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How sugar trashes your immune system

Selection of food high in sugar, copy space

Refined foods and high-plasma glucose levels cause inflammation, free radicals and dangerous proteins while reducing levels of important immune system members.

High-glycemic index foods promote inflammation, cytokines and free radicals 

A single high-glycemic-index meal leads to an immediate increase in inflammatory cytokines (1) causing oxidative stress in cells, and higher C-reactive protein levels (2).

Refined foods and sugar increase the production of free-radicals and overload mitochondrial capacity (3), whereas diets high in fibre (such as vegetables, whole grains and nuts and seeds) control inflammation in the body (4).

The consumption of refined foods and sugar increase levels of dangerous inflammatory proteins like tumour necrosis alpha (TNF-α) and interleukin-6 (IL-6) in the body. (5).

High plasma-glucose wrecks neutrophils and vascular system.

Short-term blood sugar level increases result in hyperglycemia, which activates protein kinase C, and this inhibits neutrophil migration, phagocytosis, superoxide production and microbial killing.

High plasma-glucose concentrations decrease the formation of neutrophils and inhibit neutrophil function and apoptosis (cancer cell death).

High plasma glucose concentrations decrease vascular dilation and increase permeability of the blood vessels during the initial inflammatory responses, possibly through protein kinase C activation (6).

Sugar and refined food intake damage your gut microbiome

In a 2020 study published in Science Translational Medicine (7), sugar consumption was shown to disrupt the microbiome, cause an increase in bacteria that made inflammatory molecules, and lead to illnesses such as IBS and Crohn’s.

Inflammation is an immune response. In small amounts, inflammation – like stress – may be good for you. But if it is occurring day in, day out, through the consumption of sugar, the body reaches a chronic state of inflammation which slows down the immune response.

Mice on an increased sugar diet (replicating a human consuming a can of fizzy soft drink a day) suffered aggressive colon inflammation, and even diarrhoea and colitis. In particular, sugar was seen to feed and promote numbers of Akkermansia muciniphila that can degrade the gut lining.

68% of packaged foods in the USA contain sugar according to a 2015 study in the Lancet.

Sugar can cause, feed and drive cancer

The research is clear. In a review in CANCERactive entitled ‘20 links between sugar and cancer’, 18 of the research studies (8) are from top professors in top Medical Schools. They simply cannot all be wrong.

Cancer, quite simply, is a failure of the immune system.

Go to: 20 links between sugar and cancer


  1. https://pubmed.ncbi.nlm.nih.gov/16609090/

  2. https://pubmed.ncbi.nlm.nih.gov/11864854/

  3. https://pubmed.ncbi.nlm.nih.gov/18206731/

  4. https://pubmed.ncbi.nlm.nih.gov/19055538/

  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352291/#B110-nutrients-12-01562

  6. https://pubmed.ncbi.nlm.nih.gov/26897277/

  7. https://stm.sciencemag.org/content/12/567/eaay6218

  8. https://www.canceractive.com/article/20-links-between-common-sugar-and-cancer