Nutrition, Genetics and Cancer

Nutrition, Genetics and Cancer

According to studies, the frequency of cancers related to diet, that is, our diet is increasing daily. The type, and amount of nutrients in our diet and when we take them is important in this context. It has been scientifically proven that certain diets (e.g., Mediterranean cuisine) reduce the risk of cancer, but it is difficult to work in this area because many factors are involved. Lifestyle is seen as the biggest factor in the formation of cancer risk. Based on this, it is claimed that more than half of cancers under the age of 65 can be prevented.

Consuming which food, in what quantity, and for how long causes cancer?

There is no single or simple answer to this question today. While some risk factors for diabetes and cardiovascular diseases have been clearly identified, risk factors for many cancer types are unclear. For example, there is a strong relationship between high blood glucose for diabetes and increased blood lipid level for cardiovascular diseases and the disease. For cancers, new risk factors are defined daily, or the status of suspected risk factors is becoming clearer. For example, it has been clearly demonstrated that consuming processed meat increases the risk of colon cancer. Processed meat consumption is a risk factor for colon cancer; in other words, it is a marker that indicates the possibility of developing colon cancer in the future for those who consume heavily processed meat. With a better understanding of the biological basis of cancer and the rapid development of genomic applications, new markers are emerging.

Overview of cancer biology from a nutritional perspective – Why does a tumor occur?

The root cause of all cancers is abnormal gene expression after genetic damage. Mutations, chromosome damage, telomere (end parts of DNA) shortening, peculiar epigenetic factors (gene expression change without changing DNA structure), etc. These conditions, which damage DNA, cause some changes in the cell. The cell attempts to minimize this damage: it repairs the damage, captures free oxygen radicals, and renders mutagens (substances that cause DNA damage) harmless. If the damage is beyond repair, the cell will normally die (apoptosis). Tumors are more resistant to lack of oxygen than normal body cells, form new vessels for themselves, and can migrate (metastasize) from where they started. DNA repair mechanisms deteriorate as we age, and the damage accumulates over time. Loss of function of tumor suppressor genes and oncogenes gain part play an important role in tumor development. Environmental factors (such as diet, and lifestyle) and a person's genetic makeup contribute to the difference in cancer risk among individuals.

Genome–Diet Relationship

Transferring the damaged copy in the DNA chain to the next generation is the basis of hereditary cancers. For example, mutations in the BRCA1 and two genes constitute hereditary breast cancer, but this accounts for 10-12% of cancer cases. Polymorphisms are also important in terms of cancer. Polymorphisms are different variants of a gene. It can be in one gene or more than one gene simultaneously. Single gene polymorphisms are important for cancer. Because gene polymorphisms can cause cancer if they occur under certain conditions. For example, in individuals with C677T polymorphism in the MTHFR gene, bowel cancer occurs in cases of decreased folate intake and low alcohol consumption. If individuals carrying a polymorphism in the gene encoding the acetylase enzyme consume intensely cooked red meat at high temperatures, the gene's activity increases, triggering bowel cancer. It has been shown that the gene alone does not have a say and that environmental factors and diet affect the functioning of genes. It is thought that improvement can be achieved by changing the foods and nutritional values in the diet. 
Diets rich in plant content, especially fruit and vegetables, reduce cancer risk. The anti-cancer properties of phytochemicals in herbal products are being studied seriously (such as reducing the risk of head and neck cancer in broccoli). Recognizing a person's genetic characteristics, calculating their relationship with environmental factors, and determining cancer risk are important future goals. The gene-diet relationship gains importance in terms of cancer prevention. In this context, a new branch of science was born: Nutrigenomics!