A report about a technical Food and Agriculture Organization study "World agriculture: towards 2015/2030" published in 2002, shows that meat consumption in developing countries, has risen from only 10 kg per person annually in 1964-66 to 26 kg in 1997-99. It is projected to rise to 37 kg per person per year in 2030. As it seems that we are not going to become a society of vegetarians anywhere soon, let's make sure that we know the danger that a meat rich diet can have.
In the middle of the 20th century, medical researchers began to concentrate on the role of nutrition in the two main diseases which can cut our gastronomic life short: heart disease and cancer. It happens that meat and its mouth watering taste, has its downside: a diet high in meat is associated with a greater risk of developing heart disease and cancer. In our post-industrial lifestyle which consists of a lack of physical activity and an unlimited ability to indulge our taste for meat, the high consumption of meat contributes to obesity which increase the risk of various diseases.
The first contribution of meat towards shortening our life of "gastronomes" comes from the meat itself : FATS. To be more precise saturated fats. This type of fat is known to increase our blood cholesterol levels and can contribute to heart disease. And to the extent that meat displaces from our diet the vegetables and fruits that keep heart diseases and cancer at bay, it raises our vulnerability to both.
The second one comes from the way the meat is prepared. I have to say that I was probably like most, apart from the odd cremated steak. I did not suspect that the way I cooked meat could end up creating some potentially dangerous types of carcinogenic by-products. Scientist have identified three families of chemicals created during meat preparation that potentially damage our DNA and that may increase our risk of developing cancer of the large intestine.
Let's start with the Heterocyclic Amines (HCA). They form at high temperature by the reaction of some minor meat components, creatine and creatinine (women may have heard of the first compound as some cosmetics producers advertise its benefits to tackle wrinkles) with amino acids (basic elements of proteins). HCAs are generally greatest at the meat surface where the temperature is the highest and where the meat juices collect. They also appear on meats that are grilled, broiled or fried well done. Oven roast meat surfaces are more or less free of HCAs but the pan drippings can show great amounts. It is relatively easy to reduce the production of HCAs. Acid marinades, for example, decrease the creation of HCAs. Gentle cooking and aiming for a rare or medium doneness would help too. Furthermore, the consumption of vegetables, fruits and acidophilus bacteria seem to bind HCAs in the digestive tract and prevent their absorption.
The second type of carcinogenic chemical that can be created while cooking meat is called Polycyclic Aromatic Hydrocarbons or PAH. They are created when nearly any organic material, like wood or fat, is heated to their burning point. This is what happens when butter overheats and burns. This is the reason why most food authorities have simply banned the traditional "raie au beurre noir". Back to our meat, PAHs are mainly found on meats that have been cooked over a smoky wood fire that will deposit PAHs on the meat or smokeless charcoal fire which will create PAHs from the fat, if the fat is allowed to fall and burn. Small amounts of PAHs can be produced during high temperature frying. PAHs can be minimized by cooking meats over a wood fire only if it has been reduced to coals, by leaving the grill uncovered, by avoiding fat flareups and by eating smoked meat with moderation.
Finally, there is our third bad guy. It is known by the name of nitrosamines. They form when nitrogen-containing groups on amino-acids (basic constituents of proteins) and related compounds combine with nitrite, a chemical used for centuries in salt-cured meats and prevent the development of the Clostridium Botulinum responsible for botulism. This reaction happens both in our digestive system and in a hot frying pan. Nitrosamines are well known to be a very powerful DNA- damaging chemicals, despite the lack of evidence that nitrites present in cured meats can increase the risk of developing cancer. Though, it's seems prudent to eat cured meats with moderation and cook them gently.
To end this alarmist panflet about meat, I would like to quote Harold McGee in "McGee on food and cooking", Hodder and Stoughton edition, who rightly says : "It's prudent, then to temper our species' infatuation with meat. It helped make us what we are, but now it can help unmake us."