Vitamin C supplements are linked to a lower risk of developing MS, particularly among people with a higher genetic predisposition, a study suggests.
The apparent benefit was seen in people with a genetic predisposition to the condition.
Researchers stressed that further work is needed to confirm the findings.
MS is marked by inflammation that damages healthy tissue in the brain and spinal cord.
Its causes are not fully understood, but several risk factors have been identified, ranging from viral infections to genetic variations.
Vitamin C, also known as ascorbic acid, is an essential nutrient involved in many functions in the body.
It is a powerful antioxidant, meaning it helps protect cells from damage, and has also been shown to have nerve-protective properties.
Previous studies have produced mixed results. Some have suggested that people with higher vitamin C intake have a lower risk of developing MS, while others have found no association.
Researchers in Italy analysed data from the UK Biobank, a long-term study tracking health outcomes among people in the UK who were recruited between 2006 and 2010.
The team examined data from 486,908 adults without a neurological disease and compared vitamin C intake between those who later developed MS and those who did not.
Nearly one in 10 participants reported regularly taking vitamin C supplements when they entered the study.
Over a median follow-up of more than a decade, 452 people developed MS.
Vitamin C supplementation was associated with an approximately 49 per cent lower risk of developing the condition.
The reduced risk was seen in both men and women and among people younger than 60.
Because genetics is known to affect MS risk, researchers also examined whether genetic factors influenced the association.
Vitamin C supplements were significantly associated with a lower risk of developing MS among people with high or average genetic risk scores.
Among those with low genetic risk scores, supplementation was not significantly associated with MS risk.
The researchers concluded: “In the large UK Biobank prospective cohort, regular vitamin C supplementation was associated with a lower risk of incident MS, particularly among individuals with average to high genetic susceptibility.”
The team said it remains unclear why the apparent relationship between vitamin C and MS risk may vary according to genetics, highlighting the need for further research.
Researchers also stressed that the analysis could not account for every factor that may influence MS risk, meaning the associations should be interpreted with caution.
They said the findings “provide a rationale for further investigation in independent cohorts, functional studies, and, ultimately, randomised intervention trials to determine whether vitamin C supplementation has a causal role in MS prevention and whether this differs according to genetic susceptibility.”
