A few rare cases in medical journals have described, for example, an overload of vitamin A in a person who ate polar bear liver, a meat with extremely high amounts of this vitamin. Signs of a surplus of vitamin A may include nausea, blurred vision, and dizziness.
And if you eat handfuls of Brazil nuts every day, you could be way over the Tolerable Upper Intake Limit (the maximum per day that is unlikely to cause harm, as determined by the Institute of Medicine) for selenium. Just one ounce of Brazil nuts contains 544 micrograms of selenium. The Tolerable Upper Intake Limit is 400 micrograms per day — and less if you’re younger than 14.
This is a little disappointing because I now need to scrap my weekend plan of doing a cleanse consuming only the entrails of Arctic mammals. On the other hand, I’ve always found Brazil nuts to be an intrusively large presence in the nut mix bowl, so good riddance.
Also, well, I told you so! As I’ve said before, we don’t live in the Jetsons world. In moderation, supplements are fine, but they can’t be your primary source of nutrition. Years of being a Fitness Nerd has taught me that our knowledge of human physiology is wibbly wobbly at best, so relying entirely on man-made nutrition to fuel it just doesn’t make sense. Sure, I take sups. I’m muy pro-supplement in moderation. I take a multivitamin as a safety net for anything I might have missed, as well as an omega-3 sup, but for the most part, I rely on Michael Pollan‘s example and build the bulk of my diet around foods that don’t require nutrition facts or ingredient labels. An apple is an apple is an apple.
Case in point, refined flour. I’ve researched this a fair bit and have yet to find anyone who can explain the logic – either nutritionally or economically – of stripping out wheat’s bran and germ, where you’ll find all the nutrients and fiber, then “enriching” said stripped wheat with other vitamins and minerals, making it an inferior, fiberless nutrition source. Isn’t a little pompous for us to think we can make nutrition better suited for the human body than that which nature has developed over its thousands-of-years long lab test?
But, well, heaven forbid that we involve common sense in the nutritional debate.