Fortification of foods with vitamins has been a common practice to prevent deficiencies in populations where certain nutrients may not be consumed in adequate amounts. While this can be beneficial in many respects, there are several potential disadvantages to adding vitamins to foods rather than relying on their naturally occurring forms:

1. Overconsumption: Fortified foods can lead to an excessive intake of certain vitamins, especially when consumers are not aware of the cumulative amount of nutrients they’re getting from various fortified sources in addition to their normal diet.
2. Imbalance of Nutrients: The addition of vitamins to foods can disrupt the natural balance of nutrients. Foods in their natural state tend to have a complex mixture of nutrients that work synergistically. Isolated vitamins added to foods might not provide the same health benefits as when they are consumed as part of a whole food.
3. Bioavailability Issues: The form of the vitamin added to foods may not be as bioavailable as the natural form. For instance, synthetic forms of certain vitamins may not be absorbed or utilized by the body as efficiently as their natural counterparts.
4. Potential for Toxicity: Fat-soluble vitamins such as A and D can accumulate in the body to toxic levels if consumed in large amounts over time. In their natural food sources, these vitamins are often present in amounts that pose no risk of toxicity.
5. Processing Losses: The process of adding vitamins to foods can sometimes degrade the nutrients, making them less effective. Additionally, some vitamins may not be stable during the shelf-life of the product, leading to a decrease in the nutrient content claimed on the label.
6. Masking Poor Diet: Fortification can sometimes give a health halo to otherwise nutrient-poor foods, leading consumers to choose fortified junk food over healthier options, under the false premise that they are meeting their nutritional needs.
7. Allergic Reactions and Sensitivities: Synthetic vitamins added to foods can sometimes cause adverse reactions in sensitive individuals, whereas naturally occurring vitamins in whole foods are less likely to do so.
8. Economic and Ethical Considerations: There can be additional costs associated with fortifying foods, which may be passed on to consumers. Moreover, there’s an ethical debate about whether people should have the choice to consume vitamins through their natural diets rather than through fortified foods, which may not always be labeled clearly.
9. Nutrient Interactions: The interaction of added vitamins with other components in the food may not be well understood and could potentially inhibit the absorption of other important nutrients.

In summary, while vitamin fortification serves an important role in public health, particularly in preventing nutritional deficiencies, it is not without its potential drawbacks. It can sometimes lead to an imbalance in nutrient intake, mask poor dietary patterns, and even lead to toxicity in certain cases. A diet based on a variety of whole foods is generally the best approach to ensure a balanced intake of nutrients.