Review Article

Role of diet in regulating the gut microbiota and multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disorder of the central nervous system (CNS) associated with significant progressive neurodegeneration. There is a lot of interest in the use of plant-based essential oils in traditional medicine to treat and prevent human illnesses, including MS. This research aimed to assess the neuroprotective effects of green tea oil (GTO) and pumpkin oil (PO) against myelin oligodendrocyte glycoprotein (MOG)-induced MS in Wistar rats as well as investigate the underlying molecular mechanisms. The Wistar rats were divided into four groups: group 1, normal control; group 2, MOG-injected; and groups 3 and 4, MOG-injected groups treated with 5 ml/kg body weight each of GTO and PO, respectively. The chemical profiles of components within a GTO and PO were identified using gas chromatography-mass spectrometry (GC–MS). Treatment with GTO and PO substantially improved the decreased dopamine, serotonin, norepinephrine, and acetylcholine levels in the brain of the MOG-injected rats. It also suppressed the elevated epinephrine levels. The histological injuries in the brain cortical tissue of the MOG-injected group were notably improved after supplementing with GTO and PO. Furthermore, brain lipid peroxidation and serum INF-β concentration were significantly lower in the MOG-injected rats treated with GTO and PO. The brain GSH, SOD, GPx, as well as serum coenzyme Q10, and α-tocopherol levels were significantly enhanced by GTO and PO supplementaion. Additionally, GTO and PO administration into MOG-injected rats significantly upregulated Nrf2, Bcl-2, and PCNA while significantly downregulated TNF-α, NF-κB, iNOS, p53, and Bax expression levels. Taken together, these findings suggest that GTO and PO efficiently ameliorate MOG-induced MS via enhancing the antioxidant, anti-inflammatory, and anti-apoptotic effects.

Patients with multiple sclerosis (MS) frequently report sleep complaints. The ketogenic diet (KD) is safe and tolerable in MS patients. Our aim was: 1) to investigate the effects of KD on sleep complaints in patients affected by relapsing-remitting MS and 2) to verify if sleep changes can positively impact on psychological status and quality of life (QoL) in these patients.

From January 2020 to November 2022, we consecutively enrolled 21 non-disabled or minimally disabled MS patients. We collected information regarding: 1) anthropometric measures; 2) psychological status by the Depression Anxiety Stress Scale-21; 3) QoL by the Multiple Sclerosis Quality of Life-54 (MSQOL-54); 4) subjective sleep complaints, i.e. sleep quality, by the Pittsburgh Sleep Quality Index (PSQI), and excessive daytime sleepiness (EDS), by the Epworth Sleepiness Scale (ESS).

After 6 months of KD therapy, anthropometric measures considerably changed, psychological status significantly improved, and almost all the MSQOL-54 subscales ameliorated. Regarding sleep, we observed that the global PSQI (T0: 7.7 ± 3.1 versus T1: 4.4 ± 3.1, p = 0.002) and the ESS (T0: 7.5 ± 3.9 versus T1: 4.9 ± 3.2, p = 0.001) scores significantly decreased after KD therapy. At T1, only the global PSQI score was an independent predictor of anxiety, stress, and mental health.

For the first time, we demonstrated that KD may improve sleep complaints in MS patients. In addition, KD seems to have a positive impact on psychological status and QoL of MS patients, mainly through improving sleep quality. Further controlled studies with larger sample sizes are needed to confirm these preliminary results.

One of the important challenges in the treatment of patients with multiple sclerosis (MS) is determining the effective factors in the treatment of MS, including dietary adherence. The aim of this study was to investigate the relationship between adherence to the Mediterranean diet with anthropometric indices and the expanded disability status scale (EDSS) scores in patients with MS.

The present multicenter and cross-sectional study was conducted on patients with clinically definite MS (according to the 2017 revised McDonald criteria) who were referred to the MS clinics at medical centers affiliated to Shiraz and Tehran Universities of Medical Sciences during 2019. Disease phenotype, EDSS, waist circumference (WC), body mass index (BMI), and comorbidities were assessed. Adherence to the Mediterranean diet was measured with a 14-item modified Mediterranean Diet Adherence Questionnaire. In this questionnaire, a score of 0–5 indicates low adherence, a score of 6–9 shows moderate adherence, and a score of 10 and above demonstrates high adherence (healthy eating pattern).

This study was performed on 478 patients with a mean age of 37.99 ± 9.60 years, out of which 352 patients (73.6%) were female. The percentage of low, medium, and high adherence to the Mediterranean diet in patients with MS was 26.4%, 64%, and 9.6%, respectively. The difference in the level of education between the groups based on adherence to the Mediterranean diet was statistically significant. Low adherence to the Mediterranean diet in underweight, normal, and overweight patients was, respectively, 1.31, 1.32, and 2.29 times higher than in obese patients. This increased risk was only significant in overweight patients (P = 0.019). The results revealed that the score of adherence to the Mediterranean diet had no significant relationship with mild (2.86 ± 2.18), moderate (2.76 ± 2.16), and severe (2.70 ± 2.02) levels of disability.

The level of adherence to the Mediterranean diet in Iranian patients with MS was moderate. This level was associated with BMI, such that low adherence to the Mediterranean diet was higher in overweight patients than obese patients.

As conditions that are strongly related to pain associated with inflammation, the “itises” (conditions that usually end with “itis”) are extraordinarily important in terms of individuals' suffering and the tremendous burden that they place on healthcare delivery systems throughout the world. While these conditions are important in and of themselves, they also are often strongly associated with other comorbid conditions that drive healthcare cost and detract from health-related quality of life. Based on scientific evidence reviewed in previous chapters of this book and that will be reviewed in greater detail in subsequent chapters, we know that there is a strong connection between all of these itises and diet. These disparate conditions are inextricably connected though the common feature of inflammation. The “itises” included in this chapter are gingivitis, esophagitis, gastritis, ulcerative colitis, diverticulitis, hepatitis, dermatitis, rheumatoid arthritis, and osteoarthritis. Furthermore, the chapter includes closely related conditions, such as inflammatory bowel disease, Crohn's disease, psoriasis, gout, and multiple sclerosis. There is evidence that some of these conditions are directly connected to dietary factors, with several of the listed conditions having evidence that a diet high in fruits and vegetables yields favorable outcomes. Other conditions have been shown to be affected through inflammatory pathways influenced by nutrient intake. In conclusion, for most conditions, the antiinflammatory nature of healthy diets (such as the Mediterranean diet and other diets high in fruit and vegetables) is considered a low-risk option, which is likely to improve or prevent inflammation. An enhanced understanding of how these factors can be manipulated, and how they can prevent and reduce inflammation has the potential to make great advancement in the use of nutrition to manage disease.

Multiple sclerosis (MS) is a chronic immunological, inflammatory, demyelinating, and neurodegenerative disease. Nutrition has been considered a possible factor in the pathogenesis of MS for some years. There is currently no consensus on the monitoring of eating habits to improve the course and/or symptoms of the disease, as there is insufficient evidence to recommend a specific diet for patients with MS. On this basis, the purpose of this study is to compare the daily eating habits of MS patients in three different countries (China, Spain, and Cuba) that allow us in the future to explore healthier diets for them, and assessing risk factors for relapse in patients with MS.

We have adopted a questionnaire design based on the use of the web to evaluate the daily eating habits of patients with MS in three different countries: China, Spain, and Cuba. According to the options of MS patients in the daily eating habits questionnaire, we divided them into two main eating habits: mixed diet and Mediterranean diet. We performed a logistic regression analysis to explore risk factors for relapse in patients with MS.

Our study found that in the three countries, China, Spain, and Cuba, MS patients are the most common in women, the incidence rate from women to men is 2-3:1, which usually starts between the ages of 25 and 59 years old, and relapsing–remitting is the most common type of MS, 70-80% of MS patients have experienced disease relapse to varying degrees during the course of their illness. Most MS patients in China and Cuba have a mixed diet, while MS patients in Spain have a Mediterranean diet. Through logistic regression analysis, we found that the type of diet is an important risk factor for relapse of MS (p = 0.003, OR = 2.628, 95% CI: 1.393-4.968), the risk of relapse of MS by mixed diet is 2.6 times greater than that of the Mediterranean diet.

The components of the daily diet of MS patients in three different countries are basically the same, but China and Cuba have mixed diets, while Spain has mainly a Mediterranean diet. Our research clearly shows that the Mediterranean diet can reduce the risk of relapses in MS patients. We believe that it is essential to carry out large-scale multicenter studies to verify these findings, which may be of great relevance in the management of MS.

La esclerosis múltiple (EM) es una enfermedad inmunológica, inflamatoria, desmielinizante y neurodegenerativa crónica. La nutrición se considera desde hace unos años un posible factor en la patogenia de la EM. Actualmente no existe un consenso sobre el seguimiento de hábitos alimentarios para mejorar el curso y / o los síntomas de la enfermedad, ya que no hay evidencia suficiente para recomendar una dieta específica para pacientes con EM. Sobre esta base, el propósito de este estudio es comparar los hábitos alimentarios diarios de los pacientes con EM en tres países diferentes (China, España y Cuba) que nos permitan en el futuro explorar dietas más saludables para ellos, y evaluar los factores de riesgo de brotes y recaídas de los pacientes con EM.

Hemos adoptado un diseño de cuestionario basada en la utilización de la web para evaluar los hábitos alimentarios diarios de los pacientes con EM en tres países diferentes: China, España y Cuba. Según las opciones de los pacientes con EM en el cuestionario de hábitos alimentarios diarios, los dividimos en dos hábitos alimentarios principales: dieta mixta y dieta mediterránea. Realizamos un análisis de regresión logística para explorar factores de riesgo de brotes o recaídas en pacientes con EM.

Nuestro estudio encontró que en los tres países China, España y Cuba, los pacientes con EM son los más comunes en mujeres, la tasa de incidencia de mujeres a hombres es de 2-3: 1, que suele comenzar entre los 25 y 59 años, y la remitente-recurrente es el tipo de EM más común, el 70-80% de los pacientes con EM han experimentado brotes de la enfermedad en grado diferente durante el curso de su enfermedad. La mayoría de los pacientes con EM en China y Cuba tienen una dieta mixta, mientras que los pacientes con EM en España tienen una dieta mediterránea. Mediante análisis de regresión logística, encontramos que el tipo de dieta es un factor de riesgo importante para la recaída de la EM (p = 0.003, OR = 2.628, 95%CI: 1.393-4.968), el riesgo de recaída de la EM por dieta mixta es 2.6 veces mayor que el de la dieta mediterránea.

Los componentes de la dieta diaria de los pacientes con EM en tres países diferentes son básicamente los mismos, pero China y Cuba tienen dietas mixtas, mientras que España tiene principalmente una dieta mediterránea. Nuestra investigación muestra de forma clara que la dieta mediterránea puede reducir el riesgo de brotes o recaídas en pacientes con EM. Creemos que es imprescindible realizar estudios multicéntricos a gran escala para verificar estos hallazgos que pueden tener gran relevancia en el manejo de la EM.