What is Nutrigenomics?
Nutrigenomics is the interaction of nutrition and genes with regard to the treatment and prevention of disease. Obviously, our DNA is critical for gene function, but nutrition can sometimes alter the way these functions are expressed (1).
Genomic Medicine, Nutrition, and Lifestyle
In studying genomic medicine, nutrition, and lifestyle choices (smoking vs. nonsmoking), we can understand disease risk. The human genome is defined as all of the genes in the human body. Thanks to the Human Genome Project we now know the sequence of the approximate 25,000 genes in our genome (2). Genomics is the field of science dedicated to studying all of the genes in the human body and their structure, function, location, as well as interaction with each other. When combining this with medicine we can develop a healthcare plan for each person’s unique genetic profile (3).
Changes in Our DNA
DNA damage can be natural or a result of environmental factors. During the process of DNA production in our body, there is a possibility for replication errors. However, environmental factors such as chemicals and radiation could play a role in damaging our DNA (4).
Damaged DNA is also relevant to the development of cancer. Carcinogens change DNA sequences and therefore may cause single nucleotide polymorphisms (4). Often referred to as SNPs, single nucleotide polymorphisms are changes in a single base pair of a DNA sequence (5). There are 4 nucleotides or bases in our DNA: cytosine, guanine, thymine, and adenine. An SNP in a strand of DNA could happen when a thymine takes the place of a cytosine.
These SNPs can explain some of the genetic variations between human beings. Single nucleotide polymorphisms may have little to no effect on our health, but they can be extremely helpful in researching cancer and chronic diseases (5). SNPs occur in a specific pattern throughout our DNA, and because of this, scientists can pinpoint specific genes associated with diseases such as type 2 diabetes and heart disease. SNPs can also help us detect genetic predisposition, susceptibility to environmental factors, and disease risk. Genetic predisposition can be defined as the likelihood for a person to develop cancer and chronic diseases based on their genetic makeup.
How Do Nutrients Play a Role in Gene Expression?
It is rare that a disease develops as the result of one single gene. Most of the time diseases are results of genetic makeup, diet, and environmental factors. Nutrition can lessen the severity of diseases and in some cases improve the outcome (6). Within the past 20 years, researchers have been able to demonstrate the ability of specific nutrients to help our body on a molecular level.
Nutrigenomics research aims to link DNA destruction and repair with different nutrients. DNA damage is made worse by oxidative stressors such as smoking or a high-fat diet. One way to measure oxidative stress on a cell is by looking at the concentration of 8-Oxo-2′-deoxyguanosine. This compound is made during DNA production and is a good indicator of DNA damage (1). Having a dietary intake low in fat and high in vitamin C, calcium, and fish oil has been linked to reduced amounts of 8-Oxo-2′-deoxyguanosine in the urine (and therefore lower amounts of damage to DNA) (8).
Antioxidant nutrients can enhance DNA repair and are theorized to help compensate for inherited defects in our body’s natural repair mechanisms (1). Some people have genetic variants that weaken their natural ability to repair damaged DNA. This means they should take a higher amount of dietary supplements than the average individual. In doing so they can lessen disease risk and cancer development. In nutrigenomic approaches, it is essential to focus on a combination of vitamins and nutrients. There are numerous antioxidant nutrients that affect the human genome. Examples of antioxidant nutrients are vitamin A, beta-carotene, vitamin C, selenium, and vitamin E (9). Nutrigenomics allows healthcare professionals to establish personalized nutrition plans for each patient.
Hereditary Risk Factors and Nutrigenomics
Hereditary diseases are passed from parent to child via defective genes. These defective genes could have lesser effects on the body if proper nutrition is applied. Different diets require different amounts of carbohydrates, proteins, and lipids. Knowing which gene variants our body consists of helps us create personalized nutrition plans. For example, the insulin resistance gene and FTO gene are risk factors for developing metabolic diseases. The FTO gene encodes for the fat mass and obesity-associated protein in humans. It plays a part in appetite and metabolism (10). Obesity is when a patient develops a BMI over 30 and it is usually linked to increased risk for cancer, type 2 diabetes, and heart disease.
If you know or have reason to suspect your genome contains the unfortunate FTO gene, it doesn’t mean you will definitely be overweight. It does mean that you are more susceptible to the consequences of an unhealthy lifestyle than someone who doesn’t have the gene. Obesity and the FTO gene exemplify how knowing whether or not you have a genetic predisposition can help prevent the formation of disease. People with this gene can avoid weight gain as long as they follow a proper diet and exercise routine.
Diet Choices for Healthy Gene Expression
A healthy diet consists of a good balance of carbohydrates, proteins, and lipids. Carbohydrate intake is important to monitor as carbs include starches and sugars. Proteins are great because they consist of amino acids.
There are multiple ways to enhance our dietary intake, support healthy gene expression, and help combat disease. To list a few basic concepts:
- Replace saturated fat and trans fat with unsaturated fats. Trans fats have harmful effects on our blood lipids. Removing these negative fats reduces the LDL cholesterol in our blood and therefore lowers heart disease risk. Including Omega 3-fatty acids in your food intake has been proven to reduce cardiovascular disease (7).
- Consume large amounts of fruits and vegetables. These foods contain a considerable amount of potassium and folic acid. Folic acid intake has been associated with lowered risk for certain cancers as well as heart disease (7).
- Be sure to eat enough whole grain and fiber. There are vitamins and minerals naturally present in whole grains proven to prevent type 2 diabetes. Eating the right amount of fiber can help us maintain a healthy weight (7).
- Limit sugar and sugar-based drinks. Sugar increases our dietary glycemic load and therefore puts individuals at risk for type 2 diabetes. Reduced sugar consumption also helps with weight loss (7).
- Limit sodium intake. Lower levels of sodium are associated with a healthier blood pressure.
The Future is Preventative
Moving forward American healthcare is pursuing a preventative path. Time and again, consumers rely on the medical field to cure disease instead of preventing it. This is due to millions of Americans lacking knowledge of preventative health. In addition to a proper diet, exercise, and healthy choices, preventive healthcare also includes the process of wellness visits, cancer screenings, and immunization visits. Far too many Americans are dying from preventable chronic diseases like heart disease, diabetes, and cancer (11). Our public health can significantly improve by understanding Nutrigenomics and emphasizing the importance of a healthy lifestyle as well as preventative visits to the doctor for cholesterol screenings and mammograms (11).