Bad news for bacon lovers in meat study
An American study of nearly 30,000 men and women has tied higher consumption of processed meats such as bacon, sausages and hot dogs, as well as unprocessed red meat and poultry, to a greater risk of cardiovascular disease.
The Cornell University study, which tracked participants for up to three decades, also found that both processed and unprocessed red meat were associated with a small increase in the risk of death from all causes.
The study found that higher consumption of fish was not associated with the greater risk of cardiovascular disease, or indeed all-cause mortality.
Researchers found that participants who had two serves of processed meat per week had a seven per cent increased risk of cardiovascular-related incidents compared to those who had none.
The study defined a serving of processed meat as two slices of bacon, one hot dog or two small sausages.
Project participants had an average of 1.5 servings of processed meat per week, as well as three servings of red meat, two servings of poultry and 1.6 servings of fish.
While the percentage risk increases were not large, lead researcher Dr Victor Zhong and his team said the results had "critical public health implications given that dietary behaviours are modifiable, and most people consume these four food types on a daily or weekly basis".
Australian nutritionist Dr Rosemary Stanton said the results of the study were in keeping with other research, but pointed out that the study did not accommodate dietary changes that many participants would have probably made during the course of the project.
The research also did not differentiate between different cooking methods - such as grilling or deep-frying chicken, which could have had an impact on the results for poultry, she said.
"The take-home message from this large and long-term analysis is that no single food is going to determine the overall healthiness of your diet or your subsequent health," Dr Stanton said. "However, from this and many other analyses, it's wise to limit consumption of red and processed meats, and probably chicken. For heart health, fish and seafood impose no apparent risk. This all fits with existing dietary guidelines."
Dietitian and nutritionist Dr Alan Barclay, a research associate at the University of Sydney, said meat-based protein sources were now being "demonised" in the way fat was in the 1980s and 1990s and carbohydrates were in the early 2000s.
The Cornell study was limited because participants were quizzed about what they ate only when they started with the project, and not at intervals during the study, Dr Barclay said.
"While the results of this pooled analysis are interesting, they do not constitute high-quality scientific evidence," he said.
"Serious weaknesses include the fact that few people maintain exactly the same eating habits over a 30-year time frame due to ageing, and associated life-stage changes."
Future studies should track participants' diets every five years and take account of the cooking methods used, he added.
The study is published in the journal JAMA Internal Medicine today.