While vitamins like vitamin D may help MS symptoms, some research suggests that too much vitamin C or vitamin B7 may make them worse.

Multiple sclerosis (MS) is a chronic condition that affects the central nervous system (CNS). When you have MS, your immune system attacks the protective layer around nerve fibers, causing inflammation and lesions.

There’s currently no cure for MS, but you can manage symptoms with lifestyle changes, medication, and potentially, vitamins.

Although much of the research on vitamins that benefit MS is inconclusive, many people take supplements to help manage this condition. But since some research suggests that too much vitamin C or vitamin B7 (biotin) may worsen MS symptoms, you may want to talk with your doctor about avoiding these.

Here’s what to know.

There’s some evidence to suggest that taking too much of these vitamins could worsen your MS symptoms:

Vitamin C

Even though some older research from 2002 suggests that vitamin C can benefit MS symptoms, a 2018 review suggests that too much vitamin C can actually worsen them.

Researchers say that high vitamin C levels can harm patients because they promote Fenton’s reaction. Fenton’s reaction occurs when iron and hydrogen peroxide interact and create hydroxyl radical, which is reactive and toxic to human cells.

That means that high concentrations of antioxidants like vitamin C in the blood can promote this toxic reaction and, thus, worsen inflammation in the body. This means taking vitamin C, even in therapeutic doses, may worsen inflammatory diseases like MS

Biotin (B7)

Though there’s some evidence to suggest high dose biotin improved symptoms in patients with progressive MS, there’s also evidence to suggest it does the opposite.

In a 2017 study, researchers found that daily doses (300 milligrams per day) of vitamin b7 for 1 year didn’t lead to any sustained improvement in patients with progressive MS. One-third of patients also experienced worsened symptoms.

Researchers aren’t sure why symptoms worsened in some patients. It could be since their disease was progressing already, their symptoms would have become more severe anyway.

Scientists also theorized that patients’ damaged central nervous systems could not respond efficiently to the increased metabolic demand the extra biotin caused.

Since biotin helps metabolize carbs, proteins, and fats, it’s possible that taking extra may have been too taxing on thealready weakened central nervous system.

A 2020 study also found that high dose biotin supplementation led to no improvements in MS symptoms over 1 year. As a result, researchers advise against taking high dose biotin for MS.

According to a 2018 review, vitamin D is the only vitamin with enough evidence to support regular supplementation for patients with MS.

Since lower vitamin D levels are associated with a higher risk of developing multiple sclerosis and worse disease activity, taking this vitamin may help treat symptoms.

Vitamins with much less supporting evidence that still may help treat MS include:

  • Vitamin A: Vitamin A might suppress the formation of pathogenic T-cells in MS patients, which could help improve symptoms.
  • Vitamin B1 (thiamine): Thiamine deficiencies are associated with several neurodegenerative conditions like MS. For that reason, thiamine supplementation might help MS symptoms.
  • Vitamin B6: Even though vitamin B6 deficiencies are rare, they can happen in those with autoimmune disorders like MS. For that reason, taking vitamin B6 could help MS symptoms.
  • Vitamin B12: A vitamin B12 deficiency is one of the most commonly seen deficiencies among those with MS. So, vitamin B12 supplementation theoretically might help symptoms.
  • Vitamin E: Since those with MS may already have low levels of vitamin E, taking it in supplement form could potentially help symptoms.

More research about the link between these vitamins and MS is needed before we can draw any conclusions.

Before trying any of these vitamins to treat MS, consider talking with your doctor.

According to a 2015 review, vitamin D deficiency is a risk factor for developing MS.

But so far, there’s not enough evidence to suggest that any other vitamin deficiencies could lead to MS symptoms.

Some evidence suggests that vitamin C or vitamin B7 (biotin) could worsen MS symptoms. Though we need more research to know for sure, it may be worth avoiding these in supplement form in case of potential complications.

Meanwhile, there’s evidence to suggest that vitamin D supplementation helps improve MS symptoms.

Talk with your doctor before taking any vitamins or supplements to manage MS.