Powdered fruit and vegetable supplements fail to consistently deliver meaningful health benefits in randomized, placebo-controlled trials, and many contain proprietary blends of ingredients that might be ineffective or contaminated.
For example, digestive enzymes are only active within a narrow pH range, so a random blend of powdered enzymes will likely lose their function when exposed to stomach acid unless provided with protection from the low-pH environment (e.g., an enteric capsule).[1] Likewise, the effects of probiotics are strain-specific, and have to be ingested in adequate amounts, which can’t be guaranteed with a proprietary formulation.[2]
There have been several reports of similar products – especially those containing herbal blends – having been contaminated with substances banned in sports or with dangerously high levels of certain ingredients linked to liver damage.[3] They’re also more expensive than whole fruits and vegetables per equivalent serving.[4]