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Take a nutrient, such as calcium. According to Wikipedia, the RDA (Recommended Dietary Allowance) for an average healthy 44-year-old male is a daily intake of 1000mg of calcium.

Suppose you consumed, over a week, 7000mg of calcium. On average, you consumed 1000mg of calcium per day, which is exactly the recommendation. That's only the average, though, so you might have consumed 500mg of calcium on Monday ­(50% of the RDA), and 1500mg on Tuesday (150% of the RDA); and so on, with similar variance.

Are you still satisfying your calcium needs? Is there a rule of thumb for determining that for other nutrients, or any pointers to resources that covers the specific cases? Thanks!

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At least for calcium, the answer is a definite yes.

99% of the calcium in the body is stored in the bones and teeth, and the body treats that calcium like you would treat money at an ATM. If you don't have enough calcium intake, then the body starts taking it from the stored sources. If you have an excess, then it "deposits" more in the bones/teeth.

Here is another quick read on calcium and phosphorus in the body.

As far as other nutrients, that is going to be kind of specific and differs by nutrient, the best angle is to research each nutrient separately and see how it is utilized/stored/excreted by the body to determine safe levels. As a general rule of thumb, though, one or two daily shortages won't be critical.

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    It may be helpful to comment on how absorption would be affected by dividing the dose differently across the week. If one takes 7g of calcium at once, for instance, absorption is going to be significantly less that 1g x 7 days. I suspect the same trend is true on smaller scales (e.g. 1500 mg x1 < 500 mg x 3 days). This is going to be affected by food, type of Ca preparation, etc., but the principle is consistent. (Contrast Vitamin D where monthly dosing achieves similar serum levels as the same cumulative around divided daily.) – Susan Oct 19 '15 at 4:33
  • You wrote that the sceletton works like a calcium bank. So, if you eat more calcium than you need you would increase your hight? – Constantthin Nov 16 at 4:51
  • @Constantthin no. Height is genetic. Too little calcium may have a negative effect, but nothing will make you grow past your genetic blueprint. – JohnP Nov 16 at 16:22

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