Nutrigenetics: food versus cancer?

In 2009, the Nobel Prize in medicine was awarded for the discovery of how telomeres and the telomerase enzyme protect chromosomes from damage. In 2015, the popular science book “Telomerase” by M. Fossel was published, which became extremely popular. The Wall Street Journal included this book in the list of “Best Books for Science Lovers” in 2015. The increased interest in telomeres and telomerase is associated with their unique functions.

Who is responsible for the “immortality of cancer cells”?

Telomeres are a sequence of nucleotides at the end of chromosomes that does not encode but protects the coding sequence (genes) from loss. This is a kind of protective cap. As the cells divide, this defense “erases”, telomere nucleotides are gradually lost.

With the discovery of such an interesting function of telomeres, the telomere theory of aging appeared: over time, the telomere shortens and the cell becomes incapable of division. As soon as the cell loses its ability to divide, its life cycle stops, its functional activity gradually decreases, the cell dies. On the scale of the body, this means a decrease in the function of all organs.

Telomerase is a ribonucleic reverse transcriptase, an enzyme that mends telomeres with each division by adding lost nucleotides to it. This enzyme was first discovered in 1989 in cervical carcinoma cells. It is in tumor cells that telomerase has the highest activity (approximately 80-90% higher) in comparison with “ordinary” somatic cells. Such activity helps maintain a high rate of division and immortality of cancer cells.

Telomeres and telomerases are of interest to scientists from the position that they are a drug target in the treatment of cancer. In addition, today the influence of lifestyle (physical activity, food) on telomeres and telomerase activity is being actively studied.

What does telomerase eat with?

<In order to assess the effect of nutrition on telomeres, determine its length. Telomere length is the ratio of telomeres to one copy of a gene (in the English language T / S ratio).

Potential agents that can inhibit the activity of telomerase of cancer cells are plant substances :

– Curcumin is a polyphenol that is found in turmeric root and is used in cooking. Curcumin induces the release of reactive oxygen species, which through a chain of reactions reduces the activity of telomerase, reducing the expression of its genes, and leads to apoptosis (death) of cancer cells. It was found in experiments in vitro cancer cell line cervical human . The cell culture was “treated” with various concentrations of curcumin, and a decrease in telomerase activity was found.

– Quercetin , another polyphenol found in many fruits and vegetables, has also shown its ability to reduce telomerase activity and induce apoptosis, and has shown its anti-cancer activity in in vitro studies. Epidemiological meta-analyzes revealed that a significant intake of quercetin reduces the risk of developing any cancer by about 27% . The number of participants in these studies is quite impressive: 18 studies, 18560 participants.

Another interesting study was conducted in the USA. His goal was to determine the effect of dietary fiber intake on telomere length. For this, we used DNA samples from 5674 adult volunteers who underwent a survey, which allowed each participant to calculate the amount of fiber consumed per 1000 calories per day. The following results were obtained:

– the more a person consumes fiber, the longer the telomeres;

– A daily additional 1 gram of fiber per day adds about 6.7 nucleotide pairs per year.

* The recommended fiber intake for an adult is 14 grams per day, 1 apple = 4 grams of fiber. This study found that most Americans consumed less fiber per day.

Some studies have found that polyunsaturated fatty acids, vitamins A, C, and E have a positive effect on telomere length. But at the same time, large meta-analyzes do not confirm such conclusions.

In the past few years, the consumption of a large number of fresh vegetables and fruits is gaining popularity. As you can see, scientific studies confirm the positive role of biologically active substances found in fruits and vegetables. Indeed, plant-based products are an excellent source, fiber, and biologically active substances. Reception is relatively safe (“relatively”, because there are a number of clinical conditions when taking a large amount of fruits and vegetables is unsafe, for example, chronic pancreatitis, diabetes mellitus).

Another important point that should be emphasized: the pharmaceutical industry responds well to fashion trends, and a large number of dietary supplements appear that contain both curcumin and quercetin. These drugs are often positioned as miraculous remedies for all diseases, but it is important to emphasize that these are dietary supplements, and not medicinal substances.

But it is worth remembering about the inverse effects. Regarding vitamin supplements, it is worth emphasizing that, for example, exceeding the recommended daily intake of vitamin A can lead to lung cancer.

“Everything is a cure and all poison, both determine the dose,” the known truth. In any case, if you think that your diet needs correction, then you should consult a doctor and clarify which foods and dietary supplements and in what quantity you should consume.

Fedulova Ksenia Dmitrievna, doctor 
Anne Grachikovna Gazoyan, journalist