Researchers creating a map of human metabolism around the world have found compounds in urine that point to some surprising differences affecting blood pressure, based not on genes but on what people eat and their gut bacteria.
They hope their findings, published in the journal Nature on Sunday, can help lead to the development of new drugs to fight high blood pressure or perhaps even non-drug therapy.
They analyzed urine samples from 4,630 people in the United States, Britain, Japan and China to find some surprising new links to blood pressure differences.
"On one end of the metabolic world we have got people in southern China and at the other end we have got people from Corpus Christi, Texas," said Jeremy Nicholson of Imperial College London, who led the study.
"And you can geographically map people according to their metabolic patterns," he added.
"Britain is the '51st state' as we are really in the middle of America. Our lifestyle and our diets and our ethnic mixes are quite similar in many ways to America."
The patterns do not seem to follow genetics, Nicholson said. "It has to do with their diet and lifestyle and also gut microorganisms," Nicholson said.
Bacteria in the intestines and colon help digest and break down food and many recent studies have suggested that humans and their gut bacteria have a truly symbiotic relationship.
Some of the compounds they release have drug-like effects, Nichols said.
He looked at these breakdown products, called metabolites, in human urine to see if he could find any links with heart disease.
Saying the study only scratches the surface, Nicholson said his team already identified four such compounds that can be linked with blood pressure differences.
1 billion have high blood pressure
An estimated 1 billion people globally have high blood pressure, defined as a reading of 140/90 or higher. It is a major cause of stroke, heart disease and kidney failure.
The best-known cause is high salt intake, but a diet rich in vegetables and certain minerals and steady exercise can lower blood pressure.
Nicholson's team was looking for more evidence linking salt with high blood pressure.
One link they found was a compound called formic acid or formate.
"Not much is known about what the role is of formic acid in the body. It's the thing that makes ant stings hurt and bee stings as well," Nicholson said.
It may be involved in processing chloride from salt in the kidney, Nicholson said.
"It means maybe if you modulate formate metabolism you can modulate blood pressure," he said.
They also found that people with higher levels of an amino acid called alanine in their urine had higher blood pressure. The same team had earlier shown that people who eat more meat and other animal products had higher alanine levels.