(CN) – Cancel your steak order and opt for a plant-based meal if you want to avoid bad health and even death, researchers said in a pair of studies Monday that link consumption of red meat and poultry to higher risks for heart disease.
Red meat – along with processed meats such as hot dogs, salami and beef jerky – have been linked to cancer and heart disease in numerous studies.
The established link between meat consumption and bad health is an inconvenient truth for avid meat eaters, including in North America and Europe where studies have found the average person consumes two to four servings of meat every week.
Northwestern Medicine and Cornell University researchers carefully analyzed long-term health outcomes for meat eaters, including groups of people tracked over three decades.
People who ate two servings of red meat, processed meat or poultry – but not fish – per week experienced a 3% to 7% higher risk of heart disease, researchers found.
Researchers also found people who ate two servings of red meat or processed meat – but not poultry or fish – per week faced a 3% higher risk of all causes of death, according to their study published Monday in JAMA Internal Medicine.
Norrina Allen, a professor at Northwestern University Feinberg School of Medicine, said in a statement small changes in people’s diets can boost overall health outcomes.
"It's a small difference, but it's worth trying to reduce red meat and processed meat like pepperoni, bologna and deli meats," Allen said. "Red meat consumption also is consistently linked to other health problems like cancer."
Lead study author Victor Zhong of Cornell agreed, saying in a statement that researchers found clear links between eating meat and poor health.
"Modifying intake of these animal protein foods may be an important strategy to help reduce the risk of cardiovascular disease and premature death at a population level," Zhong said. "Our study shows the link to cardiovascular disease and mortality was robust."
Zhong added that the study linked fried chicken and fried fish to chronic diseases.
Of the nearly 30,000 self-reporting participants of the study, 44% were men, nearly 31% were non-white and their mean age was 53.7.
Study co-author Linda Van Horn of Northwestern Medicine said in a statement that fish, seafood and plant-based sources of protein such as nuts and legumes are excellent, under-consumed alternatives to red meat.
The findings contradict a study published last year that downplayed negative health effects associated with red meat consumption.
In that study, researchers concluded people don’t need to reduce meat consumption to improve health outcomes since the benefits are uncertain and health risks are small.
Penn State researchers said in a separate study Monday that plant-based diets – which are lower in sulfur amino acids – are linked to reduced risks for cardiovascular disease.
Lead researcher John Richie of Penn State College of Medicine said that while amino acids are key elements of proteins, increased in sulfur amino acids – which aid the body’s metabolism functions – in diets can lead to poor health.
"For decades it has been understood that diets restricting sulfur amino acids were beneficial for longevity in animals," Richie said in a statement. "This study provides the first epidemiologic evidence that excessive dietary intake of sulfur amino acids may be related to chronic disease outcomes in humans."
Researchers tracked the diets and blood biomarkers, sourced from the Third National Examination and Nutritional Health Survey, of more than 11,000 participants of the national study.
People with a history of heart disease or heart attacks and those whose diets contained levels of sulfur amino acids below the required average were excluded from the study.
Levels of cholesterol, triglycerides, glucose and insulin in participants’ blood was measured after a 10- to 16-hour fast and ranked with a disease risk score.
"These biomarkers are indicative of an individual's risk for disease, just as high cholesterol levels are a risk factor for cardiovascular disease," Richie said. "Many of these levels can be impacted by a person's longer-term dietary habits leading up to the test."
Researchers found the average American consumes almost three times more sulfur amino acids in their diet than what is required, according to the study published in Lancet EClinical Medicine.
Penn State researcher Xiang Gao said in a statement the findings may be tied to eating trends in the United States.
"Many people in the United States consume a diet rich in meat and dairy products and the estimated average requirement is only expected to meet the needs of half of healthy individuals," Gao said. "Therefore, it is not surprising that many are surpassing the average requirement when considering these foods contain higher amounts of sulfur amino acids."
Zhen Dong, lead author on the study, said in a statement high sulfur amino acid diets were linked to every type of food except grains, vegetables and fruit.
"Meats and other high-protein foods are generally higher in sulfur amino acid content," Dong said. "People who eat lots of plant-based products like fruits and vegetables will consume lower amounts of sulfur amino acids. These results support some of the beneficial health effects observed in those who eat vegan or other plant-based diets."
Researchers said the findings point to a need to evaluate sulfur amino acid intake and its ties to heart diseases over a long period.
"Here we saw an observed association between certain dietary habits and higher levels of blood biomarkers that put a person at risk for cardiometabolic diseases," Richie said. "A longitudinal study would allow us to analyze whether people who eat a certain way do end up developing the diseases these biomarkers indicate a risk for."
Researchers on both studies did not immediately respond to a request for comment on the findings.
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