In a recent study published in Cancer Screening and Preventionresearchers reviewed existing knowledge on the beneficial and adverse effects of dietary patterns and nutritional supplements on cancer risk.
Study: Diet and Supplements in Cancer Prevention. Image Credit: Josep Suria/Shutterstock.com
Background
A major modifiable risk factor for cancer, other than lifestyle choices, is diet. An increasing number of studies are reporting not only the preventive role but also the causative role of diet in cancer.
Unhealthy diets containing high-calorie foods, sugar-sweetened beverages, processed and red meat, and foods rich in saturated and trans fats are known to increase the risk of obesity, metabolic disorders, and various types of cancer.
The cancer-related mortality rate associated with obesity is 14% among men and 20% among women. Consumption of alcohol and processed meat is also associated with liver, pancreatic and esophageal cancer, as well as colorectal cancer.
In contrast, healthy dietary patterns involving whole foods, fruits, vegetables and grains reduced cancer risk.
In addition, dietary phytochemicals have also been useful in chemoprevention, as they have shown carcinogenesis-suppressing properties and the ability to alter metastatic molecular pathways.
In this review, the researchers discussed the beneficial and harmful roles of dietary and nutritional supplements in cancer.
Diet and cancer
A large body of evidence supports a causal link between diet and cancer. However, the complex mechanisms of cancer have created challenges in finding direct correlations between cancer risk and dietary factors.
In addition, although epidemiological studies have shown that the consumption of specific foods is strongly associated with an increased risk of certain types of cancer, factors such as the timing, quantity and duration of exposure influence the cellular responses, making it difficult to essay factors identify individual food. have been linked to cancer risk.
Recently cancer prevention guidelines have adopted a more holistic approach focusing on dietary patterns rather than individual foods. Healthy eating patterns are associated with lower risks of colon and breast cancer.
Although the evidence linking red and processed meats to gastrointestinal cancer is not substantial, processed meats such as cured, salted, smoked or fermented meats, as well as red meats such as beef, are believed to increase the risk of cancer.
Although research on the association between various foods and cancer risk is limited, many studies have reported an increased risk of liver and esophageal cancer due to alcohol consumption.
However, based on current research, the World Cancer Research Fund recommends a diet rich in vegetables, fruits, and whole, unprocessed foods to reduce the risk of cancer and all-cause mortality.
In addition, manipulations of dietary patterns are also being examined as potential cancer treatment methods. Ketogenic diets consisting of high-fat and low-carbohydrate foods are being explored for the ability to target cancer cell metabolism and improve prognosis.
Cancer and dietary supplements
The review also examined the role of various nutritional components and supplements in cancer. Dietary fats consist of mono- and polyunsaturated and saturated fatty acids.
Polyunsaturated fatty acids such as omega-3 have been attributed with anti-cancer properties. Omega-3 fatty acids can be found mainly in marine fish and in small quantities in plants such as flaxseed.
Docosahexaenoic and eicosapentaenoic acid are two omega-3 fatty acids with known anti-inflammatory properties, and studies have reported that these two fatty acids can reduce the risk of colorectal cancer by 24%.
Additionally, although clinical trials have shown a link between eicosapentaenoic acid supplementation and reductions in adenomatous polyps, more research is needed to understand the effects of supplementation and fatty acid dosage.
The role of micronutrients such as selenium, folate, vitamins D, C, A, and E, calcium, and magnesium in cancer has also been examined. Studies have found that folate has a dose-dependent relationship with cancer, with certain folate levels having beneficial effects but high doses being carcinogenic.
Similarly, vitamins C, A, D, and E, and selenium have shown antioxidant properties that may be beneficial against cancers, but taking these supplements in high levels may be harmful. excessive.
Results from studies examining the link between mineral supplements and cancer risk also suggested that a balanced intake of micronutrient supplements may be beneficial. Still, over-supplementation of micronutrients can be harmful.
The review also discussed the role of polyphenols in cancer prevention. Polyphenols such as curcumin and resveratrol have been linked to antioxidant and anti-inflammatory effects, and curcumin has been explored for its role in cell cycle arrest and apoptosis for potential cancer treatment.
Conclusions
Overall, the results showed that dietary and nutritional supplements are major modifiable risk factors for cancer.
A healthy diet rich in whole foods and without processed meat, fried foods, and sugar-sweetened beverages has been recommended to reduce the risk of various types of cancers, as well as low alcohol intake.
The role of dietary supplements in reducing cancer was largely beneficial but dose dependent. Excessive levels of supplements, especially of micronutrients, have been found to be harmful, and the researchers believe that more research is needed on the effects of dietary supplements on health.