**5. Role of probiotics in functional food**

Vitamins such as A, C and E act as antioxidants. These vitamins enhance oxidation progression due to their antioxidant activities. Approximately, about 2 billion people in the whole world are micronutrient deficient, moreover, their risks of death and development of different co-morbidities have subsequently increased. Food fortification by functional foods ensures the availability of nutrients and promote a healthy life. This technique is effective for the consumption of minerals, vitamins and other nutrients to fulfill the functional food need.

Functional food in addition to probiotics are living microbes that are administered into the body of the host and can stabilize the normal flora of the human gut.

#### *An Overview of Functional Food DOI: http://dx.doi.org/10.5772/intechopen.103978*

However, new probiotics are in a developing phase for more progressive and concentrated investigations [24]. Functional food having probiotics as a major ingredient has the tendency to decrease the severity of gastrointestinal infections, it can also provide relief against lactose xenophobia and improve the gut functionality of the host and remarkably save the host from diarrheal associated diseases. Probiotics stimulate good bacterial growth. However, they are previously existing the gut and can transform metabolic accomplishments. They are also capable to increase the levels of short-chain fatty acids formed in the colon and also have the tendency to enhance mineral absorption, i.e., calcium and magnesium preservatives decrease the effectiveness of probiotics health risk [25]. The association of probiotics and prebiotics in a potential way is defined as symbiotic. The presence of glucose and sucrose in a functional food can significantly reduce the severity of pain in the host body. Caffeine can improve cognitive performance, alertness, memory, and other psychiatric performances. Cognitive performance and mental health maintenance in older individuals may be improved by consuming specifically vitamins B [26]. People often experience the association between sleep and normal foods with high carbohydrate food consumption. Tryptophan, an amino acid can reduce the sleepy condition of the individuals, while tyrosine and tryptophan can help in rehabilitation and are the part of functional food. Many ingredients, such as n-3 fatty acids, S-adenosylmethione (SAMe), and folic acid were considered as possible functional ingredients to improve depression [27].

In most cases, only animal or clinical research can be used to determine the viability of probiotics. According to the clinical research, per day consumption of probiotics via functional foods has typically been linked to promote human health. The beneficial effects of probiotics depend upon the nature of probiotic bacteria present in the functional food which ensures the development and survivability of itself in the functional food product [28]. However, several food additives such as aromatic compounds, salts, sugars, sweeteners and preservatives induce the probability of probiotic health risk [29]. The growth and survival of probiotics have been halted when chemicals and food additives interact with probiotics present in functional food. Oligosaccharide based functional foods can stimulate the growth of lactobacillus and bifdo-bacteria and induce health-promoting effects in the host body [30].
