We've found that humans are far more metabolically diverse than genetically diverse. For instance, Chinese and Japanese people are actually metabolically very distinct, despite the fact they're genetically near identical. And they have very different incidences of diseases.
How could scientists use this information to inform medicine?
I have this new concept of metabolome-wide association study. It will allow us to sample the genetic and the environmental things that cause diseases in people. We've found metabolic biomarkers that link to things like blood pressure in humans. Using this approach, we can generate new hypotheses in physiology that can be tested and may ultimately result in new drug discovery.
And you believe many of our metabolic differences have to do with gut bacteria. How did you come to realize that these microbes were so important for our health?
I've always known, ever since we started working on metabolic profiling, that there were metabolites that came from the gut microbes. We never really paid a lot of attention to it until maybe about seven or eight years ago, though. It was not just me—it was also Professor Ian Wilson [a scientist at AstraZeneca in England]. He became intrigued because he looked at colonies of rats—supposedly very, very similar groups of rats—but some produced one set of metabolites and others produced a different set. And yet they were from the same breeder; they were the same genetic strains. The differences were down to different gut microbial populations in rats residing in different parts of the laboratory.
The more we looked into it, the more we realized that microbes were so intimately involved in animal metabolic processes that they might have contributions to disease development in ways that hadn't really been thought of before. We're really just starting to expand this now, thinking about how gut microbes influence all sorts of things. They have influences on liver diseases and gut pathology like Crohn's disease and irritable bowel syndrome; there's even evidence that autistic children have very, very different gut microflora [than other children]. Almost every sort of disease has a gut–bug connection somewhere. It's quite remarkable.
What, ultimately, are you hoping to achieve with metabolomics?
We want to be able to take a set of biological data from a human being, and then, based on what we know about the metabolic makeup of that person, say how long they're going to live, what diseases they're likely to suffer from, how to treat those diseases, and how to manage their lifestyle and drug therapy optimally. We're opening up sets of doors here into the future of health care—the manipulation of biology that would be just unimaginable five years ago.
Any funny or surprising moments you'd like to share from your research?
We did some work about 10 years ago at another person's laboratory on something called magic-angle spinning spectroscopy [a kind of NMR spectroscopy that relies on spinning the sample to achieve higher resolution data]. What I was interested in was whether or not we could get some extra information out of lipoprotein signals by spinning the probe very, very fast. I put the blood plasma sample in and the spectrum that came out was totally nothing like plasma is normally. I thought, absolutely fantastic! We've liberated all this new information! We tried several more samples and the same thing happened, and so I started to chat with one of the guys in this laboratory. I said, "We got an amazing spectrum, it looks nothing like plasma spectra should be." And he said, "Oh, show me!" And I showed him and he said, "Hmm, that looks very familiar." To cut a long story short, what happened was that the previous week the guy had been running samples of blue cheese—a food science company had been conducting experiments. Rather than discovering a new part of the fundamental dynamics of lipoproteins, we discovered how to detect blue cheese in plasma.