Nutrition 101: Are You Overdoing the Zinc?

5SHARES

By: , SparkPeople Blogger
5/7/2009 1:00 PM   :  64 comments

Zinc is a lustrous bluish-white metal found in group IIb of the periodic table. It is also one of the most important minerals used by the body. Just 2-3 grams, about the weight of a penny, is found in the body and serves as a key building block for about 100 enzymes which are necessary for cell growth, reproduction and repair and regulating the body's immune response, insulin metabolism and wound healing. The RDA for zinc for adults is about 11 mg per day for men and 8 mg per day for women (12 mg if you are pregnant or breastfeeding). Zinc is found in water and food and should be included in the diet each day since the body does not have a storage mechanism for zinc.

Oysters are the richest source of zinc and the other best sources including beef, lamb, pork, crabmeat, turkey, chicken, lobster, clams and salmon. Good sources of zinc include dairy such as milk, yogurt and cheese as well as yeast, peanuts, beans, whole grain cereals, brown rice, whole wheat bread and potato. Pumpkin seeds offer one of the most concentrated non-meat food sources of zinc but the zinc from meat sources is four times more bio-available than the zinc from grain sources.

If you are healthy and eating a well-balanced diet, supplements are generally not needed to meet your body's zinc needs. However, many multivitamin supplements include zinc and provide 11-15 mg themselves which is the daily recommended intake. Safe upper intake levels of zinc are set at 40 mg per day for adults.

So why am I focusing on zinc?

Zinc intake of more than 50 mg from diet and supplements can lead to improper copper metabolism, altered iron function, a reduction of HDL’s (the good cholesterol) and reduced immune function. Research suggests that chronic and excessive zinc intake can cause neurological disorder and disease. There is also ongoing research related to iron, copper and zinc and their role in Alzheimer’s disease.

Zinc is found in many cold lozenges and some over-the-counter drugs sold as cold remedies. They can be in several different forms such as zinc gluconate, zinc sulfate and zinc acetate. The percentage of elemental zinc used by the body will vary depending on the form. For example, 23% of zinc sulfate is available as elemental zinc so 220 mg of zinc sulfate contains 50 mg of elemental zinc. You can find the elemental zinc content for specific products in the Supplemental Facts panel on the supplement container.

Being exposed to more than 10 times the recommended amount of zinc can result in zinc poisoning. Neuropathy or nerve disorder has been seen in those that wear dentures due to suspected zinc poisoning. Overuse of adhesive creams to fix ill-fitting dentures is felt to be a culprit. Because adhesives are not FDA controlled, zinc concentrations have been found to range from 17-34 mg per gram of denture cream.

The bottom line – the right amount of zinc daily is good – more is not necessarily better. Zinc is a heavy metal and can lead to heavy metal poisoning when consumed in large amounts over time. Using large amounts of denture cream to fix ill fitting dentures or taking large amounts of zinc containing vitamins or cold supplements can result in consumption of too much zinc, especially if you already have a zinc rich diet.

If you eat a well balanced diet AND you take a multivitamin with zinc AND/OR take other supplements containing zinc or are using larger amounts of denture cream because you have lost weight and your dentures aren’t fitting as well – now is the time to do a zinc check. Take a look at what you are routinely getting from your diet in zinc. Now take a look at other zinc sources and see if you are routinely exceeding 50 mg/day. If you are and you have any of the following neurological symptoms, please see your medical provider to be sure there are no toxicity issues.

Symptoms of neuropathy include :
  • numbness of tingling in the arms, legs, fingers and/or toes
  • unexplained pain in the extremities
  • a diminished ability to move the arms, hands, legs and/or feet
  • poor balance
  • unsteady gait or stride

Also, if you have family members that wear dentures and you have noticed any recent changes in their balance or walk or if they have made comments about numbness or tingling, it would be a great idea to find out how much denture cream they may be using. More than 2 tubes a week is most likely a problem that needs to be further investigated and new dentures fitted.

Is zinc something you have ever worried about or ever paid attention to in your diet or supplements? Will you do a zinc check?



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Comments

  • 64
    Today I went to my Dr, and told her I had stopped taking some medications because I was having too many bad leg cramps. She asked if I get too much zinc. I tracked Zinc in my tracker but now I realize other supplements often add to their product. Now I have tracked all the nutritional Info. Now I will put the other medications back in my regimen and observe how many other supplements I am over doing. Pat in Maine. - 11/10/2014   8:50:06 PM
  • 63
    This IS so important to know - thank you SP/Tanya! Since I'm low in zinc I started a thread about it myself: http://bit.ly/SPCDzincthread . Something else to note would be white spots on your nails. I never have them, but did this winter (AND caught two colds which is unusual) ... not until I got tested did I put it together (I was also low in vitamin C). :P I'm supplementing and will recheck in a few months. - 3/25/2010   2:23:08 AM
  • 62
    Who'd have thunk it? And the article doesn't mention absorption from zinc oxide creams for sunburn protection (not a problem for this person! but still...)
    Mad-Eye Moody has it right: "Constant vigilance!" - 8/4/2009   7:32:07 AM
  • 61
    I have not really given my zinc intake much thought...I will be mindful of it. I don't take supplements and I love cheese and yogurt and chicken; so I think I am okay. - 5/14/2009   2:18:20 PM
  • 60
    This is good information to know. I don't wear dentures but I know others that do. Plus, it's good to know how much zinc I should be getting. Time to track that as well. - 5/14/2009   7:12:45 AM
  • 59
    I didn't know about zinc!!!! My 82 year old mom has been having tingling in the head . I will ask her if she is taking zinc. - 5/11/2009   7:41:16 AM
  • 58
    WOW! I have severe tingling of my right leg, which I will discuss with my doctor next week. In the mean time I will add zinc to my nutrition tracker and I will stop taking the multi-vitimen which gives me twice what I should consume each day. This article may just have solved a medical problem of mine.
    Thank you. - 5/11/2009   4:38:59 AM
  • MKELLEY913
    57
    Another GREAT TIP from SPARK PEOPLE! THANKS - 5/11/2009   3:07:41 AM
  • 56
    It looks like it could be difficult to keep your zinc level down . . . - 5/10/2009   11:50:19 PM
  • NANADEB49
    55
    No one has mentioned that zinc has been linked to the loss of one's sense of taste and smell. I've been concerned about not being able to taste the flavor (smell) after the first couple of bites of certain foods- such as maple syrup- for a few years now. Which leads to- 'why spend the money if I can't taste it?' I realize everyone loses their sense of taste/smell over time but I've read that a pronounced sense of loss shouldn't occur until after your 70's. I'm only in my mid 50's. And yes, I've seen an Eye, Ear, and Nose Specialist. He says I'm fine. I'd really like to know more (in layman's terms) about this aspect of zinc. - 5/10/2009   6:11:42 PM
  • 54
    I didn't even know such a thing could happen. I don' t think I need to check mine. I take more when I start getting sick. Along with C and plenty of water. - 5/10/2009   3:58:25 PM
  • 53
    Sorry! I meant 100-200 mgs. as per SP. - 5/10/2009   2:59:04 PM
  • 52
    I would be curious to know where this information came from, of 50mgs of zinc per day. I track my zinc intake and Sparkpeople mentions daily needs as between 100-200%. Where does 50mgs fall in? At 100 or 200%?

    In contrast, when we do not get enough zinc, our hair starts to fall!

    Thanks for the informations. - 5/10/2009   12:27:59 PM
  • 51
    Great info! I'm going to do a zinc check when I'm finished here. - 5/10/2009   10:49:15 AM
  • THEMANSLAYER
    50
    No. I have never worried about zinc before. When I used to get a cold sometimes I would take more zinc than it said to take, and once I got a sick feeling or felt sick. - 5/10/2009   10:19:53 AM
  • VALWOS
    49
    Great blog! Please keep the blogs on suppliments coming! - 5/10/2009   9:39:13 AM
  • 48
    WOW that was news for me.
    I sometimes experience the 'tingles'...but thought it might be 'carpal tunnel' or diabetic related.
    Going to check my Zinc sources.
    Thanks - 5/10/2009   6:50:44 AM
  • 47
    A well balanced diet, exactly! We include in our diet whole grains, all natural peanut butter, seeds, milk and cereals. We don't need to take zinc supplement. Never has to go down that path. - 5/9/2009   4:56:01 PM
  • 46
    For the past couple of years, I have experience a form of neuropathy that includes hot shooting pains in my legs, feet and arms. The doctor was puzzled, as I don't have blood sugar problems or any of the other usual causes. It started up about the same time I started having problems with my dentures fitting properly (I wear partial dentures, upper, and it is harder to get a good hold with them). I use the powdered Fixodent adhesive, and it always works well, so I didn't worry about it. I am going to have to talk to my dentist and my doctor about this next visits. In the meantime, I will see about using another type of adhesive! Thanks for clearing up the mystery! I am sure both the doctor and the dentist will be interested to hear this. - 5/9/2009   2:55:36 PM
  • MKIRKLE
    45
    I have never tracked it before but will now. I guess I thought more was better so never paid attention. - 5/9/2009   1:14:27 PM
  • DHICE7398
    44
    This is scary! But why doesn't the Spark food tracker itemize zinc as well? It's not even listed! - 5/9/2009   12:44:55 PM
  • 43
    Never thought much about zinc before. I checked out my multi & found zinc isn't listed, so all is well. I'll be letting my sister & others know about this! - 5/9/2009   10:46:54 AM
  • 42
    I actually track zinc because it is a vital nutrient for umm... the bedroom. And I have discovered that if I don't get enough zinc without a multivitamin. I am aiming for 40mg a day. - 5/8/2009   5:15:41 PM
  • 41
    I don't have a problem with the amount of zinc I consume...I use the Nutrition Tracker that allows me to check the amount of zinc I receive...it just the other's which can be just a bad in large doses, i.e., sodium, iron, Vitamin E - 5/8/2009   3:25:55 PM
  • ISLOBIRDSEEDS
    40
    Everyone should bring this up at their next dental appointment... I think maybe a lot of dentists could use this info, in order to encourage people to get their dentures relined in order to fit them better without using so much of this cream to hold them into place everyday.
    Thanks for this info! - 5/8/2009   3:25:41 PM
  • 39
    My brother suffers from an autoimmune disease (as do I) and had a wound that stubbornly refused to heal...his doctor put him on a short dose of increased Zinc and Vitamin C supplements and the wound healed wonderfully! Prior to that all conventional methods had failed. So I don't need any more prof than that that ZINC is especially imprtant for men's health! - 5/8/2009   3:01:57 PM
  • 38
    I'm going to encourage my husband to read this blog post. He eats a LOT of seafood (including oysters & clams), & he also likes to have a Cold-Eeze every day or two for cold prevention. He's not having symptoms of zinc overdose, but I'm sure he'll want to avoid it.

    The form of zinc that's in Cold-Eeze does hugely help me when I start coming down with a cold; I just suck 2-3 of the lozenges in the first 1-2 days of symptoms, & the cold either goes away or turns into a "mini-cold." I'll refrain from ingesting extra zinc except at those rare times. - 5/8/2009   2:43:08 PM
  • KATREECE
    37
    This was very interesting. I use a womens multi with minerals. I also use Zicam if I am worried about a cold As well as Emergen-C And after reading this article realized that there is 2mg of Zinc Ascorbate in each packet of that, Makes me wonder exactly how much I am getting overall. - 5/8/2009   2:41:01 PM
  • LENAJB
    36
    I learn something helpful everytime I log into the blog. I will monitor my zinc intake and advise others to do the same. - 5/8/2009   1:33:44 PM
  • 35
    Zinc isn't one I usually overdo. The ones that it's way too easy to get too much of seems to be vitamin A and vitamin D for me. I go over my range in both of those almost daily! I wish my multivitamin didn't have them, because i need the multi! when I skip it I never get enough riboflavan, thiamin, iron, etc. - 5/8/2009   12:45:31 PM
  • NO-41_RAZZYS_PL
    34
    Thanks sooo MUCH for the 'heads up' on this, Tanya, because... well, I never really gave such a little mineral much thought... PLUS I have a lot of friends who NEED to know this, so I'm going to be doin' a ton of sharing!! :) gr8 additional sites too, btw!!
    ENJOY your weekend!!
    *´¨)
    ¸.·´¸.·*´¨) ¸.·*¨)
    (¸.·´ (¸.·´ *Annie - 5/8/2009   11:53:54 AM
  • 33
    Great blog thanks !! - 5/8/2009   11:44:21 AM
  • 1THING
    32
    thnks for the info, we will be on the watch - 5/8/2009   11:29:32 AM
  • 31
    I so appreciate this information. Having already been given the diagnosis of neuropathy in my hands I see that this is something I can investigate and pay more attention to from now on. Thanx - 5/8/2009   10:55:48 AM
  • 30
    I'm not a huge fan of taking any kind of supplements. I know that for some people they are helpful and necessary but I just don't like adding alot of chemicals to my body. It seems that you hear more and more of these side effects all the time. Thanks so much for the info! - 5/8/2009   10:38:45 AM
  • 29
    Thanks for this very informative article - 5/8/2009   10:34:46 AM
  • 28
    Dentures are not an issue for me (I am a dentist's daughter, and I aspire to have my original teeth when I die!). However, as a post-op gastric bypass patient, I am required to take a daily multi-vitamin. I will check the bottle and see what the dosage is. I know that my gastroenterologist monitors my calcium, B-, and D-vitamin levels with every blood test (every six months now), but I don't know about Zinc. Thanks for the heads-up! I will discuss this with him, since my food intake includes pumpkin seeds, meats, and lots of the foods mentioned in the article. Thanks again! - 5/8/2009   10:30:58 AM
  • 27
    Speaking of supplements, can someone blog about the difference between:
    IU
    mg
    mcg
    and what values of each vitamin is REQUIRED for women/men?
    It is very confusing for a lot of people and I think that it's important that they understand the differences.
    Take, for instance, B-6 and B-12. One is mcg the other is mg. One you can actually overdose on (I think it's B-6) and the smallest OTC dose is already twice the RDA so when I was taking them, I'd have to split them in half, then take them for only 3 out of 7 days.
    Also, because they CAN cause liver damage, it's important to note those as well.
    Thanks! - 5/8/2009   8:47:54 AM
  • 26
    I take a (50 mcg) Zinc vitamin if someone around me or I am catching a cold coupled with 1,000 mg Vitamin C. Otherwise I don't take any supplements. I know that I'm eating a balanced variety of foods, so I don't require supplements. In the "third world" countries, THEY require supplements because their foods aren't supplemented and they don't have the choices that we do that offer a balanced diet. - 5/8/2009   8:44:44 AM
  • 25
    Wow.... I never knew..... Thanks for this blog... Its very informative. - 5/8/2009   8:41:59 AM
  • 24
    I haven't given my zinc intake much thought, to be honest. Thanks for the information! - 5/8/2009   8:35:34 AM
  • 23
    Scary stuff. I don't have dentures or east shellfish but take suppliments so will definately monitor my zinc consumption to see where I fall. - 5/8/2009   7:53:41 AM
  • 22
    Wow - I am a huge user of Zicam, which I believe has lots of zinc? I will definitely check it out, but I have never had any problems with it (tingling, etc.), and I would be devastated if I had to stop using it - it's the only thing that gets me thru colds! - 5/8/2009   7:48:02 AM
  • 21
    Just wanted to point out that neuropathy can be the result of a whole bunch of different things including diabetes, an auto-immune disease, CTS, or other nutritional deficiencies, even without excessive zinc consumption. Since neuropathy is more common in people over 55, and denture creme use is also more common in people over 55, I have to wonder if that isn't at least some of the effect of that study. It would be interesting to know the degree of neuropathy of those using a lot of zinc laden deture creme that are under 55 or have none of the other conditions more typically associated with neuropathy. - 5/8/2009   7:39:56 AM
  • 20
    OMG - What an alarming article. I had some idea that multi-vitamins were not necessary if I were eating well balanced meals. But I'm also aware that much of the vitamins and minerals are often cooked out of foods. So, I think I better check with my doctor about taking supplements.
    - 5/8/2009   2:32:25 AM
  • 19
    Because I've had malignant melanoma, and because of one of my medications, I need to avoid sunlight. When I'm going to be in the sun, I use a largely zinc-based sunblock, and lots of it on any exposed skin.

    Is there any chance that zinc can be absorbed through the skin, and I should be concerned? Thanks for your information~ - 5/8/2009   2:08:37 AM
  • 18
    Same problems can occur with B6 vitamin overdose. I would love to see an article devoted to that kind of poisoning, which made me very sick last year and of which people are usually not aware. - 5/8/2009   2:05:12 AM
  • 17
    I'd hate to wear dentures. - 5/8/2009   1:24:03 AM
  • SEXYSYMP
    16
    I took zinc supplements for nearly a year. Then I started to get tingling sensations and leg pains.could zinc be the cause ? who knew?! - 5/7/2009   11:27:00 PM
  • 15
    who knew? Thanks for teaching me about zinc consumption. - 5/7/2009   10:25:42 PM

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