Disodium inosinate
A flavour enhancer that boosts umami taste. Derived mainly from meat or fish, so not vegan or vegetarian in most products.
Breaks down to uric acid in the body. People with gout, kidney stones, or high uric acid levels should limit foods carrying it, as regular intake may raise uric acid and trigger painful flare-ups.
What is it?
Disodium inosinate is the sodium salt of inosinic acid, a purine nucleotide found naturally in meat, fish and certain fermented foods. Commercially it is produced by fermentation of glucose using bacterial strains or by hydrolysis of yeast extract, then purified and dried to a white powder. It is closely related to E627 (disodium guanylate) and the two are almost always used together.
What does it do?
Inosinate enhances and prolongs the perception of umami (savoury depth) by binding to taste receptors on the tongue that are already activated by glutamate. Even at concentrations too low to contribute flavour on their own, inosinate and guanylate amplify the effect of glutamate (MSG or naturally present glutamic acid) many-fold, allowing manufacturers to use less total seasoning. The mechanism is synergistic: inosinate alone has modest impact; paired with glutamate the amplification is roughly 5-8 times the taste intensity.
Where you will see it
Instant noodles and cup soups, crisps and savoury snacks, stock cubes and bouillon powders, powdered soup mixes, flavoured crackers, ready meals, sauces, and some processed meats. It nearly always appears alongside E627 (disodium guanylate) and E621 (monosodium glutamate). On a UK ingredient label it appears as disodium inosinate or E631.
What the science says
Purine metabolism and uric acid
Inosinate is a purine nucleotide. The body metabolises dietary purines to uric acid, which is excreted by the kidneys. In people with gout, hyperuricaemia, or impaired kidney function, extra dietary purines can push uric acid above the threshold at which it crystallises in joints, triggering acute flare-ups. Most published evidence concerns high-purine foods such as organ meats and sardines rather than additive-level inosinate specifically, and the absolute dose from food additives is small. The concern is real but dose-dependent.
High dietary purine intake raises serum uric acid and is associated with increased risk of gout attacks in people with pre-existing hyperuricaemia.
Inosinic acid (the parent compound of E631) is a purine ribonucleotide that is catabolised via hypoxanthine and xanthine to uric acid through the xanthine oxidase pathway.
Animal origin and dietary suitability
Most commercial disodium inosinate is produced from animal sources, including pig or fish flesh, or via bacterial fermentation. Where sourced from animals, it is unsuitable for vegans and vegetarians. Fermentation-derived versions exist but are not the norm. UK and EU labelling rules do not require the production origin to be stated, so the label 'E631' alone does not tell the consumer which source was used.
Disodium inosinate may be derived from meat (pork) or fish hydrolysate, or from bacterial fermentation. The production method is not disclosed on food labels.
EFSA safety review
EFSA evaluated inosinate and related ribonucleotides (E627, E630, E631, E634, E635) as a group and set no numerical Acceptable Daily Intake, concluding that the quantities used in food are not a concern for the general population. The caveat EFSA noted was specifically for people with disorders of purine metabolism, such as gout.
EFSA's ANS Panel concluded that no numerical ADI was necessary for the ribonucleotides as a group, but flagged that people with disorders of purine metabolism should exercise caution.
Where it stands with the regulators
Who should be careful
People with gout, hyperuricaemia (high uric acid), recurrent uric acid kidney stones, or impaired kidney function should limit foods carrying E631 (or disodium inosinate on the label), particularly where it appears alongside E627, E630, or E635, as the combined purine load is higher. Vegans and vegetarians should treat E631 with caution: most commercial forms are animal-derived and the label does not identify the source.
The honest read
E631 sits at the intersection of two distinct issues that get conflated. The purine-uric acid link is real biochemistry, not speculation, but it matters most to the roughly 1-2% of the UK adult population with gout or diagnosed hyperuricaemia. For the rest, the dose from an additive present at trace seasoning levels is far below what organ meats or anchovies deliver. The vegan and vegetarian issue is practical rather than toxicological: most E631 is animal-derived and the label does not say so. These are two separate, honest reasons why certain shoppers should read the label carefully.
Related additives
Common questions
Is E631 banned in the UK?
No. E631 (disodium inosinate) is an approved food additive in both the UK and the EU, listed on the UK FSA's approved additives register and governed by assimilated EU Regulation 1333/2008.
Can E631 trigger a gout attack?
It can contribute to a higher purine load. E631 is a purine nucleotide that the body converts to uric acid. For people already managing gout or high uric acid, regularly eating foods that carry it, especially alongside E627 or E635, adds to the total dietary purine burden. The absolute dose from additive-level use is smaller than that from a serving of liver or sardines, but it is not zero.
What foods contain E631?
E631 is most common in savoury snacks, crisps, instant noodles, cup soups, stock cubes, dry sauce mixes, and some ready meals and processed meats. It almost always appears alongside E627 (disodium guanylate). Look for 'disodium inosinate' or 'E631' in the ingredients list.
Is E631 vegan?
Usually not. Most commercial disodium inosinate is produced from pig meat or fish, or occasionally by bacterial fermentation. UK labelling rules do not require the production source to be declared, so 'E631' on a label does not tell you which origin was used. Vegans and vegetarians should treat any product carrying E631 as unsuitable unless the manufacturer confirms a plant-based or fermentation-only source.
Sources
- UK FSA: E631 Disodium inosinate - Approved Regulated Products
- UK FSA: Approved additives and E numbers
- EFSA ANS Panel: Re-evaluation of ribonucleotides (E 626 - E 635) as food additives, EFSA Journal
- Choi HK et al., Purine-rich foods, dairy and protein intake, and the risk of gout in men, New England Journal of Medicine
- EU Regulation 1333/2008 on food additives (Annex II)
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