Functional foods, probiotics and prebiotics: what they are

Table of Contents

What are

Foods are defined functional when beyond their nutritional properties (caloric value, intake in macro and micronutrients) they have the ability to positively affect one or more physiological functions and this ability of theirs is scientifically proven. Functional foods or functional foods are successful improve our health helping to reduce the risk of disease onset. To be able to attribute to a food the definition of “functional food” it is necessary to have one solid scientific evidence. Generally we start from the empirical observation that recognizes that given food beneficial properties for our health. An important step is the identification of the active ingredients. The ultimate purpose of these investigations is to enrich those foods in which these substances are already naturally present. We then speak of enriched functional foods. The supplemented functional foods are those that originally did not have a specific health value but that acquired it following the addition of the active ingredient.

Utility and benefits

The growing interest in health has prompted the food industry to invest in the burgeoning functional food sector. In an era in which obesity and fat-related diseases have assumed epidemic proportions, so too has theinterest in health. The most widespread dietary model is that of western diet (Western Diet) characterized by an excess of calories and an abundance of saturated fats and simple sugars. The western one is a diet rich in energy value but low in nutritional value. This model contrasts with that of the Natural Diet in which functional foods created by Mother Nature abound. The food industry, investing in this sector, has created functional foods supplemented no more than just vitamins as was once used but of third generation substances such as inulin and other Fructo-OligoSaccharides (FOS), probiotics, flavonoids and other substances with antioxidant action. The beneficial properties of third generation substances have been discovered relatively recently. Between active principles contained in functional foods should be mentioned:

dietary fibers which act as prebiotics;
the iron;
carnosine;
vitamin B12;
polyunsaturated fatty acids (omega-3 and omega-6);
plant sterols;
the probiotics naturally contained in lacto-fermented foods.

Are functional foods and nutraceutical foods the same thing?

The term nutraceutical, coined in 1989 by Stephen L. De Felice, is composed of nutrition and pharmaceuticals. According to current legislation, nutraceutical products can be defined as “preventative of chronic diseases, improve health, delay the aging process, promote longevity or support certain body systems or functions.” Any claim that appears on the label or is used for advertising or commercial purposes and that the consumption of a particular food may be beneficial to health is a ‘health claim o Health Claim. For example, it could be argued that a food product can help strengthen the body’s natural defenses or improve learning capacity. These are called “generic functional” indications. Then there are the claims of decreasing the risk of contracting a disease. For example, “plant sterols have been shown to reduce cholesterol levels, a risk factor for the development of coronary heart disease”.

Functional foods are part of the nutraceuticals together with dietary supplements, i.e. food supplements. In food supplements, the active ingredient is contained within a capsule, tablet or liquid formulation. Functional food, being able to be consumed in the diet on a daily basis, becomes a vehicle for the same active ingredients contained in dietary supplements.

Among the nutraceutical foods there are:

pasta enriched with beta glucan barley, an active ingredient capable of reducing cholesterol levels;
the black tomato rich in anthocyanins, substances with a strong antioxidant power;
the kefir because it is particularly rich in probiotics.

Probiotics: what are they?

In accordance with the guidelines of the Ministry of Health, probiotics are defined as “live and vital microorganisms that confer benefits to the health of the host when consumed in adequate quantities as part of a food or supplement”. In addition to this definition, there is a second one that directly concerns the food or supplement. According to this definition, we can speak of probiotic foods or supplements if these “contain, in a sufficiently high number, probiotic microorganisms capable of reaching the intestine, multiplying and exerting a beneficial action for the state of health / well-being of man”. We understand from this second definition that a probiotic can do well if it is able to colonize the intestine. The vital adjective contained in the first definition means that the bacteria must be able to remain alive and to proliferate even after ingestion and ingestion by the consumer. The definition also speaks of adequate quantities. In fact, scientific research has amply demonstrated that there is a health benefit only when the probiotic is administered at the correct dosage. Today it is believed that a probiotic is valid when the single bacterial strain contained in it is present at a dosage of not less than one billion live and viable bacterial individuals. Therefore, for all those preparations that are formulated with a number of less than one billion bacteria per single strain, we cannot speak of a probiotic but more properly a food supplement of lactic ferments.

THE main strains bacteria contained in probiotic supplements are:

Bifidobacteria (Bifidobacterium breve, Bifidobacterium longum, Bifidobacterium infantis, Bifidobacterium animalis subsp. Lactis);
Enterococcus faecium;
Lactobacilli (Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus GG);
Nissle’s Escherichia coli.

Now the question is: can we think of finding these same bacterial strains and in such numerousness within one yoghurt? Unfortunately this is not the case. Modern starters are based on Lactobacillus bulgaricus and Streptococcus thermophilus. Both of these bacteria are thermophilic. This means that they are active at temperatures above 42-43 ° C and are able to make yoghurt in about 40 minutes, which makes them convenient for the food industry. On the contrary, probiotics take at least 8 hours at a temperature of 37 ° C. The former are unable to take root in our intestine because they cannot resist gastric acidity and because they find a cold environment (37 ° C instead of 42-43). We can therefore say that yoghurt is undoubtedly a good food but its bacteria do not colonize the digestive system. The case of the kefir produced at room temperature.

What are prebiotics and how they work

Prebiotics are soluble and non-soluble dietary fibers normally contained in foods of plant origin. From a chemical point of view they are complex carbohydrates that we are not able to break down into simple sugars. For this reason, dietary fibers are also referred to as indigestible carbohydrates. These substances reach the large intestine unaltered and here they come metabolized by bacterial flora intestinal favoring its numerical growth. The bacteria residing in the colon produce short-chain fatty acids from dietary fibers, including butyric acid. In the intestine, butyric acid has important functions. If on the one hand it represents a very important energy source for the cells of the intestinal mucosa, on the other hand it inhibits the proliferation of cancer cells by carrying out a possible protective effect against colorectal cancer. Among the prebiotics, i fructoligosaccharides or FOS, soluble fibers found in various fruits, vegetables and common plants. An example of FOS is the inulin of which they are particularly rich: