Should unprocessed red meat feature in the diet of those at high risk of MS?
Scientists do not fully understand what causes the condition. Many believe that the body mounts an autoimmune attack on its central nervous system (CNS), damaging the protective myelin layer, which coats many neurons. The result is a diverse range of neurological symptoms.
In the U.S., the chance of developing MS is 1 in 1,000 (0.1%) for the general population. This risk is greater for those with a first-degree relative with MS and stands at 2–4%, while people with an identical twin living with MS have a 30–50% risk of developing the condition.
A study in the journal Brain followed people for 10 years after they had received a brain MRI scan. Of the 81 participants, 83% of those with an abnormal brain scan that showed what experts call a first clinical diagnosis of central nervous system demyelination (FCD) developed MS during the follow-up period.
Experts believe that risk factors for MS include environmental factors, such as diet.
Now, researchers from the School of Public Health at Curtin University in Perth, Australia, present data on the influence of diet, specifically unprocessed red meat, on FCD in The Journal of Nutrition.
For their study, Lucinda J. Black, a postdoctoral fellow at Curtin University, and colleagues analyzed data from the AusImmune study, a multicenter, case-control study.
The dataset included 282 cases of people who had experienced FCD and 558 healthy controls. Black used the alternate Mediterranean diet score (aMED) to assess how strictly the study participants adhered to a Mediterranean diet.
A score of 9 means the greatest adherence to the diet, while a score of 0 means little or no adherence.
She also created an additional diet score called aMED-Red, with 1 point assigned to those people who consumed around one serving of 65 grams (g) of unprocessed red meat, such as beef, lamb, pork, and veal.
The team then divided the participants into four categories, as follows: category 1 (scores 0–2), category 2 (scores 3–4), category 3 (score 5), and category 4 (scores 6–9).
Black found no association between the risk of FCD and the aMED score. However, when she compared the data of individuals in categories 2, 3, and 4 to those in category 1, the data revealed a reduced risk of FCD.
"Red meat contains important macro- and micronutrients, including protein, iron, zinc, selenium, potassium, vitamin D, a range of B-vitamins, and, for grass-fed beef, omega-3 polyunsaturated fatty acids," Black commented to MNT about her findings.
"Many of these nutrients are important for healthy brain function, so it is not surprising to see this beneficial association between intake of unprocessed red meat and risk of MS," she continued.
When Black dug deeper into the data to look at the different components that make up the aMED-Red scores, she found that unprocessed red meat was the only factor that produced a statistically significant effect on the risk of FCD.
The team found that the participants' reduction in the risk of FCD had close links to how much they adhered to the aMED-Red diet.
The results show that those in category 2 had a reduction in risk by 37%, those in category 3 by 52%, and those in category 4 by 42%. For those with a first-degree relative living with MS, this would equal a reduction in risk from 2–4% to 1–2.5% and for those with an identical twin with MS from 30–50% to 14–32%.
Black previously published results utilizing data from the AusImmune study, which showed a 50% reduction in risk of FCD in participants who ate a healthful diet. Also, earlier this year, Black published results on the consumption of red meat as a standalone factor, not as part of a Mediterranean diet, and FCD risk.
"Our findings are relevant to people who are at high risk of MS, such as those who have a close family member with MS. Other research is looking at unprocessed red meat consumption and health conditions that are common in the general population."
Lucinda J. Black
However, not all agree that red meat has links to health benefits. Indeed, the World Health Organization (WHO) classified red meat as "probably carcinogenic" to humans in 2015.
Earlier this year, researchers found that people who ate small amounts of unprocessed red meat, amounting to 65 g or less per day, had a moderately higher risk of death.
Dietary choices are complex and include personal preferences, cultural influences, and socioeconomic factors. There is plenty of evidence that links a healthful diet to long-term health outcomes. How prominently unprocessed red meat will feature in the prevention of MS remains to be seen.