Until recently, due to the lack of quality statistical studies, too great of a role in the great debate between vegetarians and meat eaters was played by a rhetorical component. A large-scale study involving 120,000 people showed that consumption of red meat significantly reduces life expectancy.
The position of vegetarians, due to the lack of data on long-term effects of meat diet on health, often boiled down to not always scientifically sound and ethical reasoning. The meat eaters recognized the proven harm of pre-processed (smoked, canned, freeze dried, etc.) meat and large amounts of animal fats. However, they stood their ground, indicating that the nutrient properties of freshly prepared meats (also unproven scientifically) are more important than hypothetical long-term risk of meat diet.
A large study conducted by a group of doctors from the Harvard School of Public Health, who worked under the guidance of Doctor of Medicine An Pan, revealed that fears of vegetarians are absolutely justified. Consumption of red meat is clearly correlated with a higher risk of death from cardiovascular disease, certain cancers and metabolic diseases, while the replacement of meat from mammals with fish and poultry greatly reduces this risk.
The findings are published in the Archives of Internal Medicine – the journal of the American Medical Association.
In the analysis of long-term effects on meat diet, An Pan and his colleagues relied on a statistical study of an impressive scale. A total of 37,698 men and 83,644 women participated in the study. Their health, along with the diet, was tracked for 28 years in the second group, and for 22 years in the first group. During this time, 23,926 deaths were recorded in the two groups surveyed, of which 5,910 – from cardiovascular disease and 9,464 – from cancer.
“We found that higher consumption of red meat is associated with a significant increase in mortality from these diseases, and this relationship can be traced in the case of pre-processed and freshly prepared meats, with higher correlations for the pre-processed. When replacing red meat with fish, vegetables and poultry, there was an inverse relationship – reduced mortality,” the authors commented on the results of the study.
The study revealed that in total life expectancy falls by 13% in case of daily consumption of freshly prepared meat the size of a palm, and a whopping 20% of the daily consumption of portions of pre-processed meats – a hot dog or two strips of bacon. For the disease that became the cause of death in both groups, the dependence of risks from the consumption of red meat was as follows: the risk of cardiovascular disease increased by 18% and 21% for fresh and processed meat, respectively, and cancer – by 10% and 16%.
These numbers can be considered statistically neutral, that is, free from those observed during the variables such as age, body mass index, physical activity and family history of cardiovascular disease and cancer. It is also important that all the observed members of the group were physically healthy at the start of the study.
In the second part of the analysis, the authors assessed the combined effect of replacing red meat with other foodstuffs. It was found that the risk of death in case of the exclusion of red meat from the diet is lowered if the daily portion of meat is replaced by a portion of fish (by 7%), poultry (by 14%), nuts (by 19%), vegetables (by 10%) and cereals (by 14%).
“We also found that 9.3% of deaths among men and 7.6% among women could be prevented in the observed period of time if all participants reduced their daily consumption of red meat by 50%,” summarized the researchers.
In other words, three and a half thousand men and six thousand women who participated in the study would have survived if they had cut their meat consumption by at least in half.