Generally, the greater the diversity of nutrients that appear in food, the better. In this way, it is not only safe, but prudent to mix vitamins. However, it may not be wise to mix certain vitamin supplements. Moreover, some vitamins interact in ways that necessitate mindfulness when combining vitamins in food. On the other hand, there is no combination of vitamins that is toxic to humans.
Vitamins often complement each other when they appear together. For example, most of the B-complex vitamins rely on the others to help the body function. This means that without mixing these vitamins, they will cease to promote health when eaten. Other vitamins may become harmful due to a deficiency in another vitamin. As an example, vitamin E can increase the chance of hemorrhaging in the presence of a vitamin K deficiency. Accordingly, not only is it safe, it is necessary to mix vitamins to maintain health.
Although it is usually beneficial to ingest vitamins together, vitamin supplements are usually fashioned to act independently. In other words, they often contain vitamin dosages that you should not exceed. However, ingesting multiple vitamin supplements compounds these dosages, which can be potentially harmful. This only applies to vitamins that can be toxic -- most are not. But vitamin E, for example, can cause complications if more than 2,000 mg is ingested in a day, such as blood clotting issues and hemorrhaging. On the other hand, the recommended daily dose of vitamin E is 1,000 mg. Therefore, combining two vitamin supplements that contain full doses of vitamin E can result in negative effects associated with excess vitamin E. Ensure you discuss your supplement regimen with your doctor to prevent such mistakes.
Whereas mixing vitamin supplements can be potentially harmful under certain conditions, mixing foods that contain different -- or even the same -- vitamins is never harmful. It is rare to garner an excess of any vitamin from food, particularly with normative consumption. In fact, eating a diversity of foods that contain a variety of vitamins is usually beneficial, as the body requires all of them to function properly.
Vitamins can appear together and usually do not interact negatively. Therefore, it is actually healthy to eat foods that contain a diversity of vitamins, thereby mixing them in meals. However, mixing vitamin supplements can be potentially harmful. Therefore, you should be much more mindful of your vitamin consumption if you're integrating a supplement regimen into your diet. Consult your physician or dietitian before making any changes or introducing vitamin supplements into your diet.