Methyl cellulose is not significantly absorbed in the gut. Studies in rats and humans show that more than 90% of an ingested dose passes through the digestive tract and is excreted in faeces essentially unchanged. Unlike dietary fibre from whole plants, it is not fermented by gut bacteria to any meaningful degree. EFSA reviewed this evidence in 2018 and found no basis for concern about accumulation or systemic toxicity.
Methyl cellulose is not fermented in the gastrointestinal tract of humans or rats, and more than 90% of administered doses are recovered unchanged in faeces.
2018Regulatory reviewEFSA ANS Panel, Re-evaluation of celluloses E 460(i), E 460(ii), E 461, E 462, E 463, E 464, E 465, E 466, E 468 and E 469 as food additives, EFSA Journal