Manganese, 4-[(4-chloro-5-methyl-2-sulfophenyl)azo]-3-hydroxy-2-naphthalenecarboxylic acid complex

Exposure related observations in humans: other data

Administrative data

Endpoint:

exposure-related observations in humans: other data

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Well reported scientific publication, but no full study report.

Data source

Reference

Reference Type:

publication

Title:

Influence of tea drinking on manganese intake, manganese status and leucocyte expression of MnSOD and cytosolic aminopeptidase P

Author:

Hope S-J , Daniel K, Gleason KL, Comber S, Nelson M and Powell JJ

Year:

2006

Bibliographic source:

European Journal of Clinical Nutrition (2006) 60, 1–8

Materials and methods

Endpoint addressed:

other: Dietary uptake of Manganese by tea drinkers and non-tea drinkers

Principles of method if other than guideline:

Quantitation of Mn in human blood by atomic absorption spectrophotometry.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Manganese

EC Number:

231-105-1

EC Name:

Manganese

Cas Number:

7439-96-5

Molecular formula:

Mn

IUPAC Name:

manganese(2+)

Test material form:

solid

Method

Ethical approval:

confirmed, but no further information available

Details on study design:

A total of 52 healthy volunteers were recruited, 24 black-tea drinkers (age range 22–62 years) and 28 non-tea drinkers (age range 21–63 years) and neither group consumed green tea or fruit/herbal teas. Tea drinkers were defined as those who consumed four or more mugs (i.e. > 1l) of black tea daily. Non-tea drinkers were those who did not consume tea at all. A questionaire was used to identify relevant Mn intake from other sources. Overnight fasting venous blood samples were collected. A volume of 4ml was taken for whole blood Mn analysis and 6ml for plasma Mn analysis.

The analytical procedure was checked against contamination of leachable Mn from testing equipment. Mn determinations of whole blood and plasma were performed using a Perkin Elmer 4100ZL GF-AAS with Zeeman effect background correction using an adapted method of Luna and Campos. The accuracy and validity of the analytical data were established through the use of standard addition calibration, triplicate analysis and analysis of certified reference materials. Standard additions of 0, 2.5 and 5 µg/l Mn were used for plasma analysis and additions of 0, 5 and 10 µg/l Mn were used for whole bloods.

Results and discussion

Results:

Black tea does appear to be a major source of dietary Mn and the USA or EU upper limits of 10–11 mg/day for Mn could be reconsidered, especially for tea drinkers.

Any other information on results incl. tables

The mean ± s.d. Mn level of the certified whole blood reference material was 13.5±1.3 ng/ml (expected value 13.4 ng/ml), and the mean value of the serum reference material was 10.8 ± 0.5 ng/ml (expected value 10.6 ng/ml). Mn levels of black tea infusions were 0.51 ± 0.11 mg/100 g. Mn intake (mean (range)) was significantly greater in tea drinkers than non-tea drinkers using either the value of 0.51 mg/100 g (10 mg/day (5–20) versus 3.2 mg/day (0.5–6.5), respectively; P < 0.0001 by t-test) or 0.14 mg/100 g (5.5 mg/day (2–12) versus 3.2 mg/day (0.5–6.5), respectively; P < 0.0001 by t-test). Whole blood Mn levels (Mann–Whitney test) and expression of cAP-P (t-test) and MnSOD (Mann–Whitney test) did not differ significantly in tea drinkers compared with non-tea drinkers (P=0.11, 0.15 and 0.4, respectively). Black tea does appear to be a major source of dietary Mn and the USA or EU upper limits of 10–11 mg/day for Mn could be reconsidered, especially for tea drinkers.

Applicant's summary and conclusion

Executive summary:

Dietary Mn intakes (mean (range)) were significantly lower (Po0.0001) in non tea drinkers (3.2 mg/day (0.5–6.5)) than tea drinkers (5.5 mg/day (2–12) or 10 mg/day (5–20) depending upon the value used for Mn levels of black tea). Whole blood, plasma Mn levels and expression of MnSOD and cAP-P did not differ between the groups. In a continuous analysis, whole blood Mn levels and expression of MnSOD correlated inversely but no other parameters associated with each other. Tea drinking is a major source of dietary Mn and intakes commonly exceed proposed adequate intake values of 1.8–2.3mg Mn/day and, on occasion, exceed upper limits of 10–11 mg/day. Dietary Mn intake has little influence on markers of Mn status or expression of Mn-dependent enzymes.