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Trace Minerals
I have heard about trace minerals. Are they the same as toxic minerals?
The human body, like everything else in nature, is made up of chemicals. The strict definition of a trace mineral or trace element is one that makes up less than 0.01% (1/10,000th part) of the body weight. The term trace mineral arose because when the original work of chemical analysis was being done earlier in this century, the equipment could detect that the minerals were present, but it could not measure the amounts accurately. The scientists reported that there were “traces” of the minerals present in the body. Modern technology allows us to measure minerals down to one-billionth of a gram, but we still use the old term “trace minerals” for convenience.
Since the trace minerals group includes over 50 chemical elements, scientists further subdivide this group into three categories, to separate the minerals that are important in health from others that are in our bodies just because they are in the environment and probably have no special role. The first category is the essential trace minerals. These are minerals that are required in the diet for full health, and when the intake is insufficient, symptoms of deficiency will arise. They include nine known to be essential: zinc, copper, selenium, chromium,manganese, molybdenum, iodine, fluoride, and cobalt. About 10 more minerals are thought to be essential but the full proof is not yet in; these are arsenic, boron, bromium, cadmium, lead, lithium, nickel, silicon, tin, and vanadium.
You will note in this list several minerals (arsenic, cadmium, lead) that are normally thought to be toxic. This leads to the second category of trace minerals, the toxic trace minerals. The term is used for minerals that give problems with toxicity at levels that may be encountered normally in the environment and for which health concerns are more likely to arise from too much rather than too little in the body. This category is fairly loose, changing from time to time, and includes aluminum, arsenic, cadmium, lead, mercury, and tin.
Actually, all nutrients are toxic if too much is ingested; how much is too much depends on the nutrient. For essential minerals like copper, there is a definite gradation for health; if the intake is below the requirement, illness due to deficiency will develop; as the intake goes up, health will improve until a plateau is reached, where small increases in intake will not make any difference to health; above the top safe level (the end of the plateau), increases in intake will cause toxic illness. In extreme cases, both deficiency at one end and toxicity at the other end of the spectrum may get so severe as to cause death. This pattern is seen for all nutrients, including, for example, vitamins, macro-minerals, and protein.
The third category of nonessential trace minerals is everything else: all the other minerals that are present in the body but are not essential in the diet and are not thought to have any function, and that do not cause any concern over toxicity or deficiency.
Why should we need zinc or copper in the diet?
Zinc and copper are essential nutrients, that is, they are required by the body for growth, healthy functioning, and life itself. Zinc is used in the manufacture ofproteins for muscles, skin, nerve, and brain tissue, and in protection against infections and disease. Copper is used in the manufacture of bones, cartilage, hair, blood, and neurotransmitters (the chemicals that transmit messages in the brain and nerves).
If the amount of zinc and copper in the body is not enough to carry out these processes, they gradually slow down, resulting in illness and even death. Everyone loses a small amount every day in the urine, feces, hair, nail clippings, scrapings of skin, etc. Therefore, in order to keep the total amount of each mineral in the body at its proper level, we need a small amount in the diet each day to replace the losses. Babies need extra, because they are growing.
What happens when babies do not get enough zinc in their diets?
Mild zinc deficiency may be quite common in the United States and other western countries, in infants and preschool children who eat diets which do not provide enough zinc to meet all their needs. The risk of poor zinc nutrition may be greater in countries and regions where the diet is low in meat and high in legumes, breads, and other cereal foods made from coarsely ground flours. Mild zinc deficiency causes poor appetite, fussiness, and failure to grow. A more severe degree of zinc deficiency causes skin rashes and diarrhea.
Zinc deficiency may be suspected in infants with poor growth if no other cause can be found. Typically, these infants have recently been switched early from formula or breastfeeding to a mixed diet of solids and liquids.
Before starting zinc treatment, your doctor often will use formula for a trial period to show that the failure to grow has not been caused simply by the infant not taking enough food from the new diet of solids. Diets containing little meat or other animal foods may be low in zinc. If the diet is also high in foods like beans, flat breads, tortillas, and whole grain products, zinc absorption in the gut will be low and may make deficiency more likely.
What happens when babies do not get enough copper in their diets?
Copper deficiency occurred in the past in some full-term infants who were given cow’s milk formulas without added copper. Now, formulas generally contain adequate copper. Copper deficiency currently occurs mostly in preterm infants and those with diarrhea or liver disease. Rare cases have also occurred in full-term infants, when they are fed cow’s milk alone, rather than manufactured formulas, as cow’s milk has much lower levels of copper than breast milk and formula do.
Very high intakes of zinc from supplements may also cause copper deficiency. The main signs of copper deficiency are poor weight gain, pale skin, and loss of hair color. Laboratory tests show that copper-deficient infants have anemia, too few white cells, and low levels of copper in their blood compared with other infants of the same age. Their bones get thin, and fractures may occur spontaneously, without any stress being put on them.
I use zinc oxide for my baby’s diaper rash. Can that cause him some harm?
No. Zinc creams and ointments are a very old remedy for skin complaints, used long before it was known that zinc was essential in the diet. Although most skin rashes are not due to zinc deficiency, skin generally benefits from zinc-containing creams. However, zinc oxide creams are not a substitute for good hygiene. Make sure diapers are changed regularly; don’t leave a wet or soiled diaper too long as urine is very irritating to the skin; wash and dry the area each time. When possible, it is always a good idea to leave the baby’s bottom exposed to the air for a while to allow thorough drying.
There are copper pipes in our house. Can babies get sick from the copper?
In the 1960s and early 1970s, there were reports from hospitals in several different countries of babies suffering from stomach pains with blue-green diarrhea and vomit. The cause was eventually traced to copper poisoning from copper hot water pipes. These babies were receiving formula that had been made up with hot water from the faucet taken first thing in the morning, so that the water used in the formula had been sitting in the pipes all night. The high temperature of the water assisted in dissolving copper from the pipes, since copper is less likely to dissolve in cold water. The problem was fixed by letting the faucets run for a few minutes in the morning to clear the overnight water before taking the water to make up formula.
Copper pipes in a house will be less likely to cause poisoning as they are shorter, and the temperature of domestic hot water is lower than that used in hospitals. However, if you have copper hot water pipes, run the kitchen faucet for a few minutes first thing in the morning before getting water to boil for the baby’s formula or drink. (It also results in better tasting coffee and tea!)
We have copper wiring in our house. Does copper let off harmful vapors?
Copper wires, and the outside surfaces of exposed copper pipes, are not a problem. Copper boils, and hence gives off vapors or fumes, at 2,300°C. (Compare this with water boiling at 100°C.) People who work in copper smelters or refineries can be at risk of toxicity from the fumes, but nothing in the household or ordinary daily life reaches temperatures near this level.
I’ve heard that there are lots of other trace minerals. What are they and what do they do?
In Question 1, we said that there are nine minerals that are regarded as essential in the diet of humans. Ten other minerals are currently under investigation as possibly being essential to animals and humans, but we do not yet have complete proof that they are needed in the diet. Of the nine essential minerals, zinc, copper, and fluoride are discussed in other questions. The other six are discussed in this question.
Normal diets, including those of infants, usually supply enough to meet mineral requirements, and these minerals do not cause problems in healthy individuals. For preterm or sick infants, particularly those receiving special feeding, such as intravenous feeding or formulas for conditions like phenylketonuria (PKU), care must be taken to supply adequate amounts of these essential trace minerals, or deficiency may occur.
Selenium: Farmers recognized many years ago the importance of selenium to their livestock as both deficiency and toxicity caused stock losses in many parts of the world. Very low levels occur in parts of Europe, China, the western United States, and New Zealand; very high levels have been found in parts of China, the Great Plains of the United States (especially South Dakota), and Venezuela. Selenium levels in breast milk and infant formula depend on the selenium levels, whether low, adequate, or very high, in the area where the milk or formula ingredients come from. However, even in low selenium countries, infants appear to get enough in their diets without needing supplements. Some manufacturers may add selenium to formula to bring the content up to levels found in selenium-adequate areas. Babies should not be given selenium supplements without medical supervision: some forms of selenium are more toxic than arsenic. Selenium protects cells from the damaging byproducts which are formed when they use oxygen. Selenium is important for the proper functioning of muscles, including heart muscle.
Iodine: Iodine is a vital part of the thyroid hormones which play a role in the proper control of growth, brain development, and energy use. Iodine deficiency causes goiter, reduced growth, and defects in the central nervous system, which range from mild decreases in intellectual performance to severe mental retardation and deaf-mutism (cretinism), depending on the severity of the iodine deficiency. Poor iodine nutrition still occurs in many parts of the world where levels in the soil are low. These are regions of very old granite far from the sea and of young mountains, such as central Africa, Nepal, Switzerland, and parts of Germany and Belgium. A recent survey of infant formulas found that many of those sold in Europe, Canada, and Japan contained lower than the recommended levels of iodine, although levels in breast milk were adequate. The introduction of iodized salt in the 1920s in some western countries with low iodine levels, including the United States and New Zealand, has largely eradicated goiter from these countries, but consumers must continue to use it. Today, iodine-containing products are widely used in the food industry (eg, in baking and the dairy industry), so that the levels in the food supply are generally adequate in most western countries. Areas where seafood is an important part of the diet (eg, in Japan) also have good intakes of iodine.
Manganese: Curiously, although there has never been a true case of manganese deficiency reported in a human, there is no dispute about this mineral being essential in nutrition. Manganese is an important part of the enzymes by which the body uses carbohydrates to manufacture cartilage in the bones, ears, and similar structures and to make neurotransmitters (chemicals which carry messages along nerves and within the brain). Levels of manganese in breast milk are 50 to 100 times lower than levels in formula, but intakes of both breastfed (lower) and formula-fed (higher) infants appear to be adequate and safe. Plant foods generally contain much more manganese than do animal-based foods, so intake of manganese goes up considerably when solids are started.
Chromium: Chromium is important to ensure proper control of sugar in the body, and it may help insulin (the main hormone that controls blood sugar) to function. Intakes from formulas are usually 50 to 100 times higher than the amount a breastfed baby receives, but, as with manganese, there is no evidence that the level of intake from formula is too high or the level from breast milk is too low.
Molybdenum: This is another mineral that is important to farmers but unlikely to cause problems in humans under normal circumstances. Molybdenum is required for the body to properly use sulfur in proteins and to make structures like the lens of the eye.
Cobalt: This mineral is a part of vitamin B12. Humans cannot make B12 in the body. We need cobalt in the diet only as part of the vitamin.
How do I know if the formula has enough trace minerals?
Formulas sold as substitutes for breast milk in most countries are required by law to contain certain minimum amounts of the trace minerals that are currently recognized by medical science as being essential for health. For some minerals, upper allowable limits may also be set. These levels are based upon the amounts a baby would get when fed entirely on breast milk, with an additional allowance because minerals in formula are less well absorbed by the intestine compared with those in breast milk.
The product container gives the content of trace minerals in the formula as purchased. In fact, the manufacturers of formulas are generally very aware of current research in infant nutrition and of consumer concerns, and they adjust formulas from time to time to keep up with the newest findings. Infant formulas comply with various authoritative recommendations with regard to the content of nutrients, including trace minerals.
Does breast milk have enough trace minerals?
Although we usually think of breast milk as being the “perfect” food, providing exactly what infants need, this is not always the case. For some nutrients, the amount in breast milk is affected by what is in the mother’s diet and, if this is low, the amount going into her breast milk may also be low. Trace minerals may be divided into two sorts depending on how they behave chemically and in solution: the positive, or cations, and the negative, or anions. Metals such as iron, zinc, and gold make cations and the non-metal minerals like iodine and fluorine make anions. Selenium behaves both ways, but in the body it mostly acts like an anion.
In the body, the levels of the cation trace minerals are carefully controlled and the amount eaten in the diet does not make much difference (unless it is very inadequate). The amount of these minerals that passes into the breast milk is also carefully controlled. Human milk collected from mothers in many different parts of the world has very similar levels of the essential trace minerals zinc and copper. Consequently, breast milk provides enough of those types of trace minerals (copper, chromium, manganese, molybdenum, and zinc) for as long as breast milk alone is adequate for proper growth of the infant.
A very small number of mothers may have a defect which causes them to produce a milk that is low in zinc, compared with most mothers. Their breast milk may not have enough zinc for their baby, especially if the baby is preterm, because preterm babies grow very fast and need more zinc in relation to their size than do full-term infants. Fortunately, this syndrome is very rare.
The other types of minerals, the anions, include selenium, fluoride, and iodine. (Fluoride is the name for the anion form of fluorine.) For these minerals, the amount in the diet varies very widely, depending on the amount in the water and soil where the food is grown. There are parts of the world where the diet provides too much of these minerals and other regions where diets do not provide enough for full health. The amount of these minerals that gets into breast milk is related to the amount in the mother’s diet and can be deficient in some parts of the world. On the whole, however, in North America, Europe, and other industrialized countries, the food supply comes from many different areas, and diets provide adequate amounts of selenium and iodine, so the amounts in breast milk are usually quite sufficient for the baby’s needs. Fluoride levels in breast milk can be low depending on the local water supply, and this is discussed in latter on.
It sounds odd that we need to take metals into our body. Isn’t that kind of dangerous?
Cells keep themselves alive and carry out their functions by means of chemical reactions. They take up oxygen, use sugars and fats as fuel, replicate (ie, make copies of) DNA, make new proteins, reproduce, and all the many other processes they must carry on to make us all function as complete human beings. It is, therefore, critically important that these chemicalreactions are very carefully controlled in how fast they proceed and how much substance they make or use up.
Cells have developed systems whereby small amounts of metals are used to control rates of chemical reactions (copper, zinc, manganese, molybdenum), carry oxygen (iron, copper, vanadium), remove the damaging products of oxygen use (selenium, manganese), assist in binding hormones to cell membranes (chromium), control the shapes of proteins and DNA (zinc, chromium, nickel), and many other roles.
We require a small amount of the essential minerals in our diet, but, like all nutrients, excessive intakes can cause toxicity. This is well known, for example, for energy intake. If you do not eat enough to fill your needs (deficiency), you lose weight and starve. If you eat much more than you need (excess or toxicity), you get fat. The same situation holds with other nutrients, such as vitamins and essential trace minerals.
As well as the essential minerals, we cannot avoid taking in a little of all the other minerals that are present naturally in our food and water. The body excludes part of this intake by not absorbing it or by excreting it in feces and urine, but some will stay in the body, where it may be stored; the bone and liver in particular have special storage mechanisms which keep nonessential minerals from interfering with important bodily functions.
Older people have higher body levels of most of these minerals compared with babies and children. The amounts accumulated over a lifetime vary with factors like the mineral content of local soils and usual type of diet. However, this accumulation is of no concern, unless the long-term intake has been above safe levels. When it has occurred, the cause of trace mineral toxicity is usually found to be a specific, unusual factor. Examples are outbreaks of zinc poisoning which were caused by drinking acid fruit punch stored in a galvanized vat, and selenium poisoning from taking supplemental tablets made up incorrectly by the manufacturer. Babies are not likely to be exposed to excessive intakes of minerals under such circumstances. Even when mothers take large doses of essential trace minerals, levels in breast milk are raised only slightly. However, care must be taken not to exceed the recommended dose when giving a supplement of trace mineral, such as fluoride drops or zinc syrup.
Do I need to give my baby fluoride?
This depends on where you live and how you feed your baby. Water is our main source of fluoride. For best dental health, the recommended level of fluoride in the water supply is 0.7 to 1.0 ppm (parts of fluoride per million parts of water) and levels above 0.3 ppm are adequate. If your domestic water supply contains more than 0.3 ppm, no fluoride supplement is needed.
The American Academy of Pediatrics recommends that all infants living in areas where the water contains less than 0.3 ppm fluoride receive a fluoride supplement. This applies to both breastfed and formula-fed babies. The recommended dosage is 0.25 mg of fluoride per day from 6 months to 2 years of age, given as drops or crushed tablets in a drink. Before 6 months of age, no extra fluoride is required. The recommendation in the United Kingdom is similar,0.25 mg per day for infants only (from birth to about 2 years), regardless of water levels. Recommendations for fluoride supplementation are under review in many countries because of the widespread use of fluoride-containing toothpastes.
To prevent babies from getting too much fluoride, formula manufacturers deliberately use low-fluoride water. Therefore, infants receiving ready-to-feed formula should be given fluoride supplement, no matter what the level of fluoride is in the water where you live.
If I use bottled water to prepare formula, do I need a fluoride supplement? How much?
This is difficult to answer directly; different bottled waters come from different sources and may be processed in several different ways. The most simple processing, including the filters for use in the home, uses activated charcoal which removes some organic residues (pesticides, fertilizers, flavors) and organisms like Giardia, but not minerals.
Some bottled waters, however, may also be demineralized; demineralization may remove only metals (cations like calcium, iron, and zinc) or may remove both cations and anions, like chloride. This latter process will remove fluoride, too. The only way to know if your own water contains adequate fluoride is to get an analysis from the manufacturer/supplier (if it is not already on the container). Follow the advice about supplementation given in Question 12, according to the fluoride content of the water.
NOTE: Bottled mineral waters are not suitable for babies; these products generally have levels of sodium and other minerals that are too high for small infants.
We have no fluoride in our water. Should I use a fluoride supplement?
Yes, see the two previous questions for recommendations. However, you must be careful to distinguish between no fluoride and no added fluoride. If no fluoride has been added, this may be because the level is already naturally high enough and additional fluoride is not needed, in which case you should not give a supplement. Or, it may mean that no fluoride has been added to the water and the level is naturally low, in which case a supplement is recommended. The level in the water supplied to the consumer is the important number; if this is less than 0.3 ppm, you should use a supplement and fluoride toothpaste when the child is old enough. (In some countries, trials are being made of fluoride supplements in salt or milk supplies.)
My baby doesn’t have any teeth. What difference does it make whether my baby takes water with fluoride or not?
Teeth which contain fluoride are much more resistant to dental caries (decay) than those formed in low or no fluoride conditions. Teeth, even the second teeth, are mostly made during the first 8 years of life. This includes the period before the baby is born, so it is important that the mother has an adequate intake of fluoride during pregnancy also. After age 8, fluoride can still help to protect and strengthen the top enamel layer, so it is desirable to continue adequate intake of fluoride for life, including use of fluoride-containing toothpastes.
I read once that fluoridated water can give you bad teeth also. Is that right?
When fluoride is deliberately added to water, the final concentration in the water supply is made to be about 1.0 ppm and never gets much above this. However, levels much higher than this occur naturally in some parts of the world, such as the Middle East, Northern India, Texas, and Tennessee, where fluoride levels as high as 10 ppm have been measured. When the level of fluoride in water is above about 2.5 ppm, the tooth enamel can become mottled. The brown patches that develop on the surface of teeth are unsightly but no damage is done to the enamel. If levels are higher than this, however, the enamel may become thin and pitted.
How do I know whether my community has enough fluoride in the water?
The local water supply authority or company should be able to give you this information; otherwise, try your local water supplier. Optimum levels for good dental health are 0.7 to 1.0 ppm, but levels above 0.3 ppm are adequate.
What is fluoride, anyway? Is it really a mineral?
Fluoride is a mineral but not a metal. The term mineral is broader and includes all elements and mixtures of elements, such as rocks and concrete, that occur naturally as the products of inorganic processes (that is, chemical processes not concerned with living systems). Metals are elements or mixtures of elements that have a lustrous appearance and conduct heat and electricity, like copper; metals are a subdivision of minerals. Metals are solid at ordinary temperatures; they can be worked to make useful or decorative items like aluminum saucepans or gold jewelry.
Fluoride, on the other hand, is a gas when it is chemically on its own, and is known as fluorine. When it is dissolved in a solution or is part of a solid like tooth enamel, it exists as the negative ion (anion) fluoride, always combined with other elements, such as sodium or hydrogen. (Iodine behaves in the same way, except that when chemically on its own, iodine is a purple crystalline solid.)
If metals like zinc are dissolved in a solution or combined in solids with other elements, they make positively charged ions called cations. This difference is quite important in nutrition: anions (fluoride and iodide) are almost completely absorbed in the intestine and excess is excreted in the urine. Cations (for example, zinc, iron, or copper), on the other hand, are poorly absorbed from the intestine, with less than half and sometimes as low as 1/100th of the amount of the metal in the diet being taken into the body. Excess is excreted mainly in the feces, directly from the intestine.
I use aluminum utensils. Is that dangerous for babies?
No. When aluminum is exposed to air, water, or heat, a layer of aluminum oxide (which is chemically hard, that is, it does not react or dissolve easily) forms on the surface. Some aluminum may dissolve from the surface of utensils used with acid foods or liquids, but the amount is too small to be of any concern.
I recently read that there is aluminum in formulas and other baby products. Could that be a problem?
Because aluminum is so widespread in the environment, including food and water, it is difficult to avoid ingesting this mineral. Healthy humans, including babies, have strong barriers to prevent excessive amounts getting into the body; very little is absorbed by the gut and most of what gets passed into the blood is quickly excreted in the urine. The skin is also a strong barrier to aluminum entering the body.
Formulas and other baby products, like creams and talcs, do contain some aluminum; products that are made from plant materials, such as soy formulas, contain higher levels than animal-based products. Formulas made from cow’s milk contain 50 to 100 times more aluminum than found in breast milk; soy formulas may contain 100 to 400 times more than found in breast milk. However, this presents no problem to a healthy, full-term baby.
Care must be taken, however, with preterm babies and those with problems of the stomach, intestines, and kidneys. In such infants, the gut is not very good in stopping aluminum from entering the body, and the kidneys are not efficient in excreting the excess in the urine. Thus, toxic levels of aluminum may build up in the tissues and blood. Very high levels of aluminum in tissues may cause damage to bones and the brain.
You may have heard of some kind of relation between Alzheimer’s disease (a brain disorder in older people) and aluminum. However, the deposit of aluminum in the brains of people with Alzheimer’s disease is not the cause of the disease, but rather, the disease state causes the deposit. High levels of aluminum have been found in the blood of preterm and sick infants fed by intravenous feeding or soy formulas, and in infants given aluminum-containing antacids for stomach ulcers. Doctors and manufac-turers of formulas and other infant-care products are becoming aware that aluminum can cause problems, and are looking for ways to lower the amounts that all infants receive, especially sick and preterm infants who are most at risk from any ill effects.
There is a lot of talk about lead poisoning. Is that a real problem? How can I avoid it?
In many parts of the world, yes, lead does cause real health problems. The severity of the problems depends on the extent of exposure to lead and is usually expressed in terms of the level of lead in the blood. Levels above 80 parts per million (ppm, or 80 micrograms per liter of blood) cause bone damage, anemia, and serious brain damage. Such levels are usually only found in people working with lead or those who get an accidental overdose.
Much more common in children and infants, lead levels in the blood above 25 ppm cause less severe brain damage and result in lower IQ, slower reflexes, and poorer short-term memory. Recent large studies in children suggest that even as low as 10 ppm of lead in the blood can damage the brain and that there really is no safe level of exposure to lead.
The most important source of exposure is from leaded gasoline. This is still sold in most countries of the world, except New Zealand, Austria, and Nordic countries. More than half of all the lead entering the body comes from this source, directly in the air and indirectly through “fall-out” into soil, food crops, and water supplies.
Another important source of exposure to lead is from old house paints which often contain lead-based pigments, especially white and yellow colors. This exposure is of greatest risk to children living in poorer, urban housing, particularly rental housing which is frequently not well maintained.
If 15 ppm lead in blood is taken as the level indicating damaging exposure, it is calculated that as many as 17% of children in the United States are at risk. Most at risk are young children living in large urban areas; least at risk are those in rural areas. The most important safety measure for populations in respect of lead toxicity is to remove leaded gasoline from sale; average blood lead levels fall quickly in response to a fall in sales of leaded gasoline.
We have lots of old paints in our apartment. Do I have to be careful?
Yes. Chances are that some of the paints (especially white and primers) contain a high proportion of lead. Old paint is usually chipped, and babies may eat paint chips and dust with the dirt on their hands and toys, both inside the apartment and in the yard. This is obviously more of a problem if the paint work is in poor repair, as often happens in urban rental apartments.
The removal of old paint causes its own problems. Children can be exposed to excessive lead in vapors, as paint is burnt off, or to chips and dust from scraping and sanding. If possible, infants and children should be kept away from the apartment while paint is being removed. Clearing yards and gardens of dirt contaminated with old lead paint will be harder. Completely clearing all lead-based paint material from a house is expensive and if the paint is in reasonable repair, it may be safer to leave it be.
I hear so much about lead and lead poisoning, but do we actually need a bit of lead?
This is a question for debate by nutrition scientists, rather than of much practical concern at present. If we do require some lead in the diet, the amount that we need must be very small, and it would be very easy to have enough. All foods and water supplies contain some (small) amount of lead, as well as almost all other minerals, whether they are known to be essential or not.
In addition to lead, scientists are presently investigating arsenic, boron, lithium, nickel, silicon, tin, and vanadium to determine if they are essential in the diet. If they are in fact essential, the amount required in the diet to prevent deficiency is at least 10 to 1,000 times less than the amount that is normally present in food. Thus, it is very unlikely that deficiency will occur in humans eating ordinary diets, including healthy infants on formula or breast milk. The only situations in which deficiencies may happen would be under conditions of rigorous artificial or purified diets, such as in intravenous feeding or in a long-term space flight.
How about a bit of aluminum?
At present, no one is suggesting that we need any aluminum in the diet. Since aluminum makes up about 8% of the total surface of the earth and is the third most abundant element after oxygen and silicon, small amounts of aluminum are present in almost everything we grow or manufacture. The chances of getting a human diet without aluminum are very slight.
What about cadmium? Is it a problem for babies?
Cadmium is the mineral that makes the red color in garnets and red glass, and is widely used in the computer industry. It is chemically related to zinc, so it behaves in the same way in the body. Excessive levels of cadmium are especially damaging to the kidneys. There have been outbreaks of cadmium poisoning, due to environmental contamination, in areas of Japan where drinking water and rice fields were heavily contaminated by waste from zinc mines. However, under normal conditions, the amount of cadmium in human diets, water supplies, and breast milk is minute and excess cadmium is not regarded as a problem in most parts of the world.
Can toxins from the environment pass into the breast milk?
Yes they can. Practically anything that can enter the mother’s blood can enter the breast milk. Most environmental toxins are carried with the fat fraction of the blood and can be transferred to the fat fraction of the milk. Substances that may be found in the fat fraction of milk include agricultural chemicals and pesticides–such as DDT, PCBs (polychlorinated biphenyls), and dieldrin–fertilizers, fungicides, weed killers, and also many prescription and illicit drugs.
Fortunately, for many of these substances, the cells of the breast which make milk provide some barrier to the transfer of toxins from the blood, so amounts entering the milk are relatively small. Environmental chemicals accumulate in the body fat. While this protects the woman from any toxic effects, when she starts to breastfeed, body fat is used for milk production and so any toxic substances stored in the fat are released.
The widespread normal contamination of breast milk with environmental chemicals is not usually of concern to infant health. However, women who have worked extensively in agriculture with pesticides, particularly PCBs, before getting pregnant, may be advised not to breastfeed, especially a first child. Regrettably, there have been several outbreaks of poisoning with PCBs or other toxins, when illness was caused in children by contaminated breast milk. These outbreaks occurred in Japan and Taiwan from mothers using cooking oil accidentally contaminated with PCBs.
In 1973, in Michigan, feed for dairy cattle was accidently contaminated with PBBs (polybrominated biphenyls). Contaminated meat and dairy products were sold quite widely before the problem was identified. Mothers were recommended to stop breastfeeding if PBB levels in their breast milk were above a certain level, but there has been no evidence of harm to breastfed children who may have been exposed.
What about lawn sprays; should I be careful when they are spraying the grass?
The amounts of fertilizer and weed killers that people are exposed to when using domestic lawn sprays, including when the edges of the streets are being sprayed, are much lower than exposures which occur in agriculture. Because the fumes may cause discomfort, people are generally recom-mended to avoid exposure to these sprays as much as possible, staying indoors if necessary while spraying is being done. Only very small amounts, if any, will get into breast milk. Although there is no evidence that such minute amounts are a risk to the baby, in general, it is a good idea to keep such exposures as low as is practical, because these substances are not readily excreted from the body but will be stored in the fatty tissues.
They tell me that even formulas can have contaminants. Is that true?
Formulas may contain contaminants because the cows whose milk is used in their manufacture are usually exposed to some environmental chemicals. However, formulas are likely to contain lower levels of environmental toxins than breast milk. Cows produce much more milk than human mothers, so any toxins passed into the cow’s milk will be diluted to a much greater extent. Cows also do not use body fat for milk production as women do, so toxins will not enter the milk from that source. Furthermore, for many products, the fat fraction of cow’s milk is removed and not used in the formula, so that contaminants that are found in this fraction will be removed with the fat. Water used in formula manufacture is usually purified before use and hence would also be low in contaminants.
How do I know if the water I use to prepare the formula is safe from toxins?
In many countries, water supplied for public consumption by law must contain less than certain levels of substances which may be damaging to human health. These include many environmental toxins and toxic minerals like lead and cadmium. If you wish to know more about your local water, contact the water supply authority or company, state or city Health Departments, or the Departments of Environmental Science or Community Health at the local university or medical school. Local environmental action groups may also be able to give you specific information on local conditions.
The city uses river water. How do I know it is safe?
Public water supplies are usually regulated for allowable levels of many toxic substances. Because rivers collect drainage water from farms and industries where pesticides and fertilizers may be widely used, cities often purchase their water upstream from human activities if possible (ie, in the mountains). Before being supplied to the consumer, the water is treated extensively to remove chemicals, metals, and disease-causing organisms.
How do I know if our well water is safe?
This is more difficult to answer. Deep wells tap deep aquifers (pockets of water in the rocks of the earth’s crust) that are less likely to be contaminated by human activities than are more shallow water stores. Water obtained from shallow wells may contain toxins and other substances from water draining into the aquifer through farmland, etc. Currently, however, contamination of well water by Giardia and other disease-causing organisms appears to be a bigger problem than contamination with environmental chemicals. If your well water is untreated and you are concerned about possible contamination, contact the local Health Department, Agricultural College, or Agriculture Extension Service. These organizations may already have information on local water conditions or may be able to recommend people locally who can analyze the water for you. If it is found to contain undesirable substances, appropriate filters can be used to treat the water.
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