“Over-reliance on genetic-centered approaches in predicting, diagnosing and treating disease will lead to few future scientific breakthroughs, cautioned a researcher who co-authored an article that advocates for a greater emphasis on the body’s metabolites in understanding illnesses.”
I think that’s true. But you’d never know it to see all the genetic tests (e.g. 23andMe) and media reports on gene-based medicine, rather, “hope” for such medicine.
The quote is from the article: Metabolites’ Role In Understanding Disease Emphasized, ScienceDaily, 3 April 2014
And is based on the study: Systems Genomics Of Metabolic Phenotypes In Wild-type Drosophila Melanogaster, Genetics, March 2014
Lead author, Laura Reed, also said:
“The Human Genome Project has been sold as something that is going to revolutionize medicine — that soon we will get our genomes sequenced, and we will be able to figure out exactly what diseases we are at risk for and, maybe, the best way to treat them,” said Reed. “While it’s true there are important innovations to come from that kind of information, it is much more limited than some may have hoped.”
Lifestyle changes such as eating a healthful diet and not smoking have been found to overcome genetic predispositions. Reed’s team looked at various diets in fruit flies. Diet had a significant effect on the 187 metabolites they measured.
“One of the important things we found is that the effects of diet are relatively small for gene expression, but much more significant for all the metabolites.”
Metabolites include things like cholesterol and blood glucose, molecules we currently measure to predict disease. Reed said there are many more metabolites we could be studying, e.g. glycine “a metabolite which serves as both an essential amino acid and a neurotransmitter, has previously been shown as a predictor of heart disease and certain cancers.”
When it comes to disease, a more fruitful line of research may be study of metabolites instead of genes, for a mutation in a gene[s] does not guarantee disease (but changes in metabolites may just):
In another aspect of the research, the scientists tracked how the frequency of genes in wild flies changed through time (over multiple generations) in response to diet. Rather than seeing changes in one particular gene or a small group of genes, the researchers saw changes across the entire genome.
“We can’t expect to find a gene or just a few genes that explain any phenotype, including disease,” Reed said. Disease is a holistic problem, she said, and it’s unlikely that additional “miracle drugs” await discovery.
“It’s going to be a holistic solution,” Reed said.
Reed said she realizes the paper may not be warmly embraced by all her fellow geneticists.
“The overall point of the paper is not a very popular idea,” Reed admitted, “because it basically means things are much more complicated than we want them to be. But, that’s reality.
“This does not mean that we can’t incrementally improve things by understanding the genes that are involved, but, perhaps, a more expedient approach would be analyzing higher level traits, like metabolites, that might summarize what’s occurring in the genome in ways more useful for diagnostic or treatment purposes.”
Does this “holistic” point of view remind you of anything? It is the essential message in Campbell’s book, Whole: Rethinking the Science of Nutrition. From the book’s description:
What happens when you eat an apple? The answer is vastly more complex than you imagine.
Every apple contains thousands of antioxidants whose names, beyond a few like vitamin C, are unfamiliar to us, and each of these powerful chemicals has the potential to play an important role in supporting our health. They impact thousands upon thousands of metabolic reactions inside the human body. But calculating the specific influence of each of these chemicals isn’t nearly sufficient to explain the effect of the apple as a whole. Because almost every chemical can affect every other chemical, there is an almost infinite number of possible biological consequences.
And that’s just from an apple.
Nutritional science, long stuck in a reductionist mindset, is at the cusp of a revolution. The traditional “gold standard” of nutrition research has been to study one chemical at a time in an attempt to determine its particular impact on the human body. These sorts of studies are helpful to food companies trying to prove there is a chemical in milk or pre-packaged dinners that is “good” for us, but they provide little insight into the complexity of what actually happens in our bodies or how those chemicals contribute to our health.
Campbell explains his ideas further in his blog post: Making Ourselves Whole.
You can’t take something out of context and try to understand how it operates within a complex system. You have to observe it within its system. It’s difficult, because the thing you are observing will behave in response to the machinations of the system within which it resides. So what. That’s the challenge.
There’s an irony here in that you almost have to study in a reductionist way before you can come to appreciate the complexity and interconnectedness of things.
Regarding genetic medicine specifically, Campbell is no fan. He calls it “the ultimate reductionist fantasy.” From his book, “Whole”:
“Genetic medicine is the ultimate reductionist fantasy. It sidesteps the messy big-picture factors that influence health and the development of disease, and focuses on millions and millions of tiny, deterministic elements with no room for fuzziness or randomness. It lets scientists point to a bit of DNA and say, “There, that’s why you got pancreatic cancer!” And despite all the evidence calling in to question a direct link between genes and cancer (and most other chronic diseases), geneticists are now pointing to bits of DNA and asserting, “There, that’s why you’re probably going to get pancreatic cancer within the next forty years.”
The “messy big-picture factors that influence health” include the same “metabolites” that Reed refers to above.
People are taking extreme actions based on the results of genetic tests, e.g prophylactic mastectomies. Is it warranted? Whether it is or not, genetic medicine and it’s outcroppings (tests, drugs, surgeries) are extremely lucrative for the businesses involved.
I really like Campbell’s expansive take on wholism. It invites you to consider how things like climate change and income inequality impact on health and the human condition:
“We must be willing to embrace wholism beyond the realm of nutrition. The body is a complex system. Bodies gathered together in societies are even more complex. And human life, interwoven with all of nature on this planet, is complex beyond our imagining.”