What Is Nutrigenetics and What Could It Contribute?

Nutrigenetics is one of the most promising areas of research. It's likely to revolutionise nutritional consultation in the coming years.

Written and verified by el nutricionista Saúl Sánchez.

Last update: 21 June, 2023

Nutrigenetics is a branch of science that studies the relationships between different genes and the response of a given person to diet. In other words, this discipline investigates how the genetic load determines the body’s ability to digest and metabolize the different nutrients, for their later use.

Despite the fact that there’s still much to be discovered in terms of the genome, many advances have been made in this field in recent years. Specific polymorphisms have been discovered in certain genes that can determine the response to certain nutrients present in everyday foods. Knowing these interactions accurately would allow the preparation of a totally individualized diet.

Nutrigenetics applications

At present it isn’t possible to modify the genetic information of an already developed person. However, getting to know them thoroughly could determine many aspects of their daily life, according to a study published in Nutrients. For example, there are people who work better during the first hours of the day, while others work better at night. This variability is reflected in the genes.

Similarly, not all people have the same ability to metabolize a certain nutrient. While some respond well to eating saturated fat, others experience problems with their digestion. This phenomenon can be due to variations in the intestinal microbiota, but also to differences in the genetic material, responsible for the expression of all a person’s characteristics.

It’s also necessary to highlight that many food intolerances are marked by a strong genetic component. An example is lactose intolerance. Quite often it is due to a process of intestinal dysbiosis. However, it may also be related to the appearance of a genetic polymorphism that inhibits lactase production.

The relationship between nutrigenetics and diet

Until very recently, dietary recommendations were based on studies carried out in large population samples, but didn’t take individual variations between subjects into account. Based on these investigations, general advice regarding diet was established. Some of them are valid for a great majority.

For example, although tolerance to trans fats may not be the same for all individuals, they have been shown to be potentially harmful for everyone.

However, there are other nutrients whose effects depend much more on the person’s genetic load. We’re talking, among others, about carbohydrates. Differences can be seen between the different individuals in terms of their assimilative capacity.

Another factor that can affect the effects of carbohydrates is the percentage distribution of muscle fibers. In this way, a person with a high amount of fast fibers will assimilate these nutrients much more efficiently than a person with a predominance of slow fibers.

Nutrigenetics today

Despite the fact that all this information seems very useful in order to individualize people’s diets, today we still have certain limitations in this regard. Firstly, few genes have been identified that can determine the effects of food. There’s research on some polymorphisms that influence the metabolism of nutrients, but there isn’t extensive knowledge about them yet.

On the other hand, genetic tests to find out what DNA profile a certain person has are still very expensive, and they aren’t available to everyone. This precludes the option of carrying out a study at the nutritional consultation level, in order to generate recommendations based on current knowledge.

However, it’s expected that, in the coming years, the price of these tests will drop, in order for the nutritionist to be able to systematically implement them, thus achieving a much more precise treatment.

Even so, to reach this situation, we’ll still need to wait a few years. The most optimistic voices assure that this point could be reached within the next 10 years, which would mean a great revolution in the world of health.

It must be borne in mind that such precise nutrition wouldn’t only increase quality and life expectancy, but would also reduce the need for medication. It’ll also be necessary to see how the pharmacological industry behaves in this regard, as there are certain economic interests involved that can generate conflicts.

Complex diseases and genes

Nutrigenetics not only provides information about how the body is capable of processing certain foods or nutrients, but also allows us to get to know how the intake of some substances interacts with the risk of developing complex pathologies. This is evidenced by a study in the journal Nutrients published in 2018. This article investigates how individual genetic variations can modify the incidence of cardiovascular pathologies.

In addition, the way in which fatty acids influence the lipid profile is also studied according to the genetic polymorphisms found in each person. In this way, genetics can modulate how the organism behaves when faced with the ingestion of a certain nutrient, reflecting said behavior in the variations of blood cholesterol.

Although these days we know that cholesterol isn’t an excessively accurate marker of cardiovascular disease, it can provide useful knowledge about how the body is working.

In the same way, obesity can be another illness that is highly influenced by a genetic component. Certain polymorphisms have been detected that cause a tendency to accumulate fat weight, especially from the intake of certain types of carbohydrates.

Being able to identify all these variations could mean a great advance when it comes to producing truly individualized and effective nutritional guidelines as far as the fight against excess weight is concerned. This is evidenced by a publication in the Critical Reviews in Food Science and Nutrition magazine.

A complex field

Nutrigenetics is one of the most complex fields in terms of nutrition. The identification of genetic polymorphisms and their involvement requires complicated techniques. In addition, a deep knowledge of physiology is necessary to interpret the pathways that they modify, and how they behave according to the existing variability.

Currently, there are few qualified professionals in this matter, as it isn’t accessible to everyone. Research is carried out by doctors in the field and there are several lines to be dealt with, many of them related to obesity or the prevention of complex pathologies such as cancer.

The genetic load is probably key when determining the appearance of a tumor mass, and the interaction between genes and food may be capable of preventing this situation. Or at least reducing the risk of it happening.

However, there are many unknowns regarding complex diseases. For this reason, it isn’t only necessary to know the genes that increase the risk of occurrence, but also the physiological mechanisms by which they’re sustained. Further research in both fields will be essential in order to eradicate this type of pathology, which causes so many deaths in developed countries.

Beyond nutrigenetics

Despite the possibility that extensive and in-depth knowledge of genes and their variations may represent a turning point as far as diet is concerned, there are certain maxims that can be applied to a good part of the population. For this reason, health advice can be offered at a general level, both in the field of nutrition and in that of life habits.

In this way, even though simple sugars aren’t equally bad for everyone, it’s known that their consumption outside of the sports context isn’t recommended. It’s beneficial to limit their intake, always using complex carbohydrates. Likewise, an increase in the dietary intake of fiber can improve overall health.

In parallel, additives are also substances with which care must be taken. It’s clear that not everyone responds in the same way to these chemicals, so prudence is the best recommendation that can be offered today.

We mustn’t forget either that there are dietary strategies that have been shown to be effective for weight loss, regardless of genetic differences. They’re also designed to reduce cardiovascular risk. We’re talking, among others, about intermittent fasting, reducing carbohydrates in the diet, or increasing the consumption of unsaturated fatty acids.

Nutrigenetics, the next big revolution

As the years go by, technology will be able to change many of the current strategies. Some of them have to do with what happens in a nutrition consultation. In-depth knowledge of the genome will make it possible to offer much more precise and individualized recommendations. In this way, the percentage of success of the nutritional intervention will increase significantly.

However, we’ll have to wait before arriving at this utopian scenario. The reality is that, currently, we don’t have the necessary technology to extend this study to the general population. It’s too expensive and there’s a lack of information about many polymorphisms, as only a few have been identified.

The advancement of artificial intelligence will drive progress in genome sequencing, which will have a positive impact on nutrigenetics. From that point, it’ll be easier to create individual nutritional guidelines that meet the expectations created in this regard.