Chapter 11: The supporting cast · Part 2: Thickeners
Guar gum
- Contaminant risk
The worst fact: guar diet pills swell 10 to 20 times in water. In 26 US FDA reports on one brand, Cal-Ban 3000, there were 18 blocked oesophaguses and 7 blocked small bowels. A 1992 paper said such products had been banned in Australia.
Why brands use it: a plant thickener.
Take care if: you breathe the powder. At one carpet plant that used guar, 23% of workers had a history suggesting occupational asthma. In a ready-made cleaner it's already dissolved.
Comes from: the ground seed of the guar bean.
Myth check: "Natural means it's clean": not always (see contaminants).
Contaminants: in July 2007, batches of guar gum from India reached the EU contaminated with dioxins (up to 480 pg TEQ/g) and pentachlorophenol (up to 4 mg/kg). The EU now limits pentachlorophenol to 0.01 mg/kg. They're unlikely in a well-made product, but it's a factor you can't see on the label.
Fair to say: as a food additive, the EU found "no safety concern for the general population".
Correct as of November 2026. What the badges mean
Sources
- EFSA. Re-evaluations of xanthan gum (E415, 2017, 2023), guar gum (E412, 2017), dimethyl polysiloxane (E900, 2020); titanium dioxide (E171, 2021).
- Lewis JH. Esophageal and small bowel obstruction from guar gum-containing diet pills. Am J Gastroenterol 1992.
- Malo JL et al. Occupational asthma caused by guar gum. J Allergy Clin Immunol 1990.
The full source list is at the end of Chapter 11.