**1. Introduction**

Cognitive decline is an alarming public health concern. Intellectual debility related to aging is a staid health issue, which increases the prevalence of neurodegenerative diseases as people are active longer and the proportion of aged persons globally remains increasing rapidly [1]. World Health Organization (WHO) reported that dementia affects an estimated 50 million people, and this prevalence is projected to rise over 130 million by 2050 [2]. Further epidemiological studies advocate an adverse interaction of aging and obesity with cognitive dysfunction [3, 4]. There are additional adverse implications for cognition health which are assessed as 30% prevalent among the overweight and obese adult population [5, 6]. The strong predictors of functional disability and dependence are dementia and cognitive impairment, which leads to major socioeconomic burden [7].

The usual part of the aging process is cognitive decline, but the rate of decline may differ depending on the variations in genetic and lifestyle-associated factors [8]. Elderly people develop these protein deposits, known as amyloid plaques and tangles. Plaques and tangles are a pathology found in the brain that builds up in

between nerve cells and typically interfere with thinking and problem-solving skills. Aging acquires a toll on the body and mind. For instance, the tissue of aging human brains sometimes develops abnormal clumps of proteins, which are the hallmark of Alzheimer's disease. Currently, the brain can be protected from these effects by a healthy diet.

A healthy diet has the potential in preserving the brain and maintaining cognitive health. The potential of modifiable lifestyle factors is important as there are no effective pharmacological agents identified for the improvement of cognition or delay of the progression of cognitive decline [9]. Diet is a key lifestyle risk factor. Personalized nutrients in foods have been contradictorily related to cognitive function, which includes some vitamins, carotenoids, long-chain n-3 polyunsaturated fatty acids (PUFAs) in kinds of seafood, whole grainy foods rich in polyphenols, nuts, olive oil, coffee, fruits, and vegetables [10–12].
