Are supplements necessary?

Young woman taking vitamins ginseng pill

One of the more common questions is whether I recommend any supplements. I recommend very few of them.

For longer fasts, I recommend a general multivitamin, although there is scant evidence that it is beneficial. In fact, almost all vitamin supplements have been proven to not be beneficial in large population based studies. In some cases, like vitamin B, they may even be harmful.

All vitamins go through periods of of popularity and unpopularity. It’s worse than high school. One minute, you’re the most popular kid in class, then next you’re the laughingstock.

Vitamin C

In the 1960’s, the king of vitamins was vitamin C. Linus Pauling is the only person to have won two unshared Nobel Prizes – once for chemistry and once for peace. He had the firm unshakeable belief that many of the problems of modern nutrition could be cured by mega doses of vitamin C. He suggested that high dose vitamin C could prevent or cure the common cold, the flu and even cancer. He even suggested that “75% of all cancer can be prevented and cured by vitamin C alone”. That, of course is wildly optimistic.

Many studies were done over the next few decades that suggested that most of these vitamin C claims were simply false hopes. Turns out the only disease vitamin C cures is scurvy. As I don’t treat many 15th century pirates, it’s not too useful for me.

Vitamin E

NorVitOnce vitamin C supplementation was proven largely useless to prevent disease, the next great hope was vitamin E. Its main claim to glory was as an ‘antioxidant’. Supposedly, vitamin E would neutralize all the nasty free radicals that were causing untold damage to our vascular system. Taking vitamin E would prevent heart disease, we were told. Except, of course, it did nothing of the sort.

The HOPE trial, best remembered now as one of the trials to establish the use of the ACEI class of medication in cardiovascular protection. However, this randomized controlled trial also tested whether vitamin E could prevent disease. Unfortunately, the answer was no.

Vitamin E supplements did not prevent heart disease or stroke. Indeed, more patients in the vitamin group died, had heart attacks and strokes although this was not statistically significant. Vitamin C was a bust, and so was vitamin E. But the list of shame would not stop there.

B vitamins

DIVINeThe next great hope was vitamin B. In the early 2000s, there was a great flurry of interest in a blood test called homocysteine. High homocysteine levels were correlated with increased risk of heart disease. Vitamin B could lower homocysteine levels, but whether this would translate into better health outcomes was unknown. Several large scale trials were launched with this hope. One of these was the NORVIT trial, published in 2006 in the prestigious New England Journal of Medicine.

The news was stunning. Stunningly bad, that is. Compared to taking placebo (sugar pills), supplementation with folate, vitamin B6 and B12 was giving people more heart attacks and strokes. Yes. The vitamin group was not doing better, it was doing worse. But worse news was still to come, if you can believe it.

In 2009, researchers studied the two randomized controlled trials of vitamin B supplementation and found that in addition to raising the risk of cardiovascular disease, the risk of cancer was increased by 21%! Aw snap! The risk of dying from cancer increased by 38%. Taking useless vitamins is one thing, taking vitamins that are actively harmful is something else.

EnrichmentWheatThe use of vitamin B supplements for kidney disease was similarly dismal. The DIVINe study randomized two groups of patients with chronic kidney disease (CKD) to either placebo or vitamin B supplements with the hope of slowing down the progression of kidney disease. Homocysteine levels are high in CKD and the vitamins were able to lower these levels. But did they make any real difference? Sure did. The use of vitamin B made things worse. It doubled the incidence of poor outcomes. Another nail in the coffin of the homocysteine story and vitamin B supplements. Another 10 years of research money wasted.

The ironic part of this flawed knowledge is that we are still paying the price. Enriched wheat flour, for example is wheat with all the goodness extracted and then certain vitamins replaced. So almost all the vitamins were removed, and replaced with huge doses of iron and vitamin B. So what we got was a huge surplus of vitamin B.

Not that I believe this was malicious. People were mostly concerned about nutrient deficiencies like beri beri, iron deficiency anemia and not so much with anything else. The problem, of course, is that we now have data that show that giving large doses of vitamin B may increase rates of cancer and heart attacks.

EnrichmentWheat2But why should vitamin B supplements be bad? After all, folate supplements have reduced the incidence of neural tube defects in pregnancy significantly.

Like everything else in medicine, it’s a question of context. Vitamin B is needed for growth of cells. During growth periods, like pregnancy and childhood, this is a good thing.

The problem is completely different during adulthood. Excessive growth is NOT good. The fastest growing cells are cancer cells, so they potentially love, love, love the extra vitamin B. Not so good for us people.

Even for regular cells, the excessive growth is not good, because it leads to scarring and fibrosis. This could explain the increased risk of heart attacks, strokes and kidney disease.


Calcium1Calcium supplements, of course have been recommended by doctors for decades as a preventative strategy against osteoporosis. I explained everything in this lecture from a few years ago “The Calcium Story“. Almost every doctor has recommended calcium supplements to prevent osteoporosis.

Why? The rationale is that bones have lots of calcium so eating calcium must make bones stronger. This is, of course, the reasoning that a third grader might use, but that’s besides the point. Eating brains makes us smarter. Eating kidneys improves kidney function. Right…. But anyhow, this puerile reasoning lasted for about 50 years.

We pretend that we live in a world of evidence based medicine. Just as we discussed with calories, it seems that evidence is not needed for the status quo, but only for ‘alternative viewpoints’. They finally did a proper randomized controlled trial on calcium supplementation and published it in 2006. The Women’s Health Initiative randomized over 36,000 women to calcium and vitamin D or placebo. Then they followed them for over 7 years and monitored them for hip fractures. Did taking calcium every day for 7 years give women super-strong bones that never crack?

Hardly. There was no difference in total fractures, hip, vertebral or wrist fractures. In other words, calcium supplements were useless. Actually, that’s not true. There was a significant difference. Those people taking calcium had significantly more kidney stones. So, they were actually harmed by taking these pills. Nice. Are these women glad they faithfully took their pills every day for the last 7 years?

The problem with vitamin supplementation

What is the reason why these supplements are not beneficial and mostly harmful? It’s really quite simple. You must understand the root cause (the aetiology) of disease in order to prescribe rational treatment. The diseases that we face today – obesity, type 2 diabetes, osteoporosis, cancer, heart disease etc. ARE NOT VITAMIN DEFICIENCY DISEASES. If these are not diseases caused by a lack of vitamins, why would we expect supplementation to make a difference?

Let’s take an analogy. Suppose our car does not run because the engine has exploded. Somebody then says “Oh, hey, I had a time where our car did not run because it was out of gas. Therefore you should put more gas into the car”. But it doesn’t work. Because you must treat the root cause. The problem was that the engine exploded. I don’t really care how much gas is in the car in this situation.

So, if we are treating vitamin deficiency disease (scurvy, beri beri, osteomalacia) then replacing vitamins is very logical and effective. If we are treating obesity, then replacing vitamins is potentially useless. I don’t worry about nutrient density of foods, because I am not treating a nutrient deficiency disease. However, people love trying to sell you the latest greatest weight-loss supplement (green coffee, raspberry ketones, PGX, fibre, Sensa etc).

If you are asking the question “What can I eat/ take/ supplement to help me lose weight?” then you are going in the wrong direction. The question you need to ask is “What can I NOT eat/take/supplement to help me lose weight?” The money to be made answering the latter question is orders of magnitude smaller than trying to answer the first.

Jason Fung

Disclaimer: At Diet Doctor, we agree with Dr. Fung that supplements are not beneficial for most people. However, we also recognize a role for specific supplements, such as vitamin D or omega 3 fatty acids, when someone struggles to get enough in their daily diet. Since we all have different food preferences and tastes, some of us may fall short on these valuable nutrients. In those select cases, supplementation may be of benefit.

Bret Scher, MD FACC

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Dr. Fung has his own blog at He is also active on Twitter.

His book The Obesity Code is available on Amazon.

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His new book, The Complete Guide to Fasting is also available on Amazon.



  1. Harry
    A "general multivitamin" seems like the worst option: On the surface it sounds like a good method to cover all your micronutrient bases just to be safe. But it likely will give you less than the minimally effective dose of the elements you might be truly deficient in such as vitamin D3 or magnesium in a number of people (plus in an all-at-once combo that could block absorption over the same uptake pathways, e.g. magnesium-calcium-zinc-copper), while also giving you a lot of vitamins and minerals you might not need to supplement already getting enough over your diet. Such as the A-B-C-E vitamins mentioned, or for most men iron unless you are anemic while some women might need more of it. A standard multivitamin isn't expensive, but the upside compared to just eating real food and occasionally supplementing only against a diagnosed deficiency seems very limited.
  2. Valerie
    What about supplementation during an extended fast?
    Can't rely on "just eating real food" in that case.
  3. Adam
  4. Maria
    I've just read that JAMA article 184898, where they found increased risk of cancer. However, the people in scope of this study did not represent the average population. Rather, all participants had ischemic heart disease, so that the results may or may not apply to everybody.
    Also, rather than testing all members of the B vitamins family, only 3 of them were tested.
    To mention the risk increase without mentioning these limitations, is not such a good idea, I think. Also, these high numbers indicate that these figures are relative risks, which makes the risk appear bigger.
    We must certainly be careful not to take each vitamin pill that comes our way, but on the other hand we probably shouldn't immediately stop taking any supplement, if they make the difference between being able to survive this society without being dependent on welfare or not.
  5. Mark Niemchak
    Chemistry vs biology. Pharmaceutical supplements vs nutrients in food. The discussion is far more complex and intricate than you describe. No one would argue the benefits of micro nutrients in food but supplemental micro nutrients brings out the wolves. This is a shades of gray discussion and not a black or white comparison.
  6. Stella
    I am unable to absorb B12 from my food and would get into serious trouble without my sublingual supplement. I'm guessing your article is not addressed to people like me? Otherwise it looks like a choice between severe anaemia/neurological problems and cancer!
  7. Ben
    this article is a missed opportunity to promote Vit D and magnesium, and is a bizarre take on Vitamin C, which supports the ROS load of beta oxidation weight loss. this seems to be the standard take on vitamin status - 'adequate is not optimal', Dr Fung.
  8. Lisa
    I take supplements that include vitamin D3, magnesium malate, a multi and 2 X 300 mg calcium citrate twice daily. I have celiac disease which is a malabsorption and autoimmune condition. I've been gluten free for over 15 years and am in nutritional ketosis. I don't like to take the calcium citrate but I only get about 500 mg from food on average. I've tracked with cronometer to confirm. Without it I found my nails were breaking easily and that has since resolved. My best source of calcium is wild salmon with the bones for which I once eat daily. I don't eat any fortified foods or dairy outside of ghee and butter. Any expert opinions on the calcium for those that have a major dietary shortfall? I'm very conflicted with calcium. I know the negatives with taking it. I'd really appreciate seeing the diet doctor and Dr Fung share their opinion.
  9. Lisa
    I didn't word that well. I take 1 - 300 mg twice daily with a low calcium meal.
  10. Harper
    Here's a 20yr published study showing that users taking multiple supplements had markedly better health biomarkers than the single multivitamin group and the non-supplement group. So, there IS research showing the benefit of supplementation on overall health.
  11. Dana
    In that one study, "Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12," they used folic acid and cyanocobalamin. They only tested for one MTHFR mutation and didn't take heterozygous mutations into account which can also be problematic. I would have been surprised if they *didn't* run into problems.

    Folic acid IS NOT folate. It is a *precursor* to folate, and an artificial one at that.

    Cyanocobalamin is NOT the form of B12 we get from food. METHYLcobalamin is.

    Now if you can show me a study where they experimented with PROPER forms of folate and B12, OK, now you're cooking with gas. But until that happens, I'm going to continue to not worry about it because I'm more careful than the average bear with what supplements I buy. I won't say I'm perfect, I'm probably still missing something, but I do *not* go buy some cheap Centrum thing and content myself that it'll keep me healthy.

    Reply: #12
  12. Dana
    Two Danas agree :)
  13. jeffrey
    I've been in practice for over 40 years in the Chicagoland area so I have a lot of experience with the medical profession. John's Hopkins did a recent study and found that the third leading cause of death in 2016 in the United States was the medical profession. So having an MD after your name means nothing to me other than you tested well in school and you can the prescribe medications to match the patient's symptom. And you get to wear a lab coat. Very impressive. There are computer programs that are far more accurate. Just because they practice within medical standards keeps them safe but are they really helping anyone? Critical and emergency care I can see but when it comes to prevention they suck. When I was first in practice the entire medical profession thought nutrition was basically voodoo. Drugs were the answer to every condition even if it ended up killing the patient. Now they are starting to integrate nutrition and sell vitamins in their practices just to stay in business. What Hypocrites.

    Here is why I posted my letter. Matching drugs to symptoms is easy and we could probably train a monkey to do it but finding the true cause of disease is much harder. I always start with a comprehensive four page blood test. I test for things like B12, Homocysteine, Vitamin D, Ferritin, thyroid antibodies, marine lipids and many more. No offence to the Cochrane data base but they are wrong. Most researchers never get near a patient and yet they run these flawed studies and publish the results. Heart disease remains the #1 cause of death in the US then Cancer and then the Medical Profession. Yes the medical profession is the #3 cause of death in the United States. Why don't we create a forum on that or is that study flawed or irrelevant? I personally think killing patients is a bad thing but I'm a littlie old fashioned. When Vioxx killed all those patients (close to 100,000 that they could find so it was likely far more) that was the risk you take.

    Most medical doctors I know live and die by a lipid panel. If your cholesterol, HDL's and LDL's are within range that's the standard. Statins are supposed to be what will save planet Earth. I'm 66 and never see a medical doctor and why would I. I know more about what biomarkers matter than they ever will so I test myself. Rather than take one of the many statins that are very expensive and usually cause myalgias and arthralgias, I take Red Yeast Rice. I reduced my cholesterol from 277 to 154 in a week. I reduced my triglycerides from 240 to under 132 in a week. I lowered my LDL's from 184 to 85 in a week. Here's the kicker. This was done with ZERO side effects and for pennies a day. This is just ONE EXAMPLE of where nutritional supplements work and with less side effects and for bargain basement prices. I suggest when you make broad statements about how worthless supplements are you think outside the box. I forgot, you can't do that.

    I really liked your site until I wandered into the area where medical doctors wrote opinions about nutritional supplements. I've never killed a patient in my 41 year career and that may be attributed to that I don't use drugs. So when your medical "experts" that received almost no nutritional training in medical school what their opinion is on supplements I have to laugh. You might as well ask a plumber how to fly the space shuttle.

    Reply: #14
  14. Nathanael
    Honestly, Jeffrey, I'm not sure this was the best article all around, but Dr. Fung is best known for reversing diabetes with low carbohydrate diets and fasting - he's one of of the pioneers in this area, in fact, and definitely thinks way outside the box, so this may be an area he's just wrong on - it's probably not the only one, all doctors are fallible - I think the brush you're painting him with is just as broad and unhelpful and I can only assume the comments are made at partially out of ignorance.
  15. John S.
    When on OMAD (one meal a day) how would or should I take supplements that indicate to take twice a day with a meal. I mean should you take the whole dose for the day at one time? Would you still get the benefit or is there a limit to how much your body can utilize or process at one time?
  16. Gina
    Jeffrey, the doctor who left he comment above, is it possible to get contact info on becoming a patient? TIA
  17. Bev J Miranda
    what about taking berberine? Is that a good or bad thing?

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