Iron metabolism in rats consuming oil from fresh or fried sardines

Abstract

The influence of the consumption of diets containing oil from either fresh sardines or fried sardines, under domestic conditions, on the dietary iron metabolism of rats has been investigated. Three groups of rats were fed, over 28 d, semipurified diets containing 8% of: olive oil (00), fresh sardine (Clupea pilchardus) oil (SO) and oil from sardines previously fried in olive oil (FSO). Body mass and food intake were monitored and, during the periods 5-12 d and 21-28 d, faeces and urine were collected. At the end of the experiment, the animals were killed and blood, liver, spleen and a segment of skin were stored. Food intake and body mass decreased markedly in the SO rats. These parameters were slightly increased in the FSO group compared with 00. Iron absorption and retention were lower in SO than in 00 or FSO. This was primarily caused by the poor food intake but also by the low efficiency of absorption and high urinary Fe losses. Liver and spleen iron contents were reduced by half in SO compared with the other groups, partly owing to the smaller size of the organs, and liver Fe concentration also decreased. These results, together with the high total iron binding capacity, the decreased level of hemoglobin and total erythrocytic iron found in the SO animals, indicate that the consumption of fresh sardine oil as the only dietary fat resulted in iron depletion. The SO animals showed a higher Fe accumulation in skin than 00 or FSO. It was concluded that a diet high in sardine fatty acid administered as a unique source of fat, can cause metabolic alterations including iron depletion, but these negative effects of sardine oil disappear with frying, probably owing to the exchange that takes place between fatty acids in the olive oil used in frying and those in the sardine oil.

Maternal consumption of flaxseed during lactation affects weight and hemoglobin level of offspring in rats

“…A linatina pode interferir na absorção de vitamina B6, podendo promover sua deficiência e os compostos cianogênicos e o ácido fítico podem quelar minerais como o zinco, o ferro e o cálcio 11 . Além disso, foi demonstrado que óleo rico em ácidos graxos n-3 diminui a absorção e retenção de ferro, diminuindo assim a concentração de hemoglobina 12 . Foram demonstrados benefícios do consumo da semente na idade adulta, reduzindo colesterol e glicose 13 , porém poucos estudos avaliaram seu consumo exclusivamente durante o período de lactação.…”

Subchronic Toxicity of Fish Oil Concentrates in Male and Female Rats.

“…In humans, a daily intake of 20 mL of FOC in both sexes for ten weeks resulted in a significant reduction in serum and erythrocyte selenium concen trations (64). Rats receiving sardine oil for 4 weeks, showed a significant reduction in dietary iron absorp tion and retention (65). Another potentially harmful ef fect of high doses of FOC was a 48% reduction in serum vitamin E level in female rats and a 17% reduction in male rats both of which were statistically significant ( Table 8).…”

Comparative Effects of the Addition of Meat from Beef, Chicken, Mullet and Hake to a Bean Seed Ragout on Iron Metabolism and Iron Status in Growing Rats

“…A chemical analysis reported that mullet contains about 2-fold more fat than hake (4.3 vs. 2.5%) [2]. Thus, we think that the negative effect of mullet on the iron status may be due to the high level of fat and the nature of fatty acids present in it [24,25].…”

“…These observations are not confirmed by other research in the same circumstances. However, Perez-Granados et al [24] showed that iron absorption, iron retention and liver iron concentration were low in rats fed semipurified diets containing 8% of fresh sardine (Clupea pilchardus) previously fried in olive oil compared to the control diet. These authors concluded that the consumption of fresh sardine as the only dietary fat source provoked iron depletion.…”