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Some nutrients in excess can cause health problems in the long run, yet they are found in many or most multi-vitamins.   You should look out for these four.

It’s this reason that I never take multivitamins because they almost always contain at least one of these 4 ingredients.

It makes no difference if you have a whole food multivitamin or not, except maybe for vitamin E.

1) Iron

Most multivitamins don’t include iron, but some do, so look out for it.

Having excess iron can be detrimental in a few ways.  Some people are deficient in iron, but I will discuss why that is.

First, if you have more free iron, you will be more prone to getting sick.  Iron is needed for bacterial growth, making its bioavailability an important factor in controlling infection. Blood plasma, as a result, carries iron tightly bound to transferrin, thus preventing its access to bacteria.  Between 15 and 20 percent of the protein content in human milk consists of lactoferrin that binds iron.  As a result, breastfed babies have fewer infections.  Lactoferrin is also concentrated in tears, saliva and at wounds to bind iron to limit bacterial growth. (R)

I sometimes supplement with Lactoferrin if I am eating too much meat, to bind to the iron and prevent me from.

Second, iron is a significant cause of oxidative stress and excess free iron will increase free radicals, which contributes to aging (R).  Studies in animals have shown that it accelerates aging (R).  Some researchers suggest that women live longer as a result of menstruation.

A UCLA study published in 2013 suggests that iron is directly a significant cause of Alzheimer’s disease, by damaging tissue in the hippocampus (R).

People with higher serum iron concentrations had an increased risk of dying from cancer (R).

Many people with adequate iron intake are still deficient, and I see this sometimes in people with chronic inflammation.

To reduce bacterial growth, plasma concentrations of iron are lowered in a variety of systemic inflammatory states due to increased production of hepcidin which is mainly released by the liver in response to increased production of pro-inflammatory cytokines such as Interleukin-6 (will speak about this guy soon).  Inflammatory Bowel Disease and infections can cause this, but any chronic inflammatory state with elevated IL-6 levels will reduce blood iron levels.

Some menstruating and pregnant women are deficient in iron, but this can easily be remedied by eating red meat. Many times the deficiency is as a result of a lack of B12, Folic acid, vitamin C, Vitamin A or more rarely a lack of copper (R).

Gastric acid plays an important role in iron absorption from plant foods (R).

Otherwise, GI disorders, blood loss or parasites can also explain iron deficiency.

Many supplements such as carnosine, resveratrol, curcumin, tea and coffee bind to iron.

If you are concerned about iron deficiency then take a blood test.  Ferritin levels under 20ng/ml indicate an iron deficiency.  If you are deficient and don’t want to consume animal products, only then would I suggest supplementing with iron.

2) Copper

Copper is in the vast majority of multivitamins and for the past 5 years, I’ve made sure not to buy supplements with copper in them.  You shouldn’t either.

Copper can be found in more than adequate levels no matter what your diet.

You will especially have very high levels in plant-based diets because phytate increases the absorption of copper and pretty much all plant-based foods and rich in copper.

Like iron, copper is a significant cause of oxidative stress and increased free copper will increase free radicals, which contributes to aging (R).

People with higher serum copper concentrations had an increased risk of dying from cancer (R) and increased risk of Alzheimer’s (R) and cognitive decline in aging (R).

Part of the reason why Carnosine is beneficial is because it binds to copper (R).

There’re hundreds of studies linking copper to neurodegenerative diseases.

Sometimes I wonder if the supplement manufacturers are living under a rock because the research is ubiquitous. What’s more likely is they are just releasing products that people want and people like to see more vitamins and minerals in their supplements.

3) Manganese

It’s pretty much impossible not to get enough manganese, as it’s in all foods and in dosages that are much higher than the RDA requirements.

Almost all plant-based foods I’ve seen are rich in manganese, even refined and processed foods.  Herbs and spices also have manganese.  The water we drink has manganese.  Vegetable and fruit juices are usually loaded with manganese, with the dosage varying depending on the juice.   A slice of whole wheat bread has 30% of the required manganese,  while white bread has 7%.    Animal products aren’t rich in manganese, but no one lives solely on animal products and they still have manganese.

In the U.S., estimated average dietary manganese intakes range from 2.1-2.3 mg/day for men and 1.6-1.8 mg/day for women, which matches the adequate intake for these groups from all sources. People eating vegetarian diets and Western-type diets may have manganese intakes as high as 10.9 mg/day, which is the upper limit from all sources (R).

The thing is we get manganese from other sources, so we shouldn’t be worried that we’re not getting enough. Manganese is all over the place and we even breathe it in (toxicity is most common from the air).

A study of older adults in Greece found a high prevalence of neurological symptoms in those exposed to water manganese levels of 1.8-2.3 mg/liter (R), while a study in Germany found no evidence of increased neurological symptoms in people drinking water with manganese levels ranging from 0.3-2.2 mg/liter compared to those drinking water containing less than 0.05 mg/liter (R).

So 2mg per a liter may give people neurological symptoms.  Most people don’t drink much more than a liter of water a day.  Guess how much most multivitamins contain? 2mg.

There are hundreds of studies showing manganese can cause toxicity and a host of neurological problems, but most of the studies deal with acute toxicities from work-related incidents and not chronic ingestion of elevated manganese throughout a lifetime.  We should be worried about elevated chronic exposure because the stuff accumulates in our brains.

It is thought that chronic exposure throughout a lifetime may contribute to Alzheimer‘s and Parkinson’s, just as lead and mercury can (R).  Interestingly, Amyloid protein genes were upregulated in mice exposed to higher levels of manganese.

There have been recent studies showing negative impacts of manganese exposure within the safety limit.  

For example, a study from 2006 showed that such exposure within the safety limit decreased dopamine production in primates (R).

Manganese obviously has a lot of important roles in the body, such as forming antioxidant enzymes (MnSOD), but we’re more than fine getting the recommended levels that most of us are getting through our diet.

I don’t want to be an alarmist, as I think people don’t have to be overly concerned about this, but taking a multivitamin with manganese is simply a bad bet for your health.

4) Vitamin E

First, I’d like to say that the supplement warrior Paul Offit is a religious and unskeptical zealot, like the rest of the science-based medicine crew.  They are selectively skeptical but religious in their own ideas.

These people had a field day with trashing all supplements because studies have found that one form of vitamin E isn’t good in some ways when megadosed.   They conclude from this that all dietary supplements are bad and should be regulated. I’m not making this up.  This supposedly skeptical organization committed the most basic of logical fallacies.  That is if one particular antioxidant isn’t good in some ways in mega dosages, anything that has antioxidant properties is bad and furthermore since some supplements are antioxidants, all supplements are bad and should be regulated as drugs.  And these people parade around as “skeptical”…You can’t blame me for losing hope in human rationality. For a more nuanced approach, watch this video.

Anyway, studies have found that very high dosages of vitamin E increase prostate cancer risk among healthy men by 17% (R).

Meta analyses found that high dosages of vitamin E increase all-cause mortality (death) (R).

The problem is most multivitamins contain these mega-dosages of vitamin E that have been found to be harmful.

On the upside, another study in 2013 found that participants receiving vitamin E had slower functional decline than those receiving placebo, with the annual rate of decline reduced by 19% (R).  However, given the increased mortality, other forms of antioxidants are better suited to protect against Alzheimer‘s.

The explanation of harm is that alpha-tocopherol displaces other forms of vitamin E when taken in very large dosages.

Many of us don’t get enough vitamin E, however.  So a reasonable solution is to do what I do.  I put one capsule of Vitamin E in a container of 17 servings of a powder of your choice.    You can put it in a salt jar if you prefer or anything that you use slowly over time.

The conclusion about vitamin E doesn’t hold once you take a full spectrum vitamin.  The problem is almost all multivitamins contain mega doses of just alpha-tocopherol.

I still don’t suggest taking mega dosages, but I’d be comfortable with higher dosages if it’s a mixed vitamin E.

5) Folic Acid

Studies on folic acid are mixed.  Folic acid is the synthetic version of vitamin B9 and isn’t found in food.

Some studies indicate an increased risk of cancer and overall death rate (R, R2, R3).

However, 2 meta-analyses found no increased risk of cancer, cardiovascular disease or overall death rate (R, R2).

I would advise people with the MTHFR mutation and methylation issues to stay away from folic acid and instead consume folinic acid or MTHF.  A quarter of a pill of the suggested supplement or 200mcg is more than enough for most people to ensure adequate intake.

Which Vitamins And Minerals Do I Support Supplementing With?

The vitamins and minerals that I support supplementing with are zinc unless you eat loads of meat and magnesium if you don’t consume a plant-based diet.  I recommend chromium only if people have issues with glucose control. Zinc and magnesium have benefits at levels higher than the RDA.  Another nutrient that you should supplement with is iodine if you’re not eating seaweeds or consuming plenty of iodized salt.

Most people would benefit from iodine, zinc and magnesium supplements at reasonable dosages, but not everyone.  All three are critical for normal cognitive function.  I had a zinc and iodine deficiency even with consuming a normal diet.  I didn’t consume iodized salt…I take all 3 nutrients.

I use 4.5g Magnesium Calm (350mg elemental Mg) before bed as a sleep aid and mix it with 300mg of elemental Calcium because I don’t eat dairy.

If you don’t eat dairy you will very likely be deficient in calcium, so make sure you’re getting the RDA for that. Realize that dairy isn’t optimally healthy for most people. If you take calcium, don’t take more than 300mg at a time (or you may increase your risk for atherosclerosis).

Most people with normal diets aren’t deficient in B vitamins, but dosages over the RDA can be beneficial.

Potassium deficiency is actually quite common.  If you don’t have a plant-based diet you will be deficient.  I use Potassium gluconate because I’m sensitive to lectins.  I know I’m not getting enough potassium when I start getting muscle twitches.  Consuming potassium rids the issue in a half hour.  Beware of taking too much potassium at once, as it can cause intestinal bleeding. 500mg of elemental potassium at a time is perfectly safe.

Potatoes, avocados, bananas, and legumes are good sources of potassium (of which I only consume avocados and tempeh).

Some people are deficient in vitamin A, vitamin C and vitamin E. If you eat even moderate amounts of fruits and veggies you’ll be fine with vitamin A and C.  I had a hard time getting adequate vitamin E on some days if I didn’t consume enough nuts and seeds.  To give me peace of mind, I take one pill of vitamin E that has ~1300% of the RDA and put it in my nutritional yeast container, to ensure I get all of the vitamin E I need.  I also put a gram of vitamin C in there.  Vitamin A is abundant in Cod liver, leafy greens and other foods, so there’s no need for supplementation (not for me at least).

Vitamin K1 is important if you don’t eat ANY veggies. If you eat even a small amount of lettuce a day, you’re fine. Dosages higher than normal of K1 can be beneficial, but just eat more leafy greens rather than supplementing

I take vitamin K2 once every 3 days about -not because of deficiency, but because it has many benefits in dosages more than we need.  This has K1 as well, so you’re getting more than enough of it.  Since it’s fat soluble, it’s fine to take it once every 3 days.

If you don’t get sun 2000iu Vitamin D3 daily is a must or a UVB light (use with care).  I get  30-60 minutes of full body sun most of the year, so I don’t take it.

You’ll need Fish oil  only if you don’t consume fish at least 2-3X a week.  Supplementation can be therapeutic for many conditions, even if you consume fish, but if you’re healthy then there’s no serious need.

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  • Maddy

    Joe – I know vitamin K is fat soluable, and generally these vitamins are stored…but there is info out there on multiple sites which says K cannot be stored and must be supplied every day. Thoughts?

  • Átila Firmino

    What you said about vitamin E is not whole truth, the solution is take mixed vitamin E complex, eat pecan also you give you more gamma tocapherol.

  • Dave Clark

    Niacinamide? There are as many pro as con articles on that vitamin. Been used safely for years.

  • Rohit Sahdev

    Agreed. Also i have found copper in 3 – 4mg in elderly improves arthritis and memory. Copper can help in formation of new blood vessels. Especially when taking zinc, copper is needed as well. Also manganese in higher doses is helpful for seizures and for joint pain.

  • D

    Pure Encapsulations Multi t/d contains none of the minerals you list (iron, copper, manganese), and it contains Metafolin (not folic acid) and 100 IU of vitamin E (d-alpha tocopherol succinate). It’s chromium level is a bit under RDA, and no vitamin K.

  • Cas

    Do you have an update on this topic with your 2016 thinking? Thanks.

  • Ahmad Awadallah recent had an article basically saying that fish oil is useless according to the DART research. What are your thoughts

    1. MachineGhost

      “It is possible that fish oil has health benefits that scientific experiments are not sensitive enough to detect.

      Most trials have focused on the effects of fish oil on people who have had a history of heart trouble. The trouble with those studies is that such patients are typically taking an array of heart medicines, such as statins, blood thinners and beta blockers. It is possible, scientists say, that the effects of the fish oil can’t be detected among the effects of the other medicines.”

      Look at all those confounding variables on top of the blind leading the blind. Fish oil isn’t even the proper way to deal with CVD. This is why you should stop reading make-ruckus hit pieces in the mainstream media.

    2. MachineGhsot

      BTW, copper and manganese are critical for endogenous SOD formation as well as detoxing iron. So I wouldn’t consider them avoidable now except in excess (as with anything). The stuff about manganese being a neurotoxin was from injecting it directly into the brain and bypassing the BB barrier. You do need to add niacinimide to the list; it is toxic and accumulates in the cells acting as pro-aging mechanism.

      1. Joseph M. Cohen

        I agree, you want to have a balance of copper and manganese

        1. steve

          Joseph, I don’t believe Machineghsot’s comment was addressed by your response. Manganese was only found neurotoxic when injected directly into the brain, which is nothing like eating it in food or as a supplement.

          So, manganese shouldn’t be described as “neurotoxic”.

          You could inject organic wheat grass juice into the brain and it would be neurotoxic, that is far different from eating it: so…let’s not trash manganese by looking at that poorly done study.

  • Dan

    While I agree that unbound iron and copper are harmful, not everyone can get enough from food. Copper can easily drop too low by taking zinc and vitamin c (this happened to me). Iron, as measured by ferritin should be at least 50ng/dl, but optimally mid-range 100-200ng/dl. Under this minimum, you risk dopamine and thyroid dysfunctions.

    1. Joseph M. Cohen

      How much zinc did you take? Iron causes oxidative stress and is associated with aging. Ideal should not be between 100-200, unless you have some other bodily disfunctions. Between 100-200 is normal, but not necessary for most people, IMO.

  • Ahmad Awadallah

    People with thalassemia trait are recommended to take folic acid. Should they instead take Folinic Acid?

    1. Joseph M. Cohen


  • dan

    I occasionally have (despite my best wishes) large amount of beef while having too much iron in my diet already from spices, pea , clay , sardines, etc. can I take Lactoferrin despite being sensitive to lactose and casein?

  • MachineGhost

    Joe: I’m surprised you haven’t yet caught on to the fact that nutritional yeast is as neurotoxic as manganese; it is MSG in disguise and made by the same chemical processors. Before I wised up, I used to take it daily and really loved the excitotoxicity high from my brain cells dying off, especially in vegan macaroni and cheese. Two decades or so later, I now get excruciating headaches even from 1/8th of a teaspoon (as well as the whole plethora of hidden MSG in foods). And finally, the B vitamins in nutritional yeast are synthetic (including folic acid) and sprayed on if the amounts are over the RDA.

    Another ingredient that belongs on the avoid list are the carotenoids and xanthophylls. They cause the lipid bilayer to literally oxidise. Only astaxanthin does not feature this negative property which is probably why its such a great anti-radiation internal sunscreen. No matter what, any naked sunlight exposure causes photoaging skin damage, increased risk of DNA transcription errors due to base pair mutation, and this includes UVA, UVB, UVC and now even infrared. Here’s a wakeup call:

    Ahmad: Krill oil has an affinity for the joints unlike fish oil. So it is best that both are taken, not just one or the other. Make sure you take a high DHA, triglyceride-based which is a true fish oil.

    1. Joe

      Studies to support your assertions on N yeast being neurotoxic and krill oil having an affinity for joints?

      1. MachineGhost

        I don’t know if there are studies with nutritional yeast per se, but there’s enough on MSG and free glutamic acid that nutritional yeast and other MSG analogs contain. The undisputed master on neurotoxins is Dr. Richard Blaylock so see if his two books have references?

        Mike: I find a lot of the vegetarian foods, or so-called health foods, use yeast extracts.

        Dr. Blaylock: The worst of the things they’re doing are the soy extracts. Soybeans, naturally, have one of the highest glutamate levels of any of the plant products. When you hydrolyze it, you release the glutamate, such as with the soy protein isolates. The glutamate levels are higher than a lot of what you’ll find in other MSG-contaning products, yet the vegetarians are just eating it like it’s the healthiest thing in the world. There was a 25-year study done, which looked at people who consumed the most soy products, and they followed them for 25 years and did serial CT scans of their brain. They found out that the people who consumed the most soybean products had the greatest incidence of dementia and brain atrophy.

        These people are destroying their nervous system, and I talked to a lot of them who complained of severe migraine headaches. I said, “Get off the soy,” and they do, and that migraine headache goes away. In addition, you have very high manganese levels, which is toxic to the very same part of the brain that produces Parkinson’s . You’ve got a mixture of toxins with soy products, and the people think they are eating a healthy, nutritious product. It’s destroying their nervous system, as well as other organs.


        As for krill oil and joints:

        Krill works by different biochemical mechanisms than fish oil which is more of a general inflammation reducer in the blood. My own anecdotal evidence also validates the superiority of krill oil for joint pain. I’ve never been impressed with any fish oil, triglycerides or not.

    2. Ahmad Awadallah

      Thanks MG.

  • dan

    How much N yeast do you take daily on average?

    1. Joe

      1 serving a day

  • Ahmad Awadallah

    I take Krill oil instead of fish oil. My understanding is that it is better absorbed/utilized by the body, cleaner (because krill are tiny and much harder to accumulate toxins and heavy metals), and much harder to exhaust/kill them as they are the largest biomass on earth.
    I just wanted to get your take on Krill oil.

    1. Joe

      Overhyped. Studies comparing the two?

      1. Ahmad Awadallah

        I mainly got it from Dr. Mercola’s website. I was really just asking your thought about it. BTW, what are your thoughts on Dr. Mercola?

        1. Joe

          Mercola is a moron.

          1. Ahmad Awadallah

            So tell me how you really feel about him… LOL!

            reply icon
      2. MachineGhost

        Krill oil is not overhyped. It’s essentially liposomal fish oil so of course the bioavailability is superior (dose equivalence is about 2.2 odds ratio). But on the other hand, comparing krill oil against the poor bioavailability of ethyl ester “fish oil” is perhaps a bit unfair. Here’s some comparison studies:

        I wouldn’t make this a black and white situation; just take both krill oil and DHA triglyceride-form oil. Reducing Omega-6 is far more important than upping Omega-3 since too much of either Omega’s reduces lifespan.

        1. MachineGhost

          I no longer advocate solely DHA. EPA only is the way to go for 3-6 months to reduce the Omega6 to Omega3 ratio. Then a 2:1 EPA to DHA ratio to maintain cell membrane integrity. DHA negates out an equivalent amount of EPA during absorption and also kicks it to the crub for membrane incorporation.

  • daz

    folate/folic acid is another one to avoid.
    unless it is 100% from the l-methylfolate form (aka 5-MTHF etc.) which would be rare in a multi (more expensive). if it does use methylfolate, one of the methylfolate names will be explicitly listed.

    1. Joe

      Only if you can’t metabolize it or in high dosages.


      1. daz

        “Only if you can’t metabolize it or in high dosages” you could be right…a methylation/gene ‘thing’.

        Jaminet discusses folic acid supplementation a bit in his books & on his web site. & links to studies on his web site here . i grabbed some relevant ones.
        I have not read these studies myself.
        ‘Dietary supplements and mortality rate in older women: the Iowa Women’s Health Study’
        ‘Folic acid and risk of prostate cancer: results from a randomized clinical trial’
        ‘Colon cancer in Chile before and after the start of the flour fortification program with folic acid’
        ‘Does a high folate intake increase the risk of breast cancer?’
        ‘Cancer incidence and mortality after treatment with folic acid and vitamin B12’
        ‘Effect of B-vitamin therapy on progression of diabetic nephropathy’
        ‘Folic acid supplementation dysregulates gene expression in lymphoblastoid cells–implications in nutrition’
        ‘Methylation variation at IGF2 differentially methylated regions and maternal folic acid use before and during pregnancy’

        1. Joe

          Thanks. I will review this subject more in depth. Cancer is the major issue here… But a 2013 meta analyses in the Lancet has more weight than the studies you cite:

          In these meta-analyses, we sought all trials completed before 2011 that compared folic acid versus placebo, had scheduled treatment duration at least 1 year, included at least 500 participants, and recorded data on cancer incidence. We obtained individual participant datasets that included 49,621 participants in all 13 such trials (ten trials of folic acid for prevention of cardiovascular disease [n=46,969] and three trials in patients with colorectal adenoma [n=2652]). All these trials were evenly randomised. The main outcome was incident cancer (ignoring non-melanoma skin cancer) during the scheduled treatment period (among participants who were still free of cancer). We compared those allocated folic acid with those allocated placebo, and used log-rank analyses to calculate the cancer incidence rate ratio (RR).
          During a weighted average scheduled treatment duration of 5·2 years, allocation to folic acid quadrupled plasma concentrations of folic acid (57·3 nmol/L for the folic acid groups vs 13·5 nmol/L for the placebo groups), but had no significant effect on overall cancer incidence (1904 cancers in the folic acid groups vs 1809 cancers in the placebo groups, RR 1·06, 95% CI 0·99–1·13, p=0·10). There was no trend towards greater effect with longer treatment. There was no significant heterogeneity between the results of the 13 individual trials (p=0·23), or between the two overall results in the cadiovascular prevention trials and the adenoma trials (p=0·13). Moreover, there was no significant effect of folic acid supplementation on the incidence of cancer of the large intestine, prostate, lung, breast, or any other specific site.
          Folic acid supplementation does not substantially increase or decrease incidence of site-specific cancer during the first 5 years of treatment. Fortification of flour and other cereal products involves doses of folic acid that are, on average, an order of magnitude smaller than the doses used in these trials.

          Another meta-analyses in 2010
          Dietary supplementation with folic acid to lower homocysteine levels had no significant effects within 5 years on cardiovascular events or on overall cancer or mortality in the populations studied.

        2. Joe

          I read through your studies and most are pretty weak for different reasons. You still have those 2 meta analyses that differed…. My conclusion is you don’t want to get too much of it, surely, but most multis don’t mega-dose folic acid. Be careful if you have the mutation. Maybe I’ll add it as a fifth, but I need to do more research before I do.

      2. daz

        “Only if you can’t metabolize it or in high dosages”
        i should have broken my reply to that in to two parts. ie;

        “Only if you can’t metabolize it…” you could be right…a methylation/gene ‘thing’.

        “…or in high dosages” agreed

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