Jump to content

Mineral (nutrient)

From Wikipedia, the free encyclopedia
(Redirected from Macro-element)
Carbonic anhydrase, an enzyme that requires zinc (gray sphere near the center of this image), is essential for exhalation of carbon dioxide.

In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, but most are not.[1][2][3] Minerals are one of the four groups of essential nutrients; the others are vitamins, essential fatty acids, and essential amino acids.[4] The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium.[2] The remaining minerals are called "trace elements". The generally accepted trace elements are iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine, and selenium;[5] there is some evidence that there may be more.

Four elements comprise 96% of the human body by weight: carbon, hydrogen, oxygen, and nitrogen (CHON). These elements are usually not included in lists of nutrient minerals. They are sometimes referred to as macrominerals. The minor minerals (also called trace elements) compose the remainder and are usually the focus of discussions of minerals in the diet.

Plants obtain minerals from soil.[6] Animals ingest plants, thus moving minerals up the food chain. Larger organisms may also consume soil (geophagia) or use mineral resources such as salt licks to obtain minerals.

Finally, although mineral and elements are in many ways synonymous, minerals are only bioavailable to the extent that they can be absorbed. To be absorbed, minerals either must be soluble or readily extractable by the consuming organism. For example, molybdenum is an essential mineral, but metallic molybdenum has no nutritional benefit. Many molybdates are sources of molybdenum.

Essential chemical elements for humans

[edit]

Nineteen chemical elements are known to be required to support human biochemical processes by serving structural and functional roles, and there is evidence for around ten more.[1][7]

Oxygen, hydrogen, carbon and nitrogen are the most abundant elements in the body by weight and make up about 96% of the weight of a human body. Calcium makes up 920 to 1200 grams of adult body weight, with 99% of it contained in bones and teeth. This is about 1.5% of body weight.[2] Phosphorus occurs in amounts of about 2/3 of calcium, and makes up about 1% of a person's body weight.[8] The other major minerals (potassium, sodium, chlorine, sulfur and magnesium) make up only about 0.85% of the weight of the body. Together these eleven chemical elements (H, C, N, O, Ca, P, K, Na, Cl, S, Mg) make up 99.85% of the body. The remaining ≈18 ultratrace minerals comprise just 0.15% of the body, or about one hundred grams in total for the average person. Total fractions in this paragraph are amounts based on summing percentages from the article on chemical composition of the human body.

Some diversity of opinion exist about the essential nature of various ultratrace elements in humans (and other mammals), even based on the same data. For example, whether chromium is essential in humans is debated. No Cr-containing biochemical has been purified. The United States and Japan designate chromium as an essential nutrient,[9][10] but the European Food Safety Authority (EFSA), representing the European Union, reviewed the question in 2014 and does not agree.[11]

Most of the known and suggested mineral nutrients are of relatively low atomic weight, and are reasonably common on land, or for sodium and iodine, in the ocean. They also tend to have soluble compounds at physiological pH ranges: elements without such soluble compounds tend to be either non-essential (Al) or, at best, may only be needed in traces (Si).[1]

Essential elements for higher organisms (eucarya).[12][13][14][15][1]
H   He
Li Be   B C N O F Ne
Na Mg   Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Legend:
  Quantity elements
  Essential trace elements
  Essentiality or function debated

Roles in biological processes

[edit]
Dietary element RDA/AI male/female (US) [mg][16] UL (US and EU) [mg][16][17] Category High nutrient density
dietary sources
Terms for deficiency/excess
Potassium 4700 NE; NE A systemic electrolyte and is essential in coregulating ATP with sodium Sweet potato, tomato, potato, beans, lentils, dairy products, seafood, banana, prune, carrot, orange[18] hypokalemia / hyperkalemia
Chlorine 2300 3600; NE Needed for production of hydrochloric acid in the stomach, in cellular pump functions and required in host defense Table salt (sodium chloride) is the main dietary source. hypochloremia / hyperchloremia
Sodium 1500 2300; NE A systemic electrolyte and is essential in coregulating ATP with potassium Table salt (sodium chloride, the main source), sea vegetables, milk, and spinach. hyponatremia / hypernatremia
Calcium 1000 2500; 2500 Needed for muscle, heart and digestive system health, builds bone (see hydroxyapatite), supports synthesis and function of blood cells, helps in blood clotting Dairy products, eggs, canned fish with bones (salmon, sardines), green leafy vegetables, nuts, seeds, tofu, thyme, oregano, dill, cinnamon.[19] hypocalcaemia / hypercalcaemia
Phosphorus 700 4000; 4000 A component of bones (see hydroxyapatite), cells, in energy processing, in DNA and ATP (as phosphate) and many other functions Red meat, dairy foods, fish, poultry, bread, rice, oats.[20][21] In biological contexts, usually seen as phosphate[22] hypophosphatemia / hyperphosphatemia
Magnesium 420/320 350; 250 Required for processing ATP and for bones Spinach, legumes, nuts, seeds, whole grains, peanut butter, avocado[23] hypomagnesemia (magnesium deficiency) / hypermagnesemia
Iron 8/18 45; NE Required for many proteins and enzymes, notably hemoglobin to prevent anemia Meat, seafood, nuts, beans, dark chocolate[24] iron deficiency / iron overload disorder
Zinc 11/8 40; 25 Required for several classes of enzymes such as matrix metalloproteinases, liver alcohol dehydrogenase, carbonic anhydrase and zinc finger proteins Oysters*, red meat, poultry, nuts, whole grains, dairy products[25] zinc deficiency / zinc toxicity
Manganese 2.3/1.8 11; NE Required co-factor for superoxide dismutase Grains, legumes, seeds, nuts, leafy vegetables, tea, coffee[26] manganese deficiency / manganism
Copper 0.9 10; 5 Required co-factor for cytochrome c oxidase Liver, seafood, oysters, nuts, seeds; some: whole grains, legumes[26] copper deficiency / copper toxicity
Iodine 0.150 1.1; 0.6 Required for the synthesis of thyroid hormones and to help enzymes in host defense Seaweed (kelp or kombu)*, grains, eggs, iodized salt[27] iodine deficiency (goiter) / iodism (hyperthyroidism[28])
Molybdenum 0.045 2; 0.6 Required for the functioning of xanthine oxidase, aldehyde oxidase, and sulfite oxidase[29] Legumes, whole grains, nuts[26] molybdenum deficiency / molybdenum toxicity[30]
Selenium 0.055 0.4; 0.3 Essential to activity of antioxidant enzymes like glutathione peroxidase Brazil nuts, seafoods, organ meats, meats, grains, dairy products, eggs[31] selenium deficiency / selenosis
Cobalt none NE; NE Cobalt is available for use by animals only after having been processed into complex molecules (e.g., vitamin B12) by bacteria. Humans contain only milligrams of cobalt in these cofactors. A deficiency of cobalt leads to pernicious anemia. Animal muscle and liver are good dietary sources, also shellfish and crab meat.[32] pernicious anemia / cobalt poisoning

RDA = Recommended Dietary Allowance; AI = Adequate intake; UL = Tolerable upper intake level; Figures shown are for adults age 31–50, male or female neither pregnant nor lactating

* One serving of seaweed exceeds the US UL of 1100 μg but not the 3000 μg UL set by Japan.[33]

Dietary nutrition

[edit]

Dietitians may recommend that minerals are best supplied by ingesting specific foods rich with the chemical element(s) of interest. The elements may be naturally present in the food (e.g., calcium in dairy milk) or added to the food (e.g., orange juice fortified with calcium; iodized salt fortified with iodine). Dietary supplements can be formulated to contain several different chemical elements (as compounds), a combination of vitamins and/or other chemical compounds, or a single element (as a compound or mixture of compounds), such as calcium (calcium carbonate, calcium citrate) or magnesium (magnesium oxide), or iron (ferrous sulfate, iron bis-glycinate).[citation needed]

The dietary focus on chemical elements derives from an interest in supporting the biochemical reactions of metabolism with the required elemental components.[34] Appropriate intake levels of certain chemical elements have been demonstrated to be required to maintain optimal health. Diet can meet all the body's chemical element requirements, although supplements can be used when some recommendations are not adequately met by the diet. An example would be a diet low in dairy products, and hence not meeting the recommendation for calcium.

Plants

[edit]
Structure of the Mn4O5Ca core of the oxygen-evolving site in plants, illustrating one of many roles of the trace mineral manganese.[35]

The list of minerals required for plants is similar to that for animals. Both use very similar enzymes, although differences exist. For example, legumes host molybdenum-containing nitrogenase, but animals do not. Many animals rely on hemoglobin (Fe) for oxygen transport, but plants do not. Fertilizers are often tailored to address mineral deficiencies in particular soils. Examples include molybdenum deficiency, manganese deficiency, zinc deficiency, and so on.

Safety

[edit]

The gap between recommended daily intake and what are considered safe upper limits (ULs) can be small. For example, for calcium the U.S. Food and Drug Administration set the recommended intake for adults over 70 years at 1,200 mg/day and the UL at 2,000 mg/day.[16] The European Union also sets recommended amounts and upper limits, which are not always in accord with the U.S.[17] Likewise, Japan, which sets the UL for iodine at 3000 μg versus 1100 for the U.S. and 600 for the EU.[33] In the table above, magnesium appears to be an anomaly as the recommended intake for adult men is 420 mg/day (women 350 mg/day) while the UL is lower than the recommended, at 350 mg. The reason is that the UL is specific to consuming more than 350 mg of magnesium all at once, in the form of a dietary supplement, as this may cause diarrhea. Magnesium-rich foods do not cause this problem.[36]

Elements considered possibly essential for humans but not confirmed

[edit]

Many ultratrace elements have been suggested as essential, but such claims have usually not been confirmed. Definitive evidence for efficacy comes from the characterization of a biomolecule containing the element with an identifiable and testable function.[5] One problem with identifying efficacy is that some elements are innocuous at low concentrations and are pervasive (examples: silicon and nickel in solid and dust), so proof of efficacy is lacking because deficiencies are difficult to reproduce.[34] Ultratrace elements of some minerals such as silicon and boron are known to have a role but the exact biochemical nature is unknown, and others such as arsenic are suspected to have a role in health, but with weaker evidence.[5] In particular, trace arsenic seems to have a positive effect on some organisms, but so does lead, showcasing the uncertainty behind whether some trace elements are truly essential.[1] Strontium is tolerated and is a component of some drugs,[37] but it is not essential, only beneficial.[1] Non-essential elements can sometimes appear in the body when they are chemically similar to essential elements (e.g. Rb+ and Cs+ replacing Na+), so that essentiality is not the same thing as uptake by a biological system.[1]

Element Description Excess
Bromine Possibly important to basement membrane architecture and tissue development, as a needed catalyst to make collagen IV.[15] bromism
Arsenic Essential in rat, hamster, goat and chicken models, but no research has been done in humans.[38] arsenic poisoning
Nickel Nickel is an essential component of several enzymes, including urease and hydrogenase.[39] Although not required by humans, some are thought to be required by gut bacteria, such as urease required by some varieties of Bifidobacterium.[40] In humans, nickel may be a cofactor or structural component of certain metalloenzymes involved in hydrolysis, redox reactions and gene expression. Nickel deficiency depressed growth in goats, pigs, and sheep, and diminished circulating thyroid hormone concentration in rats.[41] Nickel toxicity
Fluorine Might have a role in biologic mineralisation, and fluoride deficiency symptoms have been found in goats, but there is no clear evidence of essentiality in humans.[42] Research indicates that the primary dental benefit from fluoride occurs at the surface from topical exposure.[43][44] However, even if not essential, fluorine would still be a beneficial element for this reason.[42] Of the minerals in this table, fluoride is the only one for which the U.S. Institute of Medicine has established an Adequate Intake.[45] Fluoride poisoning
Boron Boron is an essential plant nutrient, required primarily for maintaining the integrity of cell walls.[46][47][48] Boron has been shown to be essential to complete the life cycle in representatives of all kingdoms of life.[39][49] In animals, supplemental boron has been shown to reduce calcium excretion and activate vitamin D.[50] No acute effects (LD50 of boric acid is 2.5 grams per kilogram body weight)
Lithium Based on plasma lithium concentrations, biological activity and epidemiological observations, there is evidence, not conclusive, that lithium is an essential nutrient.[13][14] Lithium toxicity
Chromium Proposed to be involved in glucose and lipid metabolism, although its mechanisms of action in the body and the amounts needed for optimal health are not well-defined[51][52] chromium deficiency / chromium toxicity
Silicon Deficiency symptoms have been found in chickens and rats, though not humans. Circumstantial evidence suggests that it is an essential nutrient, probably having an effect on the function and composition of brain and bone.[42]
Vanadium Has an established, albeit specialized, biochemical role in other organisms (algae, lichens, fungi, bacteria), and there is significant circumstantial evidence for its essentiality in humans. It is rather toxic for a trace element and the requirement, if essential, is probably small.[42]
Tin Rats fed a tin-free diet exhibited improper growth, but the evidence for essentiality is otherwise limited.[1][42] Tin poisoning
Other Tungsten, the early lanthanides, and cadmium have specialized biochemical uses in certain lower organisms, but these elements appear not to be used by mammals.[42]

Mineral ecology

[edit]

Diverse ions are used by animals and microorganisms for the process of mineralizing structures, called biomineralization, used to construct bones, seashells, eggshells,[53] exoskeletons and mollusc shells.[54][citation needed]

Minerals can be bioengineered by bacteria which act on metals to catalyze mineral dissolution and precipitation.[55] Mineral nutrients are recycled by bacteria distributed throughout soils, oceans, freshwater, groundwater, and glacier meltwater systems worldwide.[55][56] Bacteria absorb dissolved organic matter containing minerals as they scavenge phytoplankton blooms.[56] Mineral nutrients cycle through this marine food chain, from bacteria and phytoplankton to flagellates and zooplankton, which are then eaten by other marine life.[55][56] In terrestrial ecosystems, fungi have similar roles as bacteria, mobilizing minerals from matter inaccessible by other organisms, then transporting the acquired nutrients to local ecosystems.[57][58]

See also

[edit]

References

[edit]
  1. ^ a b c d e f g h Zoroddu, Maria Antonietta; Aaseth, Jan; Crisponi, Guido; Medici, Serenella; Peana, Massimiliano; Nurchi, Valeria Marina (2019). "The essential metals for humans: a brief overview". Journal of Inorganic Biochemistry. 195: 120–129. doi:10.1016/j.jinorgbio.2019.03.013.
  2. ^ a b c Berdanier, Carolyn D.; Dwyer, Johanna T.; Heber, David (2013). Handbook of Nutrition and Food (3rd ed.). CRC Press. p. 199. ISBN 978-1-4665-0572-8. Retrieved 3 July 2016.
  3. ^ "Minerals". MedlinePlus, National Library of Medicine, US National Institutes of Health. 22 December 2016. Retrieved 24 December 2016.
  4. ^ "Vitamin and mineral supplement fact sheets". Office of Dietary Supplements, US National Institutes of Health, Bethesda, MD. 2016. Retrieved 19 December 2016.
  5. ^ a b c Berdanier, Carolyn D.; Dwyer, Johanna T.; Heber, David (19 April 2016). Handbook of Nutrition and Food, Third Edition. CRC Press. pp. 211–24. ISBN 978-1-4665-0572-8. Retrieved 3 July 2016.
  6. ^ "Minerals". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, OR. 2016.
  7. ^ Nelson, David L.; Michael M. Cox (15 February 2000). Lehninger Principles of Biochemistry, Third Edition (3 Har/Com ed.). W. H. Freeman. pp. 1200. ISBN 1-57259-931-6.
  8. ^ "Phosphorus in diet". MedlinePlus, National Library of Medicine, US National Institutes of Health. 2 December 2016. Retrieved 24 December 2016.
  9. ^ Institute of Medicine (US) Panel on Micronutrients (2001). "6, Chromium". Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Chromium, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Chromium. National Academies Press (US). pp. 197–223.
  10. ^ "Overview of Dietary Reference Intakes for Japanese (2015)" (PDF).
  11. ^ "Scientific Opinion on Dietary Reference Values for chromium". European Food Safety Authority. 18 September 2014. Retrieved 20 March 2018.
  12. ^ Ultratrace minerals. Authors: Nielsen, Forrest H. USDA, ARS Source: Modern nutrition in health and disease / editors, Maurice E. Shils, et al. Baltimore: Williams & Wilkins, c1999.[clarify], p. 283–303. Issue date: 1999.
  13. ^ a b Szklarska D, Rzymski P (May 2019). "Is Lithium a Micronutrient? From Biological Activity and Epidemiological Observation to Food Fortification". Biol Trace Elem Res. 189 (1): 18–27. doi:10.1007/s12011-018-1455-2. PMC 6443601. PMID 30066063.
  14. ^ a b Enderle J, Klink U, di Giuseppe R, Koch M, Seidel U, Weber K, Birringer M, Ratjen I, Rimbach G, Lieb W (August 2020). "Plasma Lithium Levels in a General Population: A Cross-Sectional Analysis of Metabolic and Dietary Correlates". Nutrients. 12 (8): 2489. doi:10.3390/nu12082489. PMC 7468710. PMID 32824874.
  15. ^ a b McCall AS, Cummings CF, Bhave G, Vanacore R, Page-McCaw A, Hudson BG (June 2014). "Bromine is an essential trace element for assembly of collagen IV scaffolds in tissue development and architecture". Cell. 157 (6): 1380–1392. doi:10.1016/j.cell.2014.05.009. PMC 4144415. PMID 24906154. Cite error: The named reference "bromine" was defined multiple times with different content (see the help page).
  16. ^ a b c "Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes" (PDF). Food and Nutrition Board, Institute of Medicine, National Academies of Sciences. Archived from the original (PDF) on 14 June 2022. Retrieved 25 August 2023.
  17. ^ a b Tolerable Upper Intake Levels For Vitamins And Minerals (PDF), European Food Safety Authority, 2006, retrieved 4 January 2020
  18. ^ "Dietary Guidelines for Americans 2005: Appendix B-1. Food Sources of Potassium". United States Department of Agriculture. 2005.
  19. ^ Drewnowski A (2010). "The Nutrient Rich Foods Index helps to identify healthy, affordable foods" (PDF). Am J Clin Nutr. 91(suppl) (4): 1095S–1101S. doi:10.3945/ajcn.2010.28450D. PMID 20181811.
  20. ^ "NHS Choices:Vitamins and minerals – Others". Retrieved 8 November 2011.
  21. ^ Corbridge, DE (1 February 1995). Phosphorus: An Outline of Its Chemistry, Biochemistry, and Technology (5th ed.). Amsterdam: Elsevier Science Pub Co. p. 1220. ISBN 0-444-89307-5.
  22. ^ "Phosphorus". Linus Pauling Institute, Oregon State University. 2014. Retrieved 8 September 2018.
  23. ^ "Magnesium—Fact Sheet for Health Professionals". National Institutes of Health. 2016.
  24. ^ "Iron—Dietary Supplement Fact Sheet". National Institutes of Health. 2016.
  25. ^ "Zinc—Fact Sheet for Health Professionals". National Institutes of Health. 2016.
  26. ^ a b c Schlenker, Eleanor; Gilbert, Joyce Ann (28 August 2014). Williams' Essentials of Nutrition and Diet Therapy. Elsevier Health Sciences. pp. 162–3. ISBN 978-0-323-29401-0. Retrieved 15 July 2016.
  27. ^ "Iodine—Fact Sheet for Health Professionals". National Institutes of Health. 2016.
  28. ^ Jameson, J. Larry; De Groot, Leslie J. (25 February 2015). Endocrinology: Adult and Pediatric. Elsevier Health Sciences. p. 1510. ISBN 978-0-323-32195-2. Retrieved 14 July 2016.
  29. ^ Sardesai VM (December 1993). "Molybdenum: an essential trace element". Nutr Clin Pract. 8 (6): 277–81. doi:10.1177/0115426593008006277. PMID 8302261.
  30. ^ Momcilović, B. (September 1999). "A case report of acute human molybdenum toxicity from a dietary molybdenum supplement—a new member of the "Lucor metallicum" family". Archives of Industrial Hygiene and Toxicology. 50 (3). De Gruyter: 289–97. PMID 10649845.
  31. ^ "Selenium—Fact Sheet for Health Professionals". National Institutes of Health. 2016.
  32. ^ "Vitamin B-12 (µg)" (PDF). USDA National Nutrient Database for Standard Reference Release 28. 27 October 2015. Archived (PDF) from the original on 26 January 2017. Retrieved 1 December 2022.
  33. ^ a b "Overview of Dietary Reference Intakes for Japanese" (PDF). Minister of Health, Labour and Welfare, Japan. 2015. p. 39. Retrieved 5 January 2020.
  34. ^ a b Lippard, SJ; Berg JM (1994). Principles of Bioinorganic Chemistry. Mill Valley, CA: University Science Books. p. 411. ISBN 0-935702-72-5.
  35. ^ Umena, Yasufumi; Kawakami, Keisuke; Shen, Jian-Ren; Kamiya, Nobuo (May 2011). "Crystal structure of oxygen-evolving photosystem II at a resolution of 1.9 Å" (PDF). Nature. 473 (7345): 55–60. Bibcode:2011Natur.473...55U. doi:10.1038/nature09913. PMID 21499260. S2CID 205224374.
  36. ^ Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (1997). "6, Magnesium". Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. National Academies Press (US). pp. 190–249.
  37. ^ Pors Nielsen, S. (2004). "The biological role of strontium". Bone. 35 (3): 583–588. doi:10.1016/j.bone.2004.04.026. PMID 15336592. Retrieved 6 October 2010.
  38. ^ Anke M. Arsenic. In: Mertz W. ed., Trace elements in human and Animal Nutrition, 5th ed. Orlando, FL: Academic Press, 1986, 347–372; Uthus E.O., Evidency for arsenical essentiality, Environ. Geochem. Health, 1992, 14:54–56; Uthus E.O., Arsenic essentiality and factors affecting its importance. In: Chappell W.R, Abernathy C.O, Cothern C.R. eds., Arsenic Exposure and Health. Northwood, UK: Science and Technology Letters, 1994, 199–208.
  39. ^ a b Berdanier, Carolyn D.; Dwyer, Johanna T.; Heber, David (19 April 2016). Handbook of Nutrition and Food, Third Edition. CRC Press. pp. 211–26. ISBN 978-1-4665-0572-8. Retrieved 3 July 2016.
  40. ^ Sigel, Astrid; Sigel, Helmut; Sigel, Roland K. O. (27 January 2014). Interrelations between Essential Metal Ions and Human Diseases. Springer Science & Business Media. p. 349. ISBN 978-94-007-7500-8. Retrieved 4 July 2016.
  41. ^ Institute of Medicine (29 September 2006). Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. National Academies Press. pp. 313–19, 415–22. ISBN 978-0-309-15742-1. Retrieved 21 June 2016.
  42. ^ a b c d e f Ultratrace minerals. Authors: Nielsen, Forrest H. USDA, ARS Source: Modern nutrition in health and disease / editors, Maurice E. Shils ... et al.. Baltimore : Williams & Wilkins, c1999., p. 283-303. Issue Date: 1999 URI: [1]
  43. ^ Kakei M, Sakae T, Yoshikawa M (2012). "Aspects Regarding Fluoride Treatment for Reinforcement and Remineralization of Apatite Crystals". Journal of Hard Tissue Biology. 21 (3): 475–6. doi:10.2485/jhtb.21.257. Retrieved 1 June 2017.
  44. ^ Loskill P, Zeitz C, Grandthyll S, Thewes N, Müller F, Bischoff M, Herrmann M, Jacobs K (May 2013). "Reduced adhesion of oral bacteria on hydroxyapatite by fluoride treatment". Langmuir. 29 (18): 5528–33. doi:10.1021/la4008558. PMID 23556545.
  45. ^ Institute of Medicine (1997). "Fluoride". Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride. Washington, DC: The National Academies Press. pp. 288–313. doi:10.17226/5776. ISBN 978-0-309-06403-3. PMID 23115811.
  46. ^ Mahler, RL. "Essential Plant Micronutrients. Boron in Idaho" (PDF). University of Idaho. Archived from the original (PDF) on 1 October 2009. Retrieved 5 May 2009.
  47. ^ "Functions of Boron in Plant Nutrition" (PDF). U.S. Borax Inc. Archived from the original (PDF) on 20 March 2009.
  48. ^ Blevins DG, Lukaszewski KM (June 1998). "Boron in plant structure and function". Annu. Rev. Plant Physiol. Plant Mol. Biol. 49: 481–500. doi:10.1146/annurev.arplant.49.1.481. PMID 15012243.
  49. ^ Erdman, John W. Jr.; MacDonald, Ian A.; Zeisel, Steven H. (30 May 2012). Present Knowledge in Nutrition. John Wiley & Sons. p. 1324. ISBN 978-0-470-96310-4. Retrieved 4 July 2016.
  50. ^ Nielsen, FH (1997). "Boron in human and animal nutrition". Plant and Soil. 193 (2): 199–208. doi:10.1023/A:1004276311956. ISSN 0032-079X. S2CID 12163109.
  51. ^ Kim, Myoung Jin; Anderson, John; Mallory, Caroline (1 February 2014). Human Nutrition. Jones & Bartlett Publishers. p. 241. ISBN 978-1-4496-4742-1. Retrieved 10 July 2016.
  52. ^ Gropper, Sareen S.; Smith, Jack L. (1 June 2012). Advanced Nutrition and Human Metabolism. Cengage Learning. pp. 527–8. ISBN 978-1-133-10405-6. Retrieved 10 July 2016.
  53. ^ Hunton, P (2005). "Research on eggshell structure and quality: an historical overview". Revista Brasileira de Ciência Avícola. 7 (2): 67–71. doi:10.1590/S1516-635X2005000200001.
  54. ^ Currey, JD (1999). "The design of mineralised hard tissues for their mechanical functions". The Journal of Experimental Biology. 202 (Pt 23): 3285–94. doi:10.1242/jeb.202.23.3285. PMID 10562511.
  55. ^ a b c Warren LA, Kauffman ME (February 2003). "Geoscience. Microbial geoengineers". Science. 299 (5609): 1027–9. doi:10.1126/science.1072076. PMID 12586932. S2CID 19993145.
  56. ^ a b c Azam, F; Fenchel, T; Field, JG; Gray, JS; Meyer-Reil, LA; Thingstad, F (1983). "The ecological role of water-column microbes in the sea" (PDF). Mar. Ecol. Prog. Ser. 10: 257–63. Bibcode:1983MEPS...10..257A. doi:10.3354/meps010257.
  57. ^ J. Dighton (2007). "Nutrient Cycling by Saprotrophic Fungi in Terrestrial Habitats". In Kubicek, Christian P.; Druzhinina, Irina S (eds.). Environmental and microbial relationships (2nd ed.). Berlin: Springer. pp. 287–300. ISBN 978-3-540-71840-6.
  58. ^ Gadd GM (January 2017). "The Geomycology of Elemental Cycling and Transformations in the Environment" (PDF). Microbiol Spectr. 5 (1): 371–386. doi:10.1128/microbiolspec.FUNK-0010-2016. ISBN 9781555819576. PMID 28128071. S2CID 4704240.

Further reading

[edit]
[edit]