Emerging Concept: Nutrigenomics - what you eat affects your genes
"...many chronic training adaptations are generated by the cumulative effects of the transient events that occur during recovery from each (acute) exercise bout. Evidence is accumulating that nutrient supplementation can serve as a potent modulator of many of the acute responses to both endurance and resistance training.”
-Promoting Training Adaptations Through Nutritional Interventions
Throughout history, humans have understood the foods that we eat can influence our health, behavior, mood, and performance. Some cultures have created great traditional medicine knowledge bases that literally span thousands of years of trial and error that attempt to understand the interaction between food and physiology (Ayurveda and Traditional Chinese Medicine come to mind). However only recently have we been able to begin to understand how the foods and supplements we consume impact our physiology. By combining nutrition, biochemistry, and physiology we are now able to measure the impact that specific nutritional components have on our genes. This has led to the development of the concept of nutrigenomics or how specific nutrients interact with our genes to create functional changes in our bodies. This understanding; that the foods we eat and the supplements we take exert their effects by regulating gene expression; will be critical to understanding and creating nutrition and supplementation routines for elite-level athletes.
Nearly all of the foods and supplements that we consume have an impact on our gene expression. Nowhere is this more clean than when you eat carbohydrates. The resulting spike in blood glucose after carbohydrate ingestion causes a temporary release of insulin from the pancreas. Insulin binds to receptors on the surface of tissues activating GLUT4 transporters and allowing glucose to pass from the blood into those tissues. This process, the increased transcription of insulin by the pancreas in response to elevated blood sugar, is a simple example of nutrigenomics at work.
The concept of Nutrigenomics is simple:
eat nutrient -> alter gene expression -> affect physiology
Nutrigenomics: Muscle Growth versus Endurance Signalling
Exercise activates a multitude of different genetic signaling pathways. Two of these genetic signaling pathways are of interest to athletes and exercise researchers: AMPk (generally stimulated by endurance training) and mTOR (generally stimulated by resistance training). A unique quirk of our physiological response to exercise is that when one of these two genetic pathways is activated in response to training the opposing one is generally inhibited. This a contributing factor to the concurrent training effect where the combination of strength and endurance training leads to a smaller degree of improvement in either domain when compared to strength or endurance training alone.
As it turns out there are specific nutrients that can activate these signaling pathways independent of exercise. Following our understanding of the opposing effect of AMPk and mTOR on adaptations to exercise, we need to be selecting appropriate nutrients to compliment and not inhibit our adaptive response to training. For example, Resveratrol and EGCg are both known activators of the AMPk signaling pathway. These are both touted as healthy supplements and many athletes unwittingly consume them in some form as part of a multi-nutrient supplement. Consumption of Resveratrol or EGCg in close proximity to resistance training may blunt an athletes adaptive response to the training session.
On the other hand, activation of the mTOR pathway does not appear to posses the same inhibitory effect on endurance adaptations that AMPk has on strength adaptations. Nutritional mTOR activation can be elicited specifically by the amino acid Leucine or complete proteins which contain high quantities of Leucine. In addition, the breakdown metabolite of Leucine; HMB (beta-Hydroxy beta-methylbutyric acid) has been shown to activate mTOR signaling as well, though to a lesser degree. This is the basis for the recommendation that athletes consume whey protein (high in Leucine) after resistance training in order to maximize the benefit from the training session. Only recently have we been able to discern how post strength training protein consumption imparted its benefits.
Antioxidants and Endurance Adaptations
At this point I need to introduce another concept: Hormesis. Hormesis refers to the phenomenon where low to moderate doses of a particular nutrient can be beneficial but higher intakes can create health issues. This is particularly important regarding antioxidant intake in athletes. Research consistently shows that elevated nutritional antioxidant intake is beneficial for sedentary individuals who have high levels of oxidative stress due to poor diet and lifestyle. However, research also indicates that in healthy athletes free radicals (ROS) produced by exercise actually serve as a potent signal for our bodies to make adaptations to training. The consumption of vitamin or plant based antioxidants can effectively dampen your bodies ability to adapt to endurance training. Thus the timing and dosage of antioxidant intake is critical to maximizing athletic performance.
Conclusion / Further Reading
It should be clear at this point, that basing your nutrition and supplementation routine based on headlines or marketing hype is probably not the best idea if you’re looking to maximize performance. The reason I titled this an “emerging topic” is because up until the early 2000’s very little was known about what was happening from a genetic standpoint during exercise or nutrition. The field of nutrigenomics has seen rapid growth over the past 10-15 years and many of the things that we used to “KNOW” have since been disproven, this is the way of science. I’ve always been someone who needed to understand why or how something worked. I believe that only by taking the time to better understand the way that exercise, nutrition, and supplementation affect our physiology and psychology will we be able to maximize human performance. If you are interested in learning more about this topic, I have compiled a brief reading list on the so that you may familiarize yourself further with the topic.
Book: Explosive Ergogenics for Athletes: using the science of nutrigenomics to maximize performance
Article: The Role of AMPk and mTORin Nutrient Sensing in Pancreatic B-cells
Article: Promoting Training Adaptations Through Nutritional Interventions
Article: Role of Leucine in the Regulation of mTOR by Amino Acids
Vitamin C and E Supplementation Hampers Cellular Adaptation to Endurance Training