Sentence:  Mostly, the microbiome is beneficial. It helps with digestion and enables people to extract a lot more calories from their <WSD>food</WSD> than would otherwise be possible. Research over the past few years, however, has implicated it in diseases from atherosclerosis to asthma to autism. 
Meaning of the word marked with <WSD> tags:  Any solid substance that can be consumed by living organisms, especially by eating, in order to sustain life.