Table of Contents
Calories and nutritional values
Meat is one good source of energy and essential nutrients, including proteins and some micronutrients such as iron, zinc, copper and vitamin B12. One hundred grams of adult beef provides an average of 121 kcal. Below are the main nutritional values:
- Protein: 21 grams
- Carbohydrates: 0 grams
- Fat: 4.30 grams, of which saturates: 1.03 grams
- Cholesterol: 60 grams
- Iron: 1.74 milligrams
- Zinc: 4.34 milligrams
- Copper: 0.06 milligrams
- Vitamin B12: 1.27 micrograms
Worldwide consumption
Globally, per capita meat consumption is constantly increasing but the most frequently used meats are poultry and pork.
A good portion of the meat we eat today is processed meat: due to its composition characteristics, meat can be an important source of nutrients for the populations of developing countries but, as scientific evidence shows, a its high consumption it can increase the risk of some chronic diseases. It is estimated that in the world the per capita consumption of meat is 122 grams per day of which 1/3 is represented by pork and poultry meat and 1/5 by beef. In recent decades the consumption of meat is slightly decreased in the countries of the western area while it is rising dramatically in China and Southeast Asia.
Animal farming and global warming
Meat production is one of the main ways in which humanity alters the environment. Forests are cleared to create spaces suitable for grazing or cultivation in order to satisfy the forage demand of farm animals. Animal farms are in fact there main source of greenhouse gases (Greenhouse gases or GHGs) and other pollutants. In some areas they help exploit the already scarce water resources and accelerate soil erosion.
Does it cause cancer?
It has been widely demonstrated that in Western countries all-cause mortality is modestly higher among those who make extensive use of red meat. The strongest evidence relates to the higher incidence of colorectal cancer in those who consume large quantities of processed meat (sausages, hot dogs, salami, bacon, smoked meat).
The main approach to estimate the long-term impact that meat consumption has on health are the prospective and epidemiological cohort studies. In these studies, the eating habits of hundreds of thousands of participants whose health is monitored over the years are recorded. The purpose is to identify the risk associated with meat consumption. The hardest part of these studies is eliminating the confounding factors. Large prospective studies and meta-analyzes have generally shown that total mortality is moderately higher in those who consume the most. both red meat and processed meat. Possible confounding factors are due to the association between high meat consumption and cigarette smoking, alcohol intake, obesity.
The strongest evidence of an adverse health effect of red meat consumption is colorectal cancer. Precisely because of the association between meat consumption and colorectal cancer, the IARC (International Agency for Research on Cancer) has classified processed meat as a human carcinogen. Red meat, on the other hand, has been classified as a probable carcinogen. It is estimated that 34,000 cancer deaths a year worldwide are attributable to a diet based on a high consumption of processed meats. Based on the surveys conducted by the IARC it is estimated that the average consumption of meat in Western Europe should lead to a 9% increased risk of developing colorectal cancer. We also know that high consumption of processed meat can lead to an increased risk of stomach cancer but there is no strong evidence of an increased risk for other types of cancer.
Among the substances present in meat, those that could have a carcinogenic effect are:
- hemoglobin iron;
- the nitrosamines found in some processed meats;
- the aromatic heterocyclic amines that form when meat is cooked at high temperatures.
Cardiovascular diseases
Red and processed meat can increase the risk of developing cardiovascular disease because it is usually high in saturated fat that they contribute to raise cholesterol levels. Processed meat could help raise blood pressure because it normally does rich in salt. The other mechanisms that may be involved include the production of trimethylamine oxide starting from the carnitine present in meat.
Some studies have shown a reduction in mortality from cardiovascular disease, heart attack and diabetes and from all causes when the animal protein sources are replaced with plant protein sources such as nuts, legumes and whole grains. The transition from a high-meat diet to one based essentially on the consumption of plant-based proteins can reduce global mortality by 6 to 10%.
Intestinal microbiota
Only recently has the relationship between intestinal microbiota (the set of bacteria, fungi, protozoa and viruses that live in our intestine), consumption of red meat and cardiovascular diseases been discovered. Within the scientific community it is universally accepted that a prevalent consumption of meat, eggs and cheeses may be associated with an increased cardiovascular risk. This correlation has always been attributed to the high cholesterol and saturated fat content typical of these foods.
In recent years a number of new scientific evidence has contributed to broaden our vision demonstrating that some molecules present in red meat, eggs and cheeses (phosphatidylcholine, choline and L-carnitine) can promote the onset of cardiovascular diseases through a specific mechanism that involves our intestinal bacteria. Phosphatidylcholine, choline and L-carnitine are first metabolized to trimethylamine (TriMethylAmine or TMA) by intestinal bacteria and then to trimethylamine oxide (TriMethylAmine-N-Oxide or TMAO) in the liver. The higher the consumption of meat, the more trimethylamine oxide is produced. Trimethylamine oxide or TMAO promotes the onset of cardiovascular diseases. In fact, it has recently been possible to verify that TMAO regulates various steps in cholesterol metabolism and promotes the formation of arterial plaques.
Food-born disease and antibiotics
However, the meat can be one potential source of various infections transmitted through food (food-born). Animal husbandry can represent a reservoir of some pathogens capable of infecting humans. This problem particularly affects situations in which humans and animals live in close contact.
We must not forget, then, that the antibiotics are widely used in animal production, partly as medicines where there is a health problem (lameness, mastitis), partly as growth promoters. It has been speculated that the increasing antibiotic-resistance of some pathogens can start from livestock farms and then be transferred to human pathogens.
Pasture farms
The expression “grass fed” means “fed on grass”. So it happens for the animals of the extensive farms that remain in the pasture for the entire life cycle, from birth to slaughter. In intensive farms, in which very rapid growth occurs, the animals are kept still inside stalls (in fixed housing) and are fed with cereals and feed.
In the first case the environmental impact is minimized; furthermore, no antibiotics, chemotherapy, and pesticides are present in the meat of grass-fed animals. From a nutritional point of view, the meat of animals raised on pasture has the advantage of containing high levels of omega-3, essential fatty acids essential in the prevention of cardiovascular diseases.
How much to eat per week
Several national and international institutions have recommended a upper limit for meat consumption in order to maintain good health. For example, the World Cancer Research Fund recommends that people who eat red meat should consume it less than 500 grams per week making sure that the fraction deriving from the processed meat is as low as possible.
Cooking on the grill
It has long been known that excessive consumption of grilled red meat it is linked to a higher incidence of colorectal cancer. According to the treatises on pathology this phenomenon is due to the release of polycyclic aromatic substances (see benzopyrene). It is estimated that 1 kg of grilled red meat contains the same amount of benzopyrene present in 600 cigarettes. We then realize what frequent consumption of this type of food can mean for our health. However, toxicology teaches us that “sola dosis facit venenum” which translated means “the poison is in the dose”. Just as smoking a cigarette every now and then won’t give us lung cancer, eat a barbecue every now and then it can’t be that harmful. The measures to be used to minimize the risk of exposure to benzopyrene are as follows:
- make sure of the excellent quality of the food;
- perfectly clean the grill, removing any residues from the previous grill;
- the grill must be positioned 20-30 cm from the embers in order to avoid charring …
