The Brief Guide to Nutrigenomics: How Diet Can Affect Your Genes
The saying “you are what you eat” could become “what you eat can change who you are” in the context of nutrigenomics. Your diet can affect your genes, and this is what nutrigenomics is all about.
Nutrigenomics, as the name implies, integrates the sciences of nutrition and genomics. Nutrition studies food and how it affects health, while genomics is the study of how an organism’s genes are structured and function.
This guide to nutrigenomics gives you an overview of genes, nutrition, how they’re connected, and what it means for you.
To understand nutrigenomics and how it works, you first need to know what genes and the human genome are, and how they’re related to disease.
Genes and the Genome
How many times have you said something like “it’s in my DNA,” or, “it’s genetic, I can’t change it”?
Although the words “DNA,” “genes” and “genetic” have been part of our everyday language for many years, the human genome only revealed its secrets not long ago. The Human Genome Project, which mapped all of the genes in human DNA, launched in 1990 and successfully published the first draft of the human genome in 2001 in the journal Nature. A genome is the name scientists give to the collection of all genes in a species. For humans, our genome contains about 20,500 genes.
All of our genetic material is stored as DNA– sequences of organic molecules called nucleotides. As the nucleotides line up into chains, they form your genes. These genes, which you inherit from your parents, contain “instructions” for which proteins your cells should make. Those instructions dictate how your body develops and functions.
Genes and Disease
Genes also determine if you are more likely to get a disease than another person with different genes.
Surprisingly, the genes of all people are 99.9 percent the same. The genes that make up only 0.1 of your genetic makeup — as well as other factors — determine your nutritional requirements (as well as your height, eye color and more features that make you unique). In addition, these genes determine your risk of developing a non-transmissible chronic disease. These medical conditions include diabetes and heart disease, among others.
The fact that you have certain genes that predispose you to a disease doesn’t mean you’ll get that disease. Whether you’ll develop a chronic disease or not depends of how the genome will interact with other factors. These include nutrition, lifestyle (smoking, exercise and other lifestyle choices) and environmental factors (exposure to certain toxins, for instance).
Nutrigenomics Is Like a Game of Cards
To understand how nutrigenomics works, imagine a game of cards.
Your genes would be the cards the dealer gives you. Some cards are “bad,” that is, you have genes that put you at higher risk of a certain disease. Let’s say winning the game means you won’t get the disease, and losing the game means you’ll get the disease.
As in an actual game of cards, the way you play will decide whether you win or not. For the sake of simplicity, the way you play would be your lifestyle. The aim of nutrigenomics would be to increase your chance of winning the game even if you have bad cards. It’s a bit like cheating, but for a good cause.
So, what’s the connection between genes, health or disease and nutrition? Let’s find out.
Since ancient times, people have used both food and medicinal plants to treat the symptoms of many diseases. Your diet can affect your health — hence the expression “you are what you eat.” Despite this being common knowledge, one in two Americans suffers from a preventable chronic disease, according to the government. The cause of many chronic diseases is poor diet, and lack of exercise. Of course, the debate over what sort of diet is best, has been going on for decades. Most data shows that the Mediterranean diet (fish, fruits, vegetables and nuts and seeds) is healthy for most populations. Intermittent fasting and the ketogenic diet seem to work very well for some people, and some researchers believe those diets lower the risk of cancer and neurologic disease, but it is not yet clear whether those diets are ideal for everyone.
But what is emerging more recently is that the connection between diet and health is even more astonishing than we realized. Many studies have demonstrated that food actually regulates gene expression– meaning, which genes get turned on or off. These studies in cell cultures, animals and humans have shown that diet affects gene expression. So, you may inherit certain genes from your biological parents– but depending on what you eat, those genes may be dormant or active.
The human diet includes macronutrients (such as fats and proteins), micronutrients (vitamins) and natural chemical substances found in plants and animals. All these components of the diet can affect how genes act.
The body uses many nutrients in metabolic reactions (body’s chemical reactions) that regulate hormones, immunity (how the body resists disease), and how the body uses nutrients for fuel and growth.
Some natural chemicals directly affect gene expression. One example is resveratrol, a substance found in red wine. Other essential nutrients, such as choline (found in eggs and liver, for example) indirectly affect gene expression.
In short, the nutrients in your diet may increase or decrease your risk of developing a disease. That’s because they determine whether your genetic potential will manifest as a disease or not, according to the author of a 2007 article published in Environmental Health Perspectives.
Once researchers made this discovery, there was a revolution in nutrition sciences. Two new fields of science emerged — nutrigenomics and nutrigenetics — to study the interaction between genes and nutrition.
Nutrigenetics studies how inherited genetic variations (Single Nucleotide Polymorphisms, or “SNPs”) affects the body’s response to nutrition: will people with certain SNPs do better on a ketogenic or a Mediterranean diet?
Nutrigenomics examines the effect of nutrients on gene expression within a species. The goal of nutrigenomics is to understand how that gene expression affects cellular metabolism across a species. Nutrigenomics is more interested in responses at the molecular level. More broadly, this science studies the impact of nutrients on three aspects of the body:
- the genome (the sum of all genes in a species),
- the metabolome (the sum of all metabolites from cell processes), and
- the proteome (the sum of all proteins).
Nutrition doesn’t only affect gene expression, but also genome health. For example, there’s a connection between the amount of folate in a diet and the stability of the genome. According to researchers, the body needs at least 200 micrograms of folate a day to ensure chromosomal stability and prevent genome damage. Similarly, the body needs a certain intake of other nutrients as well.
Currently in medicine the efficacy of drug treatments is very low. Only about three in 10 people benefit from a drug treatment, according to Steven Zeisel of the University of North Carolina at Chapel Hill. The ultimate goal of nutrigenomics is to give the medical and food industries the information necessary to create personalized foods and supplements based on our genes. The name of these customized nutrition treatments is nutrigenomic foods.
But achieving this goal is very challenging. Similarly to how two people will respond differently to the same drug, nutritional interventions might work for some people, but not for others. Also, some people may even be negatively affected.
Researchers need to do more studies to understand how nutritional interventions could be as efficient as possible.
Nutrigenomics researchers have to define the ideal amount of nutrients we need to keep our genes healthy. This is the main challenge in this area of research. Our genetic makeup is different, and our diets and lifestyles (smoking, exercise, stress levels and more) vary.
Nutrigenomics researchers face several other major challenges:
- They need more research to build a solid foundation for further studies and develop the right tools and methods.
- The topic of nutrition is very complex — scientists must study many foods and nutrients. This is because the human body needs many nutrients and natural chemical components.
- Nutrigenomics scientists deal with enormous amounts of data in each nutrigenomics experiment.
- Researchers need to focus on the impact of several nutritional imbalances on the genome. Having a nutritional imbalance means having a diet that is too poor or too rich in a certain nutrient.
- Our diet has many components that interact with each other and, in turn, cause changes in the body. Researchers say it’s very difficult to determine how much the risk of a disease is due to nutrition and how much is due to other causes.
In conclusion, nutrigenomics studies might be as complex as scientific research can get.
Nutrigenomics aims to understand how people can use nutrients to prevent medical conditions such as obesity, diabetes, cancer and neurodegenerative diseases. But it’s hard to predict how diet affects health, because the interactions between diet and genes are complex.
In the future, doctors will not only treat diseases, but they might also use nutrition to prevent genomic damage or reverse it. Companies might develop new foods and supplements to ensure the nutritional intake meets each individual’s needs.
Researchers have to do more work to shed light on the interaction between genes and nutrition. Also, nutritionists need to understand that people will respond differently to different diets because of their genetic makeup. They will then be able to use this information to recommend the right diets that prevent disease and promote health.
Some authors think that nutrigenomics will continue to advance as a science. To be able to make major developments in nutrition, researchers must first understand the mechanisms underlying nutrition.
Those who support nutrigenomics research say the results will be useful to prevent and treat vitamin deficiency, which is one of the main public health priorities. According to the World Health Organization, iodine, vitamin A and iron are the three most important nutrients in global public health. Many people, especially in developing countries, lack these nutrients, as well as many others. This nutritional deficiency threatens their health and that of their children.
Given the complexity of nutrigenomics studies, many researchers need to collaborate to investigate the vitamin needs in different populations with different genetic makeups, according to Nathaniel Mead, the author of the article “Nutrigenomics: The Genome–Food Interface.”
Just like other areas of genomics research, nutrigenomics has received its dose of criticism, in particular related to ethical issues. In short, some researchers fear that only rich individuals, and rich countries, will be able to afford these personalized nutritional interventions.
Since many nutrigenomics studies focus on an individual approach to nutrition, it’s not clear how personalized nutrition can solve global health problems. Also, at national level, tailoring treatments to each individual might not solve public health problems like those deriving from poor diet, infections and chronic diseases.
Despite criticism, nutrigenomics might improve public health, because it has demonstrated that malnutrition can cause genome damage in the current population and their children. This finding might promote more research and intervention to fight malnutrition in developing countries. In addition, in developed countries, nutrigenomics could improve health through personalized nutritional interventions.
Nutrigenomics, together with nutrigenetics, could revolutionize the pharmaceutical and food industries. The pharmaceutical industry expects to develop drugs tailored to a patient’s genes. In addition, the food industry aims to create foods and supplements that target an individual’s genes to prevent disease and restore health and fitness.
One of the first steps is to identify the genes that cause disease and the nutrients that can reduce the risk of disease. To fulfil this goal, a huge international effort like the Human Genome Project would be necessary, according to researchers.
You already know food is important for maintaining health and wellness. But in the future doctors may use food as medicine, to reduce the risk of getting certain chronic conditions like heart disease and diabetes.
Researchers have discovered certain nutrients can decrease the risk of getting a disease even if the genes predispose an individual to it. The fact that nutrients can affect gene expression is the base of nutritional genomics.
Nutrigenomics studies how nutrients and genes interact and how nutrients can fight and prevent disease. The aim of this science is to create personalized nutritional treatments.
But nutrigenomics research is complicated. Researchers need to do a lot of work to understand how they can use nutrients to prevent or cure disease. So, you might have to wait some time before you can get personalized food or supplements tailored to your genetic makeup.
In the meantime, there are plenty of things you can do to lower your risk of chronic diseases. Eat a balanced diet and make sure you get all the essential nutrients your body needs. To discover the foods and vitamins that are good for your health, read the current dietary guidelines that the HHS and USDA publish. In addition, do physical activity regularly to maintain your health.
Finally, keep an eye on the latest nutrigenomics research to find out about the next breakthrough in personalized nutrition treatments.