The Halal requirements for cereal that it must have a kosher symbol on the package and it should not contain any natural or artificial flavor because they contain alcohol.
Vitamins are only Halal if there is kosher symbol on the package of cereal, thise vitamins are obatined from non animal source such as plant or synthetic.
I know what I am providing is a truth and with my 35 years of experience in US food industry and most important I fear Allah all the time.
There is no account on my website you can quite any time by not logging to my website because alhumdulillah there about 3500-4000 Muslims logged on website every day. My website is logged in 186 countries according to Google Analytical stat.