Abstract: Background and Objective: Epidemiological studies show that obese patient have an increased risk for cognitive functions impairment. Reports stated that serum amyloid beta (Aβ) peptide levels may reach its peak during the early stage of Alzheimer's disease (AD). The objective of study was to recognize if the plasma Aβ can be applied as biomarker for cognitive function impairment and to demonstrate the effect of using supplements having bioactive components (whole wheat, fennel and chia seeds) with a balanced hypocaloric regimen, on the cognitive functions of middle aged obese women, in addition to their effect in reducing body weight. Materials and Methods: One hundred and forty middle age obese women suffering from different degrees of obesity volunteered in this study which lasted for 8 weeks. All patients were following a balanced low caloric diet (900-1000 calorie/day). The participants were divided into 3 groups: Group (A) consumed fennel supplement, group (B) consumed chia seeds supplement and group (C) consumed baladi bread. Evaluations were made at baseline and 8 weeks later. This included clinical examination, anthropometric measurements, determination of internal metabolic profile, serum Aβ protein and cognitive evaluation. All values were expressed as mean value±SE. Paired-sample t-tests were used to compare the data in the same group before and after dietary therapy. The obtained results of different supplement formulae were evaluated statistically using one-way-ANOVA. Results: After intervention, improving in cognitive functions decrease in serum Aβ protein and improving of the metabolic profile and body weight, especially with fennel supplement were recorded. Conclusion: It is concluded that dietary therapy especially using fennel seed proved to be effective in reducing body weight, improving metabolic profile and cognitive functions. Serum Aβ protein level may be used as a marker for cognitive functions impairment in the obese middle age female.