Studies in the past have irrefutably established a link between consuming processed meat — such as bacon, hot dogs, sausages, and other similar meats — and an increased risk of cardiovascular disease (CVD) and death. The higher amount of saturated fats, salt and preservatives, in even small amounts of processed meat, have been shown to jeopardize health.
While processed meat is definitely bad for good health, studies on the outcome of consuming unprocessed red meat, poultry and fish, had so far come up with only mixed results with regard to their impact on CVD risk or longevity. So, researchers at Cornell University in the United States decided to fill this gap in research by conducting a meta-analysis of six previous studies.
The research team looked at prospective cohort studies that had been carried out with more 29,000 adults who did not have CVD at baseline and whose dietary data had been recorded between 1985–2002 and clinically followed them for 30 years, until the end of August, 2016.
Over a median follow-up period of 19 years, there were 6,963 adverse cardiovascular events and 8,875 all-cause deaths. Of the cardiovascular events, 38.6 percent were cases of coronary heart disease, 25 percent were stroke events, and 34 percent involved heart failure.
The median consumption in terms of servings of meat, poultry, and fish per week for the participants was 1.5 for processed meat, 3 for unprocessed red meat, 2 for poultry, and 1.6 for fish. One serving was equivalent to 115g of unprocessed red meat or poultry or 85g of fish. For processed meat, one serving consisted of 2 slices of bacon, 2 small links of sausage, or 1 hot dog.
Compared with participants with lower total intake of these four food types, participants with higher total intake, were more likely to be younger and male; be smokers, have diabetes, and have a higher body mass index (BMI), as well as have higher non-high-density lipoprotein (HDL) cholesterol levels, and consume more alcohol. They were also found to have lower HDL cholesterol levels and eat a lower quality diet, as well as have a higher incidence of CVD and death from any cause.
The main outcome that the scientists looked for was the relative risk of CVD and all-cause mortality over the 30 years between people who consumed these different foods, as well as the difference in absolute risk over the same period. The intake of processed meat, unprocessed red meat, or poultry was significantly associated with incident cardiovascular disease, but fish intake was not.
More in-depth detail revealed that for every two additional servings of processed meat per week, the relative risk of all-cause mortality rose by 3 percent compared with those who did not eat processed meat. The same was true for each additional two servings of unprocessed meat.
The relative risk of CVD rose by 7 percent for every two servings of processed meat per week. For unprocessed red meat, this risk was 3 percent. An increase of two weekly servings of poultry correlated with a 4 percent higher relative risk, whereas fish was not associated with CVD risk.
The researchers said their findings were of critical public health importance, given that dietary behaviors are modifiable, and that most people consume these four food types on a daily or weekly basis. However, they admitted that far more research was needed to strengthen their findings, as the study had several limitations.
