If B12 is unable to be transported into the cells, then the serum level will not really matter.
One of the biggest concerns is that taking supplements of the nutrients that MS patients have been found low in may actually lead to even greater harm. For instance, iron is dysregulated in MS. I posted a study that shows protease are responsible for iron regulation in the body. The dysregulated iron has become a part of the pathogenic process of MS. Here is a study on on this. http://www.ncbi.nlm.nih.gov/pubmed/18408021
So, taking additional iron would likely lead to more harm.
Calcium is also not being regulated properly because of a lack of protease. The blood borne calcium is supposed to be protein-bound. The inability to carry protein-bound calcium leads to the calcium being deposited in joints and tissues. Taking additional calcium would just give your body more to deposit in your joints and tissues.
The loss of the ability to metabolize calcium would then lead to an inability to metabolize vitamin D, since it is dependent on blood-borne calcium to be properly metabolized. Excess vitamin D can damage the heart and kidneys. How much is excessive though if you are unable to properly metabolize it? Here is some information on vitamin D from my book.
"A form of vitamin D called cholecalciferol, also called vitamin D3 or calciol, is added to many foods as a supplement. It is also prescribed as a medication for people who are unable to maintain adequate levels of vitamin D. You might be surprised to learn though, that it is also commonly used as an ingredient in rodent poison. Here is an excerpt from the Merck Veterinary Manual on cholecalciferol:
“Cholecalciferol: Although this rodenticide was introduced with claims that it was less toxic to nontarget species than to rodents, clinical experience has shown that rodenticides containing cholecalciferol are a significant health threat to dogs and cats. Cholecalciferol produces hypercalcemia, which results in systemic calcification of soft tissue, leading to renal failure, cardiac abnormalities, hypertension, CNS depression, and GI upset,” (Merck & Co., 2011).
The target organs for cholecalciferol toxicity in animals are the heart and kidneys. The heart and kidneys are also the target organs for cholecalciferol toxicity in humans. A report from the Institute of Medicine in 2010 states that, “Getting too much calcium from dietary supplements has been associated with kidney stones, while excessive vitamin D can damage the heart and kidneys. Some signals suggest there are greater risks of death and chronic disease associated with long-term high vitamin D intake,” (Institute Of Medicine, 2010).
Taking supplements of vitamin B12, which you cannot properly metabolize, may also lead to harm. A large study done in Norway found a very large increased risk of cancer from folic acid and B12 supplements. http://coloncancer.about.com/b/2009/11/ ... r-risk.htm
It is really something to think about. Water is a vital necessary nutrient, but if your kitchen facet was broken and you couldn't turn the water off or on when you wanted to or direct the water where you wanted it to go, then it could do a great deal of damage.