Diet, adolescent disease and obesity

The aim of this 2014 review was to explain the mechanism in which the Western diet (characterized by the overeating of a narrow range of refined sugars, salt, and saturated fat) affects the body’s immune function. In addition to detailing the harmful consequences of consuming too much sugar, salt, and fat, this paper looks at the impacts of artificial sweeteners, gluten, and genetically modified foods. Moreover, Myles lets us know when the evidence presented is limited to animal or in vitro (done in the laboratory within the confines of a test tube or lab dish) models. Some of the literature has not performed tests on humans yet. In this review, particular attention is paid to the influence of gut microbiota on dietary factors and discusses the way in which our poor dietary choices are connected to our gut, our genes, and are passed to our offspring. Finally, today’s modern diet can potentially protect us from deficiencies in macronutrients and micronutrients, but the excessive calories and macronutrients may all lead to increased inflammation, reduced infection control, higher prevalence of cancers, and heightened risk of allergic and auto-inflammatory disease.

Perry et al. (2021) examined children on their fasting insulin levels and BMIs throughout their childhood and followed up when the participants turned 24 years old to assess their psychosis and depression risk. The goal was to find associations between the course of fasting insulin levels throughout the childhood years with the risk of psychosis and depression as an adult. The data indicated that if the child’s insulin level trajectory was persistently high throughout their childhood, they were more likely to be at risk of psychosis and psychotic disorder (but not depression) when they turned 24 years old. Higher odds of developing depression were linked with a great increase in BMI following puberty. These results suggest that disrupted insulin sensitivity could be a shared risk factor for comorbid cardiometabolic disorders and psychosis, and that a marked rise in BMI from the onset of puberty could be a risk factor or risk indicator for adult depression.

Although scientists have confirmed links between diet and diseases such as cardiovascular disease, type 2 diabetes, and cancer, Guilleminault et al. (2017) comment that it is not commonly mentioned in relation to the causes of asthma. This review focuses on the impact of diet on asthma risk and asthma control. Environmental factors are said to play a crucial role in the pathophysiology of asthma via interaction with genetics. This chronic respiratory disorder can be set off by inhaling allergens, encountering smoke, and being exposed to air pollution. The pro-inflammatory effects of some dietary patterns are also discussed since asthma is associated with airway inflammation. For example, the Western diet consists of high quantities of refined grains, processed and red meats, and desserts, and are believed to promote inflammation. On the other hand, the Mediterranean diet includes many fruits and vegetables, and has anti-inflammatory properties. The author emphasizes the fact that the dietary habits of asthma patients are rarely inspected by healthcare professionals. Furthermore, this article inform us of the effects of diet on obese patients with asthma.

Hashim et al. (2019) explain that in the United Arab Emirates (UAE), little is known about premenstrual syndrome (PMS), which is a disorder of the menstrual cycle that presents with various emotional and physical symptoms that interfere with the daily lives of women sufferers. The purpose of this study was to investigate the link between prevalence of premenstrual syndrome with dietary habits, lifestyle behaviors, and anthropometric factors (height, weight) among a sample of 300 female college students at the University of Sharjah, UAE. While 95% of respondents experienced at least one PMS symptom during their menstrual period, the prevalence of PMS was 35.3% (most people had mild symptoms). The results showed that smoking correlated with increased chance of experiencing psychological and behavioral symptoms. While physical symptoms were related to the intake of high calorie/fat/sugar/salt foods. Lastly, fruit consumption was associated with reduced incidence of behavioral manifestations of PMS. In conclusion, smoking and high calorie/fat/sugar/salt food consumption seem to be strong risk factors for premenstrual syndrome among this sample of university students in the U.A.E.

Nittari et al. (2019) expose the alarming rate at which obesity has grown over the past 40 years, particularly in Europe. In 1975, the rates of obesity and overweight were less than 5% and 10%, respectively, in most European countries. However, this trend was evidently reversed, with recent prevalence rates reported to be over 30% for overweight and over 10% for obesity. This paper evaluates the effectiveness of the prevention programs that were implemented by the WHO European Region thereafter. The WHO European Childhood Obesity Surveillance Initiative stated that the children were overeating and not doing enough physical exercise. The different prevention programs employed featured: consumption of healthy foods, physical exercise, care before conception and during pregnancy, early childhood, school age children, weight management, monitoring and evaluation. The conclusion was that it is easier to act on the adoption of healthy eating habits than intervene with diets on children who already have weight issues. This paper therefore advocates for the prioritization of primary prevention programs at a national and international level since they can potentially tackle the spread of diseases associated with obesity.

Zhang et al. (2019) examined the available literature to determine a possible link between the age at which menstruation first occurs (menarche) and insulin resistance. A systematic search was conducted to identify observational studies that compared the incidences of insulin resistance in patients with early, average, and late menarcheal ages. Data was obtained for a total of 5504 subjects (from 8 articles). The subjects who had their first menstruation early were compared with those who first experienced it late and with the average females. The fasting blood insulin levels in eight studies were discovered to be significantly higher in females who first had their periods at earlier ages (compared to average and late). Publication bias was not detected. This review concludes that early occurrence of the first menstrual period was strongly related to insulin resistance.

This 2016 study examined the relationship between the consumption of drinks containing excess free fructose (EFF beverages) and the incidence of asthma in children. Simultaneously, DeChristopher et al. tested whether the intake of high EFF beverages (such as apple juice or beverages sweetened with high-fructose corn syrup) is linked with an elevated risk of asthma via the mechanisms proposed in the past. The data was taken from the National Health and Nutrition Examination Survey 2003-2006, a nationally representative survey. Among the 1961 children (aged 2-9 years), the intake of EFF beverages (apple juice, non-diet soft drinks, fruit drinks) was associated with asthma. Analysis models revealed that kids who drank beverages containing excess free fructose at least 5 times per week were more than 5 times as likely to have asthma as children consuming these beverages ≤1 time per month. Furthermore, those who consumed apple juice on at least 5 occasions throughout the week were at double the risk of asthma, when compared with those who only drank ≤1 time/month. On the other hand, orange juice seemed to play a protective role in asthma. Overall, these results supported the theory that the intake of high EFF beverages (such as apple juice and drinks sweetened with high-fructose corn syrup) is related to asthma in children. It also appears that the hypothesis based on the possible effect of increases in the in situ intestinal formation of advanced glycation end products (enFruAGE) with EFF may be an overlooked contributor to asthma in children.

This 2018 article applied data obtained from the Framingham Offspring Cohort to analyze the association between intakes of high-fructose corn syrup (HFCS), HFCS-sweetened soda, fruit drinks and apple juice with the risk of asthma. Apple juice contains high levels of fructose, which is thought to contribute to the mediation of asthma. To allow comparisons to be made, the effects of diet soda and orange juice were included in the analysis (orange juice is a 100 % juice with a 1:1 fructose: glucose ratio). The results demonstrated that drinking more of any combination of HFCS-sweetened soda, fruit drinks and apple juice was strongly linked with progressively higher asthma risk. The highest odds of having asthma were seen for those who drank these beverages 5-7 times a week, compared with people who either consumed it seldomly or never. Notably, drinking HFCS-sweetened soda once a day related to a 49 % higher risk of asthma relative to never/seldom consumers, while moderate apple juice consumers (2-4 times/week) and moderate fruit drink consumers were more likely to have asthma by 61% and 58%, respectively. No correlation was found with diet soda and orange juice. Since the negative influence of drinks with high fructose:glucose ratios were evident, DeChristopher et al. believe that recommendations to reduce consumption may not be enough to address this issue of asthma risk.

In this 2019 study, 139 overweight children (9-11 years old) were recruited from their schools and checked for food addiction. The aim was to investigate the relationship between the consumption of ultra-processed foods and food addiction among children in the overweight BMI category. Food frequency questionnaires were firstly administered to discover the extent to which the children’s meals were processed. Almost all the kids (95%) exhibited at least one sign of food addiction, while 24% were diagnosed with this behavioral addiction. These school children that were diagnosed tended to consume high amounts of added sugar (refined sugar, honey, corn syrup) as well as ultra-processed foods. Eating cookies or biscuits was independently related to food addiction (odds ratio of 4.19), while the intake of sausages was associated with an even higher risk (odds ratio of 11.77). Filgueiras et al. emphasizes the importance of identifying the foods that may provoke addictive behavior, for the prevention and treatment of childhood obesity (a massive worldwide problem).

This 2018 article presents the findings of a systematic review conducted on the relationship between fast food (including deep-fried food) and asthma, asthma symptoms, eczema, and allergies. The systematic review backs up James & Abramson’s hypothesis that environmental factors are responsible for the increase in asthmatic patients rather than genetic factors. There have been many theories on the causal nature of this rapid rise in asthma cases, including the consumption of the Western diet (and especially fast food), the growing number of obese people (possibly linked with overconsumption of energy and insufficient physical activity), air pollution, and early-life immunity-compromising events. The previously mentioned systematic review investigated the impact of fast-food consumption on asthma and allergy. The reviewers also proposed a few possible mechanisms by which eating fast foods can increase the risk of developing asthma. Due to its pro-inflammatory effects, the intake of fast foods should be limited.

In this 2018 study, Melo et al. inspected the diet of Brazilian adolescents and assessed the relationship between the consumption of ultra-processed foods with presence of asthma and wheezing. The researchers focused on the number of ultra-processed products eaten in the past 7 days including sweet biscuits, salty biscuits, ultra-processed meats, sweets/candies, soft drinks, and packaged snacks. The results indicated that intake of sweets/candies and ultra-processed meats were associated with the number of asthmatics and appeared to correlate with presence of wheezing in the past 12 months. In addition, the ultra-processed consumption score (a combination of several scores corresponding to the weekly frequency intake of each ultra-processed product) was positively linked with the prevalence of asthma and wheezing in a dose-response manner. Moreover, it was found that participants with the highest ultra-processed consumption scores (top quintile) were more likely to have asthma and reported wheezing than those with the lowest consumption scores (by 27% and 42%, respectively). To conclude, increased intake of ultra-processed foods corresponded to more cases of asthma and wheezing in Brazilian adolescents.

The aim of this 2020 study was to explore whether the frequency of fast-food consumption is linked with the presence of wheeze and asthma among adolescents in South Africa. Nkosi et al. used the validated questionnaire published by the International Study of Asthma and Allergies in Childhood to collect relevant data on demographics, socioeconomic status, house characteristics, adolescent respiratory health, and diet. The prevalence rate of wheeze in the sample was 38.2%, while 16.37% of the population had asthma. According to the results generated from the analysis models, the consumption of fast foods on 3 or more occasions per week was significantly associated with incidences of wheeze and asthma in these adolescents in South Africa. It was concluded that unhealthy diets can strongly influence respiratory health in adolescents. Healthy eating habits should be promoted to reduce the risk of developing respiratory symptoms and diseases.

This 2015 trial investigated the effects of brief childhood/adolescent obesity and insulin resistance on cognitive function in later life, using a rodent-based model. Nine-week-old C57BL/6J mice were firstly fed a fat-rich diet for 15 weeks to cause the animals to develop obesity and insulin resistance. Later, the mice received normal low-fat diets, after which its body weight decreased back to normal and ability to control glucose levels returned. However, these rodents were found to exhibit severe deficits in learning and long-term memory consolidation at 84 weeks old. It was revealed that expression of histone deacetylases 5 increased and expression of brain-derived neurotrophic factor decreased in the mice’s brains 61 weeks after stopping the high-fat diet. Compared with control mice, those exposed to the high-fat diet earlier were more susceptible to synaptic impairments in the hippocampal region of the brain. In summary, the induction of obesity and insulin resistance during childhood/adolescence irreversibly changed the rats’ brains, leading to brain synaptic dysfunction during aging. This study provides evidence that even short-term early-life exposure to obesity and insulin resistance may result in destructive long-term effects on the brain and contribute to the onset or progression of cognitive impairment during aging.