The impact of meat consumption on our health

Meat has been and continues to be an important food source, delivering a wide range of valuable nutrients our bodies can easily absorb. Along with other animal-source foods like fish, eggs and milk, it also plays an important role in several European cultural traditions and recipes. People are biologically adapted to a diet that includes meat, which is important in a healthy and balanced diet. Some nutrients in meat and other animal-source foods are not always easily obtained or obtainable from plant-based foods.

Meat is an excellent source of vitamins, minerals, and essential micronutrients the body can absorb easily. A 100g portion of red meat, for example, will provide around 25% of the recommended daily allowance for riboflavin, niacin, vitamins B5 and B6, and two-thirds for vitamin B12. Diets poor in animal-source foods can lead to various nutritional deficiencies. Studies have shown that low-meat diets may risk brain and reproductive system development. Indeed, it is recognised that animal-source foods are essential in an infant’s first 1,000 days of life and for the skeleton and brain development of pre-adolescents.

There are several important bioactive compounds in meat and processed meat products, such as vitamin B1, iron, zinc, choline, L-carnitine, conjugated linoleic acid (CLA), glutathione, taurine and creatine, which have been studied for their physiological properties. Conjugated linoleic acid, for example, has drawn significant attention in the last two decades for its biologically beneficial effects. CLA modulates immune and inflammatory responses and improves bone mass, while carnosine possesses strong antioxidant and anti-genotoxic activities, including the anti-ageing of cells.

From an evolutionary perspective, we have developed as omnivores, and meat has been a central component of our diet for millions of years. Claims about the health dangers of meat are not only improbable in the light of our evolutionary history, but they are also far from being supported by robust scientific evidence. The majority of evidence linking red and processed meat consumption with colorectal cancer and pathologies is observational and based on intakes of red and processed meat that exceed most European countries’ average intakes.

Interestingly, a study in the UK found similar rates of bowel/colorectal cancer in vegetarians and meat-eaters, suggesting that meat consumption in general isn’t a major cause of this disease. The correlation between food, meats and cancer is very difficult to study because there are many elements, real or perceived, that may favour the onset and the development of cancer. National authorities have based recommendations on the studies developed by the International Agency for Research Studies on Cancer (IARC) that highlight and classify the considered agents that are certainly or presumably responsible for cancer onset.

“Carcinogenic” is the term given to something that can cause cancer. The problem, in terms of communication to the public, is in the verb “to cause”. It is not possible to give a determined cause-effect interpretation in this instance. In other words, it is not possible to say, “If you eat processed meat, then you will surely get colorectal cancer”. In the same way, it is not possible to say that if someone is exposed to a carcinogenic agent, they will certainly get cancer. Scientists hold to the premise that “carcinogenic” is something that, taken in certain doses and for a certain period, can increase the risk of developing a certain type of cancer throughout life. However, when such information is shared with the general public, the interpretation is often that if a substance or a food is carcinogenic, it most certainly causes cancer.

A consequence of this miscommunication is that some people will believe that if we do not eat a specific food or something with a carcinogenic substance, then surely we are safe from cancer. Unfortunately, this is not true. We may get, and statistically it happens, lung cancer even if we do not smoke and colon cancer even if we are strictly vegan. No one can say with certainty whether, even eating processed meat every single day, we will get colorectal cancer or not. But this does not mean that eating a certain food or not eating it would expose someone to the same risk.

Going back to the IARC monography, the various agents are not classified based on how carcinogenic they are, nor does the report deal with estimating the risk, individual or collective, of an exposure to a given agent once established to be carcinogenic. This means it is incorrect to treat all carcinogenic agents in the same way. Stating that “processed meat is like smoking or asbestos” is deeply wrong, and certainly, it pays no service to public opinion or knowledge. Carcinogenic agents are different, but it is not the IARC’s task to classify this aspect. There is also an interesting point regarding the consumption amounts investigated by the IARC, which are 50 grammes of processed meat or 100 red meat per day. This level of consumption is much higher than that of European consumers and, in general, of the rest of the world. For all these reasons, meat and processed meat products can be safely consumed as a part of healthy and balanced diets, but the most important thing for authorities to keep in mind is to communicate these concepts clearly and properly.