Background
In recent decades, colorectal cancer has traditionally been considered a prevalent disease among older adults. However, recent epidemiological studies have revealed a worrying increase in the incidence of this disease among young adults. While several genetic and environmental factors contribute to the risk of developing colorectal cancer, diet appears to play a crucial role. In particular, consumption of red meat and sugar has been indicated as a potential risk factor for this disease. This article explores in depth the scientific evidence linking consumption of red meat and sugar to the increase in the incidence of colorectal cancer in young adults, analyzing the biological mechanisms involved, the epidemiological data and the implications for public health.
Colorectal Cancer: A Growing Challenge among Young Adults
Colorectal cancer is the third most common cancer globally and represents a leading cause of cancer death. Traditionally, advanced age has been considered the main risk factor for the development of this disease. However, recent studies have shown an increase in colorectal cancer incidence among individuals younger than 50 years of age, a group that is not included in the usual screening recommendations (Siegel et al., 2020). This epidemiological shift has sparked growing interest in the scientific community, with a particular focus on modifiable risk factors, such as diet. In particular, consumption of red meat and sugar has been associated with an increased risk of colorectal cancer, especially among young adults. And tha number is increasing despite the efforts for prevention. Beside, how to forget Chadwick Boseman, the Black Panther that died a couple of years ago for this issue?
Red Meat and Colorectal Cancer
The consumption of red meat, including processed meat, has long been associated with an increased risk of colorectal cancer. Red meat includes beef, pork, and lamb, while processed meat includes products such as cured meats, sausages, and bacon. Numerous studies have examined the link between red meat consumption and colorectal cancer, identifying several potential mechanisms responsible for this increased risk. One of the main mechanisms through which red meat consumption may increase the risk of colorectal cancer is the formation of carcinogenic compounds during high-temperature cooking, such as polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs). These compounds are formed when meat is grilled, fried, or roasted, and have been shown to be mutagenic, meaning they can damage the DNA of cells and promote carcinogenesis (Cross et al., 2010).
Another mechanism is the high heme iron content in red meat. Heme iron can promote the formation of endogenous nitrosamines, potentially carcinogenic compounds that can damage the lining of the gut and promote the growth of cancer cells (Bastide et al., 2011). Additionally, processed meat often contains nitrates and nitrites as preservatives, which can react with secondary amines in food or the body to form nitrosamines. Red meat consumption has also been associated with increased systemic inflammation and changes in the composition of the gut microbiota, which may contribute to colorectal carcinogenesis. Recent studies have suggested that a diet high in red meat may alter the gut microbiota, promoting the growth of pro-inflammatory bacteria and the production of toxic metabolites that can damage the intestinal epithelium (O’Keefe, 2016).
Sugar and Colorectal Cancer
In parallel with red meat consumption, increased consumption of refined sugars and sugar-sweetened beverages has been associated with an increased risk of colorectal cancer. Refined sugars include table sugar (sucrose), high fructose corn syrup, and other sweeteners used in many processed foods. Excess sugar in the diet can contribute to the development of cancer through several mechanisms. Excess sugar is strongly associated with obesity, a condition that is a known risk factor for colorectal cancer. Obesity can lead to insulin resistance and hyperinsulinemia, conditions that promote cell growth and inhibit apoptosis (programmed cell death), thus favoring the development of tumors (Giovannucci et al., 2010).
Excessive sugar consumption can also increase inflammation and oxidative stress in the body, both of which can contribute to carcinogenesis. Studies have shown that a diet high in refined sugars can increase levels of inflammatory cytokines and free radicals, which can damage DNA and promote uncontrolled cell proliferation (Lustig, 2013). Similar to red meat, consumption of refined sugars can alter the composition of the gut microbiota, promoting the growth of pathogenic bacteria and reducing microbial diversity. These changes in the microbiota may contribute to gut dysbiosis, a condition associated with an increased risk of colorectal cancer (Zhang et al., 2015).
Epidemiological evidence: observational and clinical data
Several epidemiological studies have explored the association between red meat consumption, sugar consumption, and colorectal cancer risk, with a particular focus on young adults. Below are some of the major studies that have contributed to our understanding of this link.
- European Prospective Investigation into Cancer and Nutrition (EPIC) Study
The EPIC study, which followed over 500,000 participants in 10 European countries, examined the association between red meat consumption and colorectal cancer risk. The results indicated that a high consumption of red meat and processed meat was associated with a significantly increased risk of colorectal cancer (Norat et al., 2005). This study also found that the risk was particularly high among individuals who regularly consumed processed meat.
- NIH-AARP Diet and Health Study
Another major study, the NIH-AARP Diet and Health Study, examined the association between sugar and sugar-sweetened beverage consumption and colorectal cancer risk in a cohort of over 400,000 U.S. adults. The results showed that higher sugar consumption was associated with an increased risk of colorectal cancer, particularly among women (Makarem et al., 2018).
- Meta-Analysis of Meat Consumption and Colorectal Cancer
A meta-analysis that included data from several prospective studies confirmed that high consumption of red meat and processed meat is associated with an increased risk of colorectal cancer. The meta-analysis estimated that each daily serving of processed meat (about 50 grams) increases the risk of colorectal cancer by 18% (Chan et al., 2011).
Differences Between Young Adults and Older Adults: Specific Risk Factors
While colorectal cancer has historically been associated with older age, the increase in incidence among young adults suggests that there may be risk factors specific to this population. Below are some of the key differences between young adults and older adults in relation to risk factors for colorectal cancer.
- Modern Diet and Lifestyles
Young adults tend to adopt diets higher in processed foods, red meat and refined sugars than previous generations. This change in dietary habits may contribute to the increased risk of colorectal cancer in this population (Ng & Wong, 2013).
- Youth Obesity
Childhood and youth obesity is increasing globally and is a major risk factor for colorectal cancer. Individuals who develop obesity at a young age are more likely to maintain a high weight into adulthood, thereby increasing their risk of developing chronic diseases, including colorectal cancer (Renehan et al., 2015).
- Exposure to Carcinogens
Early exposure to carcinogens, such as those found in processed meat and refined sugars, may have a greater impact on young adults than older adults. Studies have shown that exposure to carcinogens during childhood and adolescence may increase the risk of cancer in adulthood (Perera, 2017).
Implications for public health and prevention
Given the evidence linking red meat and sugar consumption to increased risk of colorectal cancer in young adults, it is critical to implement effective prevention strategies. Below are some recommendations and strategies for colorectal cancer prevention in this population.
- Nutrition Education
Promoting a balanced diet, rich in fruits, vegetables, whole grains and low in red meat and refined sugars, could significantly reduce the risk of colorectal cancer. Educational campaigns should be targeted to young adults and focus on the importance of healthy food choices (WCRF/AICR, 2018).
- Promotion of Active Lifestyles
Regular physical activity is a protective factor against colorectal cancer. Promoting active lifestyles among young adults can reduce the risk of obesity and improve metabolic health, contributing to the prevention of colorectal cancer (Wolin et al., 2009). This should stars from low schools, with implementations from teachers/parental guide.
- Early Screening
Although current guidelines recommend colorectal cancer screening starting at age 50, the increasing incidence in young adults suggests that the age at which screening begins may need to be lowered, especially for individuals with additional risk factors, such as a family history of colorectal cancer or the presence of predisposing genetic syndromes (Smith et al., 2017).
- Processed Food Regulation
Public policies aimed at reducing consumption of processed foods, processed meat, and sugary drinks could have a significant impact on reducing the risk of colorectal cancer. This could include measures such as taxing sugary drinks, clear nutrition labeling, and limiting the advertising of unhealthy foods (WHO, 2016).
Conclusions and perpectives
The increasing incidence of colorectal cancer among young adults is an emerging concern that requires attention and timely interventions. Evidence suggests that red meat and sugar consumption may contribute to this increase, through mechanisms including the formation of carcinogenic compounds, inflammation, and alteration of the gut microbiota. To address this challenge, it is essential to promote healthy lifestyles, improve nutrition education, and consider early screening strategies. Future research will be crucial to deepen the understanding of risk factors and develop effective interventions to prevent colorectal cancer in young adults. Furthermore, tailoring prevention strategies based on individual risk, including genetic and environmental factors, could improve the effectiveness of interventions to prevent colorectal cancer in young adults. Future research should explore the effectiveness of personalized interventions in reducing colorectal cancer risk (Nguyen et al., 2021).
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
Scientific references
Han MA, Zeraatkar D et al. Annals Int Med 2019; 171(10):711.
Makarem N, Bandera EV et al. Ann Rev Nutr 2018; 38:17-39.
Perera FP. Environmental Health Perspect. 2017; 125(2):141-48.
O’Keefe SJD. Rev Gastroenterol Hepatol. 2016; 13(12):691-706.
Bastide NM et al. Cancer Prevention Res 2011; 4(2):177-184.
Chan DS, Lau R, Aune D et al. PloS One 2011; 6(6):e20456.
Cross AJ, Pollock J et al. Cancer Res. 2010; 63(10):2358-2360.
Norat T, Lukanova A et al. Int J Cancer 2005; 113(5):834-846.