by Marion Nestle
Jun 17 2009

Pesky problems with multi-nutrient supplements

It’s hard not to think of multivitamin supplements (which also include minerals) as perfectly safe, since the amounts of specific nutrients rarely exceed recommended levels.  But according to recent reports, formulation mistakes get made and these don’t always get caught by quality controls.  Here are two examples.

According to, 25% of Adverse Event Reports (AERs) sent into the FDA last year concerned multivitamin supplements. This, says one supplement trade association, should not be interpreted to mean that there is anything wrong with the supplements.  Maybe not, but how about checking?

I say this because of the high zinc levels in the Nutro pet food recently recalled by Mars (see previous post).  Thanks to Sophie for sending a link to a report that some bags of the kibble contained zinc at more than 2000 ppm as compared to the 75 ppm that is supposed to be there.   This, of course, is why I keep insisting that everyone, not just pet owners, should be concerned about the quality of pet food.  We only have one food supply.  If a problem exists with pet food, it’s quite likely that something similar could happen to ours.

The take-home lessons:

  • For food manufacturers: Don’t trust the suppliers of vitamin/mineral mixes; test them!
  • For the government: How about requiring all supplement manufacturers to follow HACCP (science-based food safety) plans, with testing and quality control.
  • For customers (this means you): Contact the consumer affairs representative listed on the package label, ask if the company tests vitamin and mineral levels in finished products, complain if it doesn’t, and demand to see test data if it does.

Addendum: October 16, 2009: Thanks to Anthro for sending a link to this October 7 article from the website of the New England Journal of Medicine: “American roulette – contaminated dietary supplements.”   This is only to be expected from deregulated industries.

  • Louie W.

    Why do pet owners have to test the food? What’s wrong with PET FOOD COMPANIES and FDA?

    Shame on Effem/Mars/Nutro for not paying attention to pet owner complaints.

  • Rocky

    What’s wrong?

    Wall Street has the SEC, and the pet food industry has the FDA!

    THAT’S what WRONG, IMO.

  • Janet Camp

    Are suppliers ever held accountable (by manufacturers or FDA)? I don’t use supplements, but I think it’s difficult, if not impossible, to find pet food without them. I have thought of making my own dog food (have a little dog), but it’s hard to find good info on how to do it properly–does your book include this topic? I’ve read all the others.

  • Marion

    @Janet: Suppliers are held accountable, but after the fact. The FDA went after the couple who imported melamine-laced wheat gluten. They were indicted and have just pleaded guilty. Our forthcoming book, now titled “Feed Your Pets Right,” will indeed have generic complete-and-balanced recipes for feeding dogs and cats. The latest we’ve heard about publication is that it comes out mid-May 2010.

  • Sophie

    Im with Janet on this, cant you get that book out with the pet food recipes any sooner, LOL ? So far the news Ive read said they are talking probation and maybe a fine for the Millers…I hope that is wrong. This was a statement in an article I read: “Steve Stern, former spokesman for ChemNutra and owner of Stern and Co., said: “For a period of time, there was extreme concern in the pet community. It was resolved appropriately by ChemNutra and the FDA, and it’s been resolved appropriately by the court system.”

    For a period of time there was extreme concern? How bout all the time? And no, it has not been resolved, not even close! Not to mention Mr Miller is back in business doing the same thing under

  • Sophie

    New Consumer Affairs article up today. ASPCA vet toxicologist looked at zinc level test results on Nutro recalled food, says it can cause liver & kidney damage or possibly worse in cats.

  • lesliek

    I have to take issue with Mr Stern’s comment also. Nothing has been resolved,the majority of foods:human & pet are still not safe. The probable slap on the wrist for the Millers is insulting to the animals who are still sick & the grieving families of those who died. The worst thing is that they are still in business. Not much has changed safety wise,there are 4 pfc’s with safety issues right now & still not enough media coverage to prevent people from still using those foods. Your book can’t come out soon enough Marion !

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  • Janet Camp

    Thank you, Marion, for the note about the forthcoming book. I will look forward to it and join Sophie in lamenting the delay.

  • Sophie

    Marion, some new info…Nutro responded to zinc test results and this is their statement:
    Pardon me while I go bang my head on the wall!! Aargh. I thought Nutro said at their site & press release they had no reports of sick cats but yet Ms Barrett says they are working with people that contacted them? How come they arent chging their story in a new press release so news media knows cats have gotten sick and would maybe cover the story so people than just
    those with computers can learn about the recall.

    And I wonder if that statement she made from the 2006 NRC about no studies showing excess zinc affected cats is really accurate in the way its being portrayed by Nutro, an ASPCA vet toxicologist seemed to think otherwise and there is this issued in 2002 saying otherwise:

  • Marion

    @Sophie: thanks for the comment and the links to the L.A. Times article and info on zinc toxicity. The 2006 National Research Council report on the Nutrition Requirements of Dogs and Cats is as good as it gets on review of the science. By this time, my copy opens automatically to the section on Zinc. For dogs, the report says that zinc is relatively non-toxic but that “there is insufficient information available on which to base a safe upper limit.” For cats, the report cites data that up to 600 ppm has no adverse effects, at least for short periods of time. The AAFCO zinc profile for dogs is within the range of 120-1000 ppm. For cats, it is 75 to 2000 (!). But AAFCO profiles are based on NRC data and I do not understand where the 2000 ppm safe upper limit comes from. The problem here is that there just isn’t research to say what the limit might be. And I cannot imagine anyone trying to do a study in which cats are fed zinc at levels that might make the animals sick. So the important questions are how did so much get into the mix, how come nobody noticed, and why is the FDA being so weird about this incident? Let’s hope we find out soon.

  • Rocky

    Very disturbing that Ms. Barrett would quote a statement from NRC to “minimize” high zinc levels found in Nutro recalled food.

    Last time I checked, pet food companies don’t formulate according to NRC standards.

    LOL, I guess you CAN have it both ways.

    Something very wrong with Nutro, and persons who represent the company, IMO.

  • Offy

    Also found this from NRC Subcommittee on Mineral Toxicity in Animals:

    Mineral Tolerance of domestic animals NRC pg 558:

    “Cats were found to vomit or refuse to eat a meal containing 320 or 400mg zinc as the oxide (Scott & Fisher, 1938)”

    “Table 42 summarizes data on accute toxicosis of single oral doses of zinc salts in small animals”

    So, there are 2 NRC studies specifically on cats. (Barrett failed to note the NRC amount of 600ppm and that it was short term in the LA article, didn’t she? )

    In Toxicoloby by Gary D Osweiler on pg 205 he lists clinical signs of dogs.
    1)Early signs
    2)Intermediate signs
    3)Advanced signs.

    IMO, that makes “But, Barrett said, there’s a general lack of scientific knowledge about the levels of zinc and other nutrients that are safe for cats.” incredibly misleading to readers.

    I would ask also, if her statement invalidates the Nutro nutrition & safety claims on cat food.

    Barrett also seems to have failed to mention the obvious. If there’s no science to prove it is toxic, then there is no science to prove it is safe at those levels. That’s a fairly axiomatic assessment.

    I think in the NRC 2008 book on supplements they mention AAFCO had used/extrapolated from swine for the dog level.

    I’d really like to see their “science” to support Dr Bierer’s statement on Nutro Sept 08:

    “In order for a food to provide all the essential nutrition for a pet, it must exceed the minimum requirements for all essential nutrients.”

    Is that a fact proven by science for cats & dogs or not?

    Something is very wrong in the pet food industry & with AAFCO when pet parents are being put in the position of being in-home studies on the pet food safety & nutrition.

    But then, back in 2001:

    “These improved procedures do not represent a perfect solution for nutrition of the individual animal, however. In the words of Quinton Rogers, DVM, PhD, one of the AAFCO panel experts, “although the AAFCO profiles are better than nothing, they provide false securities. I don’t know of any studies showing their adequacies and inadequacies.” Rogers also states that some of the foods which pass AAFCO feeding trials are actually inadequate for long term nutrition, but there is no way of knowing which foods these are under present regulations (Smith, 1993).”


  • Mary

    Marion, thank you so much for reporting this story. Lots of good information here, and the comments are excellent.

    Your readers certainly know a lot about pet food.

    Offy’s comment alone is an education! Wish Nutro was that well informed.

  • Claire Ginesi

    With a newly diagnosed diabetic cat (never overweight), I have been shocked to find out that feeding kibble to our cats is condemning them to disease and poor health. Of course cats are carnivores, and get some carbs in “the wild” from whole carcass of prey.
    However, the carb levels, esp the use of wheat gluten in almost all pet foods, incl canned, are what my vet says is a big cause of feline diabetes. As pet food companies “fancy up” their products, with gravies, human food allusions, etc.(why would a cat care about Tuscan menu cat food) the use of oat bran, wheat gluten and other things are dangerous to our cats.
    Would appreciate any comments on the explosion of feline diabetes. Thank you.

  • Marion

    @Claire–my guess is that feline diabetes, just like human diabetes, results from eating too much and not moving enough. Cats, like people, need to eat less and move more!

  • Offy

    Shaking Nutro’s Denial Tree:

    ” The cat’s requirement for zinc is probably between 15 ppm and 50 ppm.”

    Per NRC: “In many instances, high dietary level of one mineral antagonizes another element, resulting in physiological deficiency of minerals essential for the animal. Because many different factors affect the quantity of a mineral needed to produce toxicity diverse observations have been reported on the toxic effects of any given mineral.”

    Nutro has provided no science stating that the levels of zinc they put in their foods is safe , nor have they provided any proof that the composition of their foods is not adversely impacted by the levels of zinc. Nor have they provided any data to indicate their food is safe – feeding the Nutro food means you feed it all, not just the zinc.

    Safety is a two way street – the makers and those consuming. I’d bet on the impact on those consuming the food to be the true indicator of safety & nutrition before I would the Nutro denial program and lack of any proof to the contrary.

    Burden of proof of Safety rests with Nutro and they are not forthcoming.

    I would venture a guess that the lack of science to prove the overall composition of their food with zinc at those levels is actully safe is why they would not release the bloodwork of the cat populations they tested to the vet requesting them.

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