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Measurements & Abbreviations

International Units (IU) are a measurement system for the activity of vitamins A, D and E. Many products, particularly in the higher dosage range, are still sold in International Units (IU).

Scientists no longer tend to use International Units, and prefer to measure vitamins by weight.

Unit equivalents for A, D & E

1 IU vitamin A = 0.3 mcg (micrograms)

1 IU vitamin D = 0.025 mcg

1 IU vitamin E = 0.7 mcg as d-alpha tocopherol

Other vitamins and minerals are measured by weight.

Weights commonly used

Microgram mcg

Milligram mg (equal to 1,000mcg)

Gram g (equal to 1,000mg)

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Bland, J. 1996, Contemporary Nutrition. J & B Associates.

Davies, S. and A. Stewart., 1997, Nutritional Medicine. Pan.

Holden, S., Hudson, K., Tilman, J. & D. Wolf, 2003, The Ultimate Guide to Health from Nature. Asrolog Publication.

Pressman, A. and S. Buff, 2000, The Complete Idiot's Guide to Vitamins and Minerals. (2nd Ed.) Alpha Books.

Soothill, R. 1996, The Choice Guide to Vitamins and Minerals. A Choice Book Publication.

Sullivan, K. 2002, Vitamins and Minerals: A Practical Approach to a Health Diet and Safe Supplementation. Harper Collins.

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