Cadmium in food

Cadmium is a soft, ductile, silver-white metal that belongs together with zinc and mercury to group IIb in the Periodic Table. It has relatively low melting (320.9 °C) and boiling (765 °C) points and a relatively high vapor pressure.

Food is the primary source of cadmium exposure among general population as a consequence of the bio-concentration of cadmium from soil. Chronic cadmium exposure has been reported to be associated with chronic kidney disease, osteoporosis, diabetes, cardiovascular disease and cancer. Cadmium is toxic to the kidney, while exposure to high levels of tin from, e.g. canned food in incorrectly manufactured tins can cause gastrointestinal irritation and upsets.

According to the current knowledge kidney damage (renal tubular damage) is probably the critical health effect. Other effects of cadmium expo-sure are disturbances of calcium metabolism, hypercalciuria and formation of stones in the kidney.

It has also been associated with lung damage (including induction of lung tumours) and skeletal changes in occupationally exposed populations. Cadmium is relatively poorly absorbed into the body, but once absorbed is slowly excreted, like other metals, and accumulates in the kidney causing renal damage.

Cadmium is used to produce a wide variety of consumer and industrial materials, such as electrode in Ni-Cd batteries; pigments for plastics, ceramics, and glasses; stabilizers for polyvinyl chloride (PVC); coatings for steel and nonferrous metals; solar cells and electronic devices, and constituent of fungicides or fertilizers.

Drinking-water contains very low concentrations of cadmium, usually in the range 0.01–1 μg/liter.

For nonsmokers, food constitutes the principal environmental source of cadmium. The lowest concentrations are found in milk (around 1 μg/kg). The concentration of cadmium is in the range 1-50 μg/kg in meat, fish and fruit and 10-300 μg/kg in staple foods such as wheat, rice and potatoes.

The highest cadmium levels (100-1000 μg/kg) are found in the internal organs (kidney and liver) of mammals and in certain species of mussels, scallops and oysters. When grown on a cadmium-polluted soil, some crops, such as rice, can accumulate considerable amounts of cadmium (more than 1000 μg/kg).

Cadmium in food

Cadmium in human diet

Food is recognized as the major source of cadmium in humans, except in comparatively rare cases of occupational air exposure. The recommended upper limit for cadmium in food is 75.0 ug/day.

It is widely distributed in nature: oyster, seafood, and grains are rich sources; it also can be obtained from air and the water supply.

About 6% of the cadmium ingested in food and beverages is absorbed by the human body. Higher dietary levels of calcium and protein need to increase cadmium absorption.

Most of the absorbed cadmium is retained in the kidneys bound to a metal-binding, high sulfhydryl protein, metallothionein.

The essentiality of cadmium in humans remains to be established. Nutritional requirements, if they exist, are very low and easily met by the levels in food and drinks.

There was a study that regular high doses of cadmium caused increased blood pressure, with pressure returning to normal when the cadmium treatment ceased.

Study also found elevated cadmium levels associated with atherosclerosis, an increase in heart size and reduced kidney function.

Cadmium in human diet

Food Sources of Cadmium

Humans take in cadmium through the respiratory system or the stomach – it collects in the liver, pancreas and kidneys.

Symptoms of food poisoning include shortness of breath, bronchitis, renal malfunctions and if exposures is excessive, death.

While cadmium is found in most foodstuff, this is normally at very low levels, unless contamination has occurred.

Whole foods have a more desirable ratio of cadmium to zinc than refined foods such as white flour, white rice and sugar.

Coffee, tea and shellfish are other dietary sources of cadmium.

Cadmium levels are typically higher in people that eat excessive amounts of carbohydrates. It means that consumptions of fats or refined foods that are low in nutrients increase the body’s cadmium levels.

Cadmium in foods results mainly from the food processing and refining; in drinking water, from areas of “soft” water lacking in minerals such as calcium and magnesium, as well as from water piping; and in air from industrial pollutants.

Daily intakes by human adults have been estimated to be 25 to 60 mg/day. About 5% of dietary cadmium is absorbed.
Food Sources of Cadmium

Cadmium toxicity

Cadmium is an inorganic metal that is naturally present in the environment. Like lead, cadmium accumulates in the body and has varying degrees of toxicity.

Cadmium can contaminate food by its presence in pesticides, pigments, plaints, plastics, and cigarettes.

Cadmium’s toxic effects are kept under control when balanced by adequate body stores of zinc.

The human body can tolerate low levels of cadmium, but long term chromic exposure can lead to serious health problems.

Hazardous cadmium levels lead to nephrotoxic effects, i.e. renal tubular dysfunction. Cadmium furthermore inhibits several SH-containing enzymes in the brain, while chronic cadmium exposure leads to reduced levels of norepinephrine, serotonin and acetylcholine.

High exposure has been linked to osteomalacia, a softening of the bones.

Cadmium is a potent antagonist of several essential minerals, including zinc, copper, iron and calcium.

Cadmium cam accumulate to toxic levels over a lifetime because the mineral is not well excreted by the human body. However cadmium is poorly absorbed, so normal dietary intake does not warrant concern for toxicity.

The absorption of cadmium from food varies, depending on genetic factors, age, and nutritional factors.

Infants absorb and accumulate more cadmium than adults.

Cadmium deposits in the kidneys, causing kidney tissue damage and high blood pressure or hypertension as well as calcium kidney stones.
Cadmium toxicity

Cadmium

Cadmium is a toxic trace mineral. Although there is possibility that cadmium is an essential element at very low intakes, it is more concern because of its toxic properties.

Cadmium’s toxic effects are kept under control when balanced by adequate body stores of zinc.

Hazardous cadmium levels lead to nephrotoxic effects, i.e. renal tubular dysfunction. Cadmium furthermore inhibits several SH-containing enzymes in the brain, while chronic cadmium exposure leads to reduced levels of norepinephrine, serotonin and acetylcholine.

Cadmium is a potent antagonist of several essential minerals, including zinc, copper, iron and calcium.

Cadmium cam accumulate to toxic levels over a lifetime because the mineral is not well excreted by the human body. However cadmium is poorly absorbed, so normal dietary intake does not warrant concern for toxicity.

Whole foods have a more desirable ratio of cadmium to zinc than refined foods such as white flour, white rice and sugar.

Coffee, tea and shellfish are other dietary sources of cadmium.

Anemia, proteinuria, and amino aciduria are associated with high concentration of cadmium (10 to 100 times normal) in liver and kidney.

Cadmium levels are typically higher in people that eat excessive amounts of carbohydrates. It means that consumptions of fats or refined foods that are low in nutrients increase the body’s cadmium levels.

Daily intakes by human adults have been estimated to be 25 to 60 mg/day. About 5% of dietary cadmium is absorbed.
Cadmium

Vanadium, Silicon, Tin, Chromium, Aluminum, Boron and Cadmium

VanadiumVanadium deficiencies for human are not known; however, deficiencies of this element in birds and animals result in growth retardation, deficient lipid metabolism, impairment of reproduction function, and bone growth retardation.

Vanadium stimulates glucose uptake into cells. Enhances glucose metabolism, and inhibits catecholamine induced lipolysis in adipose tissue.

Vanadium also stimulates glycogen synthesis in the liver and inhibits gluconeogenesis.

Food rich in vanadium include shellfish, mushrooms, ill seeds, black pepper and parsley; fresh fruits and vegetables contain little of this mineral.

SiliconSilicon is found in unpolished rice and grains and is quite prevalent in beer.

The role of in human nutrition may be important in cartilage and connective tissue as the human aorta, trachea, lungs and tendons are rich in silicon.

Very low intakes can impair bone growth and depress collagen synthesis.

TinTin occurring naturally in many tissues, has been found necessary for the growth of rats. It is believed essential to the structure of proteins and possibly other biological components.

As it present in most foods, tin deficiencies should not occur except possibly in foods that undergo refinement processes.

Tin is found in most tissues, except brain, and approximately 14 mg is present in adult humans.

ChromiumChromium plays a physiological role thought to be related to glucose metabolism – perhaps by enhancing the effectiveness of insulin.

It has been suggested that chromium may decrease hepatic extraction if insulin and improve glucose tolerance.

The kidney, followed by the spleen, liver, lungs, heart and skeletal muscle are the tissues with the greatest chromium concentrations.

While it is a normal body component, its content decreases with age.

Aluminum, boron and cadmiumAluminum, boron and cadmium are also found in trace amounts in the human body, but neither their roles nor the effects of their deficient or excessive amounts are known.

The precise biochemical role of boron, if any, is not known at the present time.

Aluminum salts are found in the abnormal nerve tangles in the brain in Alzheimer’s disease and it has been suggested that aluminum poisoning may a factor in the development of the disease, although there is little evidence.

Cadmium is a trace element found in the body in minute amounts, mainly in the kidneys and liver.

Nutritional requirements, of they exist are very low and easily met by the levels in food and drink.
Vanadium, Silicon, Tin, Chromium, Aluminum, Boron and Cadmium