How far over the recommended daily values posted on food lables for vitamins is too much? I've noticed on days like today that between the cheerios I had and the one smoothie mix I've gotta around 140 of some things, and things the canned pumpkin used for pies have 300% vitamin A in their 'servings', as well as pieces of carrot cake I've gotten at the store going way over the 100% mark. At how much over does it start to get bad for you?
The concept is called "upper limit." The concept of upper limit for vitamins and minerals is that if you take in that amount, it is a safety margin well below what has been shown to cause harm. Different vitamins have different upper limits, and a few have none.
There's a myth that "water soluble vitamins are safe in large amounts and fat soluble require caution." In reality they have to be looked at case-by-case. E.g., vitamin K (fat soluble) has no upper limit. Water soluble niacin has an upper limit just 2 times the RDA.
Other upper limits:
Vitamin D - 100 mcg,* about 10 times the "daily value" on food labels.
Vitamin E - 1000 mg, about 66 times DV
Vitamin B-6 - 100 mg, about 60 times DV
There are no known adverse affects for taking large doses of B1 (thiamin), B2 (riboflavin), B5 (pantothenic acid), or B12.
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