When we say nutrigenetics, and how does it apply to everday life?

When we say nutrigenetics…


Nutrigenetics is the theory of how genes interact with certain food ingredients. Each person is unique in their genes and responds differently to certain foods. This young industry promises to recognize what foods the body tolerates and which ones it doesn’t on the basis of genes.

It sounds like science fiction and the technology of the future, but nutrigenetics is already a pervasive part of our everyday life. As early as the 1960s, the nutrigenetic testing of each child began immediately after birth for phenylketonuria disease. This is a congenital genetic disease in which, due to a genetic defect, the body is unable to break down a certain food ingredient (the amino acid phenylanine). If the illness is not properly recognized and the diet is not adequately adjusted, physical and mental disabilities will develop. Therefore, for the last 50 years each child has been tested for the presence of this disease in order to be able to intervene immediately.
We also often hear the term lactose intolerance. This is also a genetic disease. Those who eat lactose-free in relation to symptoms eat according to their genes. In neighboring Germany, for example, there are 18 million such individuals. If you are a symptomless carrier of lactose intolerant genes, you will be able to drink milk all your life, but your children may inherit the disease from you.

Also, intolerance to gluten can only occur if you have certain genes. If these genes are not present, the probability of developing gluten intolerance approaches zero. A nutrigenetic diet, that is, eating according to individual genes, has long been a part of our life, and is therefore not to be regarded as a thing of the future.

The number of sceptics and opponents is decreasing…


We often hear from people that they would never undergo genetic testing. We must disappoint them. Their first nutrigenetic analysis of FKU illness was performed shortly after birth. Their children were also nutrigenetically tested without anyone asking for permission. For decades, this has been a standard procedure that helps prevent physical and mental disability through a modified diet. Each of us underwent his/her first nutrigenetic analysis shortly after birth.


Most critics of this issue don’t even know what a nutrigenetic diet actually is. They believe that this is a comprehensive genetic analysis that presents extremely detailed information about some nutrients, which we may only be able to do in perhaps 20 years. They do not know that the most common food intolerances, such as intolerance to lactose or gluten, fall into this category.


The “I don’t want to know” approach is one we encounter especially in healthy people. A person who unconsciously suffers from intolerance to gluten and, like the majority of affected people, lives for 10 years without proper diagnosis, would normally want to know the cause as soon as possible.
We also often hear that there have not been enough studies on this topic. The argument: “It is too early and there are not enough studies” is as old as the time in which this really was true. This was the state of knowledge sometime around 1995-2000. In 2001, the Human Genome project ended. That is, for the first time, we read and published the entire human genetic code. This opened the door to an incredible amount of genetics science and a whole new research industry emerged called nutrigenetics. Two years later, the genetic cause of lactose intolerance was discovered, and shortly thereafter the genetic cause of gluten intolerance.


Today, nutrigenetics is taught at every major university (Harvard, Toronto, California, Manchester…). The number of publications on genetic variations has increased exponentially. Today, we have more than 300,000 publications in the database that investigate the effects of frequently occurring genetic defects. We already know the health effects of more than 80,000 different genetic variations and more than 300 studies have been carried out, for example, on the genetic variation of the COMT gene. For the sake of comparison: in health genetics, if 3 large studies have been carried out that investigated and proved the same, this fact is considered scientifically substantiated. For the COMT gene, we have over 300 studies. The time when it was possible to say that we do not have enough studies is long gone. Do we know everything about genetics? Not at all. But we know a lot about many things.

So why are there still people who claim that there is little scientific research? This has to do with the rapid development of the field. Those who went to university before the year 2000 did not learn anything about this field. Anyone who does not stay updated will quickly lose sight of where science is at the moment. I’m sure these people do not know that there are more than 300 studies on some genetic variations.


If you get tested…what information can you find out?


There is plenty of information. You may find out that phase 1 detoxification enzymes do not work properly. These genes are responsible for destroying everything that is burnt, that is, cancer-causing substances. When it comes to a smoker, he/she will have a 3.4 times higher risk of lung cancer than many other people.
Phase 2 detoxification genes are responsible for detoxification from heavy metals such as cadmium, lead and mercury, but also from herbicides and pesticides, that is, everything sprayed on crops to remove pests from them. This means that people should restrict the intake of heavy metal foods, such as saltwater fish and shellfish, and receive plenty of minerals that bind heavy metals, such as calcium, zinc and selenium. If your body is unable to properly dispose of weed and insect remedies, you should eat organic food.

If, due to genes, you have bad cholesterol, you would normally be recommended omega-3 MK (fish fat) capsules, but in some people this has an opposite effect due to genes. Their cholesterol levels would become even worse. We recommend phytosterols instead.

Someone has a several times higher risk of Alzheimer’s disease in relation to genes. In addition to other preventative measures, it is also possible to go on a preventive diet in such a case. Studies have shown that antioxidant-rich foods can significantly reduce the likelihood of the disease. Especially 2-5 cups of coffee a day reduce the risk by approximately 60%.

The secret of coffee…


Coffee is an excellent example of a food to which people react very differently. On the one hand, coffee is one of the healthiest foods we know. No other food has such a high concentration of antioxidants and other healthy substances. Coffee also contains potentially harmful caffeine. Caffeine can increase the risk of various illnesses such as cardiovascular disease and osteoporosis. People have a specific gene, CYP1A2, the role of which is to recognize and eliminate caffeine. About 52% of people in Central Europe have a functioning version of this gene and are therefore able to quickly degrade harmful caffeine. For example, we know from studies that in women who drink 2-5 cups of coffee a day, breast cancer appears on average seven years later than in women who do not drink coffee. Coffee is also a significant protective factor against breast cancer. However, this effect was only seen in women who had a functional version of the caffeine degrading gene. If this gene did not work properly, drinking coffee had no influence on the development of breast cancer. The protective effect of coffee can therefore only occur if the body is able to remove harmful caffeine. The question now is: can coffee be recommended? For 52% of people with a functioning gene, the answer is clearly yes. For 48% of people with limited gene function, drinking coffee raises the risk of cardiovascular and other illnesses. So rather not. Therefore, there is no unambiguous recommendation for everyone. That’s why we do DNA analysis.



Histamine intolerance…


Histamine intolerance is basically a disorder of histamine degradation. This substance is contained in many foods and, unfortunately, evolution thought it would be a good idea to use histamine in the body as a signal for inflammatory reactions. Our immune system therefore uses histamine, which it produces itself, to induce inflammation. Because wrong signals occur, the body must break down the histamine contained in food before it is absorbed into the body. There are two special safeguard mechanisms for this. The first protective mechanism is ensured by the DAO gene. It produces a histamine degrading enzyme that is injected into the intestine, where most histamine is disposed of. But if histamine gets into the body, there’s the HNMT gene that recognizes and breaks down the histamine. We now know that some genetic variations or defects in the DAO gene lead either to too low of a production of this enzyme or to the production of defective enzymes. We know that approximately 50% of people with histamine intolerance have a low level of DAO. Such genetic variations are therefore a significant risk factor, but genetics is not the only factor here. Our laboratory examines whether histamine intolerance can be caused by any genetic variation in the second gene (HNMT).


Nutrigenetics is therefore a reality. What else will the future bring?


Much more is possible today than what is actually being used. The most comprehensive nutrigenetic programs analyze more than 50 genes and provide very accurate nutritional recommendations. The number of genes that affect how we respond to certain foods will grow steadily. Our findings will be better and more accurate. At the moment, we are experiencing extraordinary growth in preventive genetics and nutrigenetics. In our laboratory alone (we have more than 1,000 worldwide), 200,000 such analyzes have been performed, and the trend continues to rise. Of course, it does not apply that every medical practice and every nutritional counselor uses nutrigenetics, but the progressive ones are already turning to us.

We think and hope that insurance will emerge to take over the costs of genetic analysis and prevention. At the moment, this is a private service, but these technologies should be available to everyone so that everyone can maintain good health. Perhaps in 20 years we will be able to analyze the entire genome of each child right after birth at the expense of the state. Our laboratory can detect 111 different illnesses directly after birth, but the potential is even greater. It is already clear at the moment of birth which foods are suitable for children. This makes it possible for parents to lead their children to their consumption.



MUDr. František Zámola


Physician of the Center for Ensuring the Health of Sports Representation, Military University Hospital Prague

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