Will the Mediterranean diet join sunshine and vitamin D as possible protective factors against the development of multiple sclerosis? Only if there is some unprocessed red meat in the diet, according to Australian researchers.

Their retrospective analysis of dietary data from Australia’s landmark study into CNS demyelination found that consumption of the traditional Mediterranean diet was not associated with any protective effect against a first clinical diagnosis of a classic demyelinating event.

However there was an apparent protective effect when the diet included consumption of more than one daily serving of unprocessed red meat.

The findings are based on data from the AusImmune Study, a case-control study that compared environmental risk factors in 282 people with a myelination disorder and 558 control subjects.

Study investigator Dr Lucinda Black PhD and colleagues from the School of Public Health, Curtin University, Perth, found no correlation between  a diagnosis of a demyelination disorders and the classic Mediterranean diet as defined by consumption patterns for fruit, vegetables, legumes, nuts, wholegrains, fish, and a low intake red and processed meat.

But when the Mediterranean diet score was modified to include higher levels of consumption of unprocessed beef, lamb and pork, there was a significant but non-linear relationship with the risk of a demyelination disorder.

Compared with the lowest intake (category 1) of red meat-supplemented Mediterranean diet consumption, higher intakes were significantly associated with reduced risk of  a first clinical diagnosis of  CNS demyelination corresponding to a 37% (p = 0.039), 52% (p = 0.009) and 42% (p = 0.034) reduced risk in categories 2, 3, and 4, respectively.

The researchers said the findings confirmed previous results from the AusImmune study that showed unprocessed red meat and omega-3 fatty acids were protective against the development of a precursor to multiple sclerosis.

They postulated that this might be because red meat contained vitamin D, iron and omega-3 fatty acids, for which low levels have been associated with increased risk of developing MS.

The consumption of at least one serving of red meat was in line with current recommendations for the Australian population. However few people followed these recommendations and there was general advice for males in particular to consume less red meat, they noted

“The new findings presented here highlight the importance of unprocessed red meat as part of a healthy Mediterranean diet and its association with a reduced risk of [demyelination],” they wrote in the Journal of Nutrition.

“The addition of unprocessed red meat to a Mediterranean diet may be beneficial for those at high risk of MS,” they concluded.