Before this site, I was at another, one that crashed and never recovered. I was at that site since 1998! Many from that site are posting here today, at our new home.

Doctors are not trained in nutrition. In fact they are very poorly trained in pharmacology too. Most patients don't know that and think doctors know alot about drugs, and it is sad to say, but most medical training is "observe, label, memorize". Most doctors get their drug information from sales people. They do not as a rule investigate anything on their own. There are exceptions, but the majority is sadly lacking.

In your case, cher, you have had 4 children in a short span of time. That puts a huge nutritional burden on you, much of it is invisible. It is only relatively recently that we have learned, for example, how damaging transfats really are. With babies, there are studies to show smaller head size of babies born to women who ate alot of transfats (which were in everything--donuts, fast food, margarine, potato chips, cookies, everything--Crisco). Transfats were linked to ADHD in children, who were also low in Omega-3 fat intake.
Did any OB tell women to not eat transfats? Nope. It took over a decade of people like me and consumer health researchers to get our FDA to stop transfat consumption. The original goal was to only have accurate labels so consumers could avoid these toxic fats, but the food industry stepped up and for the most removed them. 2006 was the target year for labeling. Now we see cities like NY banning them outright and Netherlands, a whole country, banning them. But with the introduction of Crisco in the late 30's.... 2 generations of US citizens consumed dangerous transfats, and no doctor spoke up... or even KNEW. How many people ask a bakery what kind of fat they use?
I can tell you, not many. When I asked that question, back in the early 2000's, I got blank looks. The workers didn't even know what they used! Today, you can go to some restaurants and they will have a little sign on the table, saying, we do NOT use transfats. The small town we live near in the summer with 500 residents year round, had this on one of the restaurant tables, 2 yrs ago! I was stunned.
Do you read the labels of cookies you buy? Oreo was in deep trouble with California when they refused to remove transfats from its cookies. That was in all the papers. I believe, they have come around. However, the huge snack company Lays...took transfats OUT of their products long before the labeling deadline (2006). They were extremely cooperative and health conscious for their customers!

The serum B12 test does NOT tell where you are going. So if you are borderline with it, you do not know if it has been coming DOWN for you, been there for a while (unless you have frequent testing) or going up. Some people have neuro symptoms at levels doctors call "normal"... it takes a long time at very low levels to get the anemia signs that they are taught in school herald low B12. In fact today, there is controversy that the folate we consume in USA fortified foods, is actually masking low B12 levels and causing MORE neuro symptoms.

Some people do well at 500 range of B12, and others may find they feel better at 800-1000 or even higher. People vary in genetics and their genetics determine how efficient the whole metabolism is. Some may need help. Some need more B vits than others. The classic case is in the area of infant seizures.
Some babies are born with a defect in metabolizing B6...normal levels for them don't work. They have to be given massive doses or else they have endless dangerous seizures. This is called vitamin DEPENDENCY.. and while it is not common, it does point to issues that may exist for others, in milder forms.
Dr. Bruce Ames has written and studied this his whole career, and believes people vary in how the metabolize things using vitamins. He has a website where he explains this.
http://www.bruceames.org/
I think he is a brilliant man, and he invented the Ames test, which is what the FDA uses still to see if a chemical has the potential to cause cancer (DNA damage).

My goal on the net is to educate people so that they can then take care of themselves and not fall into some painful chronic syndrome. Our modern medicine is not geared for that point of view. Modern doctors only work at end points. One exception is Dr. Anderew Weil, who went to Harvard and is still trying to get the curriculum in medical school to change and be more in tune with our bodies and their needs.

In the case with B12, there is no upper limit of toxicity... which is a good thing, because then you can deal with it safely.
The Vit D information however, is still changing, and has changed radically in the last 5 years. I would expect doctors to be very poor at treating Vit D, and they are. They will test you but then treat the low levels with outdated and poor D2. So educating the public, is important with this too, since D3 is OTC, like the B12 is.

edit to add--- You might find Dr. Blaylock MD interesting. A neurologist who decades ago used nutrition to help neuro damage in his patients!
Now he is an alternative spokesperson, and just recently was very revealing about the H1N1 flu shots. He is now retired and active as an alternative voice for healing.
http://www.blaylockreport.com/