Research on Effect of Mediterranean Diet on Alzheimer’s Disorder

INTRODUCTION

Aging is a natural phenomenon that every living thing is bound to go through in its lifetime. As a person ages, they acquire diseases such as Arthritis, Alzheimer’s Disorder, a decrease in physical activity, and difficulty in seeing. Alzheimer’s disease is a disease that makes it hard for a person to remember things such as where they parked or their family member’s names. It affects people above the age of 65. Aging plays a significant role in determining how a person’s brain is likely to function. As an individual ages, the white and grey matter of the brain decreases, and the cerebral ventricles enlarge. The age-related decrease in white and grey matter is seen in the frontal and temporal lobes. A decline in brain activity is caused by neuronal loss, neuronal morphology changes, and dendritic and synaptic reductions. The effects of aging of the brain include having trouble making decisions, learning, motor coordination, and a short span of memory. Cognitive functions are also affected. Aging increases an individual’s chances of developing neurodegenerative diseases.

The most common neurodegenerative disease is dementia. Dementia has numerous disorders and the most common disorder is Alzheimer’s Disorder. There is no specific cause for the disease, and numerous scientists have tried to come up with a cure, but none seems suitable. Alzheimer’s Disorder causes a decline in cognitive function. Studies show that people develop Alzheimer’s Disorder, but symptoms do not show. Symptoms show 15 to 20 years later. There are three types of AD, early-stage or mild AD, middle stage or moderate AD, and Late-stage or severe form of AD. In the early stages of AD, the individual slowly loses cognitive function, memory, and ability to live. At the late stage, the individual cannot engage in a conversation or cannot move. The therapies that have been approved for the treatment of AD include cholinesterase inhibitors and Memantine. Both of these therapies are only effective if used in the short term. In the long run, these therapies do not work out. Due to the ineffectiveness of these therapies, there have to be other alternative methods that can be used to manage the disorder. The aim of this research project is to show the influence of diet on Alzheimer’s Disorder.

Objectives

The best diet plan that can be used to reduce AD

How the diet works to reduce brain health decline.

A list of foods that are beneficial to AD patients

LITERATURE REVIEW

Alzheimer’s Disorder affects around 50 million people in the world. It causes a decline in cognitive functions amongst other symptoms such as having difficulty remembering simple things such as where one lives, confusion, a reduction in self-care, and personality changes (Bhardwaj, et al, 2017. pp.1141-1151) The cognitive decline comes as a result of the decrease in neurons in the brain as a result of a decrease in neurofibrillary decline in the limbic system, subcortical structures, archicortex, and progressive synaptic dysfunction. Pathologically, AD involves progressive deposition of amyloid β-peptide (Aβ) as amyloid plaques, hyperphosphorylated tau protein intracellularly as neurofibrillary tangles (NFTs), and neuronal loss in the hippocampus. Furthermore, patients suffering from AD have mitochondrial dysfunction and metabolic changes, which include impaired glucose utilization in the brain (Bhardwaj, et al, 2017. pp.1141-1151). When the mitochondria do not function well, and the respiratory chain function decreases, it affects the amyloid precursor protein (APP) processing, which causes the production of pathogenic amyloid-β fragments. The reduction in glucose absorption and inefficient glycolysis results in a progressive cognitive deficiency (Choi, et al, 2019, pp.7-8) Previous studies show that there is a high correlation between a high glycemic diet and cerebral amyloid deposition. This high correlation shows that insulin resistance of brain tissue may result in the development of AD.

Drugs that have been approved by Medicine and Healthcare Products Regulatory Agency (MHRA) galantamine, rivastigmine, donepezil, and Memantine (Bhardwaj, et al, 2017. pp.1141-1151). These drugs control the activity of neurotransmitters and partly improve behavioral symptoms. Other treatment options include immunization, the use of anti-aggregation drugs, γ- and β-secretase inhibitors. However, all these treatments are not effective in the treatment of AD. The most reliable method that can be used in managing the disease is changing the patient’s diet (Ballarini, 2021, pp.e2920-e2932). These changes include, the patient should reduce the consumption of transfats, saturated fats, dairy products, and increase the consumption of fruits, vegetables, proteins such as beans, peas, lentils, and whole grains. Various diet plans have been developed to help in the management of AD (Ballarini, 2021, pp.e2920-e2932). The Mediterranean Diet is known for being efficient in managing illnesses such as cardiovascular diseases and lifestyle diseases such as obesity. Previous studies show that MeDi is also effective in the management of Alzheimer’s Disorder (Ballarini, 2021, pp.e2920-e2932). MeDi is a plant-based diet in addition to white meat, and once in a while, people add red meat and dairy products. MeDi is beneficial for people who want to reduce their weight, reduce the blood levels of inflammatory markers, and decrease the amount of cholesterol in the body.

RESEARCH METHODOLOGY

The scoping review followed the guidelines provided by Arksey and O’Malley’s methodological framework. According to the two researchers, a scoping design should identify the research question, search for the appropriate studies, select them, chart data, and collate it. Finally, the results should be summarized and collected (Ballarini, 2021, pp.e2920-e2932. This review is effective because it enables the researcher to put together different study designs. In this review, quality assessment is unnecessary, and the results are reported in the form of a narrative.

Identifying the research question

Inclusion criteria

The studies focused on the different diet plans that can be used to manage AD. The participants that were used in this study were community-based participants. The study also focused on the effects of using these different diet plans, asking the carer givers if they observed any changes in the patients. All types of studies were included (Ballarini, 2021, pp.e2920-e2932. The studies ranged from Systematic reviews, randomized controlled trials (RCTs), controlled studies, observational studies, and qualitative studies. All the papers were written in English.

Searching for relevant studies

A wide range of studies were collected. The studies provided knowledge about the different diet plans. The information was collected from the literature that dates from 2017 to 2021. Most of the computerized studies were from PubMed, Scopus, Ovid, and Web of Science. Some of the experts in the field of Alzheimer’s Disease were also contacted. These experts were from organizations such as the Alzheimer’s Disease Society, MHR, and the Dementia and Sight Loss Interest Group. The search terms that were used include the Mediterranean diet (MeDi) An in-depth analysis of the selected papers was undertaken to identify the articles that could provide reliable data. A total of 20 articles were gathered from these databases (Ballarini, 2021, pp.e2920-e2932). Ten of them did not qualify to be included. Twelve met the criteria for selection. A large number of the studies were qualitative (McGrattan, et al., 2019. pp. 53-65) Most of the participants were people that lived in long-term care. Most of the participants were 65 years and above. 70% of the studies did not highlight the ethnicity of the patients.

Overview of study characteristics

Year of publication

Range 2017 to 2021

Type of study

Scoping number = 2

Qualitative number = 6

Case control number = 2

Other number = 2

Areas covered in study

Setting

Hospital = 5

Community = 10

Primary care number =5

Mixed community= 3

Ethnicity

White = 4

Mixed =8

NA (for example, review) number= 3

Type of participants

Most of the participants were aged from 65 to 100 years. With the mean age being 65 years. The participants were 60 in total. Twenty of these were the healthy control, and the rest were patients that suffered from Mild Cognitive Impairment (MCI) and dementia with Alzheimer’s Disease Disorder. The patients were removed from the study if they had illnesses such as depression, bipolar disorder, cancer, and they did not have non Dementia with Alzheimer’s Disorder. When carrying out the clinical review, an ICD-10 dementia severity rating was carried out. The participants were given an in-depth explanation concerning the implications of participating in the study. A 3-month follow-up was carried out on the patients. 5 of the control participants withdrew from the study. Five of the other patients who had Dementia with Alzheimer’s Disorder had died. When conducting the follow-up, a neuropsychological test battery was used to generate continuous cognitive performance data.

The following neuropsychological tests were used Mini-Mental State Examination, Verbal Learning Test II –Second Edition when analyzing the data. 40 participants finished the questionnaire. The neuropsychological tests include memory, language, executive functions, working memory, and visuospatial capabilities. Fasting blood samples of the participants were collected. The Healthy Control Group participants filled the European Prospective Investigation of Cancer (EPIC) FFQ questionnaires on their own.In contrast, the carers of the participants with Alzheimer’s Disease filled the questionnaires on behalf of the patients because they were aware of what the patients consumed. A MeDi score was developed, and a participant was awarded a value when their food intake was equal to food that contained the following, fish, vegetables, fruits/ nuts, legumes, cereals, and monounsaturated fats. They gained a score when they consumes 50g/d for men and 10g/d for women.

MRI Acquisition

The structural images of all of the participants’ brains were taken. 3T MRI scanners were used. All the images had a 1-mm isotropic nominal image resolution. The images had a resolution of 256 by 256 by 192. Data analysis took place by the use of R statistical software and SPSS.

Voxel-Based morphometry Analysis

This analysis was conducted in a bid to ascertain the relationship between gray Matter Volume and MeDi. The following tools were used to carry out analysis of these data: Computational Anatomy Toolbox (CAT) and Statistical Parametric Mapping (SPM12). The relationship between the MeDi score and the grey matter was established by the use of a linear model (1 –sample t-test in SPM 12). The variants were age, sex, and intracranial volume.

RESULTS

The Healthy participants had the highest MeDi score, followed by the participants that suffered from MCI then the participants that suffered from AD had the lowest MeDi Score (Ballarini, 2021, pp.e2920-e2932). All the three groups improved in their MeDi scores after took the MeDi diet seriously. In the follow-up period, the MeDi scores improved tremendously (Ballarini, 2021, pp.e2920-e2932). However, not much is known as what results in the conversion to AD from MCI patients. This study proved that when patients adhere to the MeDi diet, they are less likely to develop MCI, and MCI patients are less likely to contract AD Ballarini, 2021, pp.e2920-e2932).

DISCUSSION

MeDi is effective in reducing AD because it reduces cardiovascular diseases such as hypertension, abnormal glucose metabolism, and coronary heart disease. Some of the foods that are part of the MeDi include olive oil, vegetables, wine, fruits, Vitamins C, E, and B12. These foods are antioxidants (Ballarini, 2021, pp.e2920-e2932). When a patient suffering from AD consumes them, they are likely to get rid of oxidative stress that results from oxygen and nitrogen species found in the body during normal metabolic processes. Still, the body is unable to get rid of them. AD also causes inflammation (Ballarini, 2021, pp.e2920-e2932).

The consumption of MeDi results in lower C-reactive protein levels, which is an inflammatory marker found in Neuritic plaques and neurofibrillary tangles in the brains of patients suffering from MeDi. There was a high positive correlation between brain gray matter volume in the right parahippocampal gyrus and the right hippocampus (Ballarini, 2021, pp.e2920-e2932). An increase in the consumption of MeDi increases brain volume. There is a positive relationship between the strict adherence of MeDi and memory and language.

Mediterranean Diet is rich in foods such as fruits, vegetables, fish, a low amount of dairy products, and red meat. When patients consume the foods found in the Mediterranean diet, they improve their cholesterol and blood sugar levels. Their blood vessels become healthier, and they are at a lower risk of contracting Mild Cognitive Impairment or Alzheimer’s Disorder. (Panza, 2018. pp. 139-155). . The Mediterranean diet also reduces the cases of brain tissue loss that results from Alzheimer’s Disorder. There is a high correlation between the Mediterranean Diet and hippocampal and parahippocampal regions of the brain (Bhardwaj, et al, 2017, pp.1141-1151). At the biomarker level, Mediterranean Diet results in preserved cortical thickness and brain volume in the regions of the brain that are associated with aging. According to a scan conducted by using C- Pittsburgh compound P-BET, MeDi reduces the Amyloid load.

The limitations of the study include that most of the patients had a hard time adjusting to the new Mediterranean diet. Therefore, most of them skipped the diet, especially at the baseline. Patients still adhered to the MeDi diet, but they developed AD. This can be attributed to their careless smoking and drinking habits (Gardener& Caunca, 2018. pp.10-20) Collecting data concerning the patient’s family origin was not possible since most of the patients with AD could not clearly remember their family origin. Therefore, a decision was reached that family origin data should not be collected. Family history plays a significant role in determining a person’s lifestyle choices and diet. In some cultures, people are not allowed to consume meat or milk, which contributes to them not getting certain lifestyle diseases. In other instances, the carers were old spouses (Vassilaki, et al, pp. 281-290) These old spouses gave some unreliable data because they were overwhelmed with taking care of themselves and their spouses with Alzheimer’s Disorder. The questionnaire did not include foods such as snacks and soft drinks. Furthermore, the overall number of times in which a person consumes food is not taken into consideration. Therefore, the overall quantities of each of the different foods might be ignored. The follow-up period was short, which made it hard for long-term recommendations to be reached.

ETHICAL CONSIDERATIONS

Although Mediterranean Diet is effective in managing AD, the patients might gain excessive weight if they consume so mich fats that are found in olive oil and nuts. Therefore, medical practitioners and carers ought to check the quantities of olive oil and nuts in the foods of patients with Mild Cognitive impairment and Alzheimer’s Disorder (van den Brandt, et al, 2017. pp.2220-2231).. The patients should be encouraged to eat foods rich in iron and vitamin C because when they choose to adhere to this diet, they are highly likely to lack iron. They should also eat foods that have calcium but are within the Mediterranean diet Spectrum. Although wine is recommended, patients that are likely to suffer from cancer or are at a high risk of becoming drunkards should not consume wine.

In conclusion, the population of older people is growing at an alarming rate compared to younger people. Therefore, the government needs to work fast to ensure that they have funds that will be used to cater to the older generation. A large number of the people in the older generation suffer from dementia. The most common disorder that comes as a result of dementia is Alzheimer’s Disorder. Various drugs have not been successful in reducing the effects of Alzheimer’s disease or preventing a patient with Mild Cognitive impairment from progressing to Alzheimer’s Disorder. Mediterranean Diet is made up of the following foods like fruits, vegetables, fish, a low amount of dairy products, and red meat is effective in reducing the brain tissue loss that is associated with Alzheimer’s Disorder, it increases cortical thickness and brain volume in the areas of the brain that are affected by aging. It also decreases the amyloid load.

References

Ballarini, T., van Lent, D.M., Brunner, J., Schröder, A., Wolfsgruber, S., Altenstein, S., Brosseron, F., Buerger, K., Dechent, P., Dobisch, L. and Düzel, E., 2021. Mediterranean Diet, Alzheimer Disease Biomarkers, and Brain Atrophy in Old Age. Neurology, 96(24), pp.e2920-e2932.

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Gardener, H. and Caunca, M.R., 2018. Mediterranean diet in preventing neurodegenerative diseases. Current nutrition reports, 7(1), pp.10-20.

McGrattan, A.M., McGuinness, B., McKinley, M.C., Kee, F., Passmore, P., Woodside, J.V. and McEvoy, C.T., 2019. Diet and inflammation in cognitive ageing and Alzheimer’s disease. Current nutrition reports, 8(2), pp.53-65.

Panza, F., Lozupone, M., Solfrizzi, V., Custodero, C., Valiani, V., D’Introno, A., Stella, E., Stallone, R., Piccininni, M., Bellomo, A. and Seripa, D., 2018. Contribution of mediterranean diet in the prevention of alzheimer’s disease. In Role of the Mediterranean  Diet in the Brain and Neurodegenerative Diseases (pp. 139-155). Academic Press.

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van den Brandt, P.A. and Schulpen, M., 2017. Mediterranean diet adherence and risk of postmenopausal breast cancer: results of a cohort study and meta‐analysis. International journal of cancer, 140(10), pp.2220-2231.

Vassilaki, M., Aakre, J.A., Syrjanen, J.A., Mielke, M.M., Geda, Y.E., Kremers, W.K., Machulda, M.M., Alhurani, R.E., Staubo, S.C., Knopman, D.S. and Petersen, R.C., 2018.

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