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T Hazell

Publications and source records attributed to T Hazell.

8 recordsLinked to original sources
PubMed1991

Correlation between the size of the selenite-exchangeable metabolic pool and total body or liver selenium in rats.

This study explored the quantitative relationship between the size of the selenite-exchangeable metabolic pool (WSe-EMP) and total body or liver Se in rats of varying age and past Se intake. We performed four experiments. In one, weanling rats were fed either a Se-deficient or Se-supplemented diet for 30 d, followed by measurement of WSe-EMP and total body Se. For the other experiments, rats were fed natural sources of Se without added selenite until adult age and then either subjected to acute Se restriction during the 7 d of measurements or maintained on a Se-sufficient diet. For the animals fed the selenite diet, the 7-d average ratio of WSe-EMP:total body Se (Se(end),0) was 0.370 +/- 0.009, which was not significantly different from the corresponding value (0.350 +/- 0.018, P greater than 0.05) for the Se-deficient group. When the group mean values of WSe-EMP were correlated with the corresponding mean values of Se(end),0 for all experiments, we obtained highly linear relations (r2 greater than 0.96). When WSe-EMP for each animal was correlated with the corresponding value of total body endogenous Se (Se(end)) or liver Se(end) (for t = 1 or 7 d), we found equally strong linear relations (r2 greater than or equal to 0.99). We concluded that WSe-EMP accurately reflected total body Se content or the Se content of such organs as liver, regardless of past Se intake, chemical form of Se or age and size of the animals.

Administration, Oral↗
PubMed1988

Relating food composition data to iron availability from plant foods.

Correlation studies were performed relating iron availability estimated in vitro using a simulated digestion system to the concentration of protein, sugar, fibre, phytate, ascorbate and citrate in 33 different plant foods. Protein, sugar and fibre showed no significant correlation with iron availability. Phytate was significantly negatively correlated with diffusible iron in cereals, legumes and nuts. Both ascorbate and citrate were highly positively correlated with diffusible iron in vegetables and fruits. It is concluded that iron availability may be related on a quantitative basis to certain components of plant foods.

Ascorbic Acid↗
PubMed1987

In vitro estimation of iron availability from a range of plant foods: influence of phytate, ascorbate and citrate.

Plant foods were digested in vitro and the proportion of iron which diffused across a semi-permeable membrane was used as an index of Fe availability. The mean (with SEM) Fe diffusibility from a group of eighteen cereals, legumes and nuts was very low, 2.1 (0.25)%, whereas from a group of sixteen fruits and vegetables it was high, 31.7 (1.09)%. The difference between the two food groups was highly significant (P less than 0.001). The results for Fe diffusibility correlated well with literature values for the in vivo absorption of Fe from similar foods (r0.84, P less than 0.01). When phytate, citrate and ascorbate were added to selected foods in amounts corresponding to endogenous levels, only phytate and citrate gave the expected effects on Fe diffusibility. Ascorbate only enhanced Fe diffusibility to the expected extent when it was added in much larger amounts, not normally found in foods. When added to cereal foods, orange juice was found to enhance greatly Fe diffusibility even when its content of ascorbate was completely destroyed by boiling followed by prolonged storage. When citrate and ascorbate were added to cereal foods in amounts equivalent to those found in fresh orange juice, both enhanced Fe diffusibility but citrate was far more effective. It is concluded that phytate is a major inhibitor of Fe diffusibility in cereals, legumes and nuts. However, citrate rather than ascorbate would appear to be the major enhancer of Fe diffusibility from many fruits and vegetables. The implications of the present results are discussed in relation to the relative influence of phytate, citrate and ascorbate on dietary Fe availability.

Ascorbic Acid↗
PubMed1978

Iron availability from meat.

1. The distribution of radioactive iron in 59Fe-labelled rat muscle extract was determined using gel filtration. This showed that most (approximately 70%) of the radioactivity was associated with the heamatin compounds; myoglobin and haemoglobin. 2. Raw beef and freeze-dried rat muscle were digested in vitro, under simulated physiological conditions, and after centrifugation the supernatants fractionated by gel filtration. The soluble products were haematin Fe complexes of molecular weight above 10,000 and non-haematin Fe compounds of molecular weight below 6000, the major products being the non-haematin Fe complexes. The soluble compounds were also separated by dialysis and, in rat muscle, it was found that the low-molecular-weight non-haematin compounds accounted for more than 80% of the total soluble iron. 3. In vivo absorption studies with rats showed the Fe in a digested muscle dialysate to be more readily absorbed than that from an aqueous muscle extract which itself was more readily absorbed than the Fe from whole blood. 4. It may not, therefore, be the haemoproteins per se which are responsible for the high availability of Fe in meat, but rather the nature of their degradation products, formed by digestion within the meat environment.

Animals↗