What exactly is motivating you to seek out such a company?
I am going to reserve judgement on this one and give a serious answer until more is unveiled.
If you think you are at risk from anything, then the doctors is your best bet.
If you need someone to analyze your hair to tell you if your diet has problems then I've got news for you son
It should be obvious from the stuff you shovel in your face.
He does have a point as I'd imagine in the majority of cases, the sort of people who believe they have vitamin deficiencies are the sort that eat an apple a day and think they're eating healthy despite the other rubbish they put in their mouths.
OP is being rather vague, but if you're pretty knowledgeable regarding nutrition and already have your diet in check etc then it could be well worth doing.
I would like to ensure my health is optimal and there aren't any red flags with my diet. I'm 33 and as far as I know the NHS only do health checks for people over 40.
He doesn't it is extremely hard to check your vitamin and mineral level. And even harder to it. Most people do not have a properly varied diet. And symptoms can be over easily overlooked.
The only site I know that you could even try to track it is http://nutritiondata.self.com/ but doesn't have processed stuff on there. Track a week and you realise how varied a diet actually needs to be.