Expiration Dates; How Accurate are they?
How Accurate are Expiration Dates?
You have just opened the fridge and found that large bottle of pickles that was near the back shelf. Suddenly, exposed and sitting there is a full bottle of fish oil that you bought a long time ago and meant to take regularly. You immediately pick it up and check the expiry date. It is one year and 2 months past the expiration date on the label. What do you do? Do you consider trying it anyways because a new bottle would be very costly? Or do you just dump it and maybe go out and get another bottle?
Unfortunately, for many people, this is a common occurrence and in these tough economic times the potency of expired products becomes more important because the last thing we want to do is feel stupid for forgetting to take our supplements and then having to go out and spend more money on new ones. However, depending on the product and the dosage form, (liquid, capsules or tablets) your expired product may still be good.
Most of us understand the best before date on the food that we buy and consume. The smell, taste and texture can tell us right away whether the product is edible or should be discarded. However with products that you buy in the drug store or health food store there is almost no way to tell if they are still good beyond the expiry date. The truth is these dates are completely arbitrary because the cost of actually determining the exact expiry date of any supplement or analgesic is so high that from a manufacturing point of view, it is not cost-effective.
In order to accurately calculate the day that the product has zero potency and could even be harmful, a manufacturer must determine if the product will be exposed to heat or light, the composition of the tablet or capsule or the type of liquid. They must take into consideration how long the product lasts if it is left unopened on the shelf, if it is open and kept at room temperature or if it is open and kept in the fridge. Then they have to consider the chemical composition of the substance or substances in the product and what elements may cause them to break down and how long that would take. If every manufacturer did this for every lot of product produced, the cost of determining the expiration date would be more than one hundred times the actual cost of making the product. It is for that reason that manufacturers estimate the expiration date and usually underestimate it to insure that the product has full potency by the end date on the bottle. It is not as if on the 1st day of September 2010 your product simply goes “poof” and loses all its potency. Just out of interest, if the product expires in for example September, the expiry date is actually the last day of the month, not the first.
Expiration Date Study
In March of 2003 the United States Air Force found that it had a large warehouse full of pharmaceuticals, vaccines, narcotics, antibiotics and all types of injectables and topical ointments that were left over from the Iraq War of 1993. They were now going back and they knew they had to order fresh supplies but they were curious about the potency of the products that they had in that warehouse for the last 10 years. Using very sophisticated quantitative analysis, they determined that almost all the pharmaceuticals had between 93 and 97% of their original potency even though on average they were seven years beyond the labeled expiration dates. Approximately 13% of the injectables had more than 100% of the labeled amount as did 23% of the pharmaceuticals that were in tablet form. Of course the Air Force still disposed of all the merchandise and bought new but it did publish its findings in the Annals of Medicine Journal in January of 2004.
The Manufacturing Process
Since most ethical manufacturers arbitrarily pick an expiry date (usually three years from the date of manufacture), they want to insure that the product retains 100% of its potency until the expiry date on the label. They do this by actually putting in slightly more product than is indicated on the label. For instance, a bottle of vitamin C 500 mg may start out at around 530mg when it leaves the factory so that three years down the road it may still contain a minimum of 500mg of product. Health Canada requires that supplements and pharmaceuticals must have a minimum of 90% of their original potency by one year beyond the expiry date.
One exception to this rule is supplemental oils such as Udo’s Oil, Flax and hempseed oil. It is actually very easy to determine how quickly they will lose their potency because oxygen makes these oils go rancid very rapidly. These companies can be very specific and they are usually the ones whose products are much more potent when they are freshly made because they lose their potency so rapidly.
Not All Products are Created Equal
The dosage form of the product is the greatest factor in determining if you can use your expired product. If we consider the fish oil from our first example, if the bottle was never opened and kept in the fridge all that time, it would be completely safe to take and have all its potency. If the bottle had been opened and there was only a small amount left, then the oxygen in the air space in the bottle would have destroyed the chemical composition and turned the product rancid.
Tablets and Capsules
If your supplement is a hard tablet such as a Calcium Magnesium tablet or a selenium tablet it will most likely retain all if its potency as long as you kept in a cupboard, not in the bathroom or fridge where humidity could affect it. On the other hand liquid gels, and capsules made from Silica and gelatin are not as resistant to outside temperatures and light as tablets and will lose their potency much earlier. In this case I would definitely go by the date on the label.
Liquids are the least likely products to use beyond their expiration date because as you consume the liquid the oxygen in the bottle starts to break down the product. However, even within this category there are exceptions. If you have an aqueous solution of Echinacea (a solution in which the Echinacea is dissolved in water) is far more likely to break down than an alcoholic solution which will last for years beyond its expiry date. If you have an aqueous solution of a multivitamin I would adhere strictly to the expiry date but an alcoholic solution of a herbal multivitamin will last far beyond the date on the bottle. As a general rule you must exercise greater caution when consuming expired liquid solutions.
Of course none of this information would matter if we were all very efficient and took our pills regularly. However, sometimes we forget. Some times we find a bottle in the back of the cupboard that we didn’t know we had. After all, we are human and are not perfect. This might be a good article to stick up on the fridge so that the next time you do find a product that is beyond its expiry date, you can refer to this article and make an informed decision.