In its latest blog post​,​ Soylent says it has been trying to determine why some users experienced digestive issues​​ after consuming its new food bar and 1.6 powder, but not, apparently, after consuming its ready-to-drink products, Soylent 2.0, and Coffiest.

“This​ [investigation] has included product testing, an exhaustive industry search, and discussions with many of our suppliers​​​,” said the Los Angeles-based company, which has temporarily taken its powders and bars off the market. “Our tests all came back negative for food pathogens, toxins or outside contamination.​

“The absence of a positive test has allowed us to shift our focus to whether any one ingredient might be triggering a food intolerance. This would be a reasonable explanation as to why many customers haven’t experienced any discomfort (even when they eat from the same batch of bars as customers who did get sick).”​

Our tests all came back negative for food pathogens, toxins or outside contamination

It added: “During our review, we noticed that a handful of consumers (less than 0.1%) who consumed Powder 1.6 over the past several months reported stomach-related symptoms that are consistent with what our Bar customers described. Interestingly, we didn’t see similar complaints during the 1.5 formulation. This possible connection allows us to narrow the field considerably given there are only a few ingredients that are specific to only our bars and Powder 1.6. We have found no complaints for Soylent Drink (v.2.0) or Coffiest that are at all similar.​

“We are going to continue to look into this further and share our findings with the FDA so that they can do their own evaluation.”​

In the meantime, said Soylent, “We are reformulating Bar and Powder 1.6 to remove the likely ingredients. Turnaround should be fairly quick. We expect both will available in early Q1 2017, if not before.”​

There are only a few ingredients that are specific to only our bars and Powder 1.6

Soylent would not, however, say which ingredients it planned to remove, prompting reporters to wade through the ingredients declarations (which are publicly available on the website coupled with ‘release notes’ on each product) in a bid to identify which ingredients may be at issue.

Four ingredients are common to the bar and the 1.6 powder, but are not in either of the ready-to-drink products: Whole algal flour, modified food starch, mono and diglycerides, and mixed tocopherols.

Whole algal flour​

Given that the latter three ingredients are pretty ubiquitous in packaged foods, FoodNavigator-USA asked Soylent whether it believed that some of its customers may therefore be intolerant to whole algal flour, a fairly new ingredient, but one that already features in several commercial products without apparently causing digestive issues, but it declined to comment.

It also declined to say whether whole algal flour is one of the ingredients it intends to remove from its bars and powders going forward.

"During our review, we noticed that a handful of consumers (less than 0.1%) who consumed Powder 1.6 over the past several months reported stomach-related symptoms that are consistent with what our Bar customers described. Interestingly, we didn’t see similar complaints during the 1.5 formulation. This possible connection allows us to narrow the field considerably given there are only a few ingredients that are specific to only our bars and Powder 1.6. We have found no complaints for Soylent Drink (v.2.0) or Coffiest that are at all similar." ​ Soylent blog​​

Soy protein isolate, IMO​

However, attention has also focused on changes made between version 1.5 of the powder (which did not apparently cause digestive issues) and version 1.6 (which has been linked to digestive issues in a handful of consumers), notably the addition of soy protein isolate as the #1 ingredient (replacing brown rice protein), and isomaltooligosaccharide or ‘IMO' a dietary fiber that can cause gas and bloating at very high dosage levels [which Soylent products fall well below].

Version 1.6 also contains higher levels of sucralose and isomaltulose than v1.5, according to Soylent's release notes.

While IMO and soy protein isolate are also used in the ready-to-drink products (2.0 and Coffiest), which have not​ apparently generated any digestive problems, the inclusion rates may differ, while other factors such as usage trends (the RTD products are portion-controlled, the powder isn't) and different manufacturing and processing methods could also play a role, say formulation experts.

There’s a reason why larger companies have two to three year development cycles​

One industry source told us: “The problem is, there is a cocktail of things in these products that individually or collectively could be responsible for digestive issues, because you’ve got protein, fiber and high intensity sweeteners, and I don’t see how it’s possible in the time that they have had to come to any conclusions about the source of the problem.​

“You're talking about​ products with 40+ ingredients, so it’s very hard to isolate the root cause of the problem unless they do exhaustive studies involving inclusion and exclusion and you can’t do that in a few weeks.​​

“They’re a fairly new company, there’s a lot of pressure to move fast and all eyes are on them. As you can see from their release notes, they have always been transparent about their formulations, which is great, but this also means that when something goes wrong, there’s a lot of pressure and second-guessing. Food formulation is difficult and expensive and there’s a reason why larger companies have two to three year development cycles, because they don’t want this to happen.”​

The combination of many of the ingredients can overwhelm a sensitive gut​

Tim Avila, president of Systems Bioscience Inc - a California-based consultancy - told FoodNavigator-USA: "Any junior formulator should know that the combination of many of the ingredients can simply overwhelm a sensitive gut. And for those with cast iron GI tracts there are still problems."​

He added: "It's not necessarily any single ingredient; you have to look at the combination of ingredients, the dose, and the cumulative effect, because every formulation is a system, and there are a few things in there that are problematic when it comes to osmolality, indigestibility and fermentability. You've got high levels of isomaltulose and IMO, coupled with modified starch, and new things like the algal flour, and in my view, it's more likely to be some of these things causing the distress than sucralose or soy protein isolate.​

"And when you've got these things in a dense product like a bar, it compounds the problem, as these ingredients are diverting water into the gut. We're still learning about the digestive effects of some of these new carbohydrates like IMO and if they don't spend enough time testing a new formulation and really understanding what's going on and bring reformulated products to the market too early, they could end up in trouble again." ​

Soylent has not received reports of digestive problems with its new Coffiest beverage (pictured above) or its flagship Soylent 2.0 drink

TerraVia: Whole algae ingredients are GRAS and post market monitoring has not linked them to digestive problems​

Mark Brooks, senior vice president at San Francisco-based TerraVia, which manufactures whole algae ingredients, told FoodNavigator-USA that TerraVia had immediately taken action as soon as the Soylent reports started coming in, but said its ingredients had been exhaustively tested pre-market and then closely monitored post market (Soylent is one of multiple customers), and had not generated any cause for concern.

He added: “In the first instance we confirmed the safety and integrity of our ingredient, to ensure that there are no pathogens or contaminants or anything like that – which you have to do before you do anything else."​

There’s always a subset of any population that could react to any given ingredient​

TerraVia’s lipid-rich whole food algae ingredient (a strain of chlorella), has been judged GRAS (generally recognized as safe) by an independent panel, while TerraVia also received a ‘no objections’ letter from the FDA after sharing the GRAS determination, he said.

It has also been conducting post-market monitoring, which has not thrown up data indicating that there is an issue with intolerance or allergy to its products, although there are always some people that will react negatively to any given food, said Brooks.

"A 1996 publication by Hefle et. al. identifies over 160 commonly consumed foods that have been reported to cause reactions in sensitized individuals​ [Critical Reviews in Food Science and Nutrition, 36(S):S69—S89, 1996​​].

“In the last two years we have sold more than 20 million servings of algal flour and ​are aware of very few adverse reactions to products that contain the ingredient. In no cases was algal flour identified as the cause.”​