5 Common Nutrient Deficiencies (and What to Do About Them)

If the Primal way of eating is so healthy, why am I writing a post on common nutrient deficiencies? Well, mostly because you asked. For months now, I’ve received emails from Mark’s Daily Apple readers asking about iodine, selenium, magnesium and other vitamins and minerals, so I figured it’s about time to highlight these key nutrients, explain how and why some people find themselves deficient and provide my opinion as to what they can do about it.

I also wrote this article to make the point that quitting grains, legumes, seed oils, and sugar is just part of the equation. There’s a whole lot more to healthy eating than just deciding what not to eat. You also have to be mindful of the things you do eat, and – hopefully – those things will be incredibly nutritious.

Consider this post your guide to avoiding some of the most common nutrient deficiencies. Let’s jump right in…


Iodine is a trace mineral with big implications for our health, especially of the thyroid. Although most assume deficiency is relegated to developing nations, recent research has found deficiency in places like the UK and France.

Deficiency Symptoms

  1. HypothyroidismIodine is a crucial ingredient in thyroid hormone, so a lack of iodine in the diet will reduce the thyroid’s ability to manufacture thyroid hormone. Symptoms of hypothyroidism include weight gain, an inability to lose weight, fatigue, elevated blood lipids, hair loss, dry skin, loss of libido, infertility, to name a few.
  2. Goiter – In an iodine-deficient state, the thyroid gland will enlarge in order to overcompensate. This will often result in a highly visible lump in the neck.
  3. Cretinism – Iodine deficiency during pregnancy often results in abnormal neurodevelopment and lowered IQ (PDF) in the child.

Why Might Deficiency Occur?

  1. Removal of iodized salt from the diet. Most table salt is iodized with the minimum required dose, but when people switch to a whole foods, Primal eating plan, they’ll often reduce their salt intake and switch to sea salt (which contains trace minerals but insignificant amounts of iodine).
  2. Lack of iodine in the soil. Although iodine concentration remains pretty constant throughout the ocean, iodine content of soil varies dramatically by region, with some areas having so little that they’ve earned the term “goiter belt.” Coastal areas tend to have higher soil iodine levels, due to absorption from atmospheric iodine (which in turn comes from the ocean), but very little solid data exists on the iodine content of soil by region.
  3. Insufficient intake of iodine-rich foods, like seaweed and seafood.
  4. Excessive intake of goitrogen-rich foods, which interfere with iodine uptake by the thyroid gland. This, then, isn’t a true whole-body deficiency, but rather an inability of the thyroid to get the iodine it requires.

Where to Get It

  1. Eat seafood, fish, shellfish, crustaceans, and basically any creature that lives in the ocean. Iodine content of fish varies, but you can get an idea from this Japanese analysis of commonly eaten fish. Looks like pollack, codfish, and abalone rank highest, but there are lots of good sources. Cooking method will also determine iodine content, with boiling losing the most and frying retaining the most (PDF). Grilling retains far more iodine than boiling, and just a little less than frying, so that’s probably a nice middle ground between boiling and fish sticks. Iodine in the boiling water, however, accounts for most of the lost iodine, so you could do something with the water. Raw seafood will retain the most iodine.
  2. Eat seaweed, especially hijiki and kelp (or kombu). Drop a dried strip in your next pot of soup, chili, or curry, or, better yet, put several strips in your next batch of bone broth along with the bones.
  3. Eat pastured egg yolks (PDF). Although the specific amount depends on the dietary iodine of the laying hen, if there’s iodine in the diet, it’ll show up in the yolk. After all, chicken baby brains need iodine just as much as human baby brains.
  4. Supplement. Popular ones include kelp supplements, Lugol’s solution, Iodoral, and Iosol.


RDA is 150 micrograms. Seaweed-eating Japanese populations often get upwards of 12.5 milligrams (or 12,500 micrograms) per day, while the general Japanese population gets beween 1-3 mg per day. 150 mcg should be the bare minimum, and if you’re feeling any of the deficiency symptoms, consider increasing your intake. Paul Jaminet recommends starting low (500 mcg/day) and slowly increasing intake by doubling every month. As I mentioned here, you’ll also want to make sure you’re getting enough selenium (see below) before increasing iodine intake. If you stick to food sources, you’re not in much danger of going overboard.


While severe selenium deficiency in adults is pretty rare, minor deficiency is easy to get and can have some unpleasant effects on our health.

Deficiency Symptoms

  1. Selenium supports efficient thyroid hormone synthesis and is required for the conversion of thyroid hormone T4 into the active T3, so a selenium deficiency can manifest with hypothyroid symptoms (see above).
  2. Selenium deficiency symptoms look an awful lot like the side effects of statins, especially muscle damage and polyneuropathy.

Why Might Deficiency Occur?

  1. Lack of selenium in the soil. Lack all other minerals, selenium must be present in the soil to show up in the food. It isn’t created out of thin air. If you’re in the United States, this map should give you an idea of how much selenium is present in soil near you (or, more importantly, wherever your food is grown).
  2. Insufficient intake of selenium-rich foods.
  3. Intestinal disorders, like Crohn’s disease, ulcerative colitis, and celiac, can reduce the absorption of selenium from foods.

Where to Get It

  1. Brazil nuts (one or two a day are enough to improve selenium status), wild salmonkidneys, crimini and shiitake mushrooms, lamb, turkey, shrimp, cod, halibut, and egg yolks are all good sources of selenium.
  2. Supplement. Selenomethionine is the form found in plants, while selenocysteine is found in animals.


200 mcg appears to be the safe supplemental dose, but there’s very little evidence of selenium toxicity from a diet high in selenium rich foods, so that Brazil nut-encrusted salmon kidney in shiitake/crimini mushroom sauce with a turkey egg omelet should be safe.


Ah, magnesium. Everyone touts its importance, and yet few seem to get enough through diet. In fact, most research suggests that only around half of US adults reach the RDA, with low intakes being linked to type 2 diabetes, metabolic syndrome, osteoporosis, heart disease, asthma, and colon cancer.

Deficiency Symptoms (Just Some of Them)

  1. Insulin resistance.
  2. Constipation.
  3. Migraines.
  4. Restless leg syndrome.
  5. Cramping.
  6. Hypertension.
  7. Fibromyalgia.

Why Might Deficiency Occur?

  1. Lack of magnesium in the soil. US readers, check out this magnesium soil content map (similar to the selenium soil map) to see how you do.
  2. Lack of magnesium-rich foods in the diet, particularly plant foods. Animal foods are relatively magnesium-poor, while plants tend to be magnesium-rich. How many people do you know who really eat lots of leafy greens? Both Primal and SAD eaters are therefore at risk.
  3. Removal of magnesium from drinking water. I suspect magnesium-rich water (as opposed to purified, depleted modern water) was how Grok got a lot of his magnesium.

Where to Get It

  1. Leafy greens, especially swiss chard and spinach.
  2. Nuts, seeds, dark chocolate, espresso, and halibut.
  3. Mineral water. One brand, Gerolsteiner, is particularly high in magnesium. Or you could find a spring nearby for some real (free) spring water.
  4. Supplement. The chelated magnesiums (those ending in “-ate,” like citrate, glycinate, or taurate) tend to be the best absorbed. You can also apply magnesium oil topically for transdermal absorption. In my experience, transdermal magnesium absorbs best on the rib cage and inner arms (you’ll know from the tingling and the vivid dreams).


400 milligrams daily is the minimum, I’d say. Aim to get it from food if possible.

Vitamin K2

Most people haven’t even heard of vitamin K2. Is it any surprise that they might be a bit deficient, too?

Deficiency Symptoms

  1. Tartar buildup on the teeth, and eventually tooth decay.
  2. Osteoporosis.
  3. Arterial calcification, and maybe heart disease eventually.

Why Might Deficiency Occur?

  1. A total lack of knowledge of the vitamin’s existence. If you don’t know about it, you can’t go out of your way to obtain it.
  2. A lack of vitamin K2-containing foods in the diet. Even if we’re aware of K2, it’s available only in select foods.
  3. A lack of vitamin K-containing foods in the diets of the animals we eat, thus giving them nothing to convert to vitamin K2 via gut fermentation. Cows raised on pasture are able to convert the vitamin K1 in grass to vitamin K2; cows without access to pasture will have very little K1 to convert.

Where to Get It

  1. Food. For the animal form, MK-4, you need to eat pastured yolks, goose liver, grass-fed butter, aged cheese, and fish eggs. For the vegetable form, MK-7, natto – the traditional (and sticky) Japanese fermented soybeans – is your best bet. Of course, we don’t know exactly how much K2 is in any of these foods without extensive testing, and none of the online nutritional databases include vitamin K2 in their analyses. Therefore, the safest route is the one that involves eating lots of the aforementioned foods (tough, huh?).
  2. Food-based supplements like high-vitamin butter oil.
  3. Straight-up supplements, like Thorne MK-4 drops or Life Extension, which has both Mk-4 and Mk-7.


It’s tough to say. Studies on osteoporosis and heart disease use rather large doses (45 mg/day) without ill effect, but the amount you’d get from food is far lower – maybe 1 mg, max.

Vitamin B12

According to Chris Kresser, vitamin B12 deficiency is quite common, even among those who eat plenty of the richest source of B12: animals.

Deficiency Symptoms

  1. Lethargy.
  2. Unwanted weight loss.
  3. Dementia/Alzheimer’s-like symptoms.
  4. Anxiety and depression.
  5. Autism spectrum disorder in children.

Why Might Deficiency Occur?

  1. We aren’t looking for it. As meat-eaters, we assume we’re getting plenty, and doctors don’t check for it regularly.
  2. We aren’t absorbing the B12 in our food. Gut disorders like Crohn’s or diarrhea affect our ability to absorb nutrients, minerals, and vitamins, including vitamin B12.
  3. We set the bar for “normal” too low. Everything could check out and look fine on paper, but the lower end of “normal” is too low and can still cause B12 deficiency symptoms. Other countries, like Japan, have higher “normal” B12 markers and fewer cases of Alzheimer’s/dementia.

Where to Get It

  1. Animals. Liver, sardines, and salmon rank highest, with liver running away with it. There are no vegetarian sources.
  2. Supplements. Methylcobalamin is probably the best.


If you eat animal products regularly and liver occasionally, you’ll be getting plenty of B12 in your diet. No need to supplement if you have none of the symptoms listed above. But if you have some of the symptoms, or you have a gastrointestinal disorder that may be compromising your ability to absorb vitamin B12, consider getting your levels tested during your next visit to the doctor. In that case, Chris recommends 1 mg/day of sublingual methylcobalamin, which will bypass the intestinal tract and pass directly into the bloodstream.

Do any of these sound familiar? Are you getting enough of these nutrients? I hope so, and if not, now you know how. And if there are any other nutrients you’ve been wondering about, let me know in the comments and maybe I can get a sequel going. Thanks for reading, folks.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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173 thoughts on “5 Common Nutrient Deficiencies (and What to Do About Them)”

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  1. I’ve found magnesium before bedtime makes me sleep deeper.

    1. That’s the understatement of the year for me. When I take magnesium it feels like I have been darted in the neck with a horse tranquilizer. Does this mean I am taking too much or am I severely deficient?

      1. I do not know. What is the dosage and how frequently do you take it? If you were to change the times you take Mg, say in the AM or midday as opposed to night time, does Mg have the same affect?

        1. I take 250 mg. Not every night, but when I can remember (maybe 4 times a week). When I take it during the day, it just makes me feel a little more relaxed. At night time it just puts me immediately to sleep.

      2. It means you’ve flooded your muscles with magnesium, overwhelming their capacity to metabolize it, and they relax like you’ve had a good massage (or more). The muscles can increase their capacity to metabolize magnesium over time. But I like Mark’s advice, because we simply don’t know how much of the mineral we absorb from pills. Studies have shown that we absorb 40-70% of the magnesium from foods, though.

  2. does taking a bath with Epsom Salt(magnesium sulfate) count for transdermal absorbtion?

    1. Yes. Dr. Atkins’ “Vita-Nutrient Solution” indicates that many of the magnesium supplements do not provide bio-available magnesium, and that Epsom salts are actually a preferred method of increasing your intake.

      1. That’s good, I like to soak my feet in Epsom Salt bath after sports. Orchids like it too – give your orchids Epsom Salt-water every week in September for the next blooming season.

    2. Not according to Mark Sircus’ research, the sulfates are excreted quickly.

      1. This is interesting — I’ve never heard of this literature. Can you post citations or links, please?

    3. Sort of. Epsom salts will relax the muscles by flooding them with Mg., but the form of Mg in the salts isn’t well-absorbed by the body.

  3. Mark, what’s your take on the effectiveness of dessicated liver tabs? Are they as good as eating liver?

  4. After reading several places that magnesium in its various salts is absorbed readily through the skin, and not particularly efficiently in the digestive tract, I figured epsom salt baths occasionally might help maintain magnesium levels.

    At any rate, it’s a great excuse to have a nice soak a few times a week. 😀

    As for iodine, I don’t really want iodine-free “sea salt” when I have sea salt, I want “concentrated ocean”. So I always have a shaker of kelp granules next to my salt grinder. Still waiting to see coarse sea salt that has been enhanced with kelp or even krill, and maybe “sea minerals” 😛

    1. Have been looking for kelp seasoning/granules with no luck. What brand and where have you found yours? Thanks for the information.

      1. Maine Coast Sea Vegetables,sold at Whole Foods (in massachusettes, at least) used to have a shaker with kelp granules (and dulse or nori, too).
        It was called “sea seasoning”.

      2. FYI: iHerb also sells one called Maine Coast Sea Vegetables, Sea Seasonings with Sea Salt, Kelp & Dulse

  5. What is your opinion of B12 shots? They offer them to us at work but I’ve heard they could have high levels of mercury in them.

    1. Straight from docctoryourself dot com I’ve read that you should crush up aB12 sublingual tab between two spoons, add a drop of water, make a paste and apply transnasally. No joke. Absorption thru the nose is proven the best way. Doesn’t burn or hurt.

  6. Please note that the body can adapt to a lower iodine intake. You can damage your thyroid by suddenly upping your iodine intake. Proceed with caution.

  7. Vitamin K2 (menaquinone) is in pretty much any fermented food, since it is made by bacteria.

    1. Yes, but if this is like natto, it’ll be mk-7, and what you really need is mk-4, which is the form of K2 that crosses the placenta in a human pregnancy–stands to reason it’ll be needed in adults as well.

      It is known that a lack of K2 in the body during a pregnancy will result in a child with birth defects involving the middle third of the face. This is why women on coumadin (an anti-clotting drug) are advised not to get pregnant, aside from the usual risks of being pregnant and unable to clot blood. But we’re talking about development here, and there’s a range of possible outcomes that could occur in a child. We are seeing a LOT of kids growing up now with the need for orthodontic intervention and too little horizontal development in their faces. That all comes down to a lack of development in the maxilla. That’s governed by K2.

      This in an environment in which Americans are increasingly being told to avoid animal fats, particularly things like full-fat cheese, and in which the animal foods available to us in the first place are lower than normal in K2 availability. Scary situation.

      1. Actually, the research suggests that both MK4 and MK7 forms are useful. Eating fermented foods like saurkraut and cheese for MK7, along with eggs, butter and liver for MK4 is a good way to cover your K2 bases. When it comes to supplementation (other than the High Vitamin Butter Oil), I’ve seen MK7 recommended over MK4, as a small dose will last longer in the body, and be more effective. Check out Freetheanimal.com for Richard’s take on K2, it is extensive.

    1. Unfortunately they also give you a ton of sugar and caffeine too, and usually plenty of other garbage.

    2. It’s cyanocobalamin, which is not the form of B12 the body prefers and can possibly interfere with methylcobalamin production.

      It is frustrating to me that no multivitamnin that I know of contains methylcobalamin–no, wait, I think I have found one so far. There are a LOT of companies selling multivitamin supplements–it’s irritating to me that I’ve only been able to find one company that uses the right B12. I have taken to supplementing B12 separately to get the methyl version, and that’s kind of depressing that I have to spend extra. In particular I give it to my daughter (they don’t put methyl B12 in kids’ vitamins either) because it’s all I can do to get her to eat meat. We live in an area with a high vegetarian population and they’re quite vocal about their choices, which doesn’t help. 🙁

      1. Absorption. Methyl B12 *absorption.* I misspoke there. If I waited til no one was around to interrupt me before getting into these conversations, I’d have to read blogs at 3am. 🙁

      2. Vitamin companies all tend to cut corners somewhere in order to maximize profit. The ones that include the right kind of B12 often skimp on the quality of something else. Also, check the label under “Other Ingredients.” You might find fillers, coloring agents, and various other crap listed there that you don’t really want to take.

        Alternatively, shop around for a high-quality, unsweetened powdered green drink to replace your multi. The healthfood stores carry a few that are pretty good, but the better ones are only available online.

      3. Check out Dr Ron’s site. Their multivitamin is expensive, but it has all the right things in it, including methylcobalin and methylfolate instead of folic acid. The company also sells dried organ meats in pill form for those who just can’t get into cooking (and eating) organ dishes.

      4. Dr. Mercola’s B-12 spray is in Methylcobalamin form. I think I’m going to give it a shot as I’ve been reading tons of dangerous situations arising in people that are life threatening from nervous system/myelin sheath/circulatory issues stemming from major b-12 deficiency which is basically a “silent disease.” Safe than sorry, right?

  8. That USGS map showing desirable minerals like selenium in soils is also good for checking on undesirable elements like lead. I would hesitate growing vegetables in places like SE Kansas, where irresponsible lead mining from last century have left alarming levels of lead and zinc in the topsoil.

    I spoke to a soil scientist a few years ago, who said he had taken soil samples from the backyards of people living in Galena, KS in 1990. Only after getting back to his lab and doing his analyses did he realize that he had technically violated laws against transporting hazardous materials!

    1. This stinks. We bought our grass-fed cow from a farmer in Columbus, KS, which is about 20 miles from Galena. Do you know of any documentation online discussing this topic? Thanks Stan.

      1. Columbus, KS is NW of Galena. And the wind in Kansas rarely blows from the SE. So I would be more concerned if your cow grazed N and E of the former lead mining areas.

        If you’re still concerned, you might call your K-State Research and Extension Office to see how much lead contamination the Columbus area has.

    2. This is where you take up raised-bed gardening, and use bagged garden soil brought in from elsewhere. We’re trying square foot gardening this year, just to see how it goes.

  9. Thank you for this informative post and the recommendations. My son is allergic to both eggs and dairy and I have been going back and forth on adding a K2 supplement to our diet. I just needed this extra push. Have a great day.

    1. Dr. Davis, the cardiologist who wrote [i]Wheat Belly[/i], takes a K2 supplement to reduce the chance of coronary artery calcification (K2 assists in the transport of calcium the body stores there, for some reason). That’s quite an endorsement.

  10. Another reason why you might want to get your soil tested before you install your garden. The better ones will tell you about mineral content.

  11. Not too long ago I left a comment somewhere in this blog that I was taking 200mcg of selenium each day. Well, I’m not doing that anymore. It led to hair loss. I stopped taking it and my hair stopped falling out. Turns out on that map my county has lots of selenium and I mostly eat local meats and produce.

      1. I was taking iodine supplements at the same time as the selenium. I feel so much better without the selenium. Guess I didn’t need it. I thought I would just offer my experience as a warning in case anyone else starts taking selenium and their hair falls out. It might be easy to blame the relative low carb of the Primal Blueprint since it’s all the rage to say low carb diets lead to hypothyroidism which features hair loss as a symptom, but the real problem could be unnecessary supplements.

  12. Is sea salt with iodine okay (in moderation?)

    1. I use a variety of salts. Since going primal, I still use iodised table salt sometimes (perhaps in the UK, it’s less filled with chemicals – the labeled ingredients look fine to me). But I’ve also branched out into pink Himalayan salt, natural sea salt from Cornwall, some fancy sea salt from Hawaii (a gift) and Lo Salt (for potassium). I have Maldon sea salt in a grinder on the table. (Not sure if this is what you were asking – and I’m just N = 1.)

  13. I definitely try to stick to whole foods as my “supplements”, but depleted minerals in soil do make me wonder if it’s always enough.. I guess a good first step would be to make sure I’m consistently eating liver, etc. (I try for liver once a week).

  14. My hubs and I were just discussing how my migraines have all but vanished since adopting a Primal diet. I attributed it to the fact that my intake of magnesium rich nuts has pretty much quadrupled. Back in the day (early ’90’s) my hubs doctors had him on beta blockers for migraines and told him that eating nuts can trigger them, thus he should avoid them. Aaah, CW… at least they’ve given up leaching/bleeding the ill!

    1. My sister is a nurse manager at a hospital in Virginia. They have leeches that they use to help increase circulation to infected wounds on their diabetic patients. This promotes healing and it works! It’s true! Check it out!

      1. Leeches are used in reattaching severed limbs, also. They assist in maintaining circulation.

        But the old use of leeches for bleeding a patient just to bleed a patient was what she was talking about.

        1. If you are a European male with the haemo-loading gene in the days before blood donation, and are lucky enough to be eating iron-rich meat regularly, a good bleed once a month is probably quite healthful.

          But when leeches and knives are all you’ve got, everything starts looking like a job for leeches and knives.

  15. A couple friends of mine have fibro…passing this on. Hopefully it helps because both are in a lot of pain :<

    1. Tell them giving up grains and sugars really helped me and a few people I know! No more brain fog, much less pain. Encourage them to give it a try!

    1. Wow! Yours is an interesting story – I hope others will take a look at your book review.

      I sometimes hear (and produce) high notes ‘sharp’. Someone told me that some ears just do this. After reading your blog post, I looked at the book, Could it be B12? on Amazon.co.uk, and browsed it with ‘look inside’. I also have mild but unexplained neuropathies in my hands and feet, and tinnitus. These are symptoms mentioned by the book. I’ve ordered sublingual B12 (as cobalamin prep) and will look into this further. You – and Mark – may have just helped me a great deal.

      1. The best thing about taking large dose B12 is that it is safe in large quantities, and fairly cheap. So even if it doesn’t help (and you will know for sure in less than one month), it won’t hurt, and it won’t bankrupt you to buy a month’s worth.

  16. What about playing in the dirt? Does our skin absorb magnesium and other minerals that way?

  17. Would a magnesium deficiency also cause muscle twitching? For the past few weeks I’ve notices random twitching and “bubbly” feelings in my legs and upper arms. I believe it is related to a dificiency of some sort- but I’ve heard Magnesium, potassium and Calcium dificiencies could all cause these symptoms. Any ideas?

    1. I’m being treated for Chronic Lyme Disease and one of my main symptoms is muscle spasms. My doctor has me taking magnesium to get rid of them. So…if your “bubbly” feelings or twitching could possibly be small spasms, I’d say it’s worth a shot increasing your magnesium intake.

    2. Magnesium gets rid of my twitchiness. If I skip my supplement for even a day I get all twitchy. I had seizures a couple years ago, so the twitches cause me anxiety.

    3. Are you low-carbing on Primal? Make sure you’re getting that salt. Insulin being elevated signals the kidneys to hang on to sodium, which is why salt is perceived to raise blood pressure in people on SAD. Someone who’s low-carbing will dump excess sodium because most of the time their insulin is not elevated. If I start getting muscle cramps, I eat some salt. It doesn’t matter if it’s sea or table, each kind contains sodium. Not as big a deal as with the iodine.

      But I’d try the other minerals too, just to be safe. Maybe incorporate some bone broth into your diet, for best results.

    4. Get the magnesium oil and put it on your skin. No more twitches!

  18. I just wanna point out… That i was supplementing with Chelated Magnesium. I was taking around 600 Mg a day, sometimes more, which normally isn’t too much, but since the chelated version is better absorbed than the regular ones, I think I overdosed.

    My blood pressure dropped a little, which is a typical sign of magnesium overdose. But now feeling normal again after about 5-6 days off.

    I still think Magnesium is a great supplement. But unless you workout, which makes you require more magnesium, sticking with the 400 Mg dosage is good, if you have a good quality product, or maybe take more if you are already deficient.

    1. It is impossible to recommend one dosage of magnesium for everyone. People who excersise/ sweat/ stress/ more than others need more. I would recommend to slovly increase your intake until you reach the goal.

    2. I work out often and hard enough that I might need more than 400 mg./day of Mg. Do you know where I can read more about magnesium requirements for those exercising intensely?

      1. Hi, the expert on magnesium is Dr. Carolyn …. oh gosh sorry forgot her surname ah Dr.Carolyn Dean! She wrote a book on it, which I bought but was rather scientific, but if you google Dr. Carolyn Dean/magnesium you will find all the information here. I have taken 2 magnesium tablets for some years now, it is amazing the amount of people that need to take it. 400 mg a day is fine, and I take mine round about the time of my lunch or dinner. Hope that info helps. Also to Dana who was searching for Vitamin B12? Vitamin B12 Methylcobalamyn is sold by Troo Health on Amazon.co.uk probably on Amazon.com as well.The vitamin is free from most things like glutamine and is suitable for vegetarians and vegans. It is also GMP Hope this is of help. Rosina Lock

        1. Oops prior to my previous message, it shouldn’t have read free from Glutamine it should have read free from gluten”
          Rosina x

  19. I’ve been wondering how our 15 month old can get enough magnesium in her diet (and what is enough for a baby, for that matter). Any ideas on the best approach?

    She eats solid foods obviously but leafy greens and nuts are not really part of her chewing regiment yet. I slip little pieces of my 99% dark chocolate to her, but I figure there’s got to be an ideal whole food way for getting her magnesium intake. Halibut and mineral water?

    1. my daughter is also 15 months old. I steam/saute spinach, chard and beet greens and she can easily eat those and she likes it!

    2. We do kale, chard, spinach, mustard green “chips” to get my toddler to eat greens. Just toss them in coconut oil, season with salt and put in the oven for 15 or so minutes at 400 degrees (different greens cook either shorter or longer, so watch).

    3. do you have a mini food processor? just whir some green around until they become tiny specks…then add it to any soft food that our child is eating.

    4. I’d recommend mixing some Nigari (Magnesium chloride) into her bathing water. You can find nigari at Whole Foods or any asain marketplace. The magnesium will be absorbed transdermally.

  20. wow, this is probably the most timely of post so far. i’ve been primal for about a year now and am nearly done converting my wife and kids. they still like pasta.
    my wife has been experiencing some vertigo, went to see a DO, bla,bla,bla
    turns out she is having some hypothyroidism symptoms. she was advised to get more selenium as well as others. ill have her read this. it should help the cause.
    i also really appreciated the why fast posts,
    jonah lang

  21. No one fully understands autistic spectrum disorders, and we have no definitive causes for any ASD. It is extremely irresponsible to suggest that ASDs are caused by a B12 deficiency for this reason.

    1. As a spectrum disorder, there are many ways to improve symptoms through diet, and to observe worsened symptoms through insufficient nutrition. I’m sure there are also other causes for anxiety/depression and other sympoms listed, but to ignore or even downplay the role of nutrient deficiencies in mental health is tragically irresponsible, imho.

    2. I agree. Everybody wants an easy fix. It’s a neurological condition and there’s no miracle cure. Proceed with caution even with supplements…B6 made my AS daughter very difficult. I never tried B12. What I did try was going to a great team of occupational therapists and a good neuropsychiatrist. Not to say nutrition doesn’t play a huge role in improving her ability to cope during stress, and I do think she would benefit from cutting out grains and sugar, but she’s 14 now and it’s harder than it would have been when she was little.

    3. Perhaps autism is a combination of genetic susceptibility, mercury (and/or other ingredients) from vaccines/seafood, and vitamin D-deficiency.

      If so, this would explain why each attempt to “isolate” the alleged one cause has met with failure.

      1. There is no proven link between ASD and heavy metal poisoning. Just no.

        However, this spurious link has been used to justify the improper treatment and probably objective harm caused to ASD patients through the use of industrial chelators and other inappropriate and non-science-based therapies (including a doctor who injected urine into young patients). None of these “therapies” have cured or ameliorated a single case of autism.

        The removal of thimerosol, a vaccine preservative for which there was absolutely no evidence of harm (though harm might be suspected, since it contained Mercury, although not the form of Mercury known to cause mercury poisoning), from all child vaccines in the United States caused no drop whatsoever in the prevalence of autism in the US population.

        Even the Guillain-Barre syndrome associated with vaccines because of the outbreak of GBS following the 1976 swine flu vaccine is now suspected to be linked to tainted chicken eggs used to culture the vaccine. (No other vaccine has been linked to an outbreak of GBS, including contemporary swine flu vaccines.) This would imply that the risk of GBS from vaccines will be eliminated once the vaccine manufacturers transition away from the use of chicken eggs, a process which is already in motion due to the limitations of that method.

        There are no other known risks of vaccine use for persons with normal immune systems.

        Command the sea to fall back, King Antivax, but don’t be surprised when the tide goes in and out as it wills.

    4. It doesn’t matter if you have one cause or a multitude of them. It IS responsible to point out conditions that may be contributing to the disorder. B12 is cheap (even the methyl version), taking high doses is harmless, and if that particular child IS suffering a B12 deficiency, best to address it now rather than later when they have nerve damage.

  22. Thanks for this – all good info.

    I’ve been back and forth on the supplementing issue – are most supplements just expensive chemical crap targeting the growing health market and treating us like idiots, or do they actually work?

    When I remember to take ’em, I’m all about the probiotics, zinc, milkthistle and maca.

  23. Dang! Just was hinking about what supplements to order next. Some were already familiar and others not that much. Have to check into this.

  24. Mark, I’m not well versed in the differences between K1 and K2, but I do know about Vitamin K in general and it’s relation to blood coagulation. I had a DVT and leafy greens were the #1 food item I had to watch or impact my blood thinners. Excellent sources of Vitamin K include parsley, kale, spinach, Brussels sprouts, Swiss chard, green beans, asparagus, broccoli, kale, mustard greens, turnip greens, collard greens, thyme, romaine lettuce, sage, oregano, cabbage, celery, sea vegetables, cucumber, leeks, cauliflower, tomatoes, and blueberries. I’ve not seen any info on which version of K each contains, but given the nutritional value of all of those foods, my daily food includes blueberries and either spinach or kale without exception.

    1. As Mark says, plant sources provide K1 while animal and bacterial sources give us K2 (MK4 and MK7 respectively)

    2. We don’t convert K1 well, and K2 is necessary in bone mineral metabolism as well as improving insulin sensitivity.

  25. re: B-12 deficiency… Don’t forget tingling hands/feet, etc. Neuropathy is fairly common, I believe, in B-12 deficiency.

  26. Magnesium is also found in spicy peppers, the spicier the better!
    I found that supplementing with just a little iodine each day (100% DV) relieved constipation & improved my skin & feeling of well-being.

  27. If you still have mercury fillings in your teeth, stay on Selenium at 200 mcg. daily until they are removed. and for a year afterwards. I out on my clients on Selenium for life at the Diet & Health Center.

  28. Magnesium and calcium have to be in a ratio: at least as much cal as mag, but not more than twice as much.

    ex.: if 400 mg mag, at least 400 mg cal, but not more than 800

    This means the RDA for cal being 1000-1200, and the RDA for mag 350/women 400/men would have been functional mag deficiency even if getting the RDA for mag, which most Americans don’t.

  29. Iodine is a volatile mineral, which means it jumps from solid to gas at room temp, without being liquid in between. This means that iodized salt starts out having enough iodine, but it vapors away over a month or so.

    Also, kelp can be high in bromine and mercury; kelp and kelp supps are not a good source of iodine for this reason.

    Iodized salt works if in small, single-serving packets and kept cool. Iodoral – 13 mg, once per day – was for me a whole new experience of getting iodine.

  30. this is awesome!! what a great resource!! i am also curious about potassium and zinc.

    and my acuppincturist talk to me alot about a deficiency of my qi…any thought on that or ideas to replenish red blood cells?? id love to hear your take on the indications and benefits of different chinese herbs in general

    thanks again, your amazing 🙂

    1. “Qi” can’t be measured, so you can’t tell if you’re acupuncturist’s herbal concoctions are working.

      Sounds like the perfect scam to me.

  31. It seems like eating lots of eggs will help with most of these deficiencies. That’s good to know 🙂

  32. Glad to see this topic covered. Here is New Zealand there the soil is low in iodine and selenium and the Govt was so concerned that it has mandated use of iodised salt in bread. Of course this is not very helpful to those of use who don’t eat bread!! Iodine helps the body to detox from some of today’s modern nasties like heavy metals, and chloride and fluoride, so it really is essential in this day and age.

  33. If you are hypothyroid, I highly recommend that you DO NOT TAKE OR EAT IODINE!!! I followed this advice a year ago from a dr’s blog to increase my iodine for low thyroid and ended up causing an autoimmune response because iodine can attack your thyroid. I ended up diagnosed with Hashimoto’s Thyroiditis. Not fun! Well meaning advice from Mark and others, but those of us with thyroid problems don’t need anymore issues! Thyroid experts say taking iodine is like throwing fuel on a fire!

    1. Agree, however I’m not sure it can trigger an autoimmune disease – it was probably there before but taking iodine made it more obvious.

    2. A very full account of the role of iodine and autoimmune response can be found it this two part series.


      “A survey of the literature suggests that Hashimoto’s is largely unaffected by iodine intake. However, the literature may be distorted by three circumstances under which iodine increases may harm, and iodine restriction help, Hashimoto’s patients:

      1. Selenium deficiency causes an intolerance of high iodine.
      2. Iodine intake via seaweed is accompanied by thyrotoxic metals and halides.
      3. Sudden increases in iodine can induce a reactive hypothyroidism.

      All three of these negatives can be avoided by supplementing selenium along with iodine, using potassium iodide rather than seaweed as the source of iodine, and increasing iodine intake gradually.”

    3. What kind of Iodine did you take?
      Iodoral cured my Hashimoto’s

  34. Many thanks for this informative post. For a few years I refused to take supplements, believing I was getting everything I needed from my healthy diet but recently I’ve come around to the way of thinking that the fruit and veg I eat has lost a lot of nutrients by the time it gets to me. Also the soil it grows in is depleted of nutrients. As a vegan I have to be careful too so I thought it was better to cover my bases and take a supplement. Even meat eaters can be just as deficient. In the North of Scotland we don’t get much sunshine so we are also lacking in vitamin D here.

  35. Minerals “must be present in the soil to show up in the food. It isn’t created out of thin air.” Yes! Thank you!

    Years ago, before I found this website and was just beginning to get my diet on track, I was told by a friend that eating organic vegetables was a waste of money because “her friend’s medical school professor told them of a study that proved that organic and conventional vegetables were the same, nutritionally.”

    Now I thought that was just about the dumbest thing I’d ever heard. I was so struck by the stupidity of it all that I was momentarily speechless. I knew plants couldn’t manufacture minerals out of thin air. How could science defy common sense?

    If I remember correctly, I later learned that the “study” in question compared conventional, big-agra vegetables to organic, big-agra vegetables, the only difference between the two soils being that the latter didn’t have pesticides, etc. Is it really that surprising that there was no difference in the nutrients?

    1. There are have been several studies that show this but I don’t eat organic to get more vitamins or minerals, I eat it because I want to avoid pesticides and other unpleasant additives. I believe that these studies are done to deliberately cloud the issue of organic food claiming that is is no healthier than ‘normal’ food. Seems to me that these are badly framed studies designed to avoid the real issues of pesticides and additives in the food chain.

      1. Exactly. And that’s what I wound up telling her, that even if there was no nutritional difference, it would be worth eating organic to avoid all the pesticides, etc.

  36. I eat Those things…
    Im doin great!
    GROk On>>>

  37. If you can get your hands on it, Excelsior Springs Natural American Mineral Water is great stuff. They don’t ADD minerals, they occur naturally, more kinds than anyplace in the world except Baden-Baden. The one that’s currently bottled has Calcium, Potassium, Magnesium and Bicarbonates, and it’s GOOD. I believe they will ship, check the website at https://esbottling.com. (And no, I don’t own stock! I just drink a bottle every day…)

  38. Mark: I definitely would love to see some attention for zinc deficiencies if you write a follow up post, however with zinc it’s not necessarily just a deficiency that can be a problem but also its balance with copper.

    Zinc is known to be needed in 200+ various reactions in the body, so a deficiency or imbalance has far reaching effects, notably with the immune system, skin health and even mood. I personally think zinc is one of those absolutely essential nutrients that should be monitored.

  39. Is there a test you can get that measures your levels of things like this? I know for example that it’s common to test for vitamin D levels, but for all the other ones (like those listed in the article and mentioned in the comments) is it as simple as requesting them from your doc?

    1. I would also be intereseted in knowing of a way to test for all of these levels.

    2. A good test for magnesium and potassium is the EXATest (www.exatest.com). These two are intra-cellular minerals, and standard lab tests for these minerals look only at extracellular blood serum. The downside is that these tests aren’t usually covered by insurance, and your doctor might not believe that these tests are valuable and refuse to order them, especially if they work for an HMO.

  40. Great article to bring awareness to certain deficiencies. I’m noticing a lot more mineral deficiencies with my clients…

    I’ve used celtic sea salt in my water to aid in mineral supplementation…do you think that this is a good strategy?

  41. Though I support the notion of supplementing yourself with natural foodstuff to fill up your deficiency, sometimes you do need supplement salts. Just for e.g. I have migraine and I have been researching which Mg salt I should be taking, although MgO is mostly recommended, only 4% of which is absorbed. There are many arguments and counter arguments for many salts so I wonder if you could update the article with that information.

    Same goes for B12, I am ulcerative colitis patient too so my doc asked me to take 1000mcg of B12, I started taking cyanocobalamin, most widely available form. Reading through literature got me the news that Methylcobalamine is a better form.

    The supplement industry makes consumer more difficult to choose the product, as they say, if you can’t convince the consumer, confuse them, thats exactly what they do.

  42. Gerolsteiner! Awesome! I drink it all the time and loooove it. 😀

  43. I almost died because of a B12 deficiency. It will cause myoplastic anemia (where the body doesn’t make enough red blood cells and the ones that are there are HUGE and fluffy, and essentially useless)
    I had to have a 4 pint blood transfusion, could have used 6… but the drs were worried I would start to reject the blood if I went that high.

    I now have bi-monthly shots as well as 5000mcg daily. I have to take them under the tongue because my gut wasn’t absorbing what I was eating.

  44. Great post! Just proves once again that through becoming so out of touch with nature and living so far removed from how we were supposed to live (ie pretty much like Grok!), we have caused so many knock on effects!

    Guess its Kalma, we abused the earth and now this is payback!

    H x

  45. I eat kelp everyday. Iodine deficiency is one thing I don’t have.

  46. If I might add, you forgot to mention vitamin A.

    It’s a myth that everyone gets all the vitamin A they need from beta carotene. A couple small studies in the U.S. and UK showed that as many as 49 percent of the population aren’t converting enough beta carotene to meet all their vitamin A needs.

    Plus, people with hypothyroidism, type 2 diabetes, and certain other health conditions can’t convert beta carotene at all. I would imagine people missing their gallbladders are going to have some trouble as well, as bile salts are involved in the conversion.

    Additionally, children under 5 and the unborn are not yet able to make the conversion.

    And finally, when you get a surplus of real vitamin A in your diet, your liver stores the extra for later. But if you’re depending on beta carotene for your A, and that’s if you can convert it in the first place? Your body only converts enough beta carotene to meet your A requirement *for that day.* The excess beta carotene is not stored in the liver for later; rather, it’s put away in your body fat. (This is why food animals eating a lot of carotenes wind up with yellow body fat!) You can’t then take it out later to turn into vitamin A; instead, you must eat more beta carotene. Too many days of not eating enough carotenes and you go straight into deficiency.

    I know the experts say that pregnant women getting vitamin A leads to birth defects but they did not differentiate between real and synthetic retinoids for the purposes of their research. We know synthetic A causes birth defects in high enough doses. But going without real vitamin A means your baby will have birth defects anyway. If you’re deficient early in the pregnancy, your baby will have vision problems; if you’re deficient later in the pregnancy, there will be urinary tract defects.

    Interestingly, the Mayo Clinic says urinary tract defects are the most common type of birth defects occurring in the United States. Just as a data point.

    I suspect a lot of the fertility and heavy/painful menstruation issues we’re seeing in women now come from vitamin A shortages as well. Certainly I cured some of my own problems by supplementing it. It is one supplement I never go without now–and as with B12, it’s cheap and easy to obtain. Just make sure the label says “sourced from fish liver oil” or similar, take it paired with vitamin D (in a 10:1 A:D ratio or better–i.e., 9:1, 8:1, and so on) and you’ll be fine.

  47. Great article Mark. I would love to see a follow-up post discussing vitamin D, iron, and white & red blood cell deficiencies. Also, with eating Paleo over 8 months now (lots of grass fed red meat and liver), one would think iron deficiency would be a problem of the past. However, this isn’t the case for me and I am beginning to wonder if I’m experiencing issues with absorbing nutrients. Can you discuss absorption of vitamins & minerals i.e. what are the causes (besides sugars and grains) and what can be done to improve absorption i.e various foods, supplements, herbs, etc. Ultimately, my goal is to rely solely on wholefoods eating to get all my required nutrients (reduce/omit supplementation as much as possible).

    Thanks Mark!

  48. There are some animal foods high in magnesium. Here’s a list showing mg of magnesium per 100 g of food per USDA nutrient database.

    300 caviar
    250 snails
    97 mackerel
    86 pollock
    55 scallops
    54 oysters
    42 cod

    Some common plant foods with no phytates to bind the magnesium:

    121 kelp raw
    86 swiss chard cooked
    82 frozen spinach cooked
    79 spinach raw
    68 beet greens cooked

    I’ve been trying to eat more mackerel and spinach lately 🙂

  49. After being brought to my knees in despair & spending most days in bed except to care for my grandkids I began “doctoring”. Having been molested by my PT due to neck trauma from having most of my thyroid removed (and my 3 out of 4 parathyroids were also removed in a botched surgery by accident & not informed) I didn’t see a dr for 17yrs drs except emergencies. I am still on a quest to heal chronic depression since 2000 among other probs due to the botched surgery. To make this long story end I found from my great new dr that my vitamin D levels were as low as considered ok. This has now been upgraded. My dr put me on D fairly high dose but what I felt in my body was improvement of depression. By no means am I “healed” but you take what you can and being in very north of the states sunlight is not enough. Hope this helps someone-vitamin D!

  50. No vegetarian sources of b12?? You should try nutritional yeast.

    1. My meaning simply being, yeasts are not plants! (Just being cheeky, friends!)

  51. If you do a lot of workout then it is recommended that you take Magnesium supplement. Food wise, for pure vegetarians the options are Leafy greens, such as spinach, broccoli, and Nuts so if you don’t enjoy these you may have to use supplements.

  52. Vegetarian Sources of B12
    -Water Kefir/Tibicos
    -Red Star Nutritional Yeast
    -Fortified b12 meat analogues
    -Cereals such as Natures Path
    -Yogurt (if you’re lacto-veg)

  53. Herring (I like mine pickled or smoked) gives some good bang for the buck, having really high amounts of Vit D and very respectable amounts of B12.

    I didn’t see Rapini (aka Broccoli Raab) mentioned, but it’s got ridiculous amounts of Vit K and happens to be quite a nutritional powerhouse for other nutrients as well!

  54. I really don’t understand the recommendation of Gerolsteiner. Every mineral and vitamin in the body works together but this is especially true for calcium and magnesium. In other words, consuming more magnesium lowers calcium and vice versa. When I look on the website of Gerolsteiner it reads : 348 mg calcium, 108 mg magnesium per liter. So why would you, if your magnesium/calcium balance is already disrupted and you are magnesium deficient, consume more calcium than magnesium? It doesn’t make sense.

  55. Has Mark posted anything newer on supplements? I would like to know whether there are certain supplements which need to be taken separately from other supplements and/or meds. E.g, can magnesium malate be taken along with Lugol’s iodine or does it need to be taken a few hours apart? How about vitamin C and Lugol’s? Vitamin C and magnesium malate?

    Thanks in advance for any help on this.

  56. I was literally on deaths door before finding Idoral and the right doctor – hopefully I can continue to correct years of abusive medical advice and poor diet advice! Now I follow a more Paleo fashion with regular Celtic Sea Salt (1 tsp or more a day) 12.5 mg to 50 mg or Idoral Iodine a day and Natural Thyroid Meds. Thank all that is good in the Universe I am healthy again!!! or at least on my way.
    The brain fog has lifted and I can move without gasping for breath.. this from a woman that is 51 and was diagnosed with MS, Epstein Barr’s, IBS, Celiac’s, Hashimoto’s and Narcolepsy within the last 10 to 20 years.

    I almost gave up 6 months ago and I am so glad I didn’t – If you are doing all the right things and still don’t feel “quite right” please read

    “Iodine – Why you need it, Why you can’t live with out it” By Dr. Brownstein and
    “Salt Your Way To Health” By Dr. Brownstein

  57. Yo, there ARE vegetarian B12 supplements, as a matter of fact there are vegan ones. B12 can be derived from bacterial cultures, for instance nutritional yeast, and also from algae such as spirulina. Perhaps the most accessible source of B12 is animal products, but we have found a way to do without, so now, it is hard to justify.

  58. does anyone have any first hand experience of using butter oil? I’ve recently gone paleo and butter is definitely working for me. I’m wondering if I should take the step to butter oil capsules…

    Any advice?

  59. Do you ever recommend getting your vitamins from supplementary sources, or only food sources when you can?

  60. Thanks for the great post Mark. I found your article when looking for a solution to Insulin resistance. I’ve followed your suggestions for a month and feel so much better.

  61. Newbe here. Just wondering if you have ever researchd or mentioned on here anything about Vitamin B17.

    1. Hi to Greg Sullivan, yes I know all about B17. It is a form of Laetrile which is used for cancer patients etc. This is in injection form, and Apricot Kernels are a form of B17. The scare that doctors put into you is that it contains a lethal poison in the nut! But thousands all over the world are eating the kernels! I could talk for hours on many subjects as I am very medically related and a researcher but try googling: ApricotsfromGod.com it is a website with literally hundreds of testimonials about B17, even with email addresses, phone numbers. It is a brilliant site. Please be aware about buying apricot kernels from Amazon.co.uk or any other similar site because sellers are stating it is the proper kernel and it isn’t! As for being lethal and poisonous? Well the NHS and the medical profession and pharmaceutical companies cannot patent it, all they want is gigantic profits. Do your research, research and more research, and follow your own path for a better life and health! Rosina lock x

  62. B12 is neither produced by animals or by plants, it is produced by bacteria and can be found in both animal meats (the more it was out getting putrified and contaminated the more B12 will be in it).

    B12 supplements are derived from the bacteria that produce them and not the animal.

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  64. This is a very old discussion, but I wanted to point out that some people suffer from pernicious anemia and cannot properly get B-12 through normal digestion. You HAVE to get it either via injection of sublingually.