One of the things a vegetarian should be on the lookout for is Vitamin B deficiency symptoms.

With that being said, let me say one other thing: your body has the ability to store B vitamins for later use.  I would assume this is an adaptive response by the body as there would have been times where foods rich in B vitamins (primarily meats) would have been in short supply.

So, if a vegetarian is careful, they could probably avoid depleting their B vitamin stores.  Without knowing how strict your daughter is about her vegetarian eating style it's hard to say how at risk she is.  But, I can provide you with some general signs and symptoms to keep an eye on.

First of all, bare in mind that there are eight different subtypes of B vitamins:  thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), folic acid (B9), cyanocobalamin (B12) pantothenic acid and biotin.  So, it's going to be hard to answer your question about signs and symptoms of not getting enough of all of these B vitamins because they can present differently depending on which one you are short on.

But, there are some generalizations I can make.

Thiamine (Vitamin B1) Deficiency.

While rare in the US, it is most often seen in alcoholics.  If someone has diarrhea for a long time they can also get it.  As can women who are pregnant, lactating or any patient with hyperthyroidism.  This deficiency actually has a name called "Beriberi".  It's most often seen in Asia where people sustain themselves on unenriched rice and wheat.  It usually presents with water retention (edema), irritability, abdominal pain and even loss of voice.  Thiamine deficiency can also lead to heart problems like a fast heart rate and enlargement of the heart.

Riboflavin Deficiency (Vitamin B2).

Most commonly presents in the skin and eyes.  There can be cracking of the lips and sore throat.  Dermatitis can show on the vulva and scrotum.  Tearing, itching and burning of the eyes can also appear.  If the deficiency is prolonged it can cause growth problems in children as well as anemia.

Niacin Deficiency (Vitamin B3).

Called pellagra and has classic "3-D" symptoms: dementia, dermatitis and diarrhea.  If pellagra isn't taken care of by supplementing or changing the eating style it can be fatal.

Pyridoxine Deficiency (Vitamin B6).

Can cause a lot of different symptoms and therefore, tough to pinpoint.  They can include seizures, cracking of the lips and corner of the mouth, dermatitis, vomiting, jerky body movements and CNS (central nervous system) disturbances.

Cobalamin Deficiency.

Can lead to anemia -  particularly pernicious anemia.  This is characterized by low appetite with subsequent weight loss, abdominal discomfort including constipation and diarrhea, jerk-like body movements and peripheral neuropathy.

Tough to Pinpoint Specific B Vitamins

While the list I gave you is fairly comprehensive it would be extremely tough to pinpoint a specific B vitamin that might be causing any problems with your daughter because the foods that are rich in B vitamins are often together in a lot of foods.

As you can also see from the list, the symptoms can range from simply annoying to serious to even fatal.

Again, there are all sorts of reasons for someone to choose becoming a vegetarian.  Unfortunately, some people realize that this may not be the best thing for their bodies.  Not to mention down the road.  For example, should a woman continue it long term into marriage and child-bearing and risk putting her own child's health at risk?  Which, strict vegetarian women do with often lower birth weight and, possibly, smaller brain development.