How much vitamin D do adults require daily?
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200-400 IU
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400-600 IU
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600-800 IU
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1000 IU
C
Correct answer
Explanation
The Recommended Dietary Allowance (RDA) for vitamin D is 600 IU per day for adults up to age 70, and increases to 800 IU per day for adults over 70. This range supports bone health and calcium absorption. Other ranges are either outdated or represent sub-optimal intake levels.