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Biomedical subjects

S R Lynch

Publications and source records attributed to S R Lynch.

88 records · Page 5Linked to original sources
PubMed1968

Effects of iron overload on ascorbic acid metabolism.

Studies of the ascorbic acid status in two subjects with idiopathic haemochromatosis and in 12 with transfusional siderosis showed that all had decreased levels of white cell ascorbic acid. The urinary excretion of ascorbic acid was also diminished in those subjects in whom such measurements were made. The administration of ascorbic acid was followed by only a small rise in the urinary ascorbic acid output, while the oxalic acid levels (measured in two subjects) showed a significant rise. These findings resemble those described in siderotic Bantu, and support the thesis that increased iron stores lead to irreversible oxidation of some of the available ascorbic acid.

Adolescent↗
PubMed1968

Storage iron in "muscle".

In Bantu subjects with iron overload iron is visible in skeletal muscle cells and in the tissue histiocytes which lie between these cells. In the present study the concentrations of ;muscle' iron were measured chemically in subjects with varying hepatic storage iron concentrations. The results indicate that the concentrations of storage iron in ;muscle' are much lower than those in the liver. However, the muscle mass is so large that the total amount of iron present is at least equal to that in the liver in subjects with normal body stores. The concentrations of iron in ;muscle' are raised in subjects with iron overload but the degree to which they rise is far less than occurs in the liver; a thirtyfold increase in hepatic iron concentrations is associated with only a sixfold increase in ;muscle' iron. Experiments in rats revealed that storage iron in ;muscle' represents a relatively non-miscible pool which responds very little to acute changes in the iron environment.

Animals↗
PubMedDate not supplied

Ascorbic acid and iron nutrition.

Iron deficiency anemia is prevalent throughout the world because of the inefficient absorption of nonheme iron which forms the bulk of the iron in the diet. Absorption of this type of iron is impaired by substances in food which reduce its availability. Ascorbic acid reverses the effect of dietary inhibitors and is one of the most powerful known promoters of nonheme iron absorption. It facilitates iron absorption by forming a chelate with the ferric iron in food at the acid pH of the stomach; the chelated iron remains soluble at the alkaline pH of the duodenum. However, the consumption of ascorbic acid with a vegetarian meal containing primarily nonheme iron could improve the absorption of iron for an individual whose diet contains little or no heme iron. Unfortunately, relatively high cost and instability of ascorbic acid during food storage have proven to be major obstacles to its use in combating nutritional iron deficiency in developing countries.

Absorption↗