Scientists have found a gene mutation that protects heart against high-fat diet. But the mutation is found exclusively among the US Amish population in Lancaster, Pennsylvania. About five per cent of the people surveyed carry the gene in the them.
Those with the mutation had higher levels of "good" HDL-cholesterol and lower levels of "bad" LDL-cholesterol, the journal Science reported.
It is hoped the finding will lead to new therapies to reduce cholesterol.
The Amish are members of an Anabaptist Christian denomination, best known for simple living, plain dress and resisting modern conveniences. The roots of the Amish began in Switzerland among Swiss Brethren in 1693 under the leadership of Jakob Ammann. Then, in the early 18th century they began immigrating to Pennsylvania because of intense persecution.
The word "Amish" is a term used by non-Amish; the Amish would refer to themselves as the "plain folk."
Over the years, there have been several divisions among the Amish. The Old Order Amish are those that have been the most successful at resisting change and in retaining their traditional way of life. As of 2000, over 165,000 Old Order Amish live in Canada and the United States. A new study in 2008 suggests their numbers have increased to 227,000.
The researchers at the Maryland School of Medicine used blood samples from 800 volunteers in the Old Order Amish community to look for DNA markers that might be associated with levels of fat particles called triglycerides in the blood stream.
High blood levels of triglycerides, one of the most common types of fat in food, have been linked to heart disease.
They found a mutation in the APOC3 gene, which encodes a protein - apoC-III - that inhibits the breakdown of triglycerides.
As part of the study, participants drank a high-fat milkshake and were monitored for the next six hours.
Individuals with the mutation produced half the normal amount of apoC-III and had the lowest blood triglyceride levels - seemingly because they could break down more fat.
They also had relatively low levels of artery-hardening - a sign of cardiovascular disease.
Study leader Dr Toni Pollin, assistant professor of medicine, said: "Our findings suggest that having a lifelong deficiency of apoC-III helps to protect people from developing cardiovascular disease.
"The discovery of this mutation may eventually help us to develop new therapies to lower triglycerides and prevent cardiovascular disease," she added.
The researchers believe the mutation was first introduced into the Amish community in Lancaster County by a person who was born in the mid-1700s.
It appears to be rare or absent in the general population.
Cathy Ross, cardiac nurse at the British Heart Foundation said the benefits of high HDL cholesterol and low LDL cholesterol are already being achieved by drugs such as statins.
"If new drugs can be developed that mimic the effect of this mutation, it may afford more ways in which individuals could be protected from developing cardiovascular disease.
"There are also lots of other simple ways people can reduce your risk of cardiovascular disease such as eating a diet low in saturated fat, having five portions of fruit and vegetables a day and taking regular physical activity."