Kertu Liis Krigul: Can you get cancer from eating? Further research is needed!

Kertu Liis Krigul

When conversing with Kertu Liis Krigul (28), a doctoral student in gene technology at the University of Tartu, the word “faecal sample” pops up several times, with the unwavering nonchalance of an experienced laboratory worker. “It’s very easy to get bacteria from faecal matter,” says Krigul, adding that “research on the microbiome isn’t focused only on the diversity of intestinal inhabitants anymore.” As it turns out, ‘microbiome’ might also mean the symbiosis of microscopic organisms that have settled in under a tooth or inside an eye. What’s more, the cohabitation of these micro-creatures might not include only bacteria but also viruses, fungi, and protozoa. At the same time, it isn’t easy to investigate the microbiome, because while some bacteria species are visible under a simple microscope, you need much more powerful electron microscopes or other virus-specific methods to find them. Also, some of the components of the microbiome lose the will to live when they exit the human body. “There are some bacteria that can’t tolerate air at all – they die as soon as you extract them,” admits Krigul.

Although the word ‘virus’ has taken on a menacing air in the year 2020, Krigul says that we do not have a complete overview of how many viruses people carry with them. “Mostly they don’t directly affect humans, but are a natural part of the microbiome. For example, many people carry the herpes virus, which sometimes may manifest as sores.” Some bacteria have a somewhat nastier reputation. These are the “the usual suspects”, whose appearance is more and more connected to ominous changes in the gut, which can, for example, lead to colon polyps and later cancer. “There are about twenty of these species and usually it is not one “baddie”, but here we can also talk about a cohabitation situation,” says Krigul. However, she does admit that, for example, Fusobacterium nucleatum has been found in the tissue of intestinal tumours, and it has also been connected to poor results in cancer treatment. In experiments done with mice, Fusobacterium nucleatum has also been connected to a higher likelihood of mutations and a reduced activity in the immune system cells. When I ask Krigul whether the bacteria cause cancer or instead make the cancer cells grow faster, she diplomatically replies that “often the cause and effect relation is hard to determine.” She says that it might also be the concurrent effect of several factors, for example, body weight and physical activity, smoking, and many others that can impact the bacteria and thereby lead to cancer, however, we don’t yet know how. As is often the conclusion in science – further research is needed.

However, if a bacterium can hypothetically cause cancer, can you get cancer from eating, I wonder? “We can’t yet say where cancer comes from,” answers Krigul and refers to the fact that some people might carry the bacterium without any visible negative consequences. At the same time, the young doctoral student admits that the connection between intestinal cancer and nutrition has already been proven. In her own diet, Krigul values diversity above all as well as plenty of fibre. She speaks with admiration about tribes that live in the forests of Tanzania, whose microbiome is apparently especially diverse thanks to the diversity of their diet. At the same time, the microbiological diversity of people living in big cities is reduced by their “rather sterile living environment and fatty, processed foods.” “We no longer have contact with the types of sources that might diversify our living environment. We don’t pick food from the ground or from forests anymore,” says the doctoral student with a certain sadness. She adds that in order to keep the diet high in fats from ravaging our organisms, we need an “evolution” of the microbiome, however, that is a long way away. When Krigul eats an apple, she washes it only “now”, meaning during the coronavirus period, and “If I pick one from the garden or get one from a friend, I don’t wash it either.”

When it comes to the general eating habits of Estonians, Krigul notes that we eat a lot of dairy and people do like consuming yogurts, fermented milk products, sauerkraut and other foods that contain various beneficial bacteria. Estonian meat is also praiseworthy, since in its production we don’t use antibiotics as much as they do in the USA, and, of course, we have plenty of access to our own gardens and planting beds. “Many of us also have country homes, we can go to markets and buy organic fruits and vegetables, so our dietary options are quite good and not excessively expensive.”

The young scientist’s current research interest is Estonians over 60, who are participating in a colon cancer screening study, whose fecal occult blood test results have indicated a need for a further coloscopy (“It’s not dangerous, but it does require specialists and is very uncomfortable for the patient: basically, they insert a camera into the intestine from behind and look whether there are polyps there or not.”). The objective is to gather samples of all kinds from study participants in order to see whether changes in the intestines that are cause for concern could be determined, for example, from saliva or whether specific microbiomes and the results of fecal occult blood tests are somehow connected. “A number of diseases have already been identified around the world, such as obesity, severe diarrhea and colitis caused by Clostridium difficile, depression, type II diabetes and atherosclerosis, in which microbes in our bodies can contribute to the disease.” At the same time, the microbiome is also influenced by medications – not just antibiotics either – that a person takes over the course of their lifetime, and vice versa. “For example, one intestinal bacterium called Eggerthella lenta breaks down digoxin in heart medication rendering it useless, and it is possible that other bacteria also cause side effects for other medications,” says Krigul. “We would like to start researching this through the Estonian Biobank.”

How certain is it that there is no danger of such delicate health information leaking, I ask. Surely, no employer would like to hire a candidate, whose analyses hint at a possible battle against cancer in the near future. “We do not send out that information anywhere. The Human Genes Research Act does not allow it, and we even cannot disclose that information after a person’s death to their relatives,” affirms Krigul. She also explains that the information that would allow for the genetic research results to be traced back to a certain person is kept in a “room guarded by security companies,” to which only two persons in the whole of Estonia have access. It is also worth mentioning that Estonian laws prohibit employers from asking about health risks and that this information can only be disclosed voluntarily by the person seeking employment.

To conclude a long conversation about science, Krigul admits that many scientists live in a constant state of stress due to a high need for achievement. “You have to enjoy the fact that we’re doing something very interesting, and live in the moment more,” muses the young scientist. Among other activities, she has, for example, found time to go to Mauritius to microchip and sterilise homeless dogs. Lately, her motto has been, “Don’t take yourself too seriously.”

Kali or coke?

Fir or pine?

Country or city?

Dog or cat?
“ Both. I also have a cat, just a regular, simple cat. His name is Kala (fish in Estonian). .”

East or west?

Left or right?

Sour or sweet?

Red or white?

Sun or Moon?

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