Sue's Blog

Immune systems and failsafe eating


With coronavirus Covid-19 dominating the news, people are discussing how to boost their immune system.

Q. Can you explain to me why we don’t get sick when on failsafe? Something to do with improving your immune system? I practically gloat when everyone around me moans about their colds and flus they have all the time as I don’t get them anymore!! What a relief to not have infections from colds every year now! - Rosemaree (failsafe 8 years)

It is common for failsafers to report that they no longer suffer frequent colds, flu and recurrent infections once they are established on failsafe eating - and yes, there is scientific evidence.

Studies have found that certain food additives act as immunosuppressants, that is, they can actually suppress the immune system, making some people more likely to suffer from recurrent infections. This has been shown in the following studies.

  • a Greek study (1) with artificial colours tartrazine (102) and amaranth (123) using small doses normally considered to be nontoxic
  • a Brazilian study (2) with propionic acid, part of the group (280-282) that includes commonly used bread preservatives
  • an Indian study (3) with the commonly used preservative sodium benzoate (211) using small doses normally considered to be nontoxic – and see story [703] below
  • a US study (4) with beagle dogs showed they were more sensitive to fatal virus disease when fed indigotine artificial blue colour (132).

Some people also have problems with natural foods and food chemicals. Salicylate-sensitive failsafers know eating fruit to build up our immunity works the opposite way. We are better off eating failsafe vegetables as described in the Myths of Fruit:

"It's a myth that fruit is packed full of vitamins and minerals," says Tom Sanders, who is director of the Nutritional Sciences Division at King's College London. "…The really sad thing is that we don't eat enough vegetables, such as cabbage…"

Reader reports

“Since going failsafe and eating very carefully within the RPAH Moderate and Low Salicylate foods I have been well…whereas last year I was suffering chest infection after chest infection and in all I had 8 courses of antibiotics in one year“ – Charlotte from story [1355]

After 10 years of suffering breathing problems which I knew were food related and not being believed by my GP or the Chest Clinic to discover Salicylate Intolerance and FS was wonderful - Barbara from story [1273]

“My daughter ended up with croup and asthma from doing the sulphite (220-223) challenge…she also ended up with croup, asthma and a chest infection from doing the lemonade (sodium benzoate 211) challenge” – from story [703]

“We started the elimination diet 6 months ago…my youngest no longer has asthma like symptoms and only one case of tonsillitis this year, both only 1 cold this year that lasted 1 day - last year a cold would last minimum 2 weeks, and both had 3 cases of tonsillitis” – Lisa [1321]

“I had constant sinus infections…finally went off dairy and taaa daaa its much better. Infections stopped!!- Rachel from facebook group [1329]

“Before going dairy free, my son had 30 ear infections including 4 in the last two months. This has dropped to NONE in the four months since going dairy free” – mother of 3 yo from story [1073]

“My daughter … had major ear troubles when (salicylates) were reintroduced…she is asthmatic and has had frequent colds and flu and major ear troubles for a long time - salicylates may have been the problem all along – Sharon from story [1092]

“Before the diet I was constantly unwell…The worst thing was the asthma - it was getting so bad I couldn’t read a book to my children…I am intolerant to gluten, salicylates, amines, preservatives etc. Since starting the diet, I haven’t had asthma medication for over 4 years…no more constant colds and infections (sinus and chest) -  Rosemaree’s first report from story [874]

 “…we are now 4 months into the diet…Not only has their behaviour changed we have now noticed two other (surprising!) results - the boys had recurrent tonsillitis (once every five-six weeks for the past 18 months) which they have no longer have...(and) they  normally start preventers for asthma at the end of Feb and go through until at least November...We haven't used preventer, or even relievers once since starting the diet" - Jenny from story [848]

“My daughter had bouts of tonsillitis as a toddler, my son had recurring croup/asthma. Took them both off dairy...they never had it again…" - Alison from story [1311]

"I did failsafe for constant sinusitis etc … I got to the point that I didn't need antibiotics for 18mths or more which was unheard of prior. My kids also improved. My DS, the one we started failsafe for, didn't need antibiotics until the 18 mth mark...and that was only because he got bitten by a dog...prior to this he was at the doctors for antibiotics every 2 mths. We considered this a bonus since we did failsafe for behaviour - Teresa from story [1311]

Read more

The best way to find out exactly what affects you is a 2-3 week trial of the RPAH diagnostic elimination diet (5), preferably under the supervision of an experienced dietitian.

Our list of supportive dietitians 

Intro to food intolerance

How to start failsafe eating

***Warning*** the immune boosting effects of diet do not start immediately but build up over time. In any case, it is important to follow recommended methods of avoiding viruses eg, handwashing, masks if appropriate, social distancing and vaccines when available.

See related blog Wein ion units reduce coronavirus risk


1. Koutsogeorgopoulou L and others, Immunological aspects of the common food colorants, amaranth and tartrazine,Vet Hum Toxicol, 1998;40(1):1-4.

2. Wajner M and others, Inhibition of mitogen-activated proliferation of human peripheral lymphocytes in vitro by propionic acid, Clin Sci (Lond), 1999;96(1):99-103.

3. Yadav A et al, Sodium benzoate, a food preservative, affects the functional and activation status of splenocytes at non cytotoxic dose, Food Chem Toxicol, 2016;88:40-7.

4. Hansen WH and others, Chronic toxicity of two food colors, brilliant blue FCF and indigotine, Toxicol Appl Pharmacol, 1966;8(1):29-36.

5. RPAH, Diagnostic elimination diet handbook, 2019,