(OMNS January 23, 2020) Perhaps the only advantage of getting old is being able to look back and see what worked and what didn't. Knowledge of severe vitamin deficiency diseases is an example of learning the hard way. The association of vitamin B1 (thiamine) with beriberi was perhaps the first example of the consequences of refining a food. Milling away the unattractive outer husk of the rice that contained the thiamine caused the disease. No drug could substitute for that missing, essential, "vital amine." That's how "vitamins" first got their name.
In the early 1930s, more such life-sustaining substances were isolated and also named vitamins. Many studies were done to determine what vitamins were in which foods, and they would subsequently be produced as supplements. The public seemed eager to learn more; vitamins were a very popular subject. Common knowledge exceeded what has been presented to most medical students. Recently, we are seeing a recognition and correction of this inadequacy in medical students' nutrition education.
A big change took place after World War II ended: many new drugs were put on the market. Drugs are designed to either enhance or inhibit a specific biological reaction. Vitamins, as necessary cofactors for many enzymes, also do this. The difference is that the drug is designed to target a specific action, whereas a nutrient works in concert with other nutrients. This can make it difficult to assign results, good or bad, to a single nutrient. But both drugs and vitamins work under the principle of giving an amount sufficient to push the equation to the desired effect.
Insufficient quantities of a drug, or vitamin, will not get results. As Abram Hoffer, MD, has said, neither 500 units of an antibiotic, nor 500 milligrams of vitamin C, will get results. Early studies supposedly "proving" that vitamin C was worthless used amounts too small to be of any value. Linus Pauling and other researchers have said the same: if you are going to build a house, be sure you have enough bricks. This is the basis of megavitamin prevention and treatment.
Amazingly, some still claim that vitamin supplements are actually detrimental. They often refer to a gosh-awful 1994 "study" claiming that beta carotene caused lung cancer. It commenced with a foregone conclusion that beta-carotene is bad stuff. As if to guarantee that it would be found accordingly, the study used long-time smokers as subjects. It is well known that smoking, due to the carcinogenic effects of tobacco tars, is a direct cause of lung cancer. Blaming a vitamin as the cause, in spite of a myriad of studies showing that beta carotene is preventive, makes no sense. 
Abram Hoffer, MD, has pointed out that
"With this group of heavy smokers it is certain that a large fraction already had the cancer. . . [T]he beta-carotene group smoked one year more than the no-beta-carotene group . . . How significant is one year more of heavy smoking in increasing the number of advanced lung cancers? The authors do not discuss this."
Although Dr. Hoffer's commentary was published both in a medical journal  and in the Townsend Letter for Doctors , few physicians saw it. Perhaps too many doctors are too busy to read. All doctors are inhibited by having a very limited time for each patient a visit, plus by far too much time required to be spent on the computer with record-keeping, insurance and government mandates.
Doctors need to keep an open mind about vitamin therapy. We should avoid the mistake many politicians are following: If they don't agree with me, they are the enemy. Good medicine should at least listen to and examine the other side.
(We regret to announce that OMNS Contributing Editor and retired pediatrician Dr. Ralph Campbell has passed on at age 92. This previously unpublished editorial was completed by OMNS editor Andrew Saul. They are coauthors of The Vitamin Cure for Children's Health Problems and The Vitamin Cure for Infant and Toddler Health Problems.)