Nutritional Genomics in Clinical Practice – Part 1
With the mapping of the human genome, completed in 2003, we discovered there are about 22,300 protein-coding genes in human beings. We’re approximately 99.9 percent identical genetically. However, in that 0.1 percent, there is significant variability. It is within that very small percentage that the new science of nutritional genomics has grown to be very important.
It enables us to study and change how people and environment interact. The new technology that comes with this new science has allowed us to map out individual genetic blueprints for people and learn how to modify them to improve people’s lives.
Definitions of Importance in Nutritional Genomics
In general, nutritional genomics studies how foods can affect our genetic expression and how individual genetic differences affect our response to nutrients. This new science thus explores how genes and diet interact.
Nutrigenomics is the exploration of how the nutrients from the foods we eat affect our gene expression and gene regulation. It is possible through this study to develop “personalized diets” based on the genetic makeup of the person and his or her nutritional needs. It will also make it possible to understand dietary components that will have a benefit or detriment to that individual’s health. The identification of the relationship between diet and chronic diseases will also grow from this study.
Another facet of nutritional genomics is nutrigenetics. This branch of the new science explores how genetic factors in an individual affects his or her response to nutrients in the diet. It can explain why and how different people respond differently to the same nutrient.
Within the dramatically increasing field of genomics research, another fascinating tool has been developed. This is CRISPR, a genome editing tool. With CRISPR, we can literally reprogram our genetic code. CRISPR stands for clustered regularly interspaced short palindromic repeats. It is an old defense mechanism in bacteria that is naturally occurring and has the ability to protect the bacteria from viruses.
Essentially, CRISPR inserts bits of viruses into the genetic code for the bacteria in order to recognize the virus if it appears again. This enables the bacteria to defend itself against the virus. Another part of this process is the use of Cas (CRISPR-associated proteins) to literally cut apart any invading virus and prevent it from replicating. With CRISPR, practitioners now can take out parts of genes and substitute others.
CRISPR technology and epigenetic manipulation pave the way for the exploration of modifying genes in order to change risk factors for several chronic health conditions. Using these tools will allow individuals to express different aspects of their genetic code in order to avoid these illness conditions.
Single nucleotide polymorphisms (SNPs) are very common variants in human genes. Every SNP is a single difference in a nucleotide in human DNA. They are biological markers that help point out genes associated with disease. The variances in genes are proteins that can be changed.
Fundamental Role of Nutritional Genomics in Illness Conditions
The World Health Organization attributed 63 percent of the deaths that occurred in 2008 to illness conditions that were not communicable. Cancers, cardiovascular disease, Type 2 diabetes, and obesity were the major culprits. All of these have dietary factors as contributors.
All of these illness conditions can be significantly influenced by dietary factors and human genomics. The new science of nutritional genomics is very important in grasping the complex combination of diet and genes that can lead to chronic illness conditions.
Diet and nutrition are basic to making changes in the genome through epigenetic modifications. Making changes in SNPs in the genome can increase the effects of nutrition on susceptibility or resilience to illness factors due to diet.
Utilizing nutritional genomics in this way challenges the typical focus of modern medicine on illnesses and replaces it with maximizing the human potential for becoming more likely to resist chronic diseases.
A major step in using nutritional genomics as an intervention in preventing chronic illness conditions is in the area of dietary signaling. The nutrients in foods we eat act as dietary signals traveling to cells in the body where they’re interpreted by kinases. Healthy signaling comes with healthy food choices.
On the other hand, poor food choices lead to disorders of kinase signaling, bringing about poor genetic expression and, eventually, chronic illness conditions. Inadequate nutrition is one of the three factors that lead to up to 90 percent of deaths from chronic illness conditions in the U.S.
In the past, we had a relationship with foods commonly eaten. Dietary signals coming through these foods maintained health. With the introduction of the Standard American Diet (SAD), foreign substances and commercially prepared foods led to cellular stress and distorted messages that negatively impact physical functioning. With an emphasis on nutritional genomics, negative dietary signals, premature aging, and chronic illness no longer have to be part of our lives.
The ultimate goal of nutritional genomics is using whole foods in our diet to prevent or at least delay the terrible health issues that are overwhelming our children. One of those catastrophic health issues plaguing our children, and adults, today is obesity.
Obesity vs Overweight
When addressing the issue of the epidemic of obesity in the U.S., we have to consider what we meant by that term and others. Obesity is an excess amount of body fat. Overweight is an excess amount of body weight that can be muscle, bone, fat, and water.
In the U.S. today, estimates are that more than two-thirds of adults are either obese or overweight. More than one-third are obese. More than one in twenty adults are thought to be extremely obese.
About 74 percent of men in the U.S. are thought to be overweight or obese. In both men and women, the prevalence of obesity is about 36 percent. Around 8 percent of women are considered extremely obese.
Children also suffer from this chronic condition. About a third of children age 6 to 19 are overweight or obese. One in six is considered to be obese.
Some of the illness conditions that may result from being overweight or obese include osteoarthritis, Type 2 diabetes, heart disease, high blood pressure, stroke, and some forms of cancer.
It is no surprise then, that the incidence of bariatric procedures to reduce conditions of being overweight or for obesity is increasing dramatically. From about 113,000 surgeries a year in 2009, the number of these weight loss surgeries increased to about 198,000 in 2015.
About half of the recipients of these surgeries gain back five percent or more of the weight lost over the two years post-operation. All of them must undergo significant changes in eating habits and dietary considerations. Sometimes, the emotional impact of these changes is significant.
Also no surprise is the vast number of popular diets that all promise to take off the pounds easily and keep them off. Every one of these diets has a cadre of proponents who swear by them. The truth is some diets work for some people and others work for other people.
There is no perfect diet.
Weight loss programs based on the genetic makeup of the individual appear to be very effective. One study showed 33 percent more weight to be lost over two years when the diet was based on the individual’s genetic profile. One of the key elements in using a genetic profile in establishing a personalized diet is to be aware of which SNPs are relevant in the individual’s genetic makeup. Combinations of these SNPs can determine which diets work best for which individuals.
The one-size-fits-all viewpoint adopted by many in the diet industry and by many pharmaceutical companies no longer works. Multiple studies and clinical practice show sometimes contradictory results. In the diet industry, this is particularly true. When these studies show these kinds of results, there is something missing in the experiment. Some critical variable. And often that variable is genetics. More and more, research is showing this to be true in the case of obesity.
Obesity is probably the most common illness condition that is definitely nutrition related. It is closely associated with abnormalities of metabolism (metabolic syndrome) that includes insulin resistance, hyperinsulinemia, high blood pressure, impaired glucose tolerance, and non-insulin dependent diabetes mellitus. Often, obesity is the jumping-off point for other chronic illness conditions, such as cardiovascular disease and some kinds of cancer.
Whether an individual develops obesity is dependent on genetically determined energy balance regulation.
Obesity is also a strong cardiovascular risk factor. This highlights the fact that polymorphic genes play a part in making the individual at favorable or unfavorable risk for developing this illness condition. Nutritional genomics would suggest changes could be made in genetic expression to lower the risk factor for developing cardiovascular illness conditions and obesity.
We all know that through genetics we may be predisposed to certain health conditions. Obesity is one of them.
Working with a practitioner who is expert in genomic nutrition will enable the individual to understand how genes affect weight and how to modify genetic expression through nutrition to lose weight.
© Copyright 2017 Michael Lam, M.D. All Rights Reserved.
Dr. Lam’s Key Question
How does nutritional genomics affect our health?
The emerging science of nutritional genomics shows how what we eat can affect the expression of our genes and how our genes influence what we eat. Diet is a major component of our health. Thus, this new science can lead to health benefits by influencing our genetic choices of foods.