What is Multiple Sclerosis?

Multiple sclerosis (MS) is a disease that affects the central nervous system, causing a range of symptoms such as vision problems, muscle weakness, balance issues, and pain. Typically, this disease is marked by damage to the nerve fibers of the central nervous system. It’s estimated that MS affects over 700,000 people in the US and 2.3 million to 2.8 million worldwide. People with MS may experience muscle weakness, numbness, tingling, and bladder and bowel problems. In addition, they may experience mental health and behavioural problems, including depression and anxiety. MS typically affects people between the ages of 20 and 40, and genetics may play a role. However, it’s also believed that environmental factors are necessary for the disease to develop. Thus, early diagnosis and treatment are essential for managing MS symptoms and improving quality of life.

Multiple Sclerosis Symptoms

The progression, severity, and specific symptoms of MS can differ significantly from person to person, depending on the location and extent of nerve damage in the central nervous system (CNS). Over time, symptoms may evolve, flare, or remit, reflecting the unpredictable nature of the disease.

1. Sensory Disturbances: Numbness or tingling is often one of the earliest signs of multiple sclerosis (MS), typically affecting the face, arms, legs, or fingers. These sensations occur due to damaged nerve fibers disrupting the normal transmission of sensory information to the brain. Another common sensory disturbance is Lhermitte’s sign, characterized by sudden, electric shock-like sensations that radiate down the spine and into the limbs when bending the neck forward. This phenomenon results from irritation or damage to the cervical spinal cord, a hallmark of MS-related nerve demyelination.
2. Motor Symptoms: Multiple sclerosis (MS) can cause muscle weakness in the limbs due to nerve damage that disrupts the transmission of signals from the brain to the muscles. This weakness may be more intense on one side of the body or affect the legs more significantly. In addition to weakness, MS often leads to impaired coordination and balance, known as ataxia, making it difficult to perform tasks that require fine motor skills or steady movement. These motor issues can contribute to trouble walking, with individuals experiencing gait disturbances such as dragging their feet, taking unsteady steps, or, in severe cases, facing partial paralysis. Muscle spasticity, or stiffness, further complicates mobility, increasing the risk of falls and limiting independence.
3. Vision Problems: Visual disturbances are common in multiple sclerosis (MS) due to the disease's impact on the optic nerves and other parts of the visual pathway. Optic neuritis, a frequent early symptom, involves inflammation of the optic nerve, leading to partial or complete vision loss, typically in one eye at a time, and is often accompanied by pain during eye movement. MS can also affect the nerves that control eye movements, causing misalignment and double vision (diplopia), where a person sees two images of a single object. Additionally, individuals may experience generalized blurry vision, which can occur intermittently and is often worsened by heat or fatigue, a phenomenon known as Uhthoff’s phenomenon. These visual symptoms can be temporary or persistent, depending on the extent of nerve damage.
4. Vestibular Symptoms: Dizziness and vertigo are frequent vestibular symptoms in multiple sclerosis (MS), typically caused by demyelinating lesions in the brainstem or cerebellum—regions responsible for coordinating balance and spatial orientation. Vertigo is characterized by a false sensation of movement, often described as spinning, while dizziness may present as light-headedness or unsteadiness. These symptoms can be transient or persistent and may be exacerbated by changes in position, fatigue, or temperature fluctuations. Vestibular disturbances in MS can significantly impair mobility and increase the risk of falls, necessitating careful management and, in some cases, vestibular rehabilitation therapy.
5. Bladder, Bowel, and Sexual Dysfunction: Bladder, bowel, and sexual dysfunction are common complications of multiple sclerosis (MS) due to nerve damage that disrupts signals between the brain and the respective organs. Bladder issues often include frequent urination, urinary urgency, incontinence, or difficulty fully emptying the bladder, all resulting from impaired control of the muscles responsible for bladder function. Bowel dysfunction typically manifests as constipation, partly due to reduced mobility and slowed intestinal function, though bowel incontinence can occur less frequently when nerve signals to the rectal muscles are compromised. Sexual dysfunction is also prevalent in both men and women with MS, as nerve damage can interfere with arousal and sexual response. This may lead to reduced genital sensation, erectile dysfunction in men, and difficulties achieving orgasm or maintaining lubrication in women, all of which can impact the quality of life.
6. Cognitive and Emotional Changes: Fatigue, cognitive impairment, and mood changes are among the most common and debilitating symptoms experienced by individuals with multiple sclerosis (MS). Fatigue in MS is characterized by a profound, persistent sense of exhaustion that is disproportionate to activity levels and does not improve with rest, often interfering with daily functioning. Cognitive impairment can manifest as difficulties with memory, attention, processing speed, and problem-solving, resulting from damage to the brain's white matter, which disrupts neural communication. Additionally, mood changes such as depression, anxiety, and mood swings are prevalent in MS patients. These emotional disturbances may stem from both the neurological impact of demyelination on brain regions that regulate mood and the psychological stress of coping with a chronic, unpredictable illness.
7. Speech and Swallowing Difficulties: Slurred speech (dysarthria) and difficulty swallowing (dysphagia) are common complications of multiple sclerosis (MS) caused by damage to the nerves that control the muscles responsible for these functions. Dysarthria occurs when MS affects the parts of the brain that coordinate speech, leading to slow, slurred, or unclear speech that may be difficult for others to understand. Similarly, dysphagia arises when the muscles involved in swallowing are weakened or uncoordinated, increasing the risk of choking, aspiration (food or liquid entering the airway), and subsequent respiratory complications.
8. Heat Sensitivity (Uhthoff’s Phenomenon): Pseudorelapses in multiple sclerosis (MS) refer to a temporary worsening of symptoms triggered by factors such as minor increases in body temperature from exercise, hot weather, or fever. Unlike true relapses, which are caused by new inflammation or damage to the nervous system, pseudorelapses result from slowed nerve conduction in already demyelinated nerves. This temporary symptom flare-up occurs because heat further impairs the ability of damaged nerves to transmit signals efficiently. Once the triggering factor, such as elevated body temperature, is resolved, symptoms typically subside. While pseudorelapses can be distressing, they do not indicate new disease activity or progression.

Gut Microbiome and Multiple Sclerosis

Over the last decade, studies have suggested that the gut microbiome, a large community of microorganisms residing in the human gut, may play a crucial role in developing autoimmune disorders like MS. The gut microbiome plays an essential role in regulating the immune system and maintaining overall health. It can influence the development of autoimmune diseases and modulate immune responses in diseases such as MS. One of the key findings from some studies is that the gut microbiome of people with MS has a reduced diversity of bacteria compared to healthy individuals. The imbalance of gut microbiota in MS patients, known as dysbiosis, appears to play a role in the cascade of immune cell activation and the resulting neuroinflammation affecting the brain and spinal cord in MS. But how does this potentially happen?

In healthy individuals, the commensal gut bacteria produce short-chain fatty acids (SCFA) (e.g., butyrate, propionate, acetate, etc.) from dietary fiber. These short-chain fatty acids enhance the production of serotonin from food-derived tryptophan, by upregulating the activity of tryptophan hydroxylase 1 enzyme in the enterochromaffin cells of the intestinal epithelium to produce serotonin. The serotonin produced further regulates and activates a cascade of immune cells including cytokines, T-regulatory cells, and immunoglobulins which reach the vicinity of the brain through systemic circulation, promoting homeostasis. In a situation where the intestinal gut balance is altered (dysbiosis), systemic immune regulation is distorted, leading to neuroinflammation, which is evident in many neurodegenerative conditions such as MS. In this case, the levels of SCFA and resulting serotonin levels are reduced, leading to a cascade of immune responses that favors neuroinflammation over homeostasis. Notably, some bacteria groups such as Escherichia coli, Staphylococcus aureus, and Bifidobacterium adolescentis have been associated with driving the proinflammatory TH17 cells which find their way to the central nervous system and contributing to neuroinflammation. This implies that the gut microbiota can exert a significant influence on the balance between regulatory and proinflammatory immune cells, thereby influencing inflammation of the nervous system.

Multiple Sclerosis Treatments

Several treatment options are available for managing multiple sclerosis (MS) symptoms, including corticosteroids, disease-modifying therapies, and lifestyle changes that can reduce inflammation, suppress the immune system, and improve overall well-being. However, dietary modifications and certain supplements may offer possible treatment approaches for managing multiple sclerosis (MS) symptoms through gut health. A Mediterranean diet, which includes whole grains, fruits, vegetables, fish, and healthy fats, can improve overall gut health and potentially reduce MS symptoms. Similarly, a high-vegetable/low-protein diet, a modified paleolithic diet emphasizing lean protein, and fruits, and a low-fat diet have also shown promise in improving gut health and potentially reducing MS symptoms. Supplements such as probiotics, biotin, Vitamin D, and short-chain fatty acids (SCFAs) may also promote a healthy gut microbiome and the health outcomes of people living with MS. Nevertheless, consulting with a healthcare provider before making dietary changes or starting a new supplement regimen is crucial.

In summary, the gut microbiota has been found to play a vital role in MS development and progression. While further research is needed to fully understand the link between gut microbiota and MS, making nutritional changes and discussing supplement options with a healthcare provider can be beneficial in managing symptoms.