Is the consumption of red meat a health hazard?

Red meat is a source of high-quality protein as it provides the body with essential amino acids. It also contains B vitamins (particularly B12) and minerals such as selenium, zinc, and heme iron. It can therefore be recommended in cases such as anemia, since heme iron is absorbed at 20–30%, while non-heme iron (found in plants) is absorbed at only 5–15%. Although red meat contains the aforementioned essential dietary components, there are healthier ways to provide them. Meat products contain large amounts of saturated fatty acids, whose consumption should be restricted as much as possible. They contribute to increasing the total cholesterol level in the blood and the LDL cholesterol level, which has a negative impact on health and contributes to the development of many diseases. Therefore, red meat should be consumed in moderation.

Globally, a high incidence of cancer and mortality due to cancer pose a serious health concern. In 2015, the International Agency for Research on Cancer (IARC) classified processed meats as carcinogenic and red meat as likely to cause cancer. It was found that consuming 100 g of red meat and 50 g of processed meats increased the risk of developing colon cancer by nearly 18%. Furthermore, it was observed that consuming red meat was associated with a higher risk of developing pancreatic and prostate cancer, while consuming processed meats was associated with an increased risk of stomach cancer (according to a study by R. J. Turesky from 2015). It was also found that postmenopausal women who consume large amounts of red and/or processed meats are at a higher risk of developing breast cancer (according to a study by A. Diallo and colleagues from 2017).

They are most prevalent in cured and smoked products. They form when chemical compounds such as nitrite (III) and nitrate (V) are added as preservatives or when these products are heated above 130°C (frying, grilling). It is worth noting that nitrates (V) are less harmful, but can be reduced to nitrites (III) under anaerobic conditions in the large intestine. These can react with amines and amides under the influence of gut flora and lead to the formation of cancer-causing nitrosamines.

– HCA refers to heterocyclic aromatic amines, which are compounds produced through the process of degradation of amino acids and proteins under high temperatures. They form during the thermal processing of red and processed meats, such as baking, frying, cooking, and grilling. These compounds possess mutagenic and carcinogenic properties, and even small quantities of these substances can lead to DNA damage. It is important to emphasize that the amount of HCA in meat depends on the duration and temperature of thermal processing – the longer and higher the temperature of processing, the more HCA will be present in the meat.

Multicolored aromatic hydrocarbons encompass nearly 250 substances, of which 16 are particularly hazardous to health and 6 are carcinogenic. WWA are primarily found in grilled and smoked meats. They are generated through the cooking process of roasting and grilling, especially over an open flame. Multicolored aromatic hydrocarbons are genotoxic – by reacting with DNA, they affect genes, leading to mutations that can result in the development of malignant tumors. WWA are considered substances that increase the risk of colon cancer. Even small amounts of these substances can cause genetic damage, potentially leading to the development of cancer.

A combined cohort study conducted in 2017 involving more than 52,500 participants with type 2 diabetes found that consuming red meat (regardless of the degree of processing) increased the risk of developing the disease by 22%, while consuming processed meat increased the risk by 39% (S. Tian et al. 2017). However, it is not known which ingredients are responsible for this increase in risk. It is possible that they are: - saturated fatty acids - increase insulin resistance, - branched-chain amino acids (BCAA): leucine, isoleucine, valine - increase the insulin resistance of cells and contribute to the increase in glycated hemoglobin, - end products of protein glycation - increase the inflammatory state in the body, which can lead to reduced insulin sensitivity, - heme iron - high iron concentrations can lead to increased glucose production and at the same time to reduced glucose utilization and through participation in oxidation can increase oxidative stress and the inflammatory state, which affects the inhibition of insulin-glucose binding, - nitrites - the nitrosoamines formed from them impair the function of the beta cells of the pancreas, which reduces insulin secretion and thus increases the risk of developing type 2 diabetes, - L-carnitine and phosphatidylcholine - both substances are converted into TMAO (trimethylamine oxide) in the intestine, which is responsible for the increase in insulin levels in the fasting state and the impairment of glucose tolerance (A. Wolk 2017).

The association between red meat consumption and the occurrence of stroke and death from this disease is well-established. Furthermore, the consumption of red meat contributes to the development of heart disease and increases the risk of heart attack, especially in the case of processed meat. The mechanisms linking meat consumption to the occurrence of cardiovascular diseases are not yet fully understood, but it is believed that they are similar to those leading to type 2 diabetes (A. Wolk 2017). A systematic review from 2014 showed that the consumption of red meat has a significant impact on mortality from cardiovascular disease - the risk of death increases by 16%. Furthermore, increasing the consumption of processed meat by 50 g per day increases mortality from all causes as well as mortality from cardiovascular disease, while increasing the consumption of red meat by 100 g per day positively correlates with mortality from cardiovascular disease (I. Abete et al. 2014).

A plethora of research and meta-analyses advocate for the restriction of red and processed meat consumption, demonstrating their detrimental effects on the body. The consumption of these products is linked to the development of various ailments, such as type 2 diabetes, cancer, or cardiovascular diseases, and may result in premature death. High meat intake in the diet, compared to low intake, increases mortality risk by 23% for processed meat, 10% for unprocessed meat, and even 29% for whole fish meat (S. C. Larsson et al., 2014). It is worth emphasizing that the overall diet is always paramount. There is no division into allowed and prohibited products - in a healthy, well-balanced diet, there is room for red meat, but moderation is crucial. The National Centre for Nutrition Education recommends not exceeding 350–500 g per week. However, a much healthier alternative would be to replace red meat with protein-rich alternatives such as white meat (chicken, turkey, rabbit), fish, and legume seeds (peas, beans, lentils, chickpeas, soy), whose consumption would bring a range of health benefits to the body and minimize the risk of developing various diseases associated with red meat consumption.