < 24) were 2.23 and 2.28, respectively. Moreover, higher total sugar intake was significantly linked to lower word list learning scores, implicating greater sugar consumption’s link with lower cognitive function, although longitudinal studies may be required to confirm the direction of the causality. [NPID: sugar, processed food, cognition, diabetes]

This 2019 systematic review/meta-analysis evaluated the relationship between acute carbohydrate consumption and mood, since the effect has been “much debated” and is regarded important to validate given the recent rise in global intake of sugar-sweetened products. Mantantzis et. al (2019) examined the time-course of carbohydrate (CHO)-mood interactions while also considering the role of moderator variables which could potentially affect the CHO-mood relationship. From 31 studies including 1259 participants in total, 176 effect sizes were analysed to reveal no evidence of CHO inducing a positive effect on any aspect of mood at any time-point following ingestion. Instead, the review discovered that CHO consumption was associated with higher fatigue levels and less alertness when compared to placebo (within the first hour following intake). These findings challenge the idea that CHO can improve mood (which some researchers have previously reported), and can potentially aid health policies in informing them to decrease sugar consumption and promote healthier alternatives. [NPID: sugar, processed food, carbs, mood, fatigue, alertness]