The “Food Babe” is an excellent object lesson in why people who are not qualified should not be dispensing advice to the public. Spouting uninformed opinions is one thing, but presenting information in an authoritative manner as if from an expert should not be attempted by the non-expert.
If you want to dispense useful information on your blog or website (not just opinion) then it is appropriate to cite credible sources and experts and to accurately convey their information. “These are the facts concerning flu vaccines, according to the CDC,” then quote the CDC directly, with a link to the source.
Unfortunately the web is cluttered with people who really have no idea what they are talking about giving advice as if it were authoritative, and often that advice is colored by either an ideological agenda or a commercial interest. The Food Babe is now the poster child for this phenomenon...