This whole thing strikes me as rather bizarre for several reasons. First, why is the Danish government worried about people getting too much vitamin content in their food when the vast majority of people have a deficiency in these vitamins? This is especially true in the B vitamins, such as B6, B12, and folic acid. Perhaps people in Denmark get better vitamin supplementation than those in the United States, but most people in industrialized countries around the world suffer from chronic vitamin B deficiencies. This is especially true if they eat refined or manufactured foods such as breakfast cereals.
Secondly, there's the idea that people can overdose on B vitamins in the first place. You may not be aware of this, but simply eating a cow's liver or calf's liver -- something that many people order for dinner from time to time -- gives you a dose equivalent to thousands of times the U.S. recommended daily allowance. In other words, if you were to list the B vitamins on the label of a meal that included liver and onions, that label might show vitamin B6 at a level of 40,000%. People don't overdose on B vitamins from eating liver, and it certainly seems unlikely that you could overdose on B vitamins from eating breakfast cereals that have a minute quantity of these vitamins in them.
After all, the B vitamins are water-soluble vitamins, which means they don't accumulate in fat tissues in your body and they are flushed out of your system rather quickly. The human body is designed to handle super high doses of B vitamins, vitamin C, and other water-soluble vitamins.
Another point that's bizarre in all of this is that people are arguing over the nutritional value of breakfast cereals in the first place. If you want the truth on this issue, breakfast cereals are not a source of nutrition at all. Mostly they are just empty calories. Trying to get good nutrition from a manufactured food made by Kellogg's is sort of like trying to compare how much calcium is found in two leading candy bars.
These foods are made with refined white flour, which depletes nutrients from the body, most notably the B vitamins that are being fortified in the cereal in the first place. Furthermore, these cereals are sweetened with sugar or high-fructose corn syrup, meaning they pack on empty calories while further depleting vitamins and minerals from the bodies of consumers. As a result, brand-name breakfast cereals, including those from Kellogg's, are hardly a good source of nutrition in the first place. Yes, they can be part of a good diet, but they aren't a good source of nutrition in my opinion.
The whole idea of discussing the nutritional value of these breakfast cereals is, frankly, quite laughable. If you want nutrition for breakfast, you should be drinking a blended shake made with spirulina and supergreens, not eating a bowl of Rice Krispies.
Here is a case where a cereal manufacturing company is trying to add some fundamental nutrition to its products, and is actually being stopped by a government bureaucracy -- normally it's the other way around. Normally food manufacturers don't want to put nutrition into their products and only do so when mandated by government officials. For example, the current requirement to enrich white flour with certain B vitamins and folic acid is the result of a government mandate designed to ward off the more obvious vitamin deficiency diseases.
The big picture is that we have a government authority here telling cereal manufacturers to put less nutrition in their product. At the same time, the population is no doubt suffering from widespread nutritional deficiencies. The Denmark government seems to have gone so completely mad on this issue that you can only wonder if they are suffering from severe vitamin D deficiencies due to their living in a far northern climate that receives very little sunlight. It's true that lack of natural sunlight impairs mental function, which brings up the clever plan that if Kellogg's fortified their cereals with cod liver oil, the decision makers in the Denmark government might regain their right minds and allow enrichment of breakfast cereal products with minute quantities of B vitamins after all.