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Functional Foods

A food can be considered as ‘functional’ when it has proved beneficial effects for the human health beyond the normal nutritional effects.

Many foods contain health claims on their packaging. These products are known as functional foods.

According to the International Life Science Institute, a food can be described as functional when it has proved beneficial effects for the human health, beyond the normal nutritional effects. A functional food can improve the health and well-being of the consumer by reducing the risk of disease if it is consumed in usual amounts as part of a normal diet.

The term functional food covers a wide range of products that may be classified as:

  • A basic food that has been supplemented with an extra component, for example, milk with the omega 3 fatty acids

  • A food that has been processed following a specific method to remove one of its components, for example lactose free milk

  • Food in which the structure of one or more components has been modified, for example golden rice.

  • Food in which the bioavailability of one or more components has been altered, for example, hypocaloric lipids that cannot be consumed

  • Or any combination of these possibilities and of course a natural food just like it is

Functional foods might be functional for all members of a population or for particular population groups, such as pregnant women, elderly people, children, and others.

There are a number of ingredients that have been used to design functional foods. The most widely used are vitamins and minerals, phenolic compounds, functional lipids, probiotics, prebiotics, and dietary fibre.

Among vitamins, the most remarkable are those with antioxidant function, such as vitamin A, C, and E. Those related to the calcium metabolism and absorption, vitamins D and K, and those related with neural tube development in the foetus, vitamin B9.

The minerals most widely used to design functional foods are calcium, due to its relationship with bone formation, potassium, and iron.

Phenolic compounds are found in higher plants, and their main function is antioxidant, which means that they can prevent cell damage due to oxidation. Their main health benefits are a decreased rate of non-communicable chronic diseases, such as atherosclerosis, and the prevention of certain types of tumour. Some examples of food containing phenolic compounds are green tea, citrus fruits, red fruits, and soybean.

Omega-3 fatty acids are functional lipids often used as a functional ingredient. They’re called like this because of the double bond present, three carbon atoms away from the terminal carboxylic group. Functional lipids have been proved to benefit several body functions and prevent health problems. They have anti-inflammatory activity, improve the cardiovascular system, the neural development during pregnancy, lactation, and childhood, and the vision development in breastfeeding infants.

Phytosterols and phytostanols are also functional lipids present in plants. They are thought to have a cholesterol lowering effect, and are usually present in small amounts in seeds and legumes.

Probiotics are defined as live microorganisms, mostly bacteria, which, when taken in adequate amounts, confer a health benefit. Some bacteria strains, some yeasts and moulds are able to survive in the gut, are used as functional ingredients, and often added to foods such as dairy products. To be considered as a probiotic, a microorganism has to meet some requirements. It must be also present in human intestinal microbiota, it cannot be pathogenic or toxic, it has to survive after stomach and intestinal digestion, it needs to reach epithelial cells of the gastrointestinal tract, and adapt to existing intestinal microbiota. It has to produce antimicrobial compounds and enhance immune functions and metabolic abilities. There is a large amount of scientific literature that proves the health benefits of including probiotics in regular diets. Probiotics have shown to ameliorate lactose intolerance, stimulate the resistance to pathogens, reduce risk to intestinal diseases and colon cancer, and enhance the immune function. Some examples of food naturally rich in probiotics are yoghurt and sour pickles.

Related to probiotics, we can also find prebiotics, which are defined as non-digestible substances that selectively stimulate the growth and/or activity of bacteria in the gut. And thus they have a positive effect on our health. In contrast to probiotics, which provide living microorganisms, the function of prebiotics is to stimulate the growth of good bacteria in our intestine. They have to be resistant so they are not absorbed in the stomach or the intestine. They also need to be a selective substrate for colonic microbiota, which means that they promote the proliferation or the beneficial metabolism of specific bacteria in the colon. Prebiotics also modulate beneficial microbiota, and induct effect at a local or at a systematic level. Prebiotics modulate colonic microbiota, they may relieve symptoms of diarrhoea, reduce fat intake, reduce dental carries, regulate blood lipids, or improve mineral absorption. Some food naturally containing prebiotic ingredients are asparagus, banana, wheat, and oats.

Dietary fibre can be defined as carbohydrates with a high degree of polymerization that are resistant to enzymatic digestion, and therefore are not absorbed by the small intestine, so they can reach the colon. Dietary fibre is formed by components of the plant cell wall, such as non-digestible oligosaccharides and resistant starch. Including certain amounts of dietary fibre in our diet can help us to reduce caloric intake by promoting satiety, regulating the colon function, stimulating the immune system and intestinal barrier function, reducing the level of cholesterol in the blood, attenuate blood glucose or decrease the risk of suffering from colon cancer. Some examples of food naturally rich in dietary fibre are wholegrain cereals, nuts, beans, or chickpeas.

Now you know what a functional food is, which functional ingredients are often used to develop functional foods, and some of their health promoting effects. Including functional foods in your diet might have a number of beneficial effects, but it’s important to highlight that they have to be consumed as a complement, but never as a replacement, of a varied and balanced diet and a healthy lifestyle.

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Introduction to Food Science

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