Has anyone with fructose malabsorption tried the current Soylent?

TL;DR: Has anyone with fructose malabsorption tried the current Soylent that uses Isomaltulose as an ingredient? How was your experience?

While very interested in trying Soylent, the use of Isomaltulose is currently stopping me since the ingredient is broken into equal parts of fructose and glucose mostly in the small intestine.

"Ingested isomaltulose is metabolised by the isomaltase-sucrase complex in the intestinal mucosa to equal parts glucose and fructose, which are readily absorbed and utilized in carbohydrate metabolic pathways…

… the hydrolysis and absorption of isomaltulose occurs almost completely in the small intestine."

-APPLICATION FOR THE APPROVAL OF ISOMALTULOSE (Advisory Comittee on Novel Foods and Processes)

However, it is also said that fructose absorption is facilitated when equal parts of fructose and glucose are consumed.

Of the two mechanisms involved in fructose absorption, the presence of glucose facilitates the transport of fructose across the brush-border membrane of the small intestine in the glucose-dependent fructose co-transport mechanism, thereby increasing the rate at which fructose is absorbed.

-APPLICATION FOR THE APPROVAL OF ISOMALTULOSE (Advisory Comittee on Novel Foods and Processes)

Observations from a small study (10 individuals only) point that individuals with possible malabsorption succesfully processed a whooping 50g of fructose that came in the form of 100g of sucrose (50% fructose, 50% glucose). Though the form of the sugar was in sucrose, not isomaltulose.

Yet, an assesment observed that Isomaltulose could cause problems for people with problems metabolizing fructose. The assesment talks only about people with HFI (Hereditary Fructose Intolerance) and people lacking the enzyme sucrase-isomaltase. It does not mention people with fructose malabsoption, but the website in itself mentions them.

"Is isomaltulose safe?

For most people, yes. However, a FSANZ safety assessment (pdf 403 kb) suggests it is unsuitable for people with disorders in fructose metabolism, such as hereditary fructose intolerance. As isomaltulose is broken down into fructose and glucose in the digestive tract, people with this condition are likely to experience severe adverse effects. Anyone with fructose malabsorption may also be affected."


Now, my worry here is whether the hydrolisis of isomaltulose breaks isomaltulose in equal parts at the same rate or whether there could be more parts from one substance (glucose/fructose) than the other at any time.

Has anyone with fructose malabsorption tried the current Soylent that uses Isomaltulose as an ingredient? How was your experience?


I was diagnosed with fructose malabsorption and moderate lactose intolerance about 6 years ago after a hydrogen breath test. It’s an annoying condition, and I certainly know it when I eat foods high in fructose or fructans. They give me gas and make me feel bloated, so I try to avoid them. Looking at you, onions. I’m happy to report that Soylent v1.8 and v2.0 and the other flavored Soylent drinks haven’t given me any issues. I eat v1.8 for lunch most days and sometimes for supper as well with no different outcome than when I eat non-Soylent low-fructose, low-lactose meals.

The concept of Soylent was exciting for me from the outset, since I had gotten tired of figuring out safe meals to make on a regular basis. Try finding a casserole or slow-cooker meal that doesn’t contain onions. It’s hard to do. Unfortunately, the first Soylent versions that contained oats also gave me a lot of gas, but I’ve been trouble free since v1.6.


As a side question, do the minced dried onions give you gastric issues too, or just fresh ones?

Minced dried onions and onion powder seem to behave about the same as fresh onions. It’s a little hard to judge, since the dried forms have less volume but are more concentrated sources of fructans.

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Thanks for the reply. I was diagnosed with both of those as well, that’s why I wondered about others’ experience. It is indeed difficult to figure out what is safe to eat when suffering from those two. I appreciate the reply. Although everyone is different and have different levels of malabsorption, listening to others’ experiences helps make a decision of trying it.

Don’t know if the question was directed at me, but yes. Minced dried onions cause me problems too, as well as fresh ones, but they have to do with other gastrointestinal functional disorders regarding short-chain carbohydrates.

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I’m glad I could provide some relevant experience. I hope Soylent works out for you if you decide to try it.

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