In this article we begin to analyze the possible intoxications due to the presence of toxins in food. Bacterial poisoning, mushroom poisoning and marine toxin poisoning will be dealt with. Before getting to the description of these intoxications, however, it is briefly illustrated what nutrition is and how it is composed.
By nutrition we mean the intake with food of all those compounds essential to provide our body with the energy useful for carrying out various metabolic activities, but also for its development. The indispensable compounds can be classified into:
- MACROELEMENTS which are lipids, carbohydrates and proteins;
- MICROELEMENTS which are vitamins and mineral salts.
As anticipated, these elements are able to supply energy, but only the macroelements can directly bring useful Kcal to the organism. A gram of lipids provides our body with 9 Kcal, while a gram of proteins or carbohydrates provides only 4. Vitamins and mineral salts do not provide energy, but are essential because they perform antioxidant actions, are involved in the transport of nerve signals, in muscle contraction and more generally in countless metabolic functions. A balanced supply of both macro and microelements allows our body to grow and carry out all its activities correctly.
If there is an incorrect intake of micro and macro elements, adverse conditions of excess or deficiency are created. To overcome this drawback, the European Union has established guidelines for each population that serve to protect it from adverse effects due to an incorrect intake of nutritional elements. In addition, recommended daily intake levels are established, known in Italy as LARN. These levels are modified over time depending on the possible effects that may arise in the various stages of life. Remember that each nutrient has a minimum dose and a maximum dose of intake, and that exceeding these doses can cause serious health problems.
SUGARS
Carbohydrates (from the Greek glucos, which means sweet) are also known as sugars or carbohydrates. Carbohydrates are ternary chemical compounds, as they are made up of carbon, hydrogen and oxygen.
Sugars perform several functions:
- They are the primary source of energy for our body ("the fuel for our body");
- They give a sweet taste to foods;
- In the diet they occupy about 55-65% of the daily caloric ration of an adult subject.
The following table illustrates a possible classification of sugars.
MAIN CARBOHYDRATES
CLASS
GROUP
COMPOUNDS
SUGARS
Monosaccharides
Glucose, fructose, galactose
Disaccharides
Sucrose, maltose, lactose, trehalose
Polyols
Sorbitol, mannitol, xylitol, lactitol, disposal
OLIGOSACCHARIDES
Malto-oligosaccharides
Maltodextrin
Other oligosaccharides
Raffinose, stachyose, FOS, GOS
POLYSACCHARIDES
Starch
Amylose, amylopectin, modified starches
Non-starch polysaccharides
Cellulose, hemicelluloses, pectins, carrageenans, hydrocolloids.
A diet too rich in carbohydrates is not healthy, because it can lead to diseases such as obesity, diabetes mellitus, dental caries and ischemic heart disease. Streptococcus Mutans it is the main cause of dental plaque, because it is able to metabolize sucrose thus favoring the engraftment of the bacterium in the tooth enamel.
A metabolic disorder involving carbohydrates is GALACTOSEMIA. This congenital disorder is the inability of a particular enzyme to convert galactose into glucose.
In addition to galactosemia, lactose intolerance is well known. Lactose is a disaccharide formed by glucose and galactose, which in a normal subject is split by intestinal lactase into the two monosaccharides. In a subject with lactose intolerance, however, a due to the lack of the enzyme, the disaccharide is not broken down and absorbed, causing serious gastrointestinal problems.
THE LIPIDS
With the term lipids s "they indicate organic substances insoluble in water, but soluble in non-polar solvents, such as ether or benzene. Lipids - commonly called fats - are a family of heterogeneous ternary substances and in a diet they represent about 25-30% of the caloric intake of an adult individual. From a nutritional point of view, lipids can be classified into:
- DEPOSIT LIPIDS (≈ 98% and are mainly triglycerides with an energetic function);
- CELLULAR LIPIDS (≈ 2% and are cholesterol, phospholipids and glycolipids with a structural function).
From a chemical point of view they can be classified into:
- SAPONIFIABLE or COMPLEX LIPIDS
- NON SAPONIFIABLE or SIMPLE LIPIDS
Fatty acids can be classified into:
- SATURATED
- UNSATURATED: including the MONOUNSATURATED and POLYUNSATURED categories.
Saturated fatty acids have an aliphatic chain without double bonds and are solid at room temperature. Monounsaturated fatty acids have a double bond along the aliphatic chain, while when two or more double bonds are found the fatty acids are defined as polyunsaturated. Both unsaturated fatty acids are liquid at room temperature.
Lipids, compared to sugars and proteins, provide more Kcal (1 gram = 9 Kcal).
An incorrect intake of fat leads to a number of diseases such as obesity, cardiovascular disease (CVD), atherosclerosis, hypercholesterolemia and hypertriglyceridemia. Remember that a very high-fat diet can affect the development of tumors, especially in the colon.
THE PROTEINS
Proteins are quaternary compounds made up of carbon, hydrogen, oxygen and nitrogen. The building blocks of proteins are amino acids.
The structure of amino acids is very simple: one part - shown by the letter R in the figure - is variable and characterizes the amino acid; the other part is fixed and consists of a carboxylic group, an amide group and a hydrogen. As is well known, the union of an acid group with a basic group gives rise to a salt, therefore in many cases the structure of the amino acid is represented in the form of a zwitterion. The acid group -COOH becomes -COO- and the basic -NH2 group becomes -NH3 +.
In some cases there are also traces of sulfur and phosphorus.
Excessive protein intake can cause liver and kidney damage, while diets low in protein will result in insufficient intake of essential amino acids.
A metabolic disorder of amino acids is phenylketonuria. This disease is caused by the lack of an enzyme (phenylalanine hydroxylase), which is capable of metabolizing phenylalanine into tyrosine.
Among the simple intolerances we remember celiac disease, the known gluten intolerance.
Proteins are very allergenic, so in individuals predisposed to allergic forms we can have allergies to milk, egg, fish, dried and fresh fruit proteins, and finally to shellfish.
Other articles on "Nutrition: Power Notes"
- Lead: lead toxicity
- Toxicity and toxicology
- Toxins in food
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