**2. Definitions of functional food**

In the early 1980s, a Japanese scholarly society proposed the idea of functional foods. The law for functional foods was first introduced in the 1980s as FOSHU,


#### **Table 1.** *Different definitions of functional food.*

*Functional Foods and Human Health: An Overview DOI: http://dx.doi.org/10.5772/intechopen.99000*

which stands for "Foods for Specified Health Use." Functional foods were originally characterized as foods that can modulate body functions and thus help in disease prevention [9]. Functional foods are described by EFSA as "a food that, above sufficient dietary benefits, has a beneficial impact on the multiple body functions in a way that is related to either an enhanced health condition and well-being or a decreased risk of disease". The FSGs law encompasses a small number of welldefined food groups that are deemed important for human health and certain categories of, especially vulnerable individuals. Processed cereal-based diets and baby food, complete diet substitute for weight loss, infant formula and follow-up formula and food for special medical purposes [6]. A functional food should be a natural food or a portion of food to which an ingredient has been added or extracted using technical or biotechnological methods, and it must represent the effects in amounts that can be fairly believed to be consumed in the food" [10].

The Functional Food Center in the United States (FFC) has defined functional foods as "real or processed foods that contain known or unknown biologically active compounds that, efficient, in defined and non-toxic quantities, recorded health benefit or provide a scientifically validated using unique biomarkers for the prevention, treatment or control of chronic disease or its symbiotic diseases" [11]. There are different definitions of functional food are listed in **Table 1**.

#### **3. Foods that contain functional components**

Plant foods contain a variety of functional components such as vitamins (C, A and E) minerals, phenolic compounds, antioxidants and phytochemicals [14]. These Secondary metabolisms produce physiologically active molecules that are helpful for the human body. The various classes of health-promoting substances (phytosterols, carotenoids, phytosterols, phenolic compounds, nondigestible carbohydrates, tocotrienols and organosulfur compounds) are discussed together with the dietary origins as well as the biological and chemical properties that justify their mechanisms of action [15].

Plant-based functional foods (broccoli and other cruciferous vegetables, fruit, grapes, tomato, soybean, oat, oranges, flaxseed, garlic, wine, and tea) are played a functional role in the healthy body, as well as the phytochemicals concerned and benefits of health-promoting function. The study stresses the relevance of eating fruits and vegetables for people's overall wellbeing, as well as certain science and technological prospects in developing countries [16].

Phytochemicals found in whole grains, fruits, and vegetables are the most abundant sources of functional components. Conversely, animal products like milk, fermented milk products, and freshwater fish include antioxidants, covalently linked linolenic acid, long-chain omega-3, −6, and − 9 polyunsaturated fatty acids and organic acids [17]. **Table 2** lists several food ingredients, their biological roles and their typical origins.

#### **4. Functional component**

#### **4.1 Fibers**

Even though dietary fiber is not a "nutrient," it is an essential substance of our foods. Fiber is beneficial because it moves through the body without being digest. Dietary fiber is made up of polysaccharides, its present in soluble and insoluble form in different foods. Pectin, mucilages and beta-glucan soluble whereas lignin,

#### *Functional Foods - Phytochemicals and Health Promoting Potential*


#### **Table 2.**

*Components, sources and biological role of functional food.*

cellulose and hemicellulose insoluble are present in various plant foods [36]. These components are not digested or absorbed in the small intestine and passes into the large intestine in an intact form and is immune to enzymatic digestion. Fibers are graded as soluble or insoluble based on their solubility. Fiber fortification also helps dairy foods enhance their sensory qualities, shelf life, and structural properties [37].

The previous indications evaluated that fiber plays a functional role in the human body against various diseases. Because fiber is the non-digestible component that passes through the small intestine to the large intestine without absorbing. In the small intestine nutrients like fat and glucose are absorbed, however, fiber attracts extra fat and glucose, and pushes them to the large intestine, where stool is prepared. Moreover, extra fat and glucose are made part of the stool. However, in this way fiber prevents extra glucose and fat into the blood that's aids in inhibiting the chances of diabetes and CVD disease [37, 38].

#### **4.2 Vitamins**

Food fortification with essential micronutrients including vitamins A, D, and E improves human health by ensuring sufficient intake to avoid diseases (such as osteoporosis, osteoarthritis, a suppressed immune system, cancer, vision loss and *Functional Foods and Human Health: An Overview DOI: http://dx.doi.org/10.5772/intechopen.99000*

heart disease) and enhances life quality and survival. Malnutrition statistics in many populations, especially in developing countries, have increased the need for food fortification with lipophilic vitamins A, D and E. Foods usually contain these vitamins, but in inadequate quantities, and human body absorption is insufficient to achieve the optimal level of health benefits [39].

Some vitamins including A, C and E act as antioxidants. During processing, the oxidation process is started. These vitamins inhibit the oxidation process due to antioxidants activity. When these vitamins enrich foods are consumed then that's can help in different chronic diseases [40].

Around 2 billion people worldwide are believed to be deficient in one or more micronutrients, placing them at risk of death, illness, or disability. Food fortification and supplementation (i.e., the availability of nutrients in a form other than food) are both effective methods for ensuring adequate daily intakes of minerals and vitamins. A good vitamin or mineral compound for food fortification should have two main characteristics including high bioavailability and no reaction with the food matrix [41].

#### **4.3 Minerals**

The minerals have many roles and potentials in metabolism and homeostasis, mineral deficiency can cause a variety of common disorders and disease symptoms. Mineral absorption and bioavailability can be significantly improved by ensuring mineral content details in terms of safe food fortification and processing methods. The most popular minerals used to fortify various food preparations are iron, calcium, zinc, and iodine. The bioavailability of food minerals can be accurately measured using isotope ratio methods. Modern processing techniques have less detrimental effects on the consistency of micro-and macro minerals than conventional process parameters [42].

Food fortification and supplementation are the most cost-effective ways to combat global mineral malnutrition. Because of political, social, infrastructurerelated, and technical constraints, most interventions to improve mineral nutrition have been less effective in most developing countries. The most potential solution has been salt iodization (iodine fortification), which has substantially decreased the incidence of goiter and other IDD symptoms in areas where it has been introduced [43].. Selenium (Se) is an effective nutritious antioxidant that exerts natural effects by incorporating it into selenoproteins. Since selenoproteins play a vital role in the regulation of reactive oxygen species (ROS) and redox states in practically all tissues. The selenium "improving" the immune system maintained by investigation on aging immunity [44]. Zinc is an important trace mineral and plays a vital role in many physiological functions. Zinc is essential for the growth and function of immune cells in the innate and adaptive immune system. Zinc homeostasis is well controlled in all cells, and any stress-free regulation will result in compromised normal function. In several disease models, such as infections, allergies, autoimmune diseases and cancer, the significances of homeostasis disorders can be detected [45].

#### **4.4 Antioxidants**

Antioxidants are substances that aid in prevent oxidation. Fruits, vegetables, nuts, cereals and beans contained different types of antioxidants. These substances are used as functional ingredients in many foods and food products [46]. As a functional ingredient, antioxidants help to protect from many diseases. In the human body, these functional ingredients played a vital role to protect from chronic diseases such as cancer and cardiovascular diseases [47].
