Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS), including the brain, spinal cord, and optic nerve. Of the almost 1 million people living with MS in the United States, about 75 percent are women, according to the National Multiple Sclerosis Society. Although there’s a deep pool of scientific research about MS, scientists still don’t fully understand why women are more likely to develop the condition.
Inflammation in the body plays a key role in autoimmune diseases like MS — not only is it a risk factor for developing MS, but it also influences the disease progression. This article will help you understand why some people may be more likely to experience inflammation and how it’s connected to MS.
Inflammation is a normal and necessary part of your immune system. There are two types of inflammation — acute (short-term) and chronic (long-term).
Acute inflammation is your immune system’s response to an irritant or damage to your body caused by:
When your body recognizes a threat or damage, it springs into action by releasing inflammatory mediators — chemicals and proteins that call your immune system to action. This process is responsible for the symptoms of inflammation you see and feel.
Inflammatory mediators cause redness, warmth, and swelling by dilating (widening) the blood vessels and making it easier for fluid and immune cells to seep out. This process allows more blood to flow where it’s needed. Inflammatory mediators also act on the nerves in the area, causing you to feel pain. In acute inflammation, pain tells your body to protect the area.
Other inflammatory mediators called cytokines — including tumor necrosis factor-alpha (TNF-alpha) and interleukins — call immune cells like T cells and B cells to the affected area. These cells make proteins called antibodies that help your body clear an infection.
Inflammation is helpful and protective when you have an acute injury or illness. But when inflammation occurs without an injury, it can become harmful to your body.
Chronic inflammation can result when your body sends inflammatory signals even when there’s no danger. Conditions associated with chronic inflammation include:
In chronic inflammation, immune cells continue to be called to the site of inflammation. When they get there, there’s no outside threat to fight, so they begin to attack the cells of the body. Immune cells like T cells and B cells may even make antibodies against the body’s own tissues.
Research has revealed several risk factors for chronic inflammation:
MS is a chronic inflammatory disease in which the immune system attacks the myelin sheath (the protective insulation covering nerves), setting off a process called demyelination. Without the myelin sheath, nerve damage in the central nervous system occurs.
Inflammation in MS makes it easier for T cells and B cells to get through dilated blood vessels and enter the CNS, where they release more inflammatory mediators and cause damage.
Overall, women experience more inflammation than men, according to findings published in The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. Research has found that women have stronger immune responses, according to a review article in Frontiers in Immunology. Men, however, have more neurodegeneration (permanent damage to the brain) with earlier progression to disability, according to a study in Neurology.
When your body is fighting off an infection, a strong immune response is beneficial. In fact, researchers noted in the journal Biology of Sex Differences that, compared with females, males are more susceptible to infections from viruses, bacteria, and parasites. However, a stronger immune response also puts females at an increased risk of autoimmune disorders. Scientists don’t fully understand why that is, but it could be linked to hormones and obesity.
When scientists try to figure out why a medical issue affects people of different sexes in different ways, they usually look into hormones first. The primary hormones responsible for differences between sexes are estrogen for females and testosterone for males. In general, testosterone suppresses the immune system, whereas estrogen enhances the immune system. However, estrogen also has anti-inflammatory properties.
A person’s menstrual cycle makes estrogen rise and fall twice each month. Menopause also brings drastic hormone changes when hormone levels fall and the menstrual cycle stops. One study showed an increase in proinflammatory markers like TNF-alpha and interleukins after menopause.
Pregnancy also influences inflammation. The complex changes that occur in a person’s body and with hormones during pregnancy can reduce inflammation.
Obesity is an accumulation of fat that results in a weight that is higher than considered healthy for a given height, according to a measure called body mass index (BMI). A BMI of 30 is considered obese, and a BMI from 25 to under 30 is considered overweight. A BMI from 18.5 to below 25 is considered healthy.
In general, women have more body fat than men, and a woman with the same BMI as a man typically has about 10 percent more body fat than that man. Additionally, obesity is more common in women than men, wrote the authors of a review article in Current Obesity Reports.
Fat cells release inflammatory mediators such as TNF-alpha and interleukins. If you have more fat cells, you generally have more inflammation. Obesity has also been linked with lower levels of vitamin D, a nutrient that has anti-inflammatory properties.
MS is a disease of chronic inflammation. It makes sense that people who are more likely to experience inflammation are more likely to be diagnosed with MS and that their symptoms would be influenced by their hormones.
The cause of MS involves several genetic and environmental factors, but researchers have reported that some factors are specific to women.
Estrogen’s role in stimulating inflammation helps us understand why MS is more likely to occur during certain times of life. The condition generally occurs when estrogen levels are highest — during the so-called reproductive years after puberty and before menopause. Less than 5 percent of people with MS are diagnosed before puberty or after menopause.
Women with a BMI of 30 or higher at age 18 have more than double the risk of developing MS than those with a BMI from 18.5 to under 21, according to findings published in the Journal of Neurology & Neuromedicine. Childhood obesity is also a known risk factor for developing MS. It’s unclear exactly why obesity raises the risk of MS, but it is likely linked to increased inflammation and low vitamin D levels.
Inflammation all over the body may make it easier for inflammatory cells and chemicals to reach the CNS, cause symptoms, and worsen disease progression. MS symptoms in women can change depending on hormone levels.
Many people notice that their MS symptoms worsen right before and during their periods when estrogen levels drop. Some may also notice a change in MS symptoms when going through menopause. However, clinical trial results on the effect of menopause on MS have shown no definite conclusions.
Pregnancy causes many changes in hormones and inflammation. Researchers have found that these changes usually result in fewer MS flare-ups — also called MS relapses.
You can’t change some risk factors — like your family history — but you can make some lifestyle changes to reduce inflammation.
What you eat can have a big impact on inflammation. There isn’t a particular diet that people living with MS should follow. Instead, focus on eating fewer foods that can increase inflammation and eating more of those that offer anti-inflammatory benefits.
Examples of foods that you should try to avoid because they may increase inflammation are:
Eating more whole foods will give your body the nutrition and fiber it needs. Whole foods that may have anti-inflammatory benefits include:
Exercise has been shown to decrease inflammation, regardless of whether you lose weight. The Centers for Disease Control and Prevention (CDC) recommends getting at least 150 minutes of exercise a week. This weekly total can be broken down into amounts that are doable and comfortable for you.
Eating a healthy diet and staying active will help you maintain a healthy weight. Obesity increases inflammation, so staying at a healthy weight is important for reducing inflammation.
Talk to your doctor or neurologist about disease-modifying therapies (DMTs) that may slow the progression and limit the symptoms of your MS. Some MS treatments work by decreasing inflammation through the immune response. Your doctor may also recommend that you take certain vitamins or supplements.
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