A new study from researchers at Portland State College has reported {that a} weight-reduction plan excessive in saturated fat – such because the ketogenic or “keto” weight-reduction plan – can alter the Immune system in mice.

Some fat have extra affect than others

The keto weight-reduction plan is a well-liked instance of a low-carbohydrate, high-fat weight-reduction plan that’s used for weight reduction. Of their analysis, lead writer Dr. Brooke Napier, assistant professor of biology, and colleagues illustrated that mice fed both a Western (high-fat, high-sugar) weight-reduction plan or a ketogenic weight-reduction plan have been extra prone to sepsis than mice fed a standard weight-reduction plan.

The researchers recognized one saturated fats that was related to an elevated danger of sepsis when injected into mice fed a standard weight-reduction plan. This fats is palmitic acid, which exists in excessive proportions in meat and dairy merchandise and can be present in breast milk.

“It was simply publicity to this one saturated fats that made them extra prone to sepsis mortality,” said Napier. “The concept you can have a selected fats in your weight-reduction plan that might trigger such a drastic end result in illness is type of unimaginable.”

Within the mice fed Western or ketogenic diets, and the mice injected with palmitic acid, ranges of inflammatory cytokines within the blood elevated, which may end up in systemic irritation and fever throughout sepsis, suggesting palmitic acid impacts the immune system by inflicting irritation.

Nevertheless, palmitic acid additionally reprograms the innate immune system by triggering educated immunity. Educated immunity is the “realized” a part of the innate immune response, the place an incident of excessive irritation alters stem cells within the bone marrow to allow elevated manufacturing of inflammatory Innate Immune Cells in response to irritation stimuli afterward.

Napier reported that, “The fats is reprogramming [the mouse] stem cells to supply extra inflammatory innate Immune Cells, and people innate immune cells – once they’re put on this sepsis illness mannequin – produce extra cytokines, extra fever and better mortality charges.”

A fragile steadiness

Inflammatory immune cells could be useful in response to an infection, however a response that’s too sturdy can lead to sepsis.

Mice that had been injected with palmitic acid have been additionally in a position to combat off a Candida yeast an infection extra successfully than untreated mice, the researchers discovered.

“It is this double-edged sword the place when you’ve got publicity to excessive fats after which publicity to a illness the place extra irritation exacerbates the illness, then it is a unhealthy factor,” stated Napier. “However if you happen to’re within the context the place you eat excessive fats and you then get an an infection and extra irritation helps you clear an infection faster, it is a good factor.”

The analysis staff additionally discovered that oleic acid, a polyunsaturated fats, might counteract the irritation produced by the high-palmitic acid weight-reduction plan. Oleic acid can forestall the synthesis of ceramide, a molecule that induces a stress response in cells and could also be concerned within the overactive inflammatory response in sepsis.

Within the research, the upper danger of sepsis in mice fed a ketogenic weight-reduction plan for 2 weeks was reversed by including oleic acid to their diets for the final three days, which Napier described as “completely surprising.”

Sooner or later, this analysis might assist information adjustments in diets for tube-fed sufferers or in folks at increased danger of contracting infections or sepsis.

Napier’s lab is now trying into the connection between palmitic acid in breast milk and the immune responses of breastfed babies. They hypothesize that “palmitic acid in breast milk is defending neonates from an infection throughout weaning.”

This text is a rework of a press release issued by Portland State College. Materials has been edited for size and content material.

Reference: Seufert AL, Hickman JW, Traxler SK, et al. Enriched dietary saturated fatty acids induce educated immunity by way of ceramide manufacturing that enhances severity of endotoxemia and clearance of an infection. eLife. 2022;11:e76744. doi: 10.7554/eLife.76744.