The importance of the “dose”, a forgotten concept
“Everything is poison, and nothing exists without poison. Only dose causes the poison to fail.” This famous aphorism by Paracelsus, a scientist of the sixteenth century, expresses an important truth that often tends to be forgotten, especially when certain food alarms contribute to panic and to have an unjustified attitude of suspicion or total rejection of the best foods of our tradition.
All foods that are commonly part of our diet, both of animal and plant origin, contain something positive and something negative, and the effect on our body always depends on the dose and the frequency they are taken with. All the substances we are in contact with each day have their “lethal dose”, a quantity that can kill a human being in perfect health.
A striking example is water, which as we know is vital to life, but if taken within a few hours for a quantity greater than 5 liters, it may be the cause of death. Several studies show that the limit of liquids to be taken should not exceed 1-1.5 liters per hour, so as not to disturb the electrolyte balance, creating critical states of poisoning.
Even drinks such coffee or tea, if consumed in the wrong way, can in the long run cause heart dysfunction and pressure problems up to the lethal dose of 150 mg of caffeine per kg of body weight, which corresponds to about 80 coffees in a day.
Or bananas, fruit with multiple beneficial properties, but its abuse can also cause serious problems: this is because potassium content, which is good for the body in doses that meet our nutritional needs, can cause kidney failure if it is present in excess. There have been cases where more than a dozen bananas ingested in one day led to emergency dialysis: for this reason, seven bananas a day should be the maximum limit to avoid complications.
All substances, in addition to a lethal dose, also have a “beneficial” dose: one example is the plant extracts known as “poisonous”, which at low doses have “curative” properties instead. That is why, in preparing plant remedies in various pharmaceutical forms, it is essential to establish the right dosage to achieve maximum effectiveness by avoiding toxic phenomena.
Even for substances listed in IARC list 1, considered “carcinogenic”, the effect always depends on the dose: a substance can only be carcinogenic if taken at a high dose, studied and reproduced in a laboratory, and therefore also unrealistic, but not at the dose we normally come into contact with in everyday life.
An example is the sun, defined as “carcinogenic” because involved in the process of skin cancer. Yet sun is vital to life and has its functions for our well-being, such as vitamin D absorption: so exposure during the coolest hours and using protective creams against harmful components of its rays is recommended to create a “winter stock” of this important vitamin in the bones.
The same happens for cold cuts and sausages: if they are moderately consumed in a diet rich in protective plant foods, you can safely enjoy the positive contributions of these foods present in the Mediterranean tradition ever since. That is why demonizing a food and totally excluding it from the diet is not a nutritionally correct approach, which would not bring concrete benefits to our health.
There are a number of studies that exonerate red meat from any unfounded accusation: the EPIC study of 2013 (European Prospective Investigation into Cancer and Nutrition), sponsored by European Union, IARC and AIRC, conducted over half a million participants from all over Europe, has shown that consumption of small amounts of red meat has beneficial effects on health, providing important vitamins and specific nutrients. For this reason, the recommended dose to take advantage of the extraordinary nutritional intake of this food is 500 g of red meat per week.
But who is moved by ideologies and interests against meat tends to forget the “dose” concept, believing meat as “not indispensable” and judging its consumption an avoidable risk, by not coming into contact with substances considered toxic, such as heme-iron and nitrates.
If it is true that meat is not indispensable – but no food is, as all foods can be replaced by others or by supplements, on the other hand the concept “do not come into contact with” these substances is practically impossible. Not only because they also play an essential role in our health, but also because they are also found in other foods such as vegetables.
Heme-iron, for example, plays in our body the important function of transporting oxygen. It is also an oxidant, which in the long run and in massive doses can promote cancer. Oxygen also serves to breathe and live, but at the same time “oxidizes” and makes us aging. There are two faces of each substance.
As for nitrates, they are not only found in cured meat and sausages, but especially in vegetables such as beetroot, celery, rapeseed, spinach, radishes, lettuce, fennel, cabbage, zucchini, where they are naturally present in much larger quantities: the human body receives about 93% of nitrates only through the consumption of vegetables, being their intake from meat in considerably lower quantities.
You cannot reason in absolute terms. “Do not get in touch” with these substances to undo the risk is unthinkable, because in the end we could not eat anything anymore. Scientific literature also describes a number of toxic substances derived from commonly used fruits and vegetables such as parsley, potatoes, carrots, spices, nutmeg, black pepper, vegetable oils, peanuts, legumes, especially soybeans, beans and peas, just to give you some examples. But even in these circumstances, the presence of these negative components is not a reason to totally avoid these foods, which if taken in the appropriate quantities do not represent a significant risk in a varied and balanced diet.
That is why the “dose” concept, the “frequency” of intake, but also the “variety” and the “balance” of the diet is fundamental: the combination of different foods can further contribute to enhancing the protective effect.
An example is a recent study that shows how calcium and alpha tocopherols introduced with diet can effectively suppress heme-iron dangers, preventing colon cancer and constituting a valuable way to consume meat safely. The same applies to nitrates and nitrites, whose harm can be inhibited through association with antioxidants and whose role, according to recent research, has turned out to be fundamental to our health.
In short, it is advisable to have a healthy lifestyle and to follow a varied and balanced diet that includes every food in the right amount. Like those suggested by our Mediterranean Diet, rich in elements that, when combined, ensure not only the perfect coverage of our nutritional needs, but also act as a protective action. It is no coincidence that this is the most popular diet regime advised by doctors and nutritionists around the world.
Susanna Bramante is an agronomist, nutritional consultant and scientific writer, author and co-author of 11 scientific publications and numerous articles on human nutrition and its impact on health and environment. In 2010 she received the title of Doctor Europaeus and PhD in Animal Production, Health and Food Hygiene in countries with a Mediterranean climate.