The principal carrier protein for chromium is transferrin. chromium is transferred  from transferrin to low molecular weight chromium binding substance (LMWCr),  which normally exists in insulin-dependent cells in the inactive form. Binding with chromium ions converts inactive LMWCr to its active form. It is proposed that  LMWCr then participates as part of an insulin signal amplification system as it  binds to insulin-activated insulin receptors and results in stimulating its tyrosine  kinase activity. The result of this process is the activation of insulin receptor  kinase and potentiation of the actions of insulin (Vincent, 1999).

DIETARY FACTORS AFFECTING ABSORPTION AND UTILIZATION: 

  According to animal studies, following are some dietary factors that affects the  absorption and utilization of chromium: 
1) Carbohydrates: simple sugar rich diet cause increase urinary excretion of  chromium. 
2) Vitamins: chromium absorption is increased in the presence of nicotinic  acid. 
3) Amino acids: chromium absorption is increased in the presence of some  amino acids such as histidine. 
4) Metals: administration of Zn and Fe suppress chromium absorbtion  (FAIRWEATHER-TAIT & Hurrell). 

DEFICIENCY OF CHROMIUM

      The deficiency of chromium (III) causes the disturbances in metabolic processes.  The primary reaction of organism on chromium (III) deficiency, is the lowered  tolerance of glucose, which is the consequence of changes in insulin affinity to its  receptors on cells. Its deficiency also causes impaired growth, increased blood  lipid level, increased aortic plaque formation and reduced fertility and longevity  (Wallach).

TOXICITY 

  Hexavalent chromium is the most toxic form of chromium due to its high  solubility, high oxidizing potential and mobility across the membranes in living  organisms and in the environment (Oliveira). It is known as carcinogenic as it  causes cancer development by different complex mechanisms. It produces  cellular damage by elevating levels of oxidative stress, chromosome break and  DNA adduct formation (LiborioDesMarias & Costa). 
      When Cr(6) enters the cell, it eventually gets reduced to Cr(3). This reduction  induced oxidative stress and produces toxicity. While the intermediates of  chromium reacts with protein and DNA. Cr(3) can produce adducts with DNA that  may cause mutations (Sun, Brocato, & Costa). 
     Trivalent chromium is considered less toxic as it is insoluble in water, have lower  mobility. It is a micronutrient in human and is normally not harmful (Oliveira). 

ADEQUATE INTAKE OF CHROMIUM: