Teresa Nestares

Influence of cow or goat milk consumption on antioxidant defence and lipid peroxidation during chronic iron repletion

Despite Fe deficiency and overload having been widely studied, no studies are available about the influence of milk consumption on antioxidant defence and lipid peroxidation during the course of these highly prevalent cases. The objective of the present study was to assess the influence of cow or goat milk-based diets, either with normal or Fe-overload, on antioxidant defence and lipid peroxidation in the liver, brain and erythrocytes of control and anaemic rats after chronic Fe repletion. Weanling male rats were randomly divided into two groups: a control group receiving a normal-Fe diet (45 mg/kg) and an anaemic group receiving a low-Fe diet (5 mg/kg) for 40 d. Control and anaemic rats were fed goat or cow milk-based diets, either with normal Fe or Fe-overload (450 mg/kg), for 30 or 50 d. Fe-deficiency anaemia did not have any effect on antioxidant enzymes or lipid peroxidation in the organs studied. During chronic Fe repletion, superoxide dismutase (SOD) activity was higher in the group of animals fed the cow milk diet compared with the group consuming goat milk. The slight modification of catalase and glutathione peroxidise activities in animals fed the cow milk-based diet reveals that these enzymes are unable to neutralise and scavenge the high generation of free radicals produced. The animals fed the cow milk diet showed higher rates of lipid peroxidation compared with those receiving the goat milk diet, which directly correlated with the increase in SOD activity. It was concluded that goat milk has positive effects on antioxidant defence, even in a situation of Fe overload, limiting lipid peroxidation.

Influence of nutritional iron deficiency anemia on DNA stability and lipid peroxidation in rats

OBJECTIVE Oxidative stress results from an imbalance between the formation and neutralization of pro-oxidants. Disturbance of the pro-oxidant/antioxidant balance is also considered to be a causative factor underlying oxidative damage to cellular molecules, such as DNA, causing strand breaks. There is considerable controversy about the antioxidant status in iron-deficiency anemia (IDA), but scant information is available regarding DNA integrity. In the present study, we investigated the relation between DNA stability and hepatic antioxidant capacity in rats with induced IDA. METHODS Peripheral DNA damage was assessed using an alkaline comet assay. Further, the hepatic antioxidant enzyme glutathione peroxidase and the production of thiobarbituric acid-reactive substances were measured in control rats and in those with induced IDA. RESULTS Comparison of the control and anemic rats showed no differences in thiobarbituric acid-reactive substances production in the cytosolic fraction of hepatic cells. Nor were there any differences in liver glutathione peroxidase enzyme activity or DNA stability, as demonstrated by the percentage of DNA in the head (90.77 in control rats versus 88.23 in anemic rats), tail (9.23 in control rats versus 11.76 in anemic rats), and olive tail moment (0.155 in control rats versus 0.141 in anemic rats). CONCLUSION IDA does not affect DNA stability or lipid peroxidation in rats, suggesting that there is enough compensatory capacity to keep antioxidant defenses high.

Goat milk during iron repletion improves bone turnover impaired by severe iron deficiency

The effect of goat or cow milk-based diets, with either normal Fe content or an Fe overload, on bone turnover and the mineralization process was studied in control and anemic rats during chronic Fe repletion. One hundred eighty male Wistar rats were studied during a pre-experimental period of 40 d in which they were randomly divided into 2 groups, a control group receiving the AIN-93G diet with normal Fe content (45 mg/kg of diet) and the Fe-deficient group receiving the AIN-93G diet with low Fe content (5mg/kg of diet) for 40 d. After the pre-experimental period, the rats were fed for 10, 30, or 50 d with goat or cow milk-based diets with a normal Fe content (45 mg/kg of diet) or an Fe overload (450 mg/kg of diet). In anemic rats, goat milk with normal Fe content increased levels of the biomarker of bone formation N-terminal propeptides of type I procollagen and diminished parathyroid hormone levels after only 10 d of supplying this diet, indicating the beginning of restoration of the bone demineralization induced by the anemia, which was not observed with cow milk. After 30 d of supplying the milk-based diets with normal Fe content or an Fe overload, biomarkers of bone formation and bone resorption were not different between control and anemic rats, indicating that the bone demineralization induced by the Fe-deficiency anemia had recovered, although the process of stabilization of bone turnover began earlier in the animals fed goat milk. In addition, a higher Ca deposit was observed in femur, which positively affects bone mineralization, as well as an increase of Fe in sternum, which indicates that the hematopoietic process essentially recovered earlier on the goat milk diet compared with the cow milk diet.

Beneficial effect of goat milk on bioavailability of copper, zinc and selenium in rats

We studied the effects of dietary inclusion of freeze-dried goat and cow milk on the utilization of copper, zinc and selenium, and on the metabolic fate of copper and zinc, in rats using a standard (non-milk) control diet recommended by the American Institute of Nutrition and diets based on goat or cow milk. For animals given the goat milk diet, the apparent digestibility coefficient (ADC) of copper is similar to that obtained with the standard diet and higher than that in animals given the cow milk diet. The copper balance was higher among the rats given the goat milk and the standard diets than among those given cow milk. The ADC and retention of zinc and selenium were higher for the goat milk diet than for the other two diets. The copper content in the kidneys and in the femur was greater when the animals consumed a goat milk diet than a cow milk diet. Zn deposits in femur, testes, liver, kidney, heart andlongissimus dorsi muscle were greatest with the goat-milk diet, followed by the standard diet and were lowest for the rats given cow-milk diet. This study shows that the goat-milk has an important and beneficial effect on the bioavailability of copper, zinc and selenium.ResumenSe estudia el efecto de la leche de cabra y vaca sobre la utilización digestiva y metabólica de cobre, zinc y selenio así como el destino metabólico de cobre y zinc en ratas y se compara con una dieta control, estándar, recomendada por el Instituto Americano de Nutrición (AIN, 1977). En animales alimentados con dieta elaborada con leche de cabra, el coeficiente de digestibilidad aparente (CDA) de cobre es similar al obtenido con la dieta estándar y mayor que el de los animales alimentados con la dieta a base de leche de vaca. El balance de cobre es mayor en ratas alimentadas con las dietas elaboradas a base de leche de cabra y con la dieta estándar que en aquellas que ingieren la dieta elaborada con leche de vaca. El CDA y la retención de zinc y selenio son mayores para la dieta a base de leche de cabra que para las otras dos dietas. El contenido de cobre en riñón y fémur es superior con la dieta elaborada con leche de cabra respecto a la dieta a base de leche de vaca. El depósito de zinc en fémur, testículos, hígado, riñón, corazón y músculolongissimus dorsi es mayor con la dieta elaborada con leche de cabra, seguido por la dieta estándar, mientras que en ratas alimentadas con dieta a base de leche de vaca este depósito es más bajo.Este estudio muestra que la leche de cabra tiene un importante efecto beneficioso sobre la biodisponibilidad de cobre, zinc y selenio.

Calcium-enriched goats' milk aids recovery of iron status better than calcium-enriched cows' milk, in rats with nutritional ferropenic anaemia.

Ca-Fe interactions are known, but no studies are available about the effects of Ca-enriched goat or cow milk on Fe status in nutritional ferropenic anaemia (NFA). To examine this matter, control and Fe-deficient rats were fed for 14 d with goat or cow milk diets containing either normal or high Ca content (5000 or 10,000 mg/kg diet), and different indices and parameters related to iron status were measured. The apparent digestibility coefficient (ADC) and the Fe retention/intake (R/I) ratio were higher in control and anaemic rats fed goat milk diet (G diet), despite high-Ca content. Ca enrichment decreased Fe stores in liver and sternum in anaemic rats fed cow milk diet (C diet), however G diet did not modify Fe content in the organs studied in control and anaemic rats. In anaemic rats, Ca-supplementation decreased haematocrit, but platelets and serum Fe were not affected, however, in control rats platelets increased except for Ca-enriched G diet, this fact reveals that Ca-Fe interaction is minimized with G diet. Serum ferritin was always higher in rats fed G vs. C diet, both in control and anaemic rats fed either normal or Ca-enriched diets. Ca-supplementation decreased ferritin levels in control and anaemic rats fed C diet and also, though to a lesser extent, in those given the G diet. This indicates that with this G diet there is a better recovery of body Fe stores in anaemic rats, despite Ca-supplementation. In this study it is noteworthy that despite high Ca content, a goat milk diet resulted in minimal Ca-Fe interactions and did not adversely affect Fe status in rats with NFA.

Lifestyle changes in free-living patients with peripheralvascular disease (Fontaine stage II) related to plasma and LDL lipid composition: a 15 month follow-up study

Peripheral vascular disease (PVD) is characterized by arteriosclerosis and lower extremity ischemia which cause intermittent claudication. Patients grouped in the Fontaine stage II have more than 75% organic stenosis in their large coronary arteries and exhibit a number of alterations in blood coagulation and plasma lipids. The aim of this study was to evaluate an intervention program of lifestyle habits including dietary recommendations, moderate exercise and decreased smoking in a population of patients with PVD for a period of 15 months, with respect to plasma-lipid and lipoprotein composition as well as LDL susceptibility to peroxidation. These parameters are well known risk indicators of arteriosclerosis and coronary heart disease. A total 13 subjects diagnosed with PVD (Fontaine stage II) were selected, while a healthy age-matched group (n=20) was used as a reference. This study design was an uncontrolled trial of lifestyle interventions. The group of patients was examined at 0, 3, 6, 9, 12 and 15 months. Patients smoking one or more packets of cigarettes per day at the beginning of the study (54.2%) decreased smoking by as much as 7.7% 15 months later. In addition, physical activity intensified significantly (walking > 1 km: 13.1-77%) and treadmill running increased over the study period while the energy intake decreased by 10%. The percentage of saturated fat in the diet decreased by 10% while the intake of polyunsaturated fat rose, and monounsaturated-fat intake showed a parallel trend to increase; the average intake of cholesterol also fell by 10% and plasma triglycerides and HDL-cholesterol showed a trend to decrease and increase, respectively. No permanent changes in LDL lipid fractions for patients were detected during the follow-up period and no differences between patients and the age-matched reference group were found. The macrophage uptake of plasma-oxidized LDL was significantly higher in patients than in the reference group and no differences due to the intervention period were detected. In conclusion, the education in lifestyle and nutritional habits of patients with PVD led to reduced energy intake parallel with augmented physical activity as well to a fall in plasma triglycerides and a rise in HDL-cholesterol, which are good indicators of a reduced risk of vascular and myocardial complications.

Production and chemical composition of two dehydrated fermented dairy products based on cow or goat milk.

The aim of this study was to identify the differences between the main macro and micronutrients including proteins, fat, minerals and vitamins in cow and goat dehydrated fermented milks. Fermented goat milk had higher protein and lower ash content. All amino acids (except for Ala), were higher in fermented goat milk than in fermented cow milk. Except for the values of C11:0, C13:0, C16:0, C18:0, C20:5, C22:5 and the total quantity of saturated and monounsaturated fatty acids, all the other fatty acid studied were significantly different in both fermented milks. Ca, Mg, Zn, Fe, Cu and Se were higher in fermented goat milk. Fermented goat milk had lower amounts of folic acid, vitamin E and C, and higher values of vitamin A, D3, B6 and B12. The current study demonstrates the better nutritional characteristics of fermented goat milk, suggesting a potential role of this dairy product as a high nutritional value food.

Bile composition, plasma lipids and oxidative hepatic damage induced by calcium supplementation; effects of goat or cow milk consumption.

Calcium-fortified foods, especially milk and dairy products are recommended to be consumed daily for groups in risk of nutritional deficiency, including children, young adults, menopausal women, pregnant women and the elderly, however Ca-supplementation promotes gallstone formation because Ca is a nucleating factor. The objective of the current study was to assess the influence of cow or goat milk-based diets, either normal or Ca-supplemented, on bile composition, biochemical parameters and hepatic antioxidant status. Weanling male rats were randomly divided into six groups, fed standard, goat or cow milk-based diets, either with normal Ca content (5.0 g/kg), or Ca-supplemented (10.0 g/kg), for 2 weeks. Bile cholesterol concentration and output was higher in rats fed goat milk in comparison with those fed with standard and cow-milk-based diet. Ca-supplementation increased lithogenic index with the standard and cow-milk based diets, this change was not observed with the goat milk diet. Activities of plasma transaminases were also lower in the animals fed Ca-supplemented goat milk, in comparison with the other diets assayed. In general, Ca-supplement in the diet led to an increase in the hepatic oxidative damage, with an increase in the activities of all the antioxidant enzymes studied in the standard and cow milk diet, but not with goat milk. The habitual consumption of goat milk has positive effects on the plasma lipid profile, biliary composition and hepatic antioxidant defence. In addition, under our experimental conditions, Ca-supplementation of this type of milk does not increase the lithogenic index, or hepatic oxidative damage.

Effects of lifestyle modification and lipid intake variations on patients with peripheral vascular disease.

The aim of the present study was to evaluate the effects of diets enriched in monounsaturated fatty acids (MUFA) (olive oil) or MUFA plus n-3 polyunsaturated fatty acids (PUFA) (olive oil plus fish oil), associated with an intervention program that focused on lifestyle habits, physical performance, plasma lipids, and lipoprotein composition in patients with peripheral vascular disease (PVD). A 15-month longitudinal nutritional and lifestyle intervention study was carried out with 24 free-living male patients aged 58.0 +/- 2.2 years diagnosed with PVD (Fontaine grade II). The patients were clinically evaluated and counseled to change their dietary and lifestyle habits for six months, after this period they consumed an olive oil-based diet for three months: after a three-month wash-out period, their diet was supplemented with a combination of fish oil and olive oil for the final three months. Lifestyle interventions resulted in a significant decrease in cigarette smoking and an increase in physical activity. Claudicometry was lower at the end of the study than at the beginning. Intake of the fish oil supplement led to significant changes in lipid lipoprotein composition, decreasing low-density lipoprotein (LDL) cholesterol. The lifestyle intervention program, together with a high intake of olive plus fish oil, seems to produce important beneficial effects in nutritional management, physical performance, and clinical parameters of PVD patients.

Se bioavailability and glutathione peroxidase activity in iron deficient rats.

Little information is available on the relationship of Se deposit in target organs and GPx activity in iron deficiency anemia. As red blood cells (RBCs) play a crucial role on Se metabolism and during Fe deficiency anemia a lower count of RBCs is featured, we aimed to investigate the influence of this pathology on Se bioavailability and the relationship with antioxidant status. 20 male Wistar rats were randomly divided into two groups, a control group receiving AIN-93G diet with normal Fe content (45mg/kg diet) and the Fe-deficient group receiving AIN-93G diet with low Fe content (5mg/kg diet) for 40 days. Both diets were prepared with an adequate Se content (0.180mg/kg diet). The digestive and metabolic utilization of Se, the distribution in target organ, the GPx activity and TBARS production were measured after receiving the diets. Se retention increased (P<0.001) in the anemic group, fact that contributes to keep the enzymatic antioxidant activity of GPx in normal levels and the tendency observed is that stored Se increased in the organs, especially in kidney (P<0.01), however, a lower Se deposit was found in sternum of anemic rats (P<0.001). The lower count of RBCs featured in this pathology (P<0.001) causes a decrease of Se concentration in sternum meanwhile the increase in kidney deposit is a consequence of the lower urinary losses (P<0.001).