<p>The work culture of human beings is going fast and exhaustive because of innovative technology and improving expectations. To meet expectations and maintain health, society is incorporating functional food into their diets. Previously, people preferred supplementary food diets, which is pure, processed and costly. Now, the diet trend is shifting to add functional food or health benefitted food to a regular diet. Food which includes vegetables, fruits, herbal drinks and spices having many beneficial secondary metabolites for human beings. Plants produce polyphenols, which are crucial functional foods for human diet. The significant potential of polyphenols for use in food preservation and medicinal benefit accounts for their enormous interest. In the twenty-first century, the importance of the functioning of food is enhanced drastically due to its great impact on maintaining health and avoiding risk of chronic diseases. Polyphenols are considered a key plant’s secondary metabolites for the prevention of degenerative diseases. Polyphenols, known for their strong antioxidative, anti-diabetic, antihypertensive, cardioprotective, neuroprotective, and anticancer properties, are used in treating various health conditions and as bio-preservatives in the food industry, helping protect cells and organs from oxidative damage through diverse mechanisms. Moreover, food processing and their form either free or conjugated in food matrices determines the bioavailability of these compounds. Recent findings are uncovering the complex interactions between plant polyphenols and cellular homeostasis, including metabolic balance, redox stability, and inflammation, providing a stronger molecular foundation for their health benefits. This review highlights current insights into polyphenol types, their dietary sources and quantitative consumption, protective mechanisms against major diseases as well as factors affecting polyphenols availability.</p>