Reddit reviews Do You Believe in Magic?: Vitamins, Supplements, and All Things Natural: A Look Behind the Curtain

Wow, bunches of pseudoscience in this thread. Let's start from the top then:

Vitamin C doesn't boost your immune system. In fact, nothing really does.

Zicam is not risk free, and has minimal evidentiary support.

Essential oils and other forms of pseudoscience woo aren't going to stop a cold, I highly suggest Paul Offit's book Do You Believe in Magic? which contains a much longer look at all the various ways snake oil salesmen have weedled their way into modern life and why many people happily promote this nonsense because they have become convinced that it worked for them.

You're a teacher, so you should know something about trustworthy sources. Don't take medical advice from strangers on the internet, go to a real doctor and ask them for their opinion as an expert.

Offit, Paul A., M.D., Do You Believe in Magic? [amazon link, $6] The Sense and Nonsense of Alternative Medicine, 2013

(I have removed a bunch of interesting information about how Pauling was an accomplished scientist before his descent into pseudoscience, and how the supplement industry was able to get in a position where it could legally sell carcinogens with no regulation from the FDA, how they tricked people into supporting these laws, and the propaganda they have used. If you're interested in that, I recommend reading the book (linked above). Sources for his claims here are listed in the back of the book on page 265. I do not receive any compensation from sales of this book.)

Do You Believe in Magic?, Page 53:

...On December 14, 1942, about thirty years before Pauling published his first book, Donald Cowan, Harold Diehl, and Abe Baker, from the University of Minnesota, published a paper in the Journal of the American Medical Association titled “Vitamins for the Prevention of Colds.” The authors concluded, “Under the conditions of this controlled study, in which 980 colds were treated . . . there is no indication that vitamin C alone, an antihistamine alone, or vitamin C plus an antihistamine have any important effect on the duration or severity of infections of the upper respiratory tract.”

Other studies followed. After Pauling’s pronouncement, researchers at the University of Maryland gave 3,000 milligrams of vitamin C every day for three weeks to eleven volunteers and a sugar pill (placebo) to ten others. Then they infected volunteers with a common cold virus. All developed cold symptoms of similar duration. At the University of Toronto, researchers administered vitamin C or placebos to 3,500 volunteers. Again, vitamin C didn’t prevent colds, even in those receiving as much as 2,000 milligrams a day. In 2002, researchers in the Netherlands administered multivitamins or placebo to more than 600 volunteers. Again, no difference. At least fifteen studies have now shown that vitamin C doesn’t treat the common cold. As a consequence, neither the FDA, the American Academy of Pediatrics, the American Medical Association, the American Academy Dietetic Association, the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health, nor the Department of Health and Human Services recommend supplemental vitamin C for the prevention or treatment of colds.

Page 55:

...cancer researchers decided to test Pauling’s theory. Charles Moertel, of the Mayo Clinic, evaluated 150 cancer victims: half received ten grams of vitamin C a day and half didn’t. The vitamin C-treated group showed no difference in symptoms or mortality. Moertel concluded, “We were unable to show a therapeutic benefit of high-dose vitamin C.” Pauling was outraged. He sent an angry letter to the New England Journal of Medicine, which had published the study, claiming that Moertel had missed the point. Of course vitamin C hadn’t worked: Moertel had treated patients who had already received chemotherapy. Pauling claimed that vitamin C worked only if cancer victims had received no prior chemotherapy.

...Moertel performed a second study; the results were the same. Moertel concluded, “Among patients with measurable disease, none had objective improvement. It can be concluded that high-dose vitamin C therapy is not effective against malignant disease regardless of whether the patient received any prior chemotherapy.”

[…]

Subsequent studies have consistently shown that vitamin C doesn’t treat cancer.

Pauling wasn’t finished. Next, he claimed that vitamin C, when taken with massive doses of vitamin A (25,000 international units) and vitamin E (400 to 1,600 IU), as well as selenium (a basic element) and beta-carotene (a precursor to vitamin A), could do more than just prevent colds and treat cancer; they could treat virtually every disease known to man. Pauling claimed that vitamins and supplements could cure heart disease, mental illness, pneumonia, hepatitis, polio, tuberculosis, measles, mumps, chickenpox, meningitis, shingles, fever blisters, cold sores, canker sores, warts, aging, allergies, asthma, arthritis, diabetes, retinal detachment, strokes, ulcers, shock, typhoid fever, tetanus, dysentery, whooping cough, leprosy, hay fever, burns, fractures, wounds, heat prostration, altitude sickness, radiation, poisoning, glaucoma, kidney failure, influenza, bladder ailments, stress, rabies, and snakebites. When the AIDS virus entered the United States in the 1970s, Pauling claimed vitamins could treat that, too.

Page 58:

Although studies had failed to support him, Pauling believed that vitamins and supplements had one property that made them cure-alls, a property that continues to be hawked on everything from ketchup to pomegranate juice and that rivals words like natural and organic for sales impact: antioxidant.

Antioxidation vs. oxidation has been billed as a contest between good and evil. The battle takes place in cellular organelles called mitochondria, where the body converts food to energy, a process that requires oxygen and so is called oxidation. One consequence of oxidation is the generation of electron scavengers called free radicals (evil). Free radicals can damage DNA, cell membranes, and the lining of arteries; not surprisingly, they’ve been linked to aging, cancer, and heart disease. To neutralize free radicals, the body makes its own antioxidants (good). Antioxidants can also be found in fruits and vegetables—specifically, selenium, beta-carotene, and vitamins A, C, and E. Studies have shown that people who eat more fruits and vegetables have a lower incidence of cancer and heart disease and live longer. The logic is obvious: if fruits and vegetables contain antioxidants—and people who eat lots of fruits and vegetables are healthier—then people who take supplemental antioxidants should also be healthier.

In fact, they’re less healthy.

In 1994, the National Cancer Institute, in collaboration with Finland’s National Public Health Institute, studied 29,000 Finnish men, all long-term smokers more than fifty years old. This group was chosen because they were at high risk for cancer and heart disease. Subjects were given vitamin E, beta-carotene, both, or neither. The results were clear: those taking vitamins and supplements were more likely to die from lung cancer or heart disease than those who didn’t take them—the opposite of what researchers had anticipated.

In 1996, investigators from the Fred Hutchinson Cancer Research Center, in Seattle, studied 18,000 people who, because they had been exposed to asbestos, were at increased risk of lung cancer. Again, subjects received vitamin A, beta-carotene, both, or neither. Investigators ended the study abruptly when they realized that those who took vitamins and supplements were dying from cancer and heart disease at rates 28 and 17 percent higher, respectively, than those who didn’t.

In 2004, researchers from the University of Copenhagen reviewed fourteen randomized trials involving more than 170,000 people who took vitamins A, C, E, and beta-carotene to see whether antioxidants could prevent intestinal cancers. Again, antioxidants didn’t live up to the hype. The authors concluded, “We could not find evidence that antioxidant supplements can prevent gastrointestinal cancers; on the contrary, they seem to increase overall mortality.” When these same researchers evaluated the seven best studies, they found that death rates were 6 percent higher in those taking vitamins.

In 2005, researchers from Johns Hopkins School of Medicine evaluated nineteen studies involving more than 136,000 people and found an increased risk of death associated with supplemental vitamin E. Dr. Benjamin Caballero, director of the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health, said, “This reaffirms what others have said. The evidence for supplementing with any vitamin particularly vitamin E, is just not there. This idea that people have that [vitamins] will not hurt them may not be that simple.” That same year, a study published in the Journal of the American Medical Association evaluated more than 9,000 people who took high-dose vitamin E to prevent cancer; those who took vitamin E were more likely to develop heart failure than those who didn’t.

In 2007, researchers from the National Cancer Institute examined 11,000 men who did or didn’t take multivitamins. Those who took multivitamins were twice as likely to die from advanced prostate cancer.

In 2008, a review of all existing studies involving more than 230,000 people who did or did not receive supplemental antioxidants found that vitamins increased the risk of cancer and heart disease.

On October 10, 2011, researchers from the University of Minnesota evaluated 39,000 older women and found that those who took supplemental multivitamins, magnesium, zinc, copper, and iron died at rates higher than those who didn’t. They concluded, “Based on existing evidence, we see little justification for the general and widespread use of dietary supplements.”

Two days later, on October 12, researchers from the Cleveland Clinic published the results of a study of 36,000 men who took vitamin E, selenium, both, or neither. They found that those receiving vitamin E had a 17 percent greater risk of prostate cancer.

Offit, Paul A., M.D., Do You Believe in Magic? [amazon link, $6] The Sense and Nonsense of Alternative Medicine, 2013

"Do You Believe in Magic?" by Paul Offit

Article très intéressant mais sans aucune source.

Plusieurs dizaines d’expériences citées et pas un seul lien mis à part une référence vers un livre : Do You Believe in Magic?: Vitamins, Supplements, and All Things Natural: A Look Behind the Curtain. Est ce un extrait traduit de ce livre ?

Do You Believe in Magic? by Paul Offit. Generally I've loved all of Dr. Offit's books.