Is Prune Juice Good for You? Sugar, Sorbitol and Potassium

Prune juice is a fruit juice with sorbitol in it, a sugar alcohol the gut absorbs slowly. Per 100 g it carries 14.4 g of sugars, about 6 g of sorbitol, 210 mg of potassium, 57 kcal and only trace fibre, so a small 150 ml glass is roughly 22 g of free sugars against the NHS limit of 30 g a day for adults, and the NHS asks everyone to keep fruit juice to 150 ml a day.^{1, 2, 3}

Sources checked on 30 October 2026.

Whether that is "good for you" depends on what you want from it. On constipation it has one placebo-controlled trial, part-funded by the juice's maker, 54 g a day for eight weeks, and whole prunes have two trials against psyllium and an authorised claim at 100 g a day; does prune juice help constipation covers that evidence.^{4, 5} This page covers what is in the glass, why it can make you feel odd, whether it stops working, who should go carefully and how to use a concentrate. For the fibre the juice does not supply, the Wellgard fibre guide sets out the 30 g a day target.

What does prune juice contain, and how does it compare with prunes?

The UK reference figures come from McCance and Widdowson's dataset, CoFID, and the sorbitol figures from the 2001 review of prune composition.^{1, 2}

Juicing filters out the fibre and keeps the sugars, the sorbitol and the minerals, so a glass of prune juice is closer to any other fruit juice than to a handful of prunes. The things prunes are studied for beyond the bowel, bone density in post-menopausal women at 50 g a day for a year, for instance, were tested with the fruit, not the juice.⁶ Prune juice "from concentrate" on a carton has been concentrated for transport and reconstituted with water.

Is the sugar in prune juice bad for you?

It is the same sugar as in any fruit juice, and the NHS treats it the same way: the sugars in fruit juice count as free sugars because juicing releases them from the fruit's cells, adults should have no more than 30 g of free sugars a day, and unsweetened juice and smoothies together should be kept to 150 ml a day.³ A 150 ml glass of prune juice carries about 22 g, so a daily glass uses most of that allowance, and a 250 ml tumbler exceeds it on its own. "No added sugar" on a prune juice or concentrate label describes added sugar; the fruit's own sugars remain, and they are what the free-sugars figure counts. For someone with diabetes a glass of prune juice carries about 22 g of sugars to count like any other juice and to discuss with their diabetes team; whole prunes possibly behave differently, since the composition review suggests their fibre and sorbitol slow the rise in blood glucose.²

What is sorbitol, and why do you feel odd or windy after prune juice?

Sorbitol is a sugar alcohol that the small intestine absorbs poorly. What is not absorbed draws water into the bowel, and what reaches the colon is fermented by bacteria, producing gas. The juice trial's authors suggest sorbitol, with the juice's pectin and polyphenols, may explain the effect they measured; the review links the laxative action to sorbitol.^{2, 4} The same process explains the wind, cramps and, at higher amounts, loose stools some people get. Sorbitol is a polyol, the "P" in FODMAP, and the NHS advises people with IBS to avoid products containing sorbitol when bloating, wind or diarrhoea are the problem.⁷ If prune juice has given you diarrhoea, stop, drink water, and try a smaller glass later; diarrhoea that does not settle is a GP matter.

Does prune juice stop working if you drink it every day?

No trial has found that it does. In the eight-week trial, hard, lumpy stools were less common than on placebo from week three, normal stools more common from week three, and a normal consistency (type 4 on the Bristol scale) more common from week seven.⁴ If prune juice "stops working", the constipation may have another cause, such as a medicine, too little fluid or too little fibre, which the NHS lists among the common causes; our constipation guide goes through those causes, and the NHS says regular constipation is itself a reason to see a GP.⁸

Is it safe to drink prune juice every day, and who should be careful?

For most adults a small glass a day is fine within the 150 ml juice limit, and the eight-week trial reported no adverse events or changes in liver or kidney blood tests.^{3, 4} Four groups should go carefully. People with diabetes, for the sugars above. People with IBS, especially IBS with diarrhoea, for the sorbitol. People with kidney disease, because 150 g of prune juice carries about 315 mg of potassium by the UK food tables, and with high blood potassium the NHS refers people to a dietitian who sets how much to have.^{1, 9} And children: the NHS says to take a child who may be constipated to a GP, and this page gives no juice dose for a child.¹⁰ "What organ are prunes good for?" is a question about the fruit: the bowel evidence is above, and the bone trial used 50 g of prunes a day; no trial has looked at prune juice and belly fat.⁶

How do you use a prune juice concentrate?

A concentrate is prune juice with most of its water removed, diluted at home: follow its label for the serving, the dilution and how long it keeps once opened, and measure rather than pour. Its sugars are the fruit's own, so the free-sugars, sorbitol, IBS, diabetes and potassium notes above apply to a concentrate too, and the register's bowel-function claim belongs to 100 g of dried plums.^{3, 5} No trial has compared a concentrate with pressed juice or with whole prunes, so "is concentrate as good as juice?" has no trial answer.

What we don't know

Whether prune juice works as well as whole prunes: no trial has compared them, and the only juice trial is one partly industry-funded study of 84 adults over eight weeks.⁴ How much sorbitol a given carton or concentrate carries, since labels do not state it and the composition figures are averages.² Whether prunes beat psyllium: a 2024 pooling of two trials found no difference in stool frequency.¹²

Frequently asked questions

Can you make prune juice from dried prunes?

Yes: soak or stew prunes in water and blend. Strictly that is a purée, not a juice, and it keeps the fruit's fibre.²

Do prunes or prune juice need to be refrigerated?

Dried prunes keep in a cupboard. Opened juice goes in the fridge and is used within the days the carton states; an opened concentrate is refrigerated and used within the period its label states.

Is two prunes a day too much?

No. Two prunes are about 20 g, roughly 7 g of sugars and 1 g of fibre; the bowel trials used 80 to 120 g a day and the bone trial 50 g.^{1, 6, 11}

What is the healthiest prune juice to drink?

One that is 100% prune juice with nothing added. Beyond that the differences are small, and the healthiest amount is the 150 ml the NHS allows for any juice.³

Is "light" prune juice as effective as regular?

No trial has tested a reduced-sugar prune juice, and labels rarely state how much sorbitol survives the process.

Sources

1. Public Health England. McCance and Widdowson's Composition of Foods Integrated Dataset (CoFID), 2021. Food composition dataset (prune juice; prunes, ready-to-eat). gov.uk.
2. Stacewicz-Sapuntzakis M, et al. Chemical composition and potential health effects of prunes: a functional food? Critical Reviews in Food Science and Nutrition, 2001. Narrative review; non-government support listed on PubMed. PubMed 11401245.
3. NHS. Sugar: the facts. Page last reviewed 19 May 2023 (review due 19 May 2026). nhs.uk.
4. Koyama T, et al. Prune juice containing sorbitol, pectin, and polyphenol ameliorates subjective complaints and hard feces while normalizing stool in chronic constipation. American Journal of Gastroenterology, 2022. Double-blind randomised placebo-controlled trial, 84 adults, 8 weeks; part-funded by the juice's manufacturer, two authors its employees. PubMed 35971232.
5. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register. Statutory register. gov.uk.
6. De Souza MJ, et al. Prunes preserve hip bone mineral density in a 12-month randomized controlled trial in postmenopausal women: the Prune Study. American Journal of Clinical Nutrition, 2022. Randomised controlled trial, 235 women, 12 months; funded by a prune industry body. PubMed 35798020.
7. NHS. Irritable bowel syndrome (IBS): diet, lifestyle and medicines. Page last reviewed 17 March 2025. nhs.uk.
8. NHS. Constipation. Page last reviewed 26 October 2023 (review due 26 October 2026). nhs.uk.
9. NHS. Chronic kidney disease: living with. Page last reviewed 22 March 2023. nhs.uk.
10. NHS. Constipation in children. Page last reviewed 2 August 2023. nhs.uk.
11. Lever E, et al. The effect of prunes on stool output, gut transit time and gastrointestinal microbiota: a randomised controlled trial. Clinical Nutrition, 2019. Randomised controlled trial, 120 adults, 4 weeks; UK public and charity grants listed. PubMed 29398337.
12. van der Schoot A, et al. Systematic review and meta-analysis: foods, drinks and diets and their effect on chronic constipation in adults. Alimentary Pharmacology and Therapeutics, 2024. Meta-analysis, 23 studies, 1,714 people; funded by the British Dietetic Association. PubMed 37905980.

Spotted something out of date? Email support@wellgard.co.uk with the page address and the sentence.

This article is general information, not medical advice; ask a GP or dietitian first if you have diabetes, kidney disease or IBS.