Pullulan

There are three materials a capsule shell is made from. Gelatin is animal collagen. Hypromellose is modified cellulose from wood pulp. Pullulan is the third, and it is the one most people have never heard of.

It is a polysaccharide, described in the regulatory assessment as a “linear, neutral glucan consisting mainly of maltotriose units”, and it is made by fermentation rather than extraction: food-grade hydrolysed starch is fermented with a non-toxin-producing strain of the fungus Aureobasidium pullulans, then the cells are filtered out and the filtrate cleaned up.

Why it matters on a supplement label

For the same reason hypromellose does. A capsule looks identical from the outside and the ingredient list is the only place the difference appears.

Pullulan contains no animal material, so a pullulan capsule answers the question a gelatin one raises for anyone vegetarian, vegan, or keeping halal or kosher. It is made by a fungus from starch, and neither of those is an animal.

It is the least common of the three because it costs more. Where you meet it most is in products that wanted a plant capsule with better oxygen barrier properties than cellulose gives, and in breath strips and oral films, which are pullulan sheets.

The safety position

Unremarkable, which is the useful thing to be able to say.

EFSA re-evaluated it and “concluded that there is no need for a numerical ADI for pullulan (E 1204)”. No acceptable daily intake means the panel found no dose at which a limit becomes necessary, which is the strongest routine outcome an additive assessment produces.

The one recorded effect is digestive and it takes a lot. Human volunteer studies “reported mild undesirable gastrointestinal symptoms (i.e. abdominal fullness, flatulence, bloating and cramping) at doses of 10 g pullulan per day and greater”. A capsule shell weighs a fraction of a gram, so reaching that from supplements alone would take a quantity nobody takes.

In the body it is broken down by salivary and pancreatic amylase and intestinal iso-amylase, then fermented in the colon to short chain fatty acids, which is the same fate as other poorly digestible carbohydrate polymers.

What the label says

Usually nothing helpful, because pullulan is rarely called out. It appears in the ingredient list below the Supplement Facts panel, the split explained in the guide to reading a supplement label, and a manufacturer that paid for pullulan generally advertises “plant capsule” on the front without naming which plant material.

In Europe it carries E1204. If you are choosing on capsule material, the three words to look for are gelatin, hypromellose and pullulan, and two of those three answer the question the same way.