The Rat Fan Club

Chromium Extends Life Span

by Debbie “The Rat Lady” Ducommun


Chromium picolinate, a compound of chromium that is very easily absorbed by the body, has been shown to extend the average lifespan of lab rats.  Dr. Gary W. Evans, a biochemist at Bemidji State University gave chromium picolinate to 10 rats and compared them to 20 rats who received chromium in a form less readily absorbed.  After 41 months, 8 of the picolinate group were still alive while all 20 of the other group had died.  The rats who got the chromium picolinate lived an average of 45 months, one year longer than the other rats, whose average lifespan was only 33 months.


Here’s why chromium picolinate has this effect.  When the level of glucose in the blood is high, it can damage certain proteins.  This is one reason why diabetes causes damage to the body.  In humans, chromium picolinate reduces blood glucose levels, apparently by enhancing the activity of insulin.  The USDA says 90% of people don’t get enough chromium, so they recommend everyone take a 200 mcg supplement daily.  Dr. Evans recommends people take twice this amount.


Keep in mind that this study was done on lab rats who are free of mycoplasma.  While I have no doubt giving chromium picolinate to your rats is beneficial, it may not have the same life-lengthening effect on rats who have mycoplasma.  (I have found that aggressive antibiotic treatment minimizes the chance that rats will die from Mycoplasma.)


Note:  More recent studies have shown that chromium picolinate seems to have some deleterious effects on the DNA of the reproductive cells.  For instance, one study showed that it produced chromosome damage in Chinese hamster ovary cells and in another study it produced genetic damage in fruit flies.  Therefore, I do not recommend giving chromium picolinate to rats used for breeding.  Other than that there have been no studies that show there are any further risks that outweigh the benefits shown in the original study.



Dosing Your Rat


If you make the homemade rat diet, the chromium is already included.  Alternatively, you can mix it into something your rat will eat. The dosage for a rat is 189 mcg/lb per day. This is a huge dose compared to the human dose recommended by the USDA, and Dr. Evans said the dosage for rats is so large because it’s based on metabolic rate, not just on body weight.  To calculate your rat’s dose, multiply his weight in lbs by 189.  For instance, if your rat weighs ¾ lb, that would be 0.75 X 189 mcg = 142 mcg. If you want to mix up a batch of balls or cookies and you have rats of different weights, you can give them the same dose as long as each rat gets at least 189 mcg/lb and not more than 227 mcg/lb per day. 


Recently, I have started mixing the chromium picolinate into a liquid human dietary supplement (like Ensure brand) which makes it super easy to give it to my rats, as they take it eagerly from a syringe.  The chromium picolinate doesn’t dissolve, but forms a rather gritty suspension that must be stirred well before you take out each dose.  You don’t have to grind up the tablets first.  Just let them soak overnight, and then you can just stir it up.  For older rats, it’s a good idea to add a liquid B complex to the mix.


In a small bottle put 10 ml of a human dietary supplement, such as Ensure brand. Different rats like different flavors.  Add 4 tablets of 800 mcg chromium picolinate (total 3200 mcg), or 16 tablets of 200 mcg chromium picolinate. (It is best to use the 800 mcg tablets because they contain less filler.)  For a rat who weighs 1-lb, the dose is 0.3 ml twice a day, morning and night.  For a rat who weighs ¾-lb, the dose is 0.25 ml, and for a rat who weighs 1¼-lb, the dose is 0.4 ml.


When giving chromium picolinate to growing rats, the dose will need to be increased frequently as the rat’s weight increases.


If you would rather mix the chromium picolinate into food, here are 2 recipes to try:


Non-fat Cream Cheese Balls


1 T Philidelphia FREE brand spread  (if your rat is allergic to dairy products, use another recipe)

enough chromium picolinate for your rat for 40 days (your rat’s dose mulitiplied by 40)

(add 1 t peanut butter for flavoring if desired)


Mix ingredients together to make a “cookie dough.”  If too stiff, add more cheese.  If too soft, add some flour.  Form on wax paper into a rectangle and cut into 40 small squares.  Roll each into a ball and coat with flour.  Freeze half, and keep the remaining balls in the refrigerator.  Give one ball each evening.  (Note:  Chromium picolinate is often pink and may make the balls pink-this is okay.)


Peanut Butter Cookies (recipe by Cindy Lee)


2 T whole wheat flour

1 t peanut butter (if your rat is allergic to peanuts you can use any other nut butter)

fruit juice

enough chromium picolinate for your rat for 40 days (your rat’s dose mulitiplied by 40)


Mix the flour and chromium picolinate.  Cut in the nut butter with a knife.  Add just enough juice to hold the dough together.  Knead lightly and roll out on a floured plate.  Cut into 40 equal sized pieces.  Bake at 350 degrees Fahrenheit for 5-8 minutes (a toaster oven works great.)  Cookies should be slightly chewy.  Store in the refrigerator.  Feed one cookie each evening.

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