Lipopolysaccharides or LPS are bacterial toxins that can health issues if they reach the bloodstream. Normally housed safely in the gut, lipopolysaccharides can enter the blood if you have an infection, “leaky gut”, or eat too many fatty foods.
Read on to learn about the potential health risks of lipopolysaccharides and which factors may help reduce them. Potential Health Risks of High LPS Levels
The conditions we discuss here are commonly associated with high LPS levels, but this single symptom is not enough for a diagnosis.
Because they have been studied in cohort studies, we cannot conclude for certain that high LPS levels caused these conditions.
Work with your doctor to discover what underlying condition might be causing your high LPS levels and to develop an appropriate plan to improve your health. 1) Fatigue
Fatigue is reliably caused in humans by the administration of LPS , as part of LPS-induced “sickness behavior” [ 1 ].
LPS increased fatigue and inflammation (TNF-a, IL-6) in a small trial with 11 healthy participants. Pre-treatment with citalopram (SSRI) prevented the increase in fatigue [ 2 ].
In studies of 168 patients, LPS levels were greater in those with chronic fatigue syndrome and were associated with symptom severity, including fatigue, concentration problems, and failing memory [ 3 , 4 ]. 2) Poor Memory
In a small trial on 20 healthy men, intravenous LPS impaired verbal and nonverbal memory and increased anxiety and depression . Inflammatory cytokine secretion was associated with a decrease in memory performance [ 5 ].
Administration of LPS increased anxiety, depression, cortisol , and blood norepinephrine in another trial on 34 men. Low-dose LPS impaired long-term memory, while high-dose LPS increased reaction time. The authors stated that inflammation may increase short-term alertness, although this is speculative on their part [ 6 ]. 3) Anxiety and Low Empathy
In a clinical trial on115 healthy people, LPS decreased participants’ ability to accurately understand the emotional state of a person by looking at their eyes [ 7 ].
In a small trial on 18 men, LPS administration worsened mood and increased anxiety. LPS also increased the activation of the right inferior orbitofrontal cortex in response to emotional visual stimuli. This brain region is associated with fear and anger recognition, so increased activity may have increased negative emotions towards the stimuli [ 8 ].
Scientists can experimentally induce fatigue, impaired memory, and anxiety with LPS, but more research is needed. 4) Depression and Social Disconnection
LPS administration consistently increased depression in numerous studies [ 9 ].
Injection of LPS increased feelings of social disconnection, depression , and inflammation (IL-6, TNF-a) in a trial of 39 participants [ 10 ].
TNF-alpha production is increased in the hippocampus of animals after LPS injection. This activation of immune cells in the brain is believed to contribute significantly to the selective brain cell injury associated with depression [ 11 ].
In a study of 9 participants, glucose metabolism (energy use) was increased in the insula and decreased in the cingulate cortex due to LPS-induced inflammation [ 12 ].
The insula is associated with negative emotions, while the cingulate is associated with positive mood. Thus, increased energy use by the insula and reduced energy use by the cingulate may both promote negative feelings.
LPS increased fatigue and decreased vigor and social interest in a trial on 10 healthy people [ 13 ]. 5) Inability to Experience Pleasure
Injection of LPS increased depressed mood and lowered the brain response to monetary reward cues (decreased ventral striatum activity) in a clinical trial on 39 people [ 14 ].
In animals, LPS consistently lowered preference for palatable foods, stimulation-seeking behavior, and exploration of new environments [ 9 ].
In small human experiments, LPS seems to impair mood, social behavior, and the ability to feel pleasure; large-scale data are lacking. 6) Disturbed Sleep
LPS disrupted sleep and lowered REM sleep in healthy humans [ 15 , 16 ].
LPS also lowered non-REM sleep and increased sleepiness during the day in a study of 10 men [ 17 ]. 7) Fever
Fever is a sign of elevated LPS levels . LPS stimulates the release of prostaglandins (PGE2), which bind to their receptors in the hypothalamus to raise body temperature [ 18 ]. 8) Poor Reproductive Health in Women
In a study of 45 women undergoing in vitro fertilization treatment, LPS levels were associated with ovarian inflammation and reduced progesterone production . Ovarian inflammation and progesterone deficiency indicate impaired reproductive health and are associated with infertility [ 19 , 20 ]. 9) Reduced Appetite In humans, low-dose LPS reduced food intake in the first 4 hours. Reductions in food intake were associated with blood levels of TNF and IL-6 [ 5 , 21 ].LPS is hypothesized to disturb sleep, reproductive health, and appetite, but only preliminary findings are available. 10) Low Pain Tolerance In a study of 11 healthy men, LPS administration increased sensitivity to rectal pain and lowered pain tolerance [ 22 ]. LPS also decreased tolerance to pressure, mechanical pain, and cold , in a clinical trial of 59 healthy men [ 23 ]. 11) Diabetes Elevated LPS is associated with an increased risk of developing diabetes [ 24 ].Individuals with type 1 diabetes have 235.7% higher LPS levels than those without diabetes. Similarly, people with type 2 diabetes have 66.4% higher LPS levels than non-diabetic controls [ 25 ].Impaired lipoprotein metabolism in type 2 diabetes patients reduces LPS breakdown and may increase LPS-related inflammation [ 26 ].In a study of 477 people with type 1 diabetes, high LPS activity was associated with the development of diabetic kidney disease [ 27 ]. 12) Obesity LPS activity and LPS binding protein were associated with obesity in a study on over 3,500 adults [ 28 , 29 ].LPS given to mice for 4 weeks caused a weight gain comparable to that induced by a high-fat diet [ 30 ]. 13) Metabolic Syndrome Metabolic syndrome is a group of factors that increase the risk of heart disease. These […]