Observations on the connection between diet and health can be traced back to Ancient Greece, Egypt, and China â€“ the idea that what we eat makes a difference to our well-being is nothing new.
Why, then, is there now so much excitement about developments in this area?
The answer to that question lies not in a new fad diet nor a further debate on the politics of fatphobia but in a rapidly emerging new science that explores how what we eat connects to the most fundamental building blocks of who we are: our genes.
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What is nutrigenomics?
To understand nutrigenomics, you first need to know a bit about the science of genomics. When genes were first identified it was thought that they were a series of simple instructions â€“ enormous in number â€“each of which coded for a simple characteristic. We know, for instance, that a single gene code for eye color, another for tongue rolling (or the inability to do it), but in most cases â€“ as recently demonstrated in the hunt for a â€˜ gay gene â€™ â€“ itâ€™s rather more complicated. Genes are really more like switches which can be turned on or off by factors ranging from chemicals in the environment to the actions of other genes. Whatâ€™s more, some of the code for multiple things, some behave differently if activated in the presence of specific other active genes or at different stages in the life cycle, and everybodyâ€™s genetic make-up is subtly different. Even â€˜identicalâ€™ twins can be distinguished by minor mutations.
What nutrigenomics does is to explore the relationship of diet to our genes, looking at how different foods can turn them on or off, how they interact in relation to disease, and how our individual genetic profiles can affect what constitutes our optimal dietary choices.
For some time now people have been commissioning scans of their personal genomes in order to understand their disease risks. These can be very useful where thereâ€™s a family history of a disease like breast cancer which is strongly associated with the presence of particular genes, giving people the option of choosing preventative treatment where itâ€™s available. But in other situations, they can create worry which itâ€™s difficult to respond to usefully. What nutrigenomics is gradually doing is making it easier for people with particular genetic disease risks to adapt their diets in order to decrease the potential for problem genes to be activated and do them harm.
The crucial role of the gut biome
In considering all this, itâ€™s crucial to remember that thereâ€™s another major factor involved in nutrition and health besides our genomes and the food we eat, and thatâ€™s the gut biome. This is unique to each individual, a collection of microorganisms living inside the digestive system and constituting approximately 43% of all the cells in the body. We need it in order to digest our food but, depending on the specific microbes involved, it can produce waste products that are bad for our health (and smelly â€“ itâ€™s actually bacteria, rather than you, that are responsible when you pass gas). Increasingly, research suggests that a poorly balanced gut biome can cause problems like obesity and increase the risk of autoimmune diseases even when people are eating what would otherwise be considered to be a healthy diet. It is possible to rebalance the biome through interventions in diet and lifestyle, though this can take quite some time to do.
The complexity of healthy eating
In light of all these competing factors, it becomes clearer why some people really can eat the same food as others and end up a different shape with a different set of health issues. According to nutrigenomics enthusiast Amy Yasko, tailoring diets to individuals is a much more effective way to improve health outcomes. This has already been done to an extent in the case of diseases like Type 2 diabetes, where there is a genetic risk that can usually be identified through family history, but nutrigenomics has the potential to see it refined much more. As science develops and the mechanics of the relationship between diet and genes become better understood, it may even become possible to activate specific genes intentionally or turn off others in order to produce beneficial effects.
Part of the excitement around nutrigenomics stems from the fact that it has the potential to help treat a number of illnesses that have traditionally been neglected or seen as difficult to manage, from obesity to depression to irritable bowel syndrome. It may also be helpful in controlling or mitigating the development of the metabolic syndrome. As medicine moves increasingly towards a focus on prevention rather than cure, and as improved symptom management options are sought for diseases the mechanisms of which remain elusive, nutrigenomics could have an important role to play.
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