A piece by Paul Offit in The Atlantic titled, The Vitamin Myth: Why We Think We Need Supplements points out that vitamin supplements typically are not only unnecessary, they may be harmful:
On October 10, 2011, researchers from the University of Minnesota found that women who took supplemental multivitamins died at rates higher than those who didn’t. Two days later, researchers from the Cleveland Clinic found that men who took vitamin E had an increased risk of prostate cancer. ‘It’s been a tough week for vitamins,’ said Carrie Gann of ABC News.
These findings weren’t new. Seven previous studies had already shown that vitamins increased the risk of cancer and heart disease and shortened lives….
This is a positive for the produce industry as it argues that one should get one’s nutritional needs supplied by food, not vitamin supplements. Most of the article is a fascinating biography of Linus Pauling, who was a genius but became a bit of a quack when he fell off the deep end regarding vitamin C supplements without evidence to back up his claims that high doses could prevent colds, cancer and whatnot.
There is, how, a cautionary tale here for how the produce industry ought to use research. The article explains how Pauling came to think vitamin supplements could be a miracle worker:
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.
The piece goes on to explain that the research shows this isn’t true:
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.
During the time that the Pundit Poppa was dying of cancer, we had many opportunities to speak with oncologists, many of whom pointed out that free radicals play a role in killing cancer cells. Clearly we need anti-oxidants, but to what extent is very unclear. The article explains:
Given that free radicals clearly damage cells — and given that people who eat diets rich in substances that neutralize free radicals are healthier — why did studies of supplemental antioxidants show they were harmful? The most likely explanation is that free radicals aren’t as evil as advertised. Although it’s clear that free radicals can damage DNA and disrupt cell membranes, that’s not always a bad thing.
People need free radicals to kill bacteria and eliminate new cancer cells. But when people take large doses of antioxidants, the balance between free radical production and destruction might tip too much in one direction, causing an unnatural state in which the immune system is less able to kill harmful invaders. Researchers have called this ‘the antioxidant paradox.’
Whatever the reason, the data are clear: high doses of vitamins and supplements increase the risk of heart disease and cancer; for this reason, not a single national or international organization responsible for the public’s health recommends them.
The caution for the produce industry is that it is one thing to say that studies show that people who eat diets rich in fruits and vegetables, on average, gain health benefits over those who do not. It is another thing entirely to promote particular fruits or vegetables by their specific health benefits! Most probably there is no harm… the concentrations in even the richest produce items of any of these vitamins do not approach the concentrations found in supplements.
Still, we really don’t have very much research to establish that eating more of any individual produce item is, on net, beneficial to long-term health. Most research done on produce does not prove an enhancement to human longevity or anything like that. It typically establishes that the produce item is rich in a vitamin or in antioxidants, etc.
The effects of these things in the body are complex and, very possibly, they have both positive and negative effects. We need to carefully monitor the claims we promote to make sure the promotional cart does not get ahead of the research horse.