Not everyone believes that chromium is an essential nutrient; we will discuss this more in the next paragraph.
Below, we will describe the various functions and biological role, also citing the nutritional needs - including the risks of deficiency and excess - to reach the most common food sources and the "possible usefulness of a" food supplement.
For further information: Chromium Picolinate of insulin, sugars and lipids. Therefore, the "National Institutes of Health" of the United States (and not only) considers the trivalent chromium ion [Cr (III)] an essential trace element for man.
However, in 2014, the "European Food Safety Authority" (EFSA) - acting on behalf of the "European Union - concluded that:"there was not enough evidence to recognize chromium as essential'.
Some forms of chromium, such as hexavalent, are highly toxic.
molecular - which may play a role in the insulin signaling pathway.Some experts believe that these reflect more pharmacological rather than nutritional responses, while others suggest that they are even side effects of a toxic metal.
As anticipated - unlike EFSA - the "National Institutes of Health" of the United States and other government departments recognize chromium as an essential trace element, due to its evident role in the "action of the hormone insulin - essential for the metabolism of carbohydrates and for the storage of glycogen, adipose and muscle tissue.
However, the related biological mechanisms have not yet been precisely defined, leaving a strong doubt about the essentiality of chromium in healthy people.
is absorbed, while the rest is excreted in the faeces.
Amino acids, vitamin C and niacin (vit PP) can increase the absorption of chromium from the intestinal tract.
After absorption, this metal accumulates in the liver, bones and spleen.
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Ingestion of chromium (VI) with contaminated water has been linked to the diagnosis of stomach cancer; it can also cause allergic contact dermatitis (ACD). This is why chromium-producing sites often require environmental remediation.
, is highly controversial. It can only manifest itself later long-term total parenteral nutrition.Symptoms of chromium deficiency are: impaired glucose tolerance, weight loss, peripheral neuropathy and confusion.
Neither plasma nor urinary concentrations can serve as useful clinical indicators of chromium status in the body.
Before chromium became a standard ingredient in total parenteral nutrition (TPN), people undergoing this treatment who developed deficiency symptoms could recover in just two weeks from the nutritional addition of the trace element.
, processed meats, high-bran breakfast cereals, coffee, nuts, green beans, broccoli, spices, and some brands of wine and beer.
Most fruits, vegetables, and dairy products contain only minimal amounts.
On the other hand, the chromium content in foods varies widely due to:
- different level of mineral in the soil;
- contained in fertilizers and feed;
- growing season;
- vegetable cultivar;
- possible contamination during processing.
Furthermore, chromium - like nickel - passes inside food cooked in stainless steel pots, with a greater effect on new tools than on used ones.
Even acidic foods, such as citrus juice, vinegar and tomato puree, cooked for many hours in stainless steel pans, exacerbate this effect.
Food composition databases such as those maintained by the "U.S. Department of Agriculture" do not contain information on the chromium content of foods.
A dietary analysis study conducted in Mexico reported an "intake of 30 μg / day [Grijalva Haro, MI; Ballesteros Vázquez, MN; Cabrera Pacheco, RM."Chromium content in foods and dietary intake estimation in the Northwest of Mexico". Arch Latinoam Nutr (in Spanish). 51: 105–110].
In the United States it is estimated that about 31% of adults consume multivitamin / mineral dietary supplements which often contain 25 to 60 μg of chromium [Kantor, Elizabeth D; Rehm, Colin D; Du, Mengmeng; White, Emily; Giovannucci, Edward L (11 October 2017). "Trends in Dietary Supplement Use Among US Adults From 1999-2012". JAMA. 316: 1464–1474].
Chromium in fish
Chromium is naturally present in the environment in traces, but industrial use in the production of rubber and stainless steel, chrome plating, dyes for fabrics, tanneries and other uses contaminate aquatic systems.
In Bangladesh for example, rivers near industrialized areas show significant heavy metal contamination.
The standard of chromium in irrigation water is 0.1 mg / L, but some rivers contain more than five times as much.
The standard of chromium levels for fish intended for human consumption is <1 mg / kg, but many samples tested were more than five times higher.
Chromium, especially hexavalent chromium (VI), is highly toxic to fish because it is easily absorbed through the gills, easily enters the bloodstream, crosses cell membranes and bioconcentrates along the food chain.
on the contrary, the toxicity of trivalent chromium is very low, attributed to poor membrane permeability and poor biomagnification.
Acute and chronic chromium (VI) exposure affects fish behavior, physiology, reproduction and survival. Hyperactivity and erratic swimming in contaminated environments have been reported. Hatching and survival are affected. In adult fish there are histopathological damage to the liver, kidneys, muscles, intestines and gills.
Mechanisms include mutagenic genetic damage and disruption of enzyme functions.
of chromium, chromium (III) picolinate, chromium (III) polynicotinate and other chemical compositions.The benefit of supplements has not been proven.
with the request for a very specific wording on the label: "A small study suggests that chromium picolinate may reduce the risk of insulin resistance and the risk of type 2 diabetes.The FDA concludes, however, that the "existence of such a relationship between chromium picolinate and insulin resistance or type 2 diabetes is highly uncertain."
At the same time, the FDA rejected claims for a correlation between chromium picolinate and cardiovascular disease, retinopathy, or kidney disease caused by abnormally high blood sugar levels.
In 2010, chromium (III) picolinate was approved by "Health Canada" in food supplements. Approved labeling claims include: "maintenance factor for good health, provides support for healthy glucose metabolism, helps the body metabolize carbohydrates, and helps the body metabolize fat."
EFSA approved claims in 2010 that chromium contributes to normal macronutrient metabolism and maintenance of normal blood glucose concentration, but rejected requests for maintenance or achievement of a normal body weight or reduction of tiredness or fatigue.
Given the evidence that a chromium deficiency can cause problems with glucose management in the context of intravenous nutrition products formulated without it, the research interest has turned to whether chromium supplementation would benefit people. who have type 2 diabetes but are not chromium deficient.
Looking at the results of four meta-analyzes, one reported a statistically significant decrease in fasting plasma glucose (FPG) levels and a non-significant trend in lower hemoglobin A1C.
A second reported the same, a third observed significant reductions for both measures, while a fourth reported no benefit for either measure.
A review published in 2016 listed 53 randomized clinical trials that were included in one or more of the six meta-analyzes. He concluded that:
'While there may be modest decreases in FPG and / or HbA1C reaching statistical significance in some of these meta-analyzes, few of the trials obtained decrease enough to be expected to be relevant to the clinical outcome.'.
Two systematic reviews looked at chromium supplements as a means of managing body weight in overweight and obese people. One, limited to chromium picolinate, reported statistically significant weight loss of -1.1 kg (2.4 lbs) in trials lasting more than 12 weeks.
The other included all chromium compounds and reported a statistically significant weight change of -0.50 kg (1.1 lb). The change in body fat percentage did not reach statistical significance.
The authors of both reviews considered the clinical relevance of this modest weight loss to be uncertain / unreliable.
EFSA reviewed the literature and concluded that there was insufficient evidence to support a "weight loss indication."
Chromium is promoted as a dietary supplement for sports performance, based on the theory that it enhances insulin activity, resulting in increased muscle mass and faster post-exercise glycogen recovery.
A review of clinical studies reported that chromium supplementation did not improve physical performance or increase muscle strength.
In 2018, the International Olympic Committee examined dietary supplements for high-performance athletes and concluded that it was not necessary to increase chromium intake for athletes, nor to support their slimming function.
45 μg / day.AI for men is:
- between 14 and 50 years it is 35 μg / day;
- equal to or greater than 50 is 30 μg / day;
For children aged 1 to 13 years, AI increases with age from 0.2 μg / day to 25 μg / day.
Regarding safety, the NAM establishes "Tolerable Upper Intake Levels" (UL) for vitamins and minerals only when the evidence is sufficient. In the case of chromium, there is still not enough information.
Australia and New Zealand consider chromium essential, with AI of 35 μg / day for men, 25 μg / day for women, 30 μg / day for pregnant women and 45 μg / day for breastfeeding women. A UL has not been established due to lack of sufficient data.
India considers chromium an essential nutrient, with a recommended adult intake of 33 μg / day.
Japan considers chromium an essential nutrient, with AI of 10 μg / day for adults, including pregnant or lactating women.
A UL has not been set.
The EFSA of the European Union, however, does not consider chromium to be an essential nutrient; chromium is the only mineral that the United States and the European Union disagree with.
principal of stainless steel, to which it adds anticorrosive properties.Chromium is also highly regarded as a matte-resistant polishing metal.
Polished chrome reflects nearly 70% of the visible spectrum and nearly 90% of infrared light.
Ferrochrome alloy is produced from chromite and metallic chromium.
Stainless steel production and chrome plating (electroplating with chromium) account for 85% of the commercial use of chromium.
