In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, but most are not.[ there is some evidence that there may be more.
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The four organogenic elements, namely carbon, hydrogen, oxygen, and nitrogen (CHON), that comprise roughly 96% of the human body by weight,
Plants obtain minerals from soil.
Finally, although mineral and elements are in many ways synonymous, minerals are only bioavailability 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
Twenty chemical elements are known to be required to support human biochemical processes by serving structural and functional roles, and there is evidence for a few more.
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.
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,
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).[
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Roles in biological processes
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| Potassium | 4700 | ; | A systemic electrolyte and is essential in coregulating ATP with sodium | Sweet potato, tomato, potato, beans, lentils, dairy products, seafood, banana, prune, carrot, orange | hypokalemia / hyperkalemia |
| Chlorine | 2300 | 3600; | 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; | A systemic electrolyte and is essential in coregulating ATP with potassium | Table salt (sodium chloride, the main source), , 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 | , eggs, canned fish with bones (salmon, sardines), green leafy vegetables, nuts, seeds, tofu, thyme, oregano, dill, cinnamon. | 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. | hypophosphatemia / hyperphosphatemia |
| Magnesium | 420/320 | 350; 250 | Required for processing ATP and for bones | Spinach, , nuts, seeds, whole grains, peanut butter, avocado | hypomagnesemia (magnesium deficiency) / hypermagnesemia |
| Iron | 8/18 | 45; | Required for many proteins and enzymes, notably hemoglobin to prevent anemia | Meat, seafood, nuts, beans, dark chocolate | 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 | Oysters*, red meat, poultry, nuts, whole grains, dairy products | zinc deficiency / zinc toxicity |
| Manganese | 2.3/1.8 | 11; | Required co-factor for superoxide dismutase | Grains, legumes, seeds, nuts, leafy vegetables, tea, coffee | manganese deficiency / manganism |
| Copper | 0.9 | 10; 5 | Required co-factor for cytochrome c oxidase | Liver, seafood, oysters, nuts, seeds; some: whole grains, legumes | 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 | iodine deficiency (goiter) / iodism (hyperthyroidism |
| Molybdenum | 0.045 | 2; 0.6 | Required for the functioning of xanthine oxidase, aldehyde oxidase, and sulfite oxidase | Legumes, whole grains, nuts | molybdenum deficiency / molybdenum toxicity |
| 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 | selenium deficiency / selenosis |
| Cobalt | (trace); (trace) | ; | Cobalt (as vitamin B12) is required for the DNA synthesis, erythropoiesis (red blood cell formation), and the development, myelination, and function of the central nervous system. It is available for use by animals only after having been processed by bacteria. Humans contain only milligrams of cobalt in these cofactors | Animal muscle and liver are good dietary sources, also shellfish and crab meat | pernicious anemia / cobalt poisoning |
| Sulfur | (abundant); (abundant) | ; | Sulfur (as essential amino acid methionine and its derivative cysteine) is required for the synthesis of proteins, Antioxidant, and the transcription, epigenetic expression, and gene regulation of DNA. It is unusual in that it is a mineral that may be taken in both inorganic and organic combinations. Sulfur is the most abundant mineral found in our body after calcium and phosphorus | Nuts, legumes, meats, eggs, fish, seafood, also fermented foods | compromised glutathione synthesis |
| Bromine | (trace); (trace) | ; | Important to basement membrane architecture and tissue development, as a needed catalyst to make collagen IV | | bromism |
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.
Dietary nutrition
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; iodised salt fortified with iodine). Dietary supplements can be formulated to contain several different chemical elements (as compounds), a combination of 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).
The dietary focus on chemical elements derives from an interest in supporting the biochemical reactions of metabolism with the required elemental components.
Plants
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
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.[ The European Union also sets recommended amounts and upper limits, which are not always in accord with the U.S.][ Likewise, Japan, which sets the UL for iodine at 3000 μg versus 1100 for the U.S. and 600 for the EU.][ 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.]
Elements considered possibly essential for humans but not confirmed
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.[ 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.][ Some elements were once thought to have a role with unknown biochemical nature, but the evidence has not always been strong.][ For example, it was once thought that arsenic was probably essential in mammals,][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.] but it seems to be only used by microbes;[ and while chromium was long thought to be an essential trace element based on rodent models, and was proposed to be involved in glucose and lipid metabolism,][ Boron is essential to plants,][
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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.[
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| Nickel | Nickel is an essential component of several enzymes, including urease and hydrogenase. | Nickel toxicity |
| Fluorine | There is no evidence that fluorine is essential, but it is beneficial. | Fluoride poisoning |
| Lithium | Based on plasma lithium concentrations, biological activity and epidemiological observations, there is evidence, not conclusive, that lithium is an essential nutrient. | Lithium toxicity |
| Silicon | Silicon is beneficial to most plants, but usually not essential. It seems to have beneficial effects in humans, strengthening bones and connective tissue, but these effects are still being studied. In any case deficiency symptoms do not arise because silicon occurs significantly in food made from plants. | |
| 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. | |
| Other | There are several elements that are not used by mammals, but seem to be beneficial in other organisms: boron, aluminium, titanium, arsenic, rubidium, strontium, cadmium, antimony, tellurium, barium, the early (from lanthanum to gadolinium), tungsten, and uranium. (In the cases of Al and Rb the mechanism is not well understood.) In particular, B, Ti, Sr, Cd, and Ba are used by eukaryotes, and Al and Rb might be as well.[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]] | |
Mineral ecology
Diverse ions are used by animals and microorganisms for the process of mineralizing structures, called biomineralization, used to construct , seashells, ,
Minerals can be bioengineered by bacteria which act on metals to catalysis mineral Solubility and precipitation.[ Mineral nutrients cycle through this marine food chain, from bacteria and phytoplankton to and zooplankton, which are then eaten by other marine life.][ In terrestrial ecosystems, fungi have similar roles as bacteria, mobilizing minerals from matter inaccessible by other organisms, then transporting the acquired nutrients to local .]
See also
Further reading
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Humphrey Bowen (1979) Environmental Chemistry of the Elements. Academic Press, .
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Humphry Bowen (1966) Trace Elements in Biochemistry. Academic Press.
External links
