Effects of the MIND Diet on Fatigue, Quality of Life, and Brain Fog in Patients With Multiple Sclerosis: A Randomized Controlled Trial

Multiple Sclerosis (MS) is defined as an autoimmune disease of the central nervous system that causes myelin loss and axonal damage and is characterized by inflammation. MS can also occur as acute optic neuritis, brainstem syndrome, pyramidal system demyelination and/or spinal cord syndromes. In addition to neurological symptoms such as vision loss, weakness, numbness, difficulty walking and dysesthesia due to demyelination occurring during the formation of the disease, atypical symptoms such as fatigue, depression and cognitive disorders are also observed. Although early and accurate diagnosis of MS is essential, diagnosis is based on the presence of clinical symptoms and findings on magnetic resonance imaging (MRI), which is highly sensitive in detecting characteristic central nervous system lesions. McDonald 2017 criteria are used in the diagnosis of the disease.

There are four clinically defined types of the disease. The types of MS are; relapsing-remitting MS, which constitutes approximately 85% of cases, primary progressive MS, which constitutes 10-20% of cases, secondary progressive MS, and clinically isolated syndrome. In patients with relapsing-remitting MS, the transmission of nerve impulses is affected during relapses, while the course of the disease and symptoms tend to improve or improve during remission. When relapses increase, progressive neural dysfunction occurs, and when remission is not achieved, progressive neurological damage occurs. This condition is defined as secondary progressive MS. In order to diagnose primary progressive MS, the disability status that continues for at least one year must be progressive. However, distinguishing between primary progressive MS and secondary progressive MS is often challenging. Although the course of the disease varies greatly depending on the type, many people develop irreversible disability, and MS continues to be the leading cause of neurological disability in young adults. The disability levels of individuals with MS are determined by the Expanded Disability Status Scale (EDSS). EDSS is a scale used worldwide in the evaluation and follow-up of neurological examinations of patients. The EDSS score ranges from 0 to 10. A score of 0 means "normal neurological examination, no disability", while a score of 10 means "death due to MS".

Genetic factors, microbial and viral infections, smoking, serum vitamin D levels, obesity and nutritional habits are effective in the development of MS. Although the immune system seems to have a major effect on protection from MS, it is stated that the innate or acquired immune system may be effective in the development and occurrence of the disease. Although the mechanism is not clearly explained, it is stated that the disease may develop due to an autoimmune response that occurs as a result of damage to the blood-brain barrier caused by antigens formed against neurodegenerative diseases such as Alzheimer's or any viral infection.

MS is more common and economically burdensome in high-income countries such as Western Europe and North America, which are farthest from the equator. It is known that Western-style nutrition is dominant in these countries and that there is insufficient exposure to sunlight. The average age of onset of the disease has been determined as 32. Although it is more common in young adults and women, the female/male patient ratio has been reported to be between 1.5:1 and 2.5:1. It is estimated that there are 70 thousand MS patients in Turkey. It is known that approximately 2.8 million people have MS worldwide. The prevalence of the disease is determined as 35.9 MS patients per 100,000 people.

There is currently no known definitive treatment for the disease. However, disease-modifying treatments (DMTs) such as interferon beta-1a, interferon beta-1b, peginterferon beta-1a, glatiramer acetate, dimethyl fumarate, teriflunomide, natalizumab, fingolimod, cladribine, ocrelizumab and alemtuzumab are used to control the frequency of relapses, disability and progression of symptoms. Lifestyle changes applied in addition to DMTs can also improve the course of the disease. The aim of lifestyle changes applied to MS patients is to improve quality of life, reduce perceived fatigue and disability, and help improve the effects of brain fog that has come to the fore after the Covid-19 outbreak.