A new study shows that high carbohydrate intake increases the disease burden for multiple sclerosis (MS), whereas high fat intake has the opposite effect. A researcher says that the study will help to understand the links between diet, obesity and MS, although it is still too early to make specific dietary recommendations for people.
A new study that examined how diet affects the expression of MS in mice indicates that diet can increase or reduce the burden of disease for MS.
Disease activity increased if the mice had a high-carbohydrate diet. Conversely, a high-fat diet appears to protect against disease.
According to a researcher behind the results, a study involving mice is not sufficient to make recommendations for people, but it may comprise the basis for further research into how best to protect health and keep MS at bay.
“This study sought to understand how the proportions of the macronutrients carbohydrate, fat and protein in the diet affects the expression of a disease so that we can eventually make recommendations for people with the disease. The study took an initial step in this direction,” explains Romain Barrès, Professor, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Denmark.
The research, which involved leading contributions from Laurence Macia, Ralph Nanan, Stephen James Simpson and Duan Ni from the University of Sydney, Australia, was published in Advanced Science.
Experiments with mice
The researchers used a mouse model to investigate how diet affects the progression of MS. They also used nutritional geometry analysis to investigate how increasing and reducing the proportions of carbohydrate, fat and protein in the mice’s diet affected the expression of MS.
This method enables researchers to determine whether the effect of a specific diet results, for example, from a high content of protein or the correspondingly lower content of fat and carbohydrate.
“The method enables us to determine the effects of the three macronutrients, and we also carried out genetic and epigenetic studies of the mice to determine how the diet affected them at the cellular level. Our working hypothesis was that specific macronutrients differentially influence MS,” says Romain Barrès.
High carbohydrate increases disease activity
The study revealed that the more carbohydrate in the diet, the worse the mice fared; the more fat in the diet, the better they did.
The genetic and epigenetic studies of the immune system’s lymphocytes, which are involved in the development of MS, also showed that they acted differently depending on whether the mice had eaten a high-carbohydrate or high-fat diet.
The immune cells, which are overactive in MS, became less active from a high-fat diet and more active from a high-carbohydrate diet.
“MS is an autoimmune disease, so the immune cells have a role. We found that diet influences the function of immune cells. The diet can reduce their overactivation or compromise their response,” explains Romain Barrès.
Surprising results
Romain Barrès says that the results could appear surprising because the risk of developing MS and its severity are well known to be positively associated with having obesity.
You might think that a high-fat diet would lead to an increased risk of overweight and therefore an increased risk of MS. However, Romain Barrès says that this is not the case.
“For many years, many people have been deliberately trying to reduce the intake of fat in the diet with the aim of losing weight, but today we know that reducing fat in the diet is quite inefficient at reducing body weight. Instead, we now know that the carbohydrate content from, for example, raw sugar in the diet is a more important contributor to obesity. Perhaps the association between obesity and MS is that many people with overweight have a high intake of carbohydrate, which this study linked to increased disease activity,” he notes.
Studies with people required
According to Romain Barrès, caution is warranted in trying to transfer the results from the experiments with mice to people with MS.
However, he explains that there are already dietary recommendations for people with MS to reduce the intake of saturated fatty acids and sugar, since both are associated with increased inflammation.
Inflammation is precisely what is bad for MS. The mouse experiments should be used to establish theories that can then be tested in later studies with people.
If these studies involving people can show similar results, it opens the way to making recommendations not only for improving the quality of life for people with MS but also for the general population to avoid developing MS.
“This applies not only to MS but also to other immune and inflammatory diseases. We are learning more about how the components of the diet interact together to affect the development of disease,” says Romain Barrès.
He acknowledges that things are also very complex. For example, other studies have indicated that a high carbohydrate intake is associated with a longer lifespan.
This seems to virtually contradict the results of the study with mice with MS.
“Exercise is probably another important factor, and a high-carbohydrate diet might be healthy if you want to live longer but also requires exercise,” concludes Romain Barrès.
