Fast food makes the immune system more aggressive in the long term

Fast food makes the immune system more aggressive in the long term
Prof. Dr. Eicke Latz and Dr. Anette Christ from the Institute for Innate Immunity of the University of Bonn investigated this question in a study. Credit: Volker Lannert/Uni Bonn

The immune system reacts similarly to a high fat and high calorie diet as to a bacterial infection. This is shown by a recent study led by the University of Bonn. Particularly disturbing: Unhealthy food seems to make the body's defenses more aggressive in the long term. Even long after switching to a healthy diet, inflammation toward innate immune stimulation is more pronounced. These long-term changes may be involved in the development of arteriosclerosis and diabetes, diseases linked to Western diet consumption. The results will be published in the journal Cell.

The scientists placed mice for a month on a so-called "Western ": high in fat, high in sugar, and low in fiber. The animals consequently developed a strong inflammatory response throughout the body, almost like after infection with dangerous bacteria. "The unhealthy diet led to an unexpected increase in the number of certain in the blood of the mice, especially granulocytes and monocytes. This was an indication for an involvement of immune cell progenitors in the bone marrow," Anette Christ, postdoctoral fellow in the Institute of Innate Immunity of the University of Bonn explains. To better understand these unexpected findings, bone marrow progenitors for major immune cell types were isolated from mice fed a Western diet or healthy control diet and a systematic analysis of their function and activation state was performed.

"Genomic studies did, in fact, show that the Western diet had activated a large number of genes in the progenitor . The genes affected included those responsible for proliferation and maturation," explains Prof. Dr. Joachim Schultze from the Life & Medical Sciences Institute (LIMES) at the University of Bonn and the German Center for Neurodegenerative Diseases (DZNE). Fast food thus causes the body to quickly recruit a huge and powerful army. When the researchers offered the rodents their typical cereal diet for another four weeks, the acute inflammation disappeared. What did not disappear was the genetic reprogramming of the immune cells and their precursors: Even after these four weeks, many of the genes that had been switched on during the fast food phase were still active.

"Fast food sensor" in the immune cells

"It has only recently been discovered that the innate immune system has a form of memory," explains Prof. Dr. Eicke Latz, Director of the Institute for Innate Immunity of the University of Bonn and scientist at the DZNE. "After an infection, the body's defenses remain in a kind of alarm state, so that they can respond more quickly to a new attack." Experts call this "innate immune training." In the mice, this process was not triggered by a bacterium, but by an unhealthy diet.

The scientists were further able to identify the responsible " sensor" in immune cells. They examined blood cells from 120 subjects. In some of the subjects, the innate immune system showed a particularly strong training effect. In these subjects, the researchers found genetic evidence of the involvement of a so-called inflammasome. Inflammasomes are key intracellular signaling complexes that recognize infectious agents and other harmful substances and subsequently release highly inflammatory messengers. How exactly the NLRP3 inflammasome recognizes the exposure of the body to Western type diets remains to be determined.

Interestingly, in addition to the acute , this also has long-term consequences for the immune system's responses: The activation by Western diet changes the way in which the genetic information is packaged. The genetic material is stored in the DNA and each cell contains several DNA strands, which together are about two meters long. However, they are typically wrapped around certain proteins in the nucleus and thus many genes in the DNA cannot be read as they are simply too inaccessible.

Unhealthy eating causes some of these normally hidden pieces of DNA to unwind, similar to a loop hanging out of a ball of wool. This area of the genetic material can then be read much easier as long as this temporary unwrapping remains active. Scientists call these phenomena epigenetic changes. "The inflammasome triggers such epigenetic changes," explains Dr. Latz. "The immune system consequently reacts even to small stimuli with stronger inflammatory responses."

Dramatic consequences for health

These inflammatory responses can in turn accelerate the development of vascular diseases or type 2 diabetes. In arteriosclerosis for example, the typical vascular deposits, the plaques, consist largely of lipids and immune cells. The inflammatory reaction contributes directly to their growth, because newly activated immune cells constantly migrate into the altered vessel walls. When the plaques grow too large, they can burst, leading to blood clotting and are carried away by the bloodstream and can clog vessels. Possible consequences: Stroke or heart attack.

Wrong nutrition can thus have dramatic consequences. In recent centuries, average life expectancy has steadily increased in Western countries. This trend is currently being broken for the first time: Individuals born today will live on average shorter lives than their parents. Unhealthy diets and too little exercise likely play a decisive role in this.

"These findings therefore have important societal relevance," explains Latz. "The foundations of a healthy diet need to become a much more prominent part of education than they are at present. Only in this way can we immunize children at an early stage against the temptations of the food industry. Children have a choice of what they eat every day. We should enable them to make conscious decisions regarding their dietary habits."

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More information: Anette Christ et al, Western Diet Triggers NLRP3-Dependent Innate Immune Reprogramming, Cell (2018). DOI: 10.1016/j.cell.2017.12.013
Journal information: Cell

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Citation: Fast food makes the immune system more aggressive in the long term (2018, January 12) retrieved 23 July 2019 from
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User comments

Jan 12, 2018
Medicines refusal to acknowledge that high glycemic index carbs such as milled grains, pasta, bread, rice and white potatoes are dangerous to one's health is borderline criminal. After sugar, they blame dietary fats and oils for medical problems. This is a totally biased and unproven position. Fats, even animal fats, and oils are an essential part of a healthy diet. In fact they should represent 70% of the calories consumed. Junk carbs as mentioned above should not be a part of any healthy diet. Natural oils are the best. Many processed oils such as corn oil are not ideal because of their high omega-6 content. Even canola oil is thought to be a poor choice due to the processing involved.

Jan 12, 2018
Much of this anti-fat nonsense stems form a fraudulent Harvard study that was funded by a sugar company. It was the start of the low fat high carb "Healthy Heart" diets that have led to the diabetes crises the US has today. It is strengthened by the actions of the anti-meat faction in the US.

Jan 12, 2018
3. Artery inflammation is caused by insufficient anti-oxidants in the diet. This inflammation, shown by a high LDL 'marker' reading, leads to calcification,. 2 high calorie,high sat fat egg yolks daily have sufficient anti-oxidants, selenium, l-cysteine amino acid and vitamins to stop inflammation in arteries, and thus prevent calcification from this cause. Eggs are high in vitamin K2. Eggs are high in the phosphotidyls.. serine and choline both essential for the nervous system and the development of young brains and maintenance of older ones! 2 or more egg yolks at breakfast stabilize blood sugars through the day, preventing the after lunch and dinner 'lows'.

3 High triglycerides are blood fats elevated by too many carbs, especially sugar and.. alcohol Interestingly.. grass fed animal fat is high in protective Omega3, CLA and LCFA

Jan 12, 2018

1. High blood homocysteine clogs arteries.and needs to be lowered with B vitamins B12, B6 and folates.. Butter and cream synthesize all the B vitamins in the gut with the help of the 'friendly bacteria'. In along term, large scale study.. two groups were geographically separated by their work. They were of the same genetic origin, the same age group and the same activity level. Those that ended up in the North cooked all their food in butter and ate plenty of animal fat. They smoked more than the Southern group. The Southern group had a pure vegetarian diet. YET… The Southerners had 15X (fifteen times) the heart disease incidence of the northerners. Note butter contains vitamin K2.. that directs calcium to hard tissues, bones, and away from soft tissues, arteries! (Malhotra SL, Dr. 1974- Published 11X in The Lancet).

Jan 12, 2018
Thom I am convinced that the baking industry/ grain farmers lobby is a major part of disinformation presented by our government. Medical science likes the status quo because it sells lots of pills and visits. One would think that the National Diabetes Association would inform people about high glycemic carbs and their dangers. Nope, they only hate sugar.

Jan 12, 2018
BTW Tom thanks for a great post.

Jan 12, 2018
Thom I am convinced that the baking industry/ grain farmers lobby is a major part of disinformation presented by our government. Medical science likes the status quo because it sells lots of pills and visits. YES. Th emisinfo has fuelled the annual 3.5T$ USsickness Industry as well as enriched grain growers. low calorie food Industry, etc..

Problem arose in the early 1960s when Harvard Med Sch. were conducting a study on the harmful effects of sugar. The sugar industry hijacked the study,by bribing the Profs who then rewrote their work.. blaming high calorie. high sat fat animal fat for most ills. That sugar industry operative went on to join the US Agric. Dept where he wrote-up the calories, cholesterol, food groups, pyramid, RDAs total baloney. (From research by U of San Fransisco into Sugar Industry docs).

Jan 14, 2018
..s, arteries! (Malhotra SL, Dr. 1974- Published 11X in The Lancet).

Br Heart J. 1967 Nov; 29(6): 895–905.
Epidemiology of ischaemic heart disease in India with special reference to causation.
S L Malhotra. Malhotra never published his epidemiology studies of Indian workers in The Lancet.

Malhotra was hardly the first to notice the association of diet and diseases. Here is a quote from 1932:
One swears by whole meal bread, one by sour milk; vegetarianism is the only road to salvation of some, others insist not only on vegetables alone, but on eating those raw. At one time the only thing that matters is calories; at another time they are crazy about vitamins and roughage. The scientific truth may be put quite briefly; eat moderately, have an ordinary mixed diet and don't worry.
Sir Robert Hutchinson, in Newcastle Medical Journal 1932, Vol 12

Jan 15, 2018
Wild speculation; maybe cultivating the population of microbes in one's gut that specialize in breaking down meat and fat sends some kind of warning signal to one's immune system.

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