Vitamins: should you stop taking the pills? – Q&A with Dr Paul Offit

For many of us, the days begin with popping 1000mg of Vitamin C, 500 of Vitamin E, and a chewable Calcium tablet – maybe two. But according to Dr Paul Offit, chief of the infectious diseases unit at Children’s Hospital of Philadelphia, we should reconsider how much we rely on our vitamins.

Offit has garnered a lot of attention over the past month for his anti-supplement stance, as laid out in his recent book Do You Believe in Magic?: The Sense and Nonsense of Alternative Medicine. In it, Offit says that vitamin supplements are far from a panacea – in high doses, they may actually harm your health. 

An excerpt from the book published by the Guardian earlier this month was shared over 10,000 times and earned upwards of 700 comments – a mixed bag of supporters, skeptics and personally offended critics. 

Today, Offit has returned to the Guardian for a conversation with readers about the vitamin industry, alternative medicine and the placebo effect. We asked him a few things to get started but toss your own questions in the comments and Offit will respond today at 12pm ET | 5pm BST.

We all need vitamins, but how much is the big question. Has the vitamin industry been overselling this point?

You need vitamins to convert food into energy. The question is how best to get them. Most people who eat a reasonable diet will get everything they need in the food that they eat. But there are some people who have special diets – for example vegans or those who live in climates where it's never sunny – who would benefit from supplemental vitamins. But, for the most part, we get what we need in foods.

Other people think: “Because I'm not sure I'm getting all my vitamins, let me just take take a multivitamin every day” – which is OK. Multivitamins contain at or about the recommended dose of vitamins for that day. But then there are some people who believe that more is better – that by taking large quantities of daily vitamins they will do even better, live even longer and decrease the risk of cancer or heart disease. But in fact, many studies have shown that the exact opposite is true – that if you choose to take these large quantities of excess vitamins, then you increase risk of cancer and heart disease and shorten your life.

The idea that vitamins can’t hurt us is widely accepted, even though studies have shown that large quantities may actually do harm. Why has this idea of vitamins as a panacea really stuck around?

Look at the root of the word: 'Vita' means life. I think people can't imagine you could ever get too much of a good thing. But the second thing is that this industry is very good at projecting the idea that this product lives under an untouchable halo.

It’s a matter of perception. If you go into a General Nutrition Center, you can get a preparation which contains 3,333% of the recommended daily allowance of Vitamin E. In fact, that's a typical Vitamin E preparation that's available. If you open up the bottle and take out one capsule, you'll find that it's smaller than an almond. And, in fact, almonds are a good source of Vitamin E. One almond has about 2% of the recommended daily allowance. But to get to 33 times the daily recommended allowance, you would need to eat about 1,700 almonds – or about 17 pounds of almonds.

And when you do things like this, when you take 33 times the recommended daily allowance of Vitamin E, you are messing around with mother nature. I think if people saw that one capsule as 1,700 almonds, they would be hesitant to take it. But they don't see it that way.

In your book [extract] you talk about the history of Vitamin C – how it was once touted as a cure for the cold and even cancer. While it has not been proven as a medical cure for the cold (and certainly not for cancer), aren’t the effects partly psychological?

I think that in many ways alternative medicine lives in the realm of the placebo effect. When taking Vitamin C for a cold, you can learn to up-regulate your immune system – and you can learn to down-regulate your immune system. But you have to be careful not to take something that could also hurt you. You know, we pop 1,000mg of Vitamin C when we have a cold without thinking. You would have to eat eight cantaloupes to get that quantity of Vitamin C – and Vitamin C can cause kidney stones and other problems. So I’d say don't take vast excesses of vitamins, because that can be a problem.

But our health is linked to both to the psychological and physiological, and psychological matters.

I'll give you a story about my daughter, because she's the perfect example of this. She's on crew – she rowed at the national level in high school. And when she rows she gets an occasional tingling in her fingers, and she was convinced by her fellow rowers that she has exercise-induced asthma – which she doesn't have. She wanted a bronchodilator – which she wasn't going to get – so instead, my wife took her down to the General Nutrition Center and they got something called a Himalayan sea-salt puffer. It's just basically this salt which presumably came from the Himalayan mountains, and it's put in this plastic canister at the top of which there are holes. So you're just breathing in salt. And my daughter thought this was great – she's sitting at the breakfast table reading this box about Himalayan formations thousands of years old – and I say to her: “Honey, do you really think that the sodium chloride in this is going to be any different than the sodium chloride in that salt shaker?” She looks at me and says: “Will you let me believe in something, damnit?”

And she's right. If I say nothing instead of being a jerk like I was, she'd believe in this, and then it would help her relax – and that's really her problem, she gets tense and she forgets to breathe. Now, she inhales this, remembers to breathe, she feels better, and she thinks it's the salt. But even if it's not the salt, that's OK because it certainly isn't hurting her.

In the comments section to many of your pieces – including the Guardian's extract – you often see many incensed commenters defending supplements. Why do you think attitudes towards vitamin pills are so entrenched? 

What, you're saying people don't like me? Just kidding.

This is a belief system. It's emotional. When I ask someone to think about this, that's threatening because belief I important. When my daughter says “Let me believe in something, damnit”, that's it right there. She's saying “Don't get all scientific on me, I need to believe in this.” She's a little bit nicer than many commenters, but it's basically the same response.

You could reasonably argue, in a more rational world, that scientific issues are not elite issues of belief but are evidence-based issues subject to study. But belief is a part of this.

In defence of my detractors, when I say “but look at the science”, what they're saying is: “Let me keep my religion. Let me still be a member of the church of vitamins and supplements.”

In the US, vitamins are regulated by the FDA as “dietary supplements” – and in the EU and UK they are similarly classified. What does this mean for consumers? Do you advocate an alternative?

If there's any ask in my book, that's it. When you use the term “regulated", that's nice way to put it. It is essentially and practically an unregulated industry.

In the US, you can put a dietary supplement or vitamin on the shelf and you don't have to have data supporting your claims or data admitting your harms. One megavitamin study showed that if you take very large quantities of Vitamins A and E, you increase your chances of getting lung cancer. Were the FDA to actually regulate this industry, I think megavitamins would have a black box warning on them. But they don't – the consumer doesn't know about many of the risks.

There was one line I put in the book briefly. A few years ago, after two studies in one month that showed that showed how megavitamins hurt, there was a headline in the Wall Street Journal that asked “Is this the end of popping vitamins?”

Buried in that article, there was a quote from a higher-up in the GNC corporation that said: “We just let these studies go. We ride them out. They don't have any effect on our business, we were up 4.4% last year.” And he's right. Until this industry is regulated, the consumer will always be uninformed.

Do you see that happening?

No. The industry is far too powerful. In the US, it's a more than $30bn per year industry with lobbyists that spread money out on both sides of the aisle. Both parties have little incentive to go against them.

Dr. Offit will be answering questions in the comments section relating to his new book and the excerpt featured on the Guardian. His answers on this site are meant general information for the public, not official medical advice. For personal medical inquiries please consult your physician.

Excerpts from the Q&A

What vitamin supplements do you think are most over-consumed? Also, surely you're not arguing against prenatal vitamins during pregnancy.

Guardian contributor

Hi Caroline,

Certain situations clearly require vitamins. Pre-natal vitamins are necessary because they contain vitamin B9 (folic acid), which is necessary to avoid congenital abnormalities such as spina bifida. Also, babies who are exclusively breast fed should receive supplemental vitamin D.

As a general rule, people who aren't food fadists (like vegans) get the vitamins they need in their diet. The notion we have that we can just pop in a vitamin in lieu of a healthy diet isn't a good one. Focus on the diet, not the pill.


Is there any benefit to taking a slightly elevated amount of Vitamin C at the onset of a cold? Say, if I cut an airborne into four pieces? Or do I really only like it because it fizzes?

Guardian contributor

To Steph Wortel,

It is hard to find a vitamin or supplement that has been studied more extensively than vitamin C. One thing is clear. Vitamin C does not prevent or treat the common cold. However, once Linus Pauling said that it did in the 1970s, it's been hard to unring the bell. And people assume, what the heck, it can't possibly hurt. But one should be suspicious of taking large quantities of vitamin C for long periods of time. Of interest, Linus Pauling's wife, who followed his lead of taking megadoses of vitamin C for years, died of stomach cancer as a young woman. And Arthur Robinson, who worked as a researcher with Pauling at the Pauling Institute for years, found that in studies in experimental rats, vitamin C increased the risk of cancer. So Pauling fired him.

I didn't include this story in the book but now I wish I had.


There's already a move afoot to have the FDA restrict vitamin B-6. Because it's dangerous? No: because a pharmaceutical company wants to use it as part of a new patented medicine. I suspect B-6 is just the beginning of a new pharmaceutical trend to, let's just say, increase the price of vitamins. I also suspect the big Pharma potential of vitamins has as much to do with the current fear-mongering as any actual concern for consumers' best interests.

Guardian contributor

To howardmk,

One thing that has surprised me in the writing of this book is that consumers assume that Big Pharma and their patented, synthesized drugs are on one side and little Mom and Pop companies who make vitamins are on the other. In fact, two of the biggest players in the megavitamin business are Pfizer (which recently bought the megavitamin maker Alacer) and Hoffman LaRoche. The megavitamin industry IS Big Pharma.

The vitamin and supplement industry, now a $34 billion industry in the US, has continued to be able to sell itself as something small and caring. But big business is big business, intent on convincing us that we need their products whether we do or not.


This comment has been chosen by Guardian staff because it contributes to the debate

Any view on Glucosamine for joint health? I've read that it's essentially a placebo.

Guardian contributor

To ItsMeYoshi,

You're right. One excellent, placebo controlled study found that glucosamine and chondroitin sulfate didn't relieve the pain or decrease inflammation associated with osteoarthritis. But just because something doesn't work better than placebo doesn't mean that it can't work as a placebo. If believing that glucosamine or chondroitin sulfate works causes one to avoid non-steroidal anti-inflammatory drugs or COX-2 inhibitors, like Celebrex, you could argue that it is of value.

Of course, if you're going to take a placebo than it should be as safe and inexpensive as possible.


Hi Dr Offit,  I really enjoyed your book. My question is, were the studies that showed a negative effect of vitamin a or e consumption performed within set age brackets - in fact is that normal for such studies, or are they subsequently age adjusted? Thanks!

Guardian contributor

To Mestizo,

Studies showing an increased risk of cancer and heart disease associated with megadoses of vitamins A, E, beta-carotene, and selenium were performed in adults with an increased risk of cancer, such as exposure to asbestos or smokers. Studies weren't done in adolescents or young adults.


Guardian staff

In the comments section of your book excerpt, Guardian reader StrawBear wrote:

"It's hard to know what, or who to believe any more. So many advocates and nay sayers produce studies for everything that are either skewed or statistically inaccurate, that even when an article like this pops up, I have to say I can't help but roll my eyes and think that no one knows what or who to believe any more.
It wasn't so long ago we were all being told that calcium wasn't any good for helping bones."

So, how does an average person parse through the many, many studies we see reported on on a regular basis?

Guardian contributor
This comment has been chosen by Guardian staff because it contributes to the debate

To nadjap,

You've asked the critical question. It probably wouldn't surprise you to know that there are about 4,000 studies published in the world's medical and scientific literature every day. So how are you supposed to sort through all of this.

As you might imagine, studies follow a bell shaped distribution. Some are excellent. Some are awful. And most are more or less mediocre. The trick is to pick out the studies that are the most robust, internally consistent, published in excellent journals by excellent institutions, and reproducible. Many people don't have the background or expertise to do this. So, in a more perfect world, one should be able to find someone with expertise and experience in the field who can help guide you through this dense thicket of information (and misinformation).

This isn't easy. But it's possible.


I've heard that as a vegan you need to make sure to get enough iron, calcium and B12, should I be taking any supplements or not?
Any other advice would be appreciated.

Guardian contributor

To Simon Cook,

Your comment is probably the one I am asked to address most frequently. And the one that I find the hardest to understand.

Of course, conventional medicines are more harmful than dietary supplements. That's because serious diseases require serious treatments. When a child comes into our hospital with cancer, they typically receive drugs like cyclophosphamide, methotrexate, vinblatine, vincristine or other immune suppressive drugs that can cause significant bone marrow suppression resulting in fatal infections or fatal hemorrhage. If we gave these children emu oil, glucosamine, and acupuncture, I'm sure they wouldn't suffer from the therapies. But they wouldn't work.

Similarly, children who come into our hospital with asthma often get a bronchodilator (like albuterol) that can cause heart arrythmias or steroids. We could give a homeopathic bronchodilator that would no doubt be safe. It just wanted treat the patient. It's always a matter or risk, reward. The more serious the disease, the more serious the therapy.

Most outpatient diseases are self-limited. So, by definition, anything works. The trick here is to do no harm. So one could argue here that homeopathic arnica would be better than a pseuodephedrine containing cough and cold prep. Because the patient is going to get better just as fast with either so don't expose them to something potentially dangerous.


This comment has been chosen by Guardian staff because it contributes to the debate

Myth or true? I've always been told that you can't overdose on vitamins except on A D E and K. I'd be curious to hear if this is actually the case.

Guardian contributor

To LaLunya85,

Not surprisingly, you can overdose on practically anything, including B complex vitamins. Indeed, you can overdose on water. People who drink large quantities of water during a short period of time have occasionally suffered seizures as they've exceeded their bodies ability to hold onto sodium.

As Paracelsus, a chemist, once said, "The dose makes the poison."


Guardian staff

What are your thoughts on taking Vitamin D supplements?

Guardian contributor

To AmandaHolpuch,

The vitamin D story is a mess. It's clear that people who live in climates where there is very little sunshine should supplement themselves with vitamin D. And initial studies suggested that vitamin D plus calcium was a good way to avoid thinning of the bones that comes with advancing age. Now, however, the data for prevention of bone thinning is less clear. And the US National Center for Prevention does not recommend vitamin D.

In the US, it seems that everyone now is suddenly vitamin D deficient. My sense is that this will soon pass.


Guardian staff

It seems like beauty specialists are always recommending that I take pre-natal vitamins to improve the condition of my face and hair and such. I am most certainly not pregnant, and don't plan on being pregnant for the foreseeable future. Does these supplements actually have any benefits for regular women or are all these estheticians and hair dressers just talking nonsense? Are there any harmful effects of non-pregnant women taking pre-natal vitamins?

Guardian contributor

To KaylaEpstein,

My sense of this is that multivitamins (i.e., vitamins that contain at or about the recommended daily allowance) don't hurt you. Most people don't need them, and it makes for a lot of expensive urine, but they don't hurt. Megavitamins (which contain many times the recommended daily allowance), on the other hand, are a different story. We should be very careful about taking large quantities of concentrated anything (including vitamins).

Also, the claims about vitamins often exceed reason and common sense, including makes for thicker hair, more energy, better immunity, stress relief, etc.


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