Vitamin stability and expiration
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Vitamin Stability in Supplements and Foods
Factors Affecting Vitamin Stability: Temperature, Light, Oxygen, and Moisture
Vitamin stability is influenced by several key factors, including temperature, light, oxygen, moisture, pH, and the presence of other chemicals or metallic ions. These factors can accelerate the degradation of vitamins in both supplements and foods, leading to a reduction in their potency over time 789. For example, water-soluble vitamins are especially prone to degradation in solutions, particularly when exposed to light .
Stability of Specific Vitamins: A, C, E, and Thiamine
Studies show that vitamins A and E in commercial supplements often decrease significantly over a 12-month storage period, with only a few products maintaining their original concentrations. Vitamin C tends to be more stable in the short term, but after 12 months, most samples show significant losses. Thiamine and other water-soluble vitamins also degrade over time, especially under less favorable storage conditions 1346.
In enteral formulas, higher temperatures and longer storage times lead to greater losses of vitamins A, E, and thiamine, while vitamin C remains relatively stable under moderate conditions. However, all vitamins are more stable when stored at lower temperatures and humidity .
Impact of Storage Conditions and Packaging
Storage conditions play a crucial role in vitamin stability. Vitamins stored at room temperature and protected from light generally retain their potency better than those exposed to heat, humidity, or frequent opening. In liquid multivitamin preparations, daily removal of product increases vitamin loss, highlighting the importance of minimizing exposure to air and light during use 136.
Vitamin Stability During Food Processing and Fortification
Processing methods such as heating, drying, and exposure to oxygen can cause substantial losses of vitamins, particularly vitamin C. Alternative preservation techniques and careful control of processing steps can help retain more vitamin content in fortified foods 510. Even after fortification, vitamin C in prepared and stored foods can degrade, sometimes resulting in lower levels than those stated on product labels .
Expiration Dates and Overfortification
Because vitamins degrade at different rates, the shelf life of a multivitamin product is often determined by its most unstable component. Manufacturers may add extra amounts of certain vitamins (overfortification) to ensure that products meet label claims throughout their shelf life. However, predicting exact expiration dates can be challenging, especially when using accelerated stability models like the Arrhenius equation, which may not always provide accurate results for complex multivitamin products 127.
Conclusion
Vitamin stability is affected by many factors, including temperature, light, oxygen, and storage conditions. Most vitamins degrade over time, with water-soluble vitamins and those in liquid or opened preparations being especially vulnerable. Proper storage, careful processing, and overfortification are common strategies to maintain vitamin potency until the expiration date. However, expiration dates should be set with caution, considering the unique stability profile of each vitamin and the conditions under which the product will be used 12345678+2 MORE.
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