How Food Affects Our Genes
By Dr. Ola Buhr
The topic of nutrition has been my passion (and possibly obsession) and has peaked my interest particularly when dealing with disease prevention and reversal of chronic illness. I have incredibly expanded my knowledge of nutrition working at the Riordan Clinic over the past year. Unfortunately, this important topic has been grossly undervalued in my conventional medical training and I have come to realize that nutrition is the key, the bedrock, the foundation to optimal health and wellness. Many of our Health Hunter readers already know that a nutrient dense, whole food, largely plant based, and organic diet supports our body’s metabolic needs, cellular processes, and hormone functions. However, there is a growing field of study, one that is quickly expanding, called nutritional genomics (or nutrigenomics). This molecular and genetic process involves the interplay of nutrients (dietary chemicals) upon our human genome, creating a causal effect on the way our genes are expressed. I find this to be a rather complex topic relating to advanced biomolecular chemistry and genomics, but a fascinating field nonetheless still in its infancy. In this article I hope to introduce you to this new and rapidly expanding paradigm of medicine.
The concept of nutrition affecting our genes and their expression is not a new one. Doctor Roger Williams, PhD (a renowned biochemist) began describing the phenomenon in an article published in The Lancet in 1950 entitled “The Concept of Genetotrophic Disease”. Through his research he observed that certain individuals are genetically predisposed to require higher levels of vitamins, minerals, and specific nutrients beyond the average daily intake for them to support “optimal function and prevent premature disease”.1 (p. 65) We are beginning to discover that “the unique genes of each individual require different levels of nutrition and a specific lifestyle for optimal health.”1 (p. 65) Doctor Williams theorized that when these specific needs are not met, chronic degenerative diseases result. Majority of the groundbreaking work within this expanding concept comes from the international scientific efforts of the Human Genome Project, funded by the United States government and completed in 2003. The thirteen-year project resulted in the sequencing and encoding of 99% of the 3,164.7 million base pairs of human DNA. The analysis and interpretation from this vast amount of genomic data is still in its initial stages but scientists and biomedical companies are already researching its clinical applications. Scientists are particularly
interested in identifying and understanding causes of disease in order to act upon them for prevention and treatment. The human genome is estimated to encode 30,000 genes while over 50% of the functions of those genes remain yet to be discovered.
A gene is the functional and physical unit of heredity passed from parent to offspring. Our genes (these pieces of DNA) contain the information necessary for making a cell; they are the blueprints for the proteins and structures in our body. It is the job of these proteins to carry out highly specialized functions. The small molecules that result from these enzymatic reactions “provide the signaling and communication activities throughout our bodies”. 1 (p. 72) The process of making these proteins from DNA is called gene expression. The genome comprises the complete genetic composition of an organism, you can think of it as the entire Encyclopedia Britannica encoding all the DNA of just one person. Each cell contains this vast genome, but the cell only uses the portions of the material relevant for its specific functions. For example a liver cell possesses genetic information to make bone but this material is “turned off” and therefore never expressed or created within the liver.
Just as we humans physically look a little different from everybody else so do our biochemical pathways and the genetic material residing within our cells. This concept is known as “biochemical individuality” and was first coined by Doctor Roger Williams in his book of the same name, published in 1956. “Each and every person is unique at the level of [their] DNA.”1 (p. 65) This uniqueness is becoming a subject of discussion specifically surrounding the field of pharmacology and pharmacogenetics. Even Allen Roses, the vice-president of genetics at GlaxoSmithKline, stated: “The vast majority of drugs—more than 90%—only work in 30 or 50% of the people. I wouldn’t say that most drugs don’t work. I would say that most drugs work in 30 to 50% of people. Drugs out there on the market work, but they don’t work for everybody.”1 (p. 69) We are beginning to find out that the reason certain medications are not effective for some people is due to the different expression of their genetic material. The enzymes that are encoded by genes involved in metabolizing specific medications (termed cytochromes) may have an altered function (for example they may work poorly or not at all while others work “overtime”). These alterations in the DNA sequence are called SNPs or Single Nucleotide Polymorphisms. SNPs are transcribed into proteins or enzymes that become more active or less active in their specific function, “and are considered to account for much of the variability seen among different individuals.” 1 (p. 67) Pharmaceutical companies have created a “one size fits all” model with drug therapies but we are beginning to see that a drug may be highly effective for one person, cause a fatal reaction in another, and for the third have no therapeutic effect at all. Even scarier is the information gathered from a 1998 meta-analysis published in the medical journal JAMA where a conclusion was made “that adverse drug reactions from properly prescribed medications represent between the fourth and sixth leading cause of death in the United States.” (pg 69)
One more important genetic phenomenon I want to define is that of epigenetics. Our genes (DNA base pairs) may be “fixed” at birth but the way they become expressed as proteins, enzymes, chemical messengers, and signaling molecules in our body is highly dependent on our diet, lifestyle, behavior, and environment (even in the periconceptual, fetal, and infant phases of life). Much more attention is being received in the field of epigenetics and this is now becoming regarded as a critical mechanism for in-utero development, aging, chronic diseases, and the formation of cancer. Nutrition influences epigenetic gene regulation and by learning about this relationship we see that disease processes can be altered or modulated as we grow into adulthood. Therefore even though our parents may have high blood pressure, diabetes, heart disease, or even cancer does not mean that this will be our lot in life too. We have plenty of control in what we put into our bodies and how we treat them that determines whether we live a life full of vitality and wellness or one of chronic degenerative disease. If we sustain our body with phytonutrient-rich minimally processed, whole foods “we can change the ways our genes get stimulated and the way they respond, and since genes regulate or direct our biological functions, that can also change our pattern of health.”2 (p. 5) Thus the epigenome is a multitude of chemical compounds that can tell the human genome what to do.
What do green tea, turmeric, red grapes, hops, soy, folate, retinoids, zinc, vitamin B12, and cruciferous vegetables all have in common? These are termed bioactive food components (BFCs) and all have the ability to directly communicate with our genetic material to enhance “DNA repair, hormonal regulation, cell differentiation, inflammation, controlled cell death (apoptosis), cell cycle control/proliferation, carcinogen metabolism, [detoxification, mitochondrial function], among others.” 3 (p. 208) These BFCs are powerful because through epigenetic modulation they inherently possess properties to fight against cancer cells. Countless research studies have indicated that they are capable of activating genes, which suppress tumor growth and can silence specific sets of genes that contribute to the pathogenesis of cancer. Examples of dietary polyphenols affecting the epigenome involve DNA methylation (chemically modifying the DNA strand itself), histone acetylation (proteins closely associated with DNA), and chromatin remodeling. I cannot go into these details as they are beyond the scope of this article.
Here is a list of specific foods that contain phytochemicals known to positively support genetic expression: (List taken from the book The Disease Delusion)
1) Green tea, which contains catechins
2) 2) Turmeric, which contains curcumin
3) Soy, which contains genistein
4) Cruciferous vegetables, which contain glucosinolates (sulforaphanes, diindolylmethane (DIM), indole-3-carbinol)
5) Red grapes and Spanish peanuts, which contain resveratrol (in the skin of the peanuts)
6) Watercress and pomegranate, which contain ellagic acid
7) Hops, which contain humulones
We are just at the beginning stages of exploration and understanding regarding this magnificent interaction of bioactive food components upon our epigenome. There is still much to be discovered regarding how these dietary factors influence our complex network of bio-molecular communication pathways, therefore additional research opportunities abound. Just this month the Journal of the American Medical Association published an article stating that although the “interplay between genes, environment, epigenetics, and disease is complicated and still poorly understood” the authors acknowledged that the interrelationship of nutrition has control over the human epigenome. The article also mentioned a 2014 study published in the Journal Science in which in-utero mice were fed a nutrient deficient diet and their epigenetic changes were passed on to the next generation. This is startling information, especially in this day and age where we are bombarded by fast food restaurants, food additives and chemicals, and highly processed meals that are nutrient deficient. In our American society where millions of people consume the Standard American Diet and eat processed, highly caloric meals they unfortunately remain nutritionally starved on a cellular level. This information can imprint on our epigenome and be passed on to our children. Remember, food is information for our genes. The information we receive from a calorie of a refined and enriched bagel is much different than that of a calorie from broccoli. Make wise food choices and pass those on to your children so that all generations can thrive in health and happiness. Eat those bright, colorful, fresh vegetables because they hold the information and control mechanisms to manifest and maintain a disease free balance within our bodies.
Food by way of nutrients is not the only factor influencing our epigenome. “…Prenatal and early postnatal environmental factors, xenobiotic chemical exposures, behavioral cues, and low-dose radiation can also alter epigenetic marks and processes and subsequent changes in the risk of developing disease.”3 (p. 212) We are also seeing studies exemplify this inheritance transgenerationally, thereby affecting the health of our children. Xenobiotics (synthetic chemicals foreign to the body and ecological system) such as bisphenol A (BPA), a chemical found in a multitude of plastic products, has shown to be associated with higher body weight, increased breast and prostate cancer, and altered reproductive function in mouse models wherein mouse fetuses and neonates were exposed to the substance. Scientists also observed that when the mothers of these mice fetuses were exposed to bioactive food components (like genistein) the negative epigenomic effect was counteracted by the dietary supplements. This means that the phenomenon is modifiable and reversible showing us that “gene function [can change] under exogenous influence.”3 (p. 229) Researchers acknowledge “there is also a need to further our understanding of the interaction between diet, epigenetics, and crucial times of exposure during development and throughout the entire life span.”3 (p. 213).
This is new cutting-edge knowledge that brings us into an educated state of empowerment. We are no longer powerless human beings, victims of an inherited long strand of DNA material. Our cards have not necessarily been dealt at the moment of conception. Every fork-full we consume has the power to determine a complex interplay of reactions that can touch the very core of our genetic make-up. I want to leave you with a quote penned by holistic health practitioner Ann Wigmore “the food you eat can be either the safest and most powerful form of medicine or the slowest form of poison.”
1) Jones, David, et al. Textbook of Functional Medicine. Boulder: Johnson Printing. 2005 and 2006. Print.
2) Bland, Jeffrey. The Disease Delusion. New York City: Harper Wave, 2014. Print.
3) Choi, Sang-Woon and Simonetta Friso. Nutrients and Epigenetics. Boca Raton: CRC Press, 2009. Print.
4) Feinberg A, Fallin D. “Epigenetics at the Crossroads of Genes and Environment.” Journal of the American Medical Association. 2015 Sept 15; 314(11): 1129-1130.