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Role of diet in absorption
and toxicity of oral cadmium- A review of literature
Samuel Ogheneovo Asagba
Department of Biochemistry, Delta State University, PMB 1,
Abraka, Nigeria.
E-mail:
asagbabch@yahoo.com. Tel: +2348068561853.
Accepted
25 December, 2009 |
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The role of diet or its components in the absorption,
distribution and toxicity of cadmium (Cd) has received
attention in recent times. Experimental evidence in
literature strongly suggests that the absorption of Cd is
dependent on factors such as age, pH, diet and intestinal
metallothionein (MT) production. The chemical forms of Cd
such as Cd-MT in foods or inorganic Cd administered directly
in foods or drinking water have also been considered in
literature. The bioavailability or absorption of Cd as Cd-MT
in foods has been shown in many reports to have decreased in
relation to Cd administered directly as inorganic Cd in
drinking water or foods. However, some other studies have
reported contrary findings. Although research evidence has
indicated that the type or components of a diet may also
influence the absorption or toxicity of Cd irrespective of
the chemical form involved. Diets low in proteins, minerals
and certain vitamins have been reported to increase Cd
absorption and toxicity. Conversely, diets rich in fibres
have the reverse effect. The lack of conclusive information
on the availability of Cd in Cd-MT for intestinal uptake in
relation to that of ionic Cd is noticeable, and as a result
there is a great need for further studies in this area.
Also, since humans are usually exposed to Cd-MT in foods and
rarely to inorganic Cd, the toxicity of food-incorporated Cd
deserves further investigation, in view of the observed
differences in tissue accumulation from these forms of Cd.
Key
words:
Cadmium, cadmium-metallothionein, cadmium absorption, diet
components. |
