A new study, published in the Journal of the American Society of Nephrology, investigated the long-term impact of red meat consumption on kidney health. Their findings justify the current caution suggested in regard to red meat and organ health.
Red meat, such as beef, lamb, and pork, can be included as part of a healthy diet.
But, as with many dietary components, it is best to limit the amount consumed.
A study, published in JAMA in 2012, documented 23,926 deaths and concluded that red meat consumption was associated with an increased risk of cardiovascular disease and cancer mortality.
The present study, carried out at Duke-NUS Medical School and Saw Swee Hock School of Public Health at the National University of Singapore, further investigated red meat's potential impact on kidney health.
A rise in kidney disease
An increasing number of people are developing chronic kidney disease (CKD); globally, an estimated 500 million people have CKD. Many patients with CKD go on to develop end-stage renal disease (ESRD). This is a serious condition that requires kidney dialysis or transplant.
Currently, a reduced protein intake is suggested to patients with CKD to slow the progression to ESRD. However, the role of different protein sources in the development of ESRD has not been investigated previously.
Researcher Woon-Puay Koh and her team delved into data from the Singapore Chinese Health Study, which included more than 63,000 adults, aged 45-74. They linked the data with the Singapore Renal Registry, which holds the records of all Singapore ESRD patients. The overall aim was to uncover the role of different protein sources on kidney health outcomes.
"We embarked on our study to see what advice should be given to CKD patients or to the general population worried about their kidney health regarding types or sources of protein intake," explains Koh.
In China, the primary red meat is pork, accounting for 97 percent of red meat intake. Other popular protein sources included eggs, dairy, shellfish, fish, soy, legumes, and poultry.
The participants were followed up for an average of 15.5 years. During that time, 951 cases of ESRD occurred; the resultant data showed a clear trend.
Red meat intake was associated with a dose-dependent increased ESRD risk. Individuals who consumed the highest amounts of red meat - the top 25 percent - showed a 40 percent higher risk of developing ESRD than those who consumed the least red meat - the bottom 25 percent.
Other sources of protein - fish, eggs, dairy, and poultry - showed no associations with the development of ESRD. Additionally, soy and legumes appeared to play a slightly protective role.
"Our findings suggest that these individuals can still maintain protein intake but consider switching to plant-based sources; however, if they still choose to eat meat, fish/shellfish and poultry are better alternatives to red meat."
One less portion of red meat reduces risk
The researchers estimate that replacing one serving of red meat per week with a different protein source reduces the risk of developing ESRD by up to 62 percent.
These results back up other recent studies, giving them added weight. For instance, a Japanese study found that geographical regions where more animal protein is consumed have a higher rate of ESRD.
Also, The Nurses' Health Study conducted in the United States found that individuals with higher red meat and processed meat intake had a higher risk of decline in estimated glomerular filtration rate - a measure of kidney function.
Although red meat can be a healthy component of a varied diet, current and previous research suggests that anyone at risk of developing kidney problems could benefit from reducing their intake.