A paper published in the world's top immunology journal by authors working in the fields of neurology, food toxicology, human genetics and immunology at universities across Germany presents further evidence of the direct impact that dietary fatty acids have on central nervous system autoimmunity.
The immune system, in rudimentary summary, comprises a complex network of cells designed to protect our bodies from foreign invaders, toxins and disease.
Amongst these cells are the T cells, a type of white blood cell which develops into sub-types with different functions which combine to exact the correct immune response.
Implicated in MS however, are the sub-types Th1 and Th17 which excite the immune response and which, without the correct balance from the suppressor cells to calm it down again, have the capacity to cause inflammation and promote MS activity.
Crucially, what the research paper here shows is that these original T cells are profoundly influenced by the dietary fatty acids we introduce to the gut, through their interaction with bacteria living in our gut, the so-called gut microbiome.
The more middle- and long-chain fatty acids we consume, the greater the growth (from the T cells) of the potentially damaging Th1 and Th17 cells. The more short-chain fatty acids we consume, the more likely there is to be growth of the suppressor T cells (Tregs) which modulate the immune system and therefore avoid autoimmune disease.
The researchers showed for instance in the laboratory that lauric acid, which makes up over 50% of coconut oil, markedly (by about 50%) increased Th1 and Th17 cell lines, those responsible for driving the inflammatory process in MS, and decreased (by about a third) the Tregs, those that suppress the inflammation in MS.
They then showed that feeding mice with the animal form of MS a mixture of lauric acid and palm oil-supplemented diets caused them to have a more severe course of the disease.
The researchers found that feeding these dietary fatty acids when the intestine contained no bacteria however did not have any effect.
This means that intestinal bacteria are directly involved in how fatty acids affect the immune system. In fact, it was actually the metabolic products of the bacteria as a whole that were responsible for the effects they noted.
The authors highlight in the introduction to the paper, the gut is the largest zone of interaction between the environment and the human organism, therefore fatty acids, as an integral component of daily diet, play a crucial role in disease avoidance and management through their interaction with the bacteria in our gut.
Other experiments in the past have shown that diets like the OMS diet result in dramatically different populations of gut bacteria than typical Western diets; this may be how the OMS diet exerts its beneficial effects.
Long-chain saturated fatty acids, described by the authors as the most abundant component of the so-called Western diet, are chains of carbon atoms which are fully saturated with hydrogen atoms.
This results in straight and inflexible chains, which renders saturated fats solid at room temperature. Sources of saturated fats in the diet include meat, dairy products, palm oil, and coconut oil.