Nutrigenetics is the theory of how genes interact with certain food ingredients. Each person is unique in their genes and reacts differently to certain foods, and this burgeoning industry promises to recognize which foods the body tolerates and which it does not based on genes.
It sounds like science fiction or future technology, but nutrigenetics is already an integral part of our daily lives. As early as the 1960s, nutrigenetic screening of newborns for the disease phenylketonuria began. Phenylketonuria is a disease in which, due to a genetic defect, the body is unable to break down the amino acid phenylanine. If the disease is not recognized and a child’s diet is not adapted accordingly, physical and mental disabilities will develop. Therefore, over the past 50 years, every newborn in many places, including the United States, has been tested for the presence of this disease.
We also often hear the term lactose intolerance. It’s also a genetic condition, so those who eat lactose-free from symptoms are eating according to their genes. If you are an asymptomatic carrier of lactose intolerance genes, you will be able to drink milk all your life, but your children could inherit your intolerance.
Gluten intolerance is another dietary problem that can only occur if you have certain genes. Without these genes, the likelihood of developing gluten intolerance is close to zero. A nutrigenetic diet, that is, eating according to individual genes, has long been part of our lives and is far from a thing of the future.
Although the number of skeptics and opponents is diminishing, many still do not trust the process of genetic testing and analysis.
We often hear people say they would never have genetic testing, but they probably don’t realize that their first nutrigenetic test for PKU was done shortly after birth. Their children were also nutrigenetically tested without anyone asking permission. For decades, it has been standard procedure that helps prevent physical and mental disabilities through modified diet. Each of us underwent our first nutrigenetic analysis shortly after birth.
Most critics of this issue don’t even know what a nutrigenetic diet really is. They believe it is a comprehensive genetic analysis that presents extremely detailed information about certain nutrients. They don’t know that the most common food intolerances, such as lactose or gluten intolerance, fall into the category of nutrigenetic diets.
The “I don’t want to know” approach is another approach we encounter, especially in healthy people. A person who unknowingly suffers from gluten intolerance and who, like the majority of sufferers, lives for 10 years without a 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 subject. The argument that “it is too early and there are not enough studies” is outdated, but would have been more valid around 1995-2000.
In 2001, the Human Genome Project came to an end. It was then that, for the first time, we read and published the entire human genetic code. This opened the door to an incredible amount of genetic science and a whole new research industry emerged called nutrigenetics. Two years later, the genetic cause of lactose intolerance was discovered, and soon after the genetic cause of gluten intolerance.
Today, nutrigenetics is taught in all major universities. The number of publications on genetic variations has increased exponentially. Today, we have over 300,000 publications in the database that study the effects of common genetic abnormalities. We already know the health effects of over 80,000 different genetic variations and over 300 studies have been done; For example, on the genetic variation of the COMT gene. For comparison: in health genetics, if three large studies have been conducted that have investigated and proven the same, that fact is considered scientifically substantiated. For the COMT gene, we have over 300 studies. The time when it was possible to say that one does not have enough education is long gone.
Do we know everything about genetics? No way. But we know a lot about many aspects.
So why are there still people who claim that there is little scientific research? This has to do with the rapid development of the domain. Those who went to college before the year 2000 learned nothing about this field, and anyone who doesn’t keep up to date will quickly lose sight of where the science is right now. I’m sure these people don’t know that there are over 300 studies of certain genetic variations.
If you get tested, what can you find out?
There are many things you can learn about yourself through genetic testing. For example, you may find that the phase 1 detoxification enzymes – the genes responsible for starting the destruction of carcinogens like smoke – are not working properly. If you smoke, you have a 3.4 times greater risk of lung cancer than many other people.
Phase 2 detox genes are responsible for toxins like heavy metals such as cadmium, lead and mercury, but also herbicides and pesticides, which are sprayed on crops to kill weeds and pests. Limit your consumption of foods containing heavy metals; such as saltwater fish and shellfish; and get lots of minerals that bind heavy metals; such as calcium, zinc and selenium; is recommended if your body has trouble eliminating these toxins. If your body has trouble eliminating weed and insect remedies properly, you should also eat organic foods.
If you have bad cholesterol due to your genes, omega-3 (fish oil) capsules are a common recommendation. But in some people it has the exact opposite of the intended effect due to their genes and can make cholesterol levels worse. Phytosterolsthat come from plants, might better suit those who fall into this category.
Depending on their genes, a person could also have a several times higher risk of developing Alzheimer’s disease. Along with other preventative measures, diet can play a big role in prevention. Studies have shown that foods high in antioxidants can significantly reduce the likelihood of disease. In at least one studydrinking 3-5 cups of coffee a day was associated with a 65% lower risk of Alzheimer’s disease/dementia later in life.
The secret of coffee…
Coffee is a great example of a food that people react to very differently. For one, coffee is one of the healthiest foods we know. No other food contains such a high concentration of antioxidants and other healthy substances. But coffee also contains potentially harmful caffeine.
People have a specific gene, CYP1A2, which recognizes and metabolizes caffeine. If a person’s body processes caffeine slowly, it can increase the risk of various diseases, such as heart disease and osteoporosis. The fact is that only about 52% of Central Europeans have a working version of this gene and are able to process it quickly. This means that coffee’s antioxidant benefits and other good qualities are highly dependent on a person’s genes.
For example, we know from studies that breast cancer appears on average seven years later in women who drink 2-5 cups of coffee a day compared to women who do not drink coffee, which may be a factor. important protection against breast cancer. But this effect was only seen in women who had a functional caffeine-degrading gene and could metabolize it quickly. If this gene was not working properly, coffee consumption had no influence on the development of breast cancer. Thus, the protective effects of coffee only seem to occur if the body is able to process it effectively.
The question now is: can coffee be recommended? For people with a fully functioning gene, the answer is clearly yes. But for those with limited genetic function, coffee consumption increases the risk of heart attacks and other illnesses. Therefore, there is no simple recommendation for everyone – that’s why we carry out DNA analysis.
Genetics and histamine intolerance…
Histamine intolerance does not mean that your body is sensitive to histamine – a substance involved in routine bodily functions like digestion as well as the body’s inflammatory responses after an injury or allergic reaction – but that your body has too much of it. This can happen when your histamine levels get too high or when your body can’t break it down properly.
The human immune system produces histamine, but it is also present in food. The fact is, the body has to break down histamine in food before it is actually absorbed by the body. There are two backup mechanisms for this.
The first protective mechanism is the DAO gene, which produces a histamine degrading enzyme that is present in the gut (where most histamine is eliminated). But if histamine is absorbed by the body, there is the HNMT gene, which recognizes and breaks down histamine.
We now know that certain genetic variations or defects in the DAO gene lead either to too little production of the DAO enzyme or to the production of faulty enzymes, and about 50% of people with histamine intolerance have a low level of CAD. Such genetic variations are therefore an important risk factor, but genetics is not the only factor here. Our lab is investigating whether histamine intolerance may be caused by a genetic variation in HNMT.
What else will the future of nutrigenetics bring?
We are currently experiencing tremendous growth in preventive genetics and nutrigenetics, but much more can be done today than is actually used. The most comprehensive nutrigenetics programs analyze over 50 genes and provide very specific nutritional recommendations, but the number of genes that affect how we respond to certain foods will steadily increase and our results will be better and more accurate.
In our laboratory [FITGEN SE in Prague] alone (we have more than 1,000 in the world), 200,000 analyzes have been carried out, and the trend continues to increase. Of course, not all medical practices and nutritional advisers use nutrigenetics, but the most progressive are already turning to us.
Currently, our lab can detect 111 different diseases right after a child is born, but the potential is even greater. And it is already clear immediately after birth which foods children are tolerant to, allowing parents to tailor their children’s diets to their intolerances right from the start.
We believe and hope that insurance policies will begin to cover the costs of genetic analysis and prevention. At the moment it is a private service, but these technologies should be available to everyone as a tool to help them stay healthy. Maybe in 20 years we can analyze the entire genome of every child right after birth at public expense.
František Zámola, MD, is an expert in sports medicine, sports genomics and nutrigenomics, and physician at the Military University Hospital in Prague.
