Your body is smart. It breaks down the food you eat, then processes, uses and stores vitamins and minerals to support your health.
So which nutrients are stored? Fat-soluble vitamins (which dissolve in fat), such as vitamins A, D, E and K, are stored in the liver and the body’s fatty tissues when you consume more than you need. Because of this, you don’t have to ingest them every day, and, in some cases, weeks or even months can pass before stores are depleted.
Water-soluble vitamins (which dissolve in water), such as vitamin C and the B vitamins, are not stored in the body and must be replaced every day. If you consume more than you need, the excess will be excreted in your urine. Vitamin B-12 is an exception; it’s water soluble, but stored in the liver.
Minerals are also stored in the body. For example, calcium and other minerals are stored in your bones. The difference between vitamin and mineral storage is that minerals are stored mainly for metabolism and structure, not nutrient reserves. The body adjusts mineral absorption according to its needs and naturally excretes the excess.
Can you consume too much of a vitamin that’s stored by the body? Fat-soluble vitamins can accumulate, but there shouldn’t be any danger if they’re consumed within the safe upper limits (also known as “Upper Tolerable Limit” or UL) indicated for them. Taking too much vitamin A during pregnancy is one exception, as it may pose a risk to the developing fetus.
The Institute of Medicine determined Upper Tolerable Limits for 24 nutrients. Keep these in mind if you take multiple or high-potency supplements:
Boron 20 mg/day
Calcium 2,500 mg/day
Choline (Vitamin B Complex) 3,500 mg/day
Fluoride 10 mg/day
Folic Acid (folate)1,000 micrograms/day (from synthetic sources; there is no limit for
natural food sources)
Iodine 1,100 micrograms/day
Iron 45 mg/day
Magnesium 350 mg/day
Manganese 11 mg/day
Molybdenum 2,000 micrograms/day
Nickel 1.0 mg/day
Phosphorus 4,000 mg/day (up to age 70); 3,000 mg/day (over 70)
Sodium 2,300 mg/day
Vanadium 1.8 mg/day
Vitamin A 10,000 IU/day
Vitamin B3 (Niacin) 35 mg/day
Vitamin B6 100 mg/day
Vitamin C2,000 mg/day
Vitamin D 2,000 IU/day
Vitamin E1,500 IU/day
Zinc 40 mg/day