nutriture in an individual", a definition somewhat different from that used by the world health organization and food and agriculture organization of a "basal requirement to indicate the level of intake needed to prevent pathologically relevant and clinically detectable signs of a dietary inadequacy". in setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity. for example, for vitamin c, recommended intakes range from 40 mg/day in india to 155 mg/day for the european union. the table below shows u.s. estimated average requirements (ears) and recommended dietary allowances (rdas) for vitamins and minerals, pris for the european union (same concept as rdas), followed by what three government organizations deem to be the safe upper intake. rdas are set higher than ears to cover people with higher than average needs. adequate intakes (ais) are set when there is not sufficient information to establish ears and rdas. countries establish tolerable upper intake levels, also referred to as upper limits (uls), based on amounts that cause adverse effects. governments are slow to revise information of this nature. for the u.s. values, with the exception of calcium and vitamin d, all of the data date from 1997 to 2004. nutrientu.s. earhighest u.s.rda or aihighest eupri or aiupper limitunit u.s.eu japan vitamin a6259001300300030002700µg vitamin c75901552000ndndmg vitamin d101515100100100µg vitamin kne12070ndndndµg α-tocopherol (vit e)1215131000300650-900mg thiamin (vit b1)1.01.20.1 mg/mjndndndmg riboflavin (vit b2)1.11.32.0ndndndmg niacin* (vit b3)12161.6 mg/mj351060-85mg pantothenic acid (vit b5)ne57ndndndmg vitamin b61.11.31.81002540-60mg biotin (vit b7)ne3045ndndndµg folate (vit b9)32040060010001000900-1000µg cobalamin (vit b12)2.02.45.0ndndndµg cholinene5505203500ndndmg calcium80010001000250025002500mg chloridene2300ne3600ndndmg chromiumne35nendndndµg copper700900160010000500010000µg fluoridene43.4107____mg iodine9515020011006003000µg iron618 (females)8 (males)16 (females)11 (males)45nd40-45mg magnesium*350420350350250350mg manganesene2.33.011nd11mg molybdenum3445652000600450-550µg phosphorus5807006404000nd3000mg potassiumne47004000ndnd2700-3000mg selenium455570400300330-460µg sodiumne1500ne2300nd3000-3600mg zinc9.41116.3402535-45mg * the daily recommended amounts of niacin and magnesium are higher than the tolerable upper limit because, for both nutrients, the uls identify the amounts which will not increase risk of adverse effects when the nutrients are consumed as a serving of a dietary supplement. magnesium supplementation above the ul may cause diarrhea. supplementation with niacin above the ul may cause flushing of the face and a sensation of body warmth. each country or regional regulatory agency decides on a safety margin below when symptoms may occur, so the uls may differ based on source. ear u.s. estimated average requirements. rda u.s. recommended dietary allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating. ai u.s. adequate intake; ais established when there is not sufficient information to set ears and rdas. pri population reference intake is european union equivalent of rda; higher for adults than for children, and may be even higher for women who are pregnant or lactating. for thiamin and niacin, the pris are expressed as amounts per megajoule (239 kilocalories) of food energy consumed. upper limit tolerable upper intake levels. nd uls have not been determined. ne ears, pris or ais have not yet been established or will not be (eu does not consider chromium an essential nutrient). plant main articles: plant nutrition and fertilizer plant nutrients consist of more than a dozen minerals absorbed through roots, plus carbon dioxide and oxygen absorbed or released through leaves. all organisms obtain all their nutrients from the surrounding environment. plants absorb carbon, hydrogen and oxygen from air and soil in the form of carbon dioxide and water. other nutrients are absorbed from soil (exceptions include some parasitic or carnivorous plants). counting these, there are 17 important nutrients for plants: these are macronutrients; nitrogen (n), phosphorus (p), potassium (k), calcium (ca), sulfur (s), magnesium (mg), carbon (c), oxygen(o) and hydrogen (h), and the micronutrients; iron (fe), boron (b), chlorine (cl), manganese (mn), zinc (zn), copper (cu), molybdenum (mo) and nickel (ni). in addition to carbon, hydrogen and oxygen; nitrogen, phosphorus, and sulfur are also needed in relatively large quantities. together, the "big six" are the elemental macronutrients for all organisms. they are sourced from inorganic matter (for example, carbon dioxide, water, nitrates, phosphates, sulfates, and diatomic molecules of nitrogen and, especially, oxygen) and organic matter (carbohydrates, lipids, proteins).