Prooxidant effects of maternal smoking and formula in newborn infants

Effects of environmental tobacco smoke on the oral health of preschool children

AIMS

This study investigated the association between the prevalence of oral health problems (caries, gingivitis, mucosal pigmentation and enamel defects in one to 5 year-old children exposed and not exposed to environmental tobacco smoke before and/or after birth. Exposure to environmental tobacco smoke (ETS) in childhood may have significant health effects.

METHODS

A structured questionnaire was used to collect data on a child's current and previous illnesses, oral health behaviours, dietary habits, parental smoking behaviours and parents' dental history. The intraoral examination recorded dental caries (dmfs), enamel defects, gingival health, melanin pigmentation and soft tissue health. Stimulated saliva was collected. Total sIgA levels were quantified using indirect competitive ELISA with a SalimetricsTM kit.

RESULTS

The 44 children (aged 15-69 months) recruited were divided into two groups: ETS and non-ETS (control). There were 22 children in each: 16 who were exposed to ETS during and after gestation were identified as the ETSB subgroup. Participants exposed to ETS were more likely to have had upper respiratory tract and middle ear infections during the neonatal period and had higher mean dmft, mean dmfs, mean percent of surfaces with demarcated opacities and mean GI than the non-ETS participants. The children exposed to ETS before and after birth had the highest occurrence of enamel opacities showed a higher risk for dental caries even though more children in this group used the recommended fluoride toothpaste (1000 ppm fluoride). Mothers who smoked either never breastfed their children or breastfed their children for less than the recommended period of 6 months. Children exposed to ETS were shown to have higher mean total sIgA (μg/ml) than the children in the control group.

CONCLUSIONS

Associations between ETS exposure before and after gestation and oral health, including salivary changes in young children were shown in the present study. Dental health professionals should include a question about household smoking in children's dental histories, which would allow opportunities to discuss the impact of smoking on child oral health. Longitudinal oral health studies should include a history of maternal smoking during pregnancy and afterwards.

Tobacco smoking and breastfeeding: Effect on the lactation process, breast milk composition and infant development. A critical review

Approximately 10% of women report smoking during pregnancy. The number of breastfeeding women who relapse back to smoking is even greater. Smoking may cause adverse changes to the milk's composition by not only reducing its protective properties, but also by affecting the infant's health. The pathophysiological mechanisms underlying these adverse effects are not entirely known. This article is a review of previous reports about the effects of smoking on the lactation process, breast milk composition and infant development. A systematic search for English language articles published until 2015 was made, using a MEDLINE data. The key search terms were "smoking and breastfeeding", "smoking and lactation", "smoking and milk composition", "nicotine and breast milk". Studies have shown that nicotine levels in breast milk of women who smoke are three times higher than those in the plasma levels. Breast milk volume is reduced and the duration of lactation period is shorter. Smoking causes adverse changes to the milk's composition by not only reducing its protective properties, but also affecting infants' response to breastfeeding and to breast milk.

Protective effects of N-acetylcysteine on peroxidative changes of the fetal rat lungs whose mothers were exposed to cigarette smoke

Background: This experimental study investigated the protective effects of N-acetylcysteine (NAC) on peroxidative changes in fetal lungs in the offspring of rats exposed to cigarette smoke. Methods: Thirty fetal rats used for analysis, were divided into three groups as follows: control group (n = 10), whose mothers were exposed to fresh air; group I (n=10), whose mothers were exposed to cigarette smoke; and group II (n=10), whose mothers were exposed to cigarette smoke and given 10 mg/kg per day NAC. In groups I and II, smoke exposure was started 4 weeks before the pregnancy, and continued to the 14th day of pregnancy, and in Group II, NAC was administered intraperitoneally for 14 days. The mothers and their fetuses were decapitated on the 14th day of pregnancy. Malondialdehyde (MDA) and glutathione (GSH) levels were determined in the lung tissues of fetuses to determine the oxidant-antioxidant balance. Results: While tissue MDA levels in Group I were found significantly higher than the control group (129.7±65.4 versus 63.4±15.4 nmol/100 mg protein, P <0.05), GSH levels were significantly lower (17.1±7.3 versus 45.4±8.1 nmol/mg protein, P <0.01). Furthermore, in Group II, MDA levels were significantly lower (56.9± 20.6 versus 129.7±65.4 nmol/100 mg protein, P <0.05), and GSH levels were significantly higher (34.57±10.7 versus 17.1±7.3 nmol/mg protein, P <0.0001) when compared with Group I. No statistically significant difference was found in tissue MDA and GSH levels between Group II and the control group (P >0.05). Conclusions: These results suggest that smoke exposure during pregnancy causes oxidative damage in fetal lungs. This smoke-induced damage might be prevented by NAC. Human & Experimental Toxicology (2007) 26, 99-103

Maternal smoking does not influence vitamin A and E concentrations in mature breastmilk

OBJECTIVES

The aim of this study was to analyze the effects of maternal smoking on the total antioxidant status (TAS) and the concentrations of vitamins A and E in human breastmilk.

METHODOLOGY

The study group (n=20) comprised postpartum women who declared smoking more than five cigarettes per day (confirmed by urinalysis of the cotinine concentration). The control group included 25 nonsmoking postpartum women. Breastmilk samples were collected between day 30 and day 32 after delivery. TAS was determined by Rice-Evans and Miller method, whereas the amount of vitamins A and E was measured by high-performance liquid chromatography.

RESULTS

No significant differences were observed between breastmilk samples from smoking and nonsmoking mothers in terms of TAS and vitamin A and E concentrations. Additionally, no significant correlations were found between urinary cotinine and TAS (R=0.35, p=0.144) or vitamin A (R=0.14, p=0.571) and vitamin E (R=0.31, p=0.228) concentrations in breastmilk samples from smoking mothers.

CONCLUSIONS

Maternal smoking is not reflected by decreased TAS and vitamin A and E concentrations in mature milk.

The effect of tobacco smoking during pregnancy on plasma oxidant and antioxidant status in mother and newborn

OBJECTIVE

The aim of the study was to estimate the effect of tobacco smoking during pregnancy on oxidative damage and antioxidant defence in matched samples of maternal blood and cord blood.

STUDY DESIGN

Healthy, pregnant women (n=140) were divided into non-smoking and smoking groups according to the concentration of cotinine in serum and urine. Oxidative damage was measured through levels of malondialdehyde (MDA) and plasma antioxidant status was evaluated by measuring concentrations of total radical trapping parameters (TRAP) and selected antioxidants (β-carotene, vitamin A, vitamin E, uric acid). Statistical analysis was done using the SAS System for Windows (SAS Institute, Cary, NC).

RESULTS

In the course of pregnancy the concentration of MDA increased, but to higher values in smoking women than in non-smoking ones. It was accompanied by significantly lower TRAP in the smoking group than in the controls (p<0.05). Plasma concentration of uric acid (p<0.05) and antioxidant vitamins E (p<0.01), A and β-carotene (p<0.0001) were all reduced in smokers as compared with non-smoking pregnant women especially in the third trimester. Concentration of MDA in plasma of cord blood of newborns of smoking mothers was significantly higher (p<0.01) but the antioxidant defence was lower (p<0.0001) than in non-smoking ones. It was particularly pronounced for β-carotene (32%; p<0.0001) and vitamin A (28%; p<0.001). A significant negative correlation was found between MDA and TRAP levels of maternal plasma (non-smoking and smoking: r=-0.50, p<0.0001) and cord plasma (non-smoking: r=-0.54, p=0.0057; smoking: r=-0.71, p=0.0004) in all the study subjects. Total antioxidant status positively correlated with concentrations of uric acid and vitamin E in non-smoking and smoking mothers as well as their newborns.

CONCLUSION

Tobacco smoke enhances lipid peroxidation and depletes antioxidant potential in the plasma of pregnant women and umbilical cord blood. Therefore smoking during pregnancy may stimulate free radical damage in the mother and the growing fetus.

The influence of maternal smoking on maternal and newborn oxidant and antioxidant status

BACKGROUND

Maternal smoking has been suggested as a source of oxidant stress in pregnant women and in newborns exposed in utero. The aim of this study was to determine the influence of maternal smoking on oxidant status and antioxidant vitamins of mother-infant pairs.

MATERIALS AND METHODS

Socioeconomic and diet characteristics were recorded from 20 smoker and 20 non-smoker pregnant women of 36 weeks' gestation. On the day of delivery, venous blood samples of the women and cord bloods were taken. On postpartum day 7, milk and infant urine samples were collected. Plasma and milk beta-carotene, retinol, alpha-tocopherol and cotinine levels, plasma malondialdehyde levels, and urine cotinine levels were measured.

RESULTS

Milk alpha-tocopherol levels of smoking mothers were lower than those of non-smoking mothers. In smokers, there were no correlations between maternal vitamin A intakes and milk levels of retinol, and between maternal plasma levels and milk levels of beta-carotene.

CONCLUSIONS

Maternal smoking may lead to decreased milk levels of vitamin E, as a result of making use of this antioxidant in order to limit lipid peroxidation, as well as may lead to a possible limitation on the transfer of lipophilic antioxidants including vitamin A from blood plasma to milk. Further investigations conducted in large populations will be needed to assess the effects of maternal smoking on the oxidant and antioxidant status of breast milk.

The effect of passive smoking and breast feeding on serum antioxidant vitamin (A, C, E) levels in infants

AIM

Toxic substances in tobacco smoke are known to have negative effects on the antioxidant capacity of human body. In order to investigate the effect of passive smoking on serum antioxidant levels in infants, serum vitamin A, E, C levels and urinary cotinine/creatinine levels were measured in 254 infants at the age of 6 months.

METHODS

The information about infants' nutrition and exposure to tobacco smoke was obtained from the mothers by the help of a questionnaire. The infants were grouped according to both smoking status of mother and urinary cotinine/creatinine levels.

RESULTS

The mean serum vitamin A, C and E levels of infants of smoking mothers were significantly lower than those of non-smoking mothers (p < 0.05). Vitamin A, E and C levels were negatively correlated with urinary cotinine/creatinine levels (p < 0.05, r: -0.61, -0.42, -0.53, respectively). Multivariate analysis revealed independent factors determining the serum vitamin A, E and C levels of infants as maternal smoking and breast feeding (p < 0.05).

CONCLUSION

Tobacco smoke exposure of infants significantly decreases their serum antioxidant vitamin A, C and E levels. However, breast feeding may help to prevent the decrement of antioxidant vitamin levels of passive smoking infants.

Influence of maternal nicotine exposure on neonatal rat oxidant-antioxidant system and effect of ascorbic acid supplementation

There have been a few studies that examined the oxidative stress effects of nicotine during pregnancy and lactation. We aimed to determine the adverse effects of maternal nicotine exposure during pregnancy and lactation on oxidant-antioxidant system, and to determine a protective effect of ascorbic acid (Asc). Gravid rats were assigned into four groups. In Group 1, pregnant rats received 6-mg/kg/day nicotine subcutaneously during pregnancy from 1 to 21 days of gestation and lactation (until postnatal day 21). Group 2 received nicotine and Asc for the same period. In Group 3, the rats received nicotine during lactation. Control pregnant rats (Group 4) received only saline subcutaneously. Serum malondialdehyde (MDA), myeloperoxidase (MPO), and superoxide dismutase (SOD) levels were determined at 21 days of age. Nicotine exposure decreased birth weight and pregnancy weight gain. MDA values of the rat pups exposed to nicotine in both Groups 1 and 2 were higher than those of control and Group 3. SOD and MPO values of the groups were similar. Mean birth weight and serum MDA levels of Groups 1 and 2 were similar. Nicotine exposure via placental transfer increases oxidative stress as manifested by an increase in MDA level. Asc supplementation does not prevent the adverse effects of maternal nicotine exposure.

Embryonic oxidative stress as a mechanism of teratogenesis with special emphasis on diabetic embryopathy

Reactive oxygen species (ROS) are involved in the etiology of numerous diseases including cardio-vascular diseases and diabetes mellitus. There is evidence that several teratogens affect the developing embryo by increasing its oxidative stress and, because of its relatively weak antioxidant defense, especially at the early stages of organogenesis, result in severe embryonic damage. This mechanism seems to operate in diabetes-induced embryonic damage as well as in the mechanism of teratogenicity caused by ionizing radiation, hypoxia, alcohol and cocaine use and cigarette smoking. We studied the role of oxidative stress in diabetic induced embryopathy, both in vivo and in vitro. Under diabetic condition there was a significant decrease in the activity of endogenous antioxidant enzymes and of vitamins C and E in the embryos and their yolk sacs. The lowest activity was observed in the malformed experimental embryos when compared to experimental embryos without anomalies. Similar results were obtained in the Cohen diabetic rats, where the diabetic prone (CDs) rats were unable to increase their antioxidant enzyme activity in spite of the diabetes. Studies performed by other investigators show similar results. Human and animal studies show that the main mechanism of fetal damage induced by high levels of ionizing irradiation, cocaine and alcohol abuse, hypoxia and cigarette smoking is also by increased embryonic oxidative stress. Similarly, several drugs exert their teratogenic activity via embryonic oxidative stress. Abnormal placentation may also cause enhanced placental oxidative stress, resulting in embryonic death, preeclampsia or congenital anomalies. Inability of the developing embryo to cope with that stress may result in embryonic death and/or congenital anomalies. Animal studies also show that a variety of antioxidants are effective in decreasing the damaging effects of heightened oxidative stress induced by teratogens. Effective antioxidants, which might also be of clinical use, include vitamins C and E, carotenoids, folic acid, as well as synthetic products. Appropriate clinical studies with antioxidants in pregnancies of high risk to develop oxidative stress are needed, since non-toxic antioxidants might prove an efficient and inexpensive way to reduce the rate of some serious and sometimes fatal congenital anomalies.

Smoking-gene interaction and disease development: relevance to pancreatic cancer and atherosclerosis

There is little doubt that cigarette smoking remains a major environmental health risk that humans are facing in the twenty-first century. Cigarette smokers are more likely to develop many forms of diseases than nonsmokers, including cancers and vascular diseases. With the availability of the human genome sequence, we become more aware of the genetic contributions to these common diseases, especially the interactive relations between environmental factors (e.g., smoking) and genes on disease susceptibility, development, and prognosis. Although smoking is responsible for up to 30% of pancreatic cancers and about 10% of cases are ascribed to genetic reasons, some genetic variants do not predispose carriers to disease development unless they are exposed to a specific adverse environment such as smoking. This smoke-gene interaction could potentially be responsible for most of the cases. Certain polymorphisms in genes such as CYP1A1 have been shown particularly sensitive to smoking-induced pathogenesis, including pancreatic cancer and atherosclerosis. We found that individuals with CYP1A1 CC genotype had a more than three fold increase in risk for severe coronary atherosclerosis when they smoked. Patients with endothelial nitric oxide synthase (eNOS) intron 4 27 repeat homozygotes were more likely to develop severe coronary stenosis when they smoked. On the other hand, DNA variants at the eNOS gene also dictate how smoking affects the expression of eNOS. We showed that GSTM1 deficiency was not involved in smoking-induced vascular diseases, but p53 polymorphisms tended to modify the disease severity in smokers. We are still at an early stage of defining the pairs and mechanisms of smoke-gene interaction, and this etiologic mechanism may hold great potential for risk assessment, treatment strategy, and prognostic predictions.

Antioxidant status of neonates exposed in utero to tobacco smoke

To investigate the influence of maternal smoke exposure on neonatal and maternal antioxidant status, 39 mothers who were active smokers, 14 mothers exposed to environmental tobacco smoke (ETS), 17 controls, and their newborns were included in a prospective, controlled study. Plasma total antioxidant capacity, measured as total radical-trapping antioxidant parameter (TRAP) and ferric reducing antioxidant power (FRAP), and concentrations of specific antioxidants were measured in cord and in maternal blood. A similar, significant increase in ceruloplasmin concentration was observed in neonates born to actively smoking mothers and in those born to ETS exposed mothers. Uric acid and TRAP concentrations were significantly increased in ETS-exposed newborns and their mothers, compared to newborns and mothers from the active smoking and no-exposure groups with a trend towards increased uric acid, TRAP and FRAP concentrations being observed in the active smokers group. Neonatal and maternal antioxidant concentrations correlated significantly, except for ceruloplasmin. Cord blood vitamin A, E and C concentrations were unaffected by smoke exposure. These results show that maternal active smoking as well as ETS exposure significantly affect neonatal and maternal antioxidant status.

Effect of storage on breast milk antioxidant activity

BACKGROUND

Human milk, which contains compounds beneficial to infants, is often expressed and stored before use. Changes in its antioxidant activity with storage have not been studied.

OBJECTIVES

To measure antioxidant activity of fresh, refrigerated (4 degrees C), and frozen human milk (-20 degrees C), stored for two to seven days; to compare the antioxidant activity of milk from mothers delivering prematurely and at term; to compare the antioxidant activity of infant formulas and human milk.

METHODS

Sixteen breast milk samples (term and preterm) were collected from mothers within 24 hours of delivery and divided into aliquots. Fresh samples were immediately tested for antioxidant activity, and the rest of the aliquots were stored at -20 degrees C or 4 degrees C to be analysed at 48 hours and seven days respectively. The assay used measures the ability of milk samples to inhibit the oxidation of 2,2'-azino-di-3-(ethylbenzthiazolinesulphonate) to its radical cation compared with Trolox.

RESULTS

Antioxidant activity at both refrigeration and freezing temperatures was significantly decreased. Freezing resulted in a greater decrease than refrigeration, and storage for seven days resulted in lower antioxidant activity than storage for 48 hours. There was no difference in milk from mothers who delivered prematurely or at term. Significantly lower antioxidant activity was noted in formula milk than in fresh human milk.

CONCLUSIONS

To preserve the antioxidant activity of human milk, storage time should be limited to 48 hours. Refrigeration is better than freezing and thawing.

Serum levels of bile salt-stimulated lipase and breast feeding

OBJECTIVES

Bile salt-stimulated lipase (BSSL) is present in the sera of healthy humans, may affect lipoprotein structure and composition, and reduce atherogenicity of oxidized LDL-cholesterol. Our aims were to examine serum levels of BSSL in breast- and formula-fed infants, and explore the influence of BSSL on serum lipid profile and oxidative status.

METHODS

Infants (2-8 weeks old) were prospectively enrolled. Blood was drawn for serum levels of BSSL, total antioxidant status (TAS), and lipid profile.

RESULTS

Serum levels of BSSL were similar in breast-fed (0.28 +/- 0.15 microg/l, n = 18) and formula-fed (0.31 +/- 0.09 microg/l, n = 15) infants, and were much lower than reported levels for adults. In breast-fed infants only, BSSL levels were correlated with LDL-cholesterol serum levels (r = -0.53, p = 0.04). Total cholesterol (119.2 +/- 34.3 mg/dl vs 97 +/- 27.2, and p = 0.05) and LDL-cholesterol serum levels (50.5 +/- 26.1 mg/dl vs 33.3 +/- 20.3, p = 0.05), were elevated in breast-fed compared with formula-fed infants, but TAS was similar in both groups (1.02 +/- 0.18 mmol/l and 0.98 +/- 0.12 mmol/l, respectively).

CONCLUSIONS

Lack of difference in BSSL serum levels between formula- and breast-feeding, and lower BSSL levels in infants compared to adults, suggest that human milk does not contribute to BSSL serum levels.

Genetic influence on cigarette-induced cardiovascular disease

Cigarette smoking as an addictive habit has accompanied human beings for more than 4 centuries. It is also one of the most potent and prevalent environmental health risks human beings are exposed to, and it is responsible for more than 1000 deaths each day in the United States. With recent research progress, it becomes clear that cigarette smoking can cause almost all major diseases prevalent today, such as cancer or heart disease. These detrimental effects are not only present in active smokers who choose the risk, but also to innocent bystanders, as passive smokers, who are exposed to cigarettes not-by-choice. While the cigarette-induced harm to human health is indiscriminate and severe, the degree of damage also varies from individual to individual. This intersubject variability in cigarette-induced pathologies is partly mediated by genetic variants of genes that may participate in detoxification process, eg, cytochrome P450 (CYP), cellular susceptibility to toxins, such as p53, or disease development. Through population studies, we have learned that certain CYP1A1 variants, such as Mspl polymorphism, may render the carriers more susceptible to cigarette-induced lung cancer or severe coronary atherosclerosis. The endothelial nitric oxide synthase intron 4 rare allele homozygotes are more likely to have myocardial infarction if they also smoke. In vitro experimental approach has further demonstrated that cigarettes may specifically regulate these genes in genotype-dependent fashion. While we still know little about genetic basis and molecular pathways for cigarette-induced pathological changes, understanding these mechanisms will be of great value in designing strategies to further reduce smoking in targeted populations, and to implement more effective measures in prevention and treatment of cigarette-induced diseases.

Causes of oxidative stress in the pre- and perinatal period

Oxidative stress may be defined as an imbalance between pro-oxidant and antioxidant forces resulting in an overall pro-oxidant insult. Pregnancy is a physiological state accompanied by a high energy demand of many bodily functions and an increased oxygen requirement. Because of the increased intake and utilization of oxygen, augmented levels of oxidative stress would be expected. Arguments for a role of oxidative stress/oxidative lipid derivatives in the pathogenesis of preeclampsia are documented in many papers and evidence continues to accumulate that oxidative stress is a mediator of endothelial dysfunction and thus contributes to the cardiovascular complications of preeclampsia. Also other conditions, such as toxic substance exposure, smoking and asphyxia likewise induce oxidative stress. The oxidized lipid products generated as a consequence of these conditions are highly reactive and cause damage to cells and cell membranes. Thus, increased oxidative stress accompanied by reduced endogenous defences may play a role in the pathogenesis of a number of diseases in the newborn.

Breath biomarkers for detection of human liver diseases: preliminary study

Chronic liver disease is initially occult, has multiple aetiologies, involves complex diagnostic questions, and requires follow-up because progression is likely. Blood tests and biopsies are generally used, but have disadvantages. We have developed a new test for liver disease based on abnormal concentrations of metabolic products detected in exhaled breath. This test can be used, in conjunction with other clinically accepted diagnostic protocols, to detect and classify chronic liver diseases. Samples of breath collected from spontaneously breathing human subjects (86 patients presenting with 13 liver diseases and 109 subjects with normal liver function) were concentrated cryogenically and analysed by wide-bore capillary gas chromatography using various detectors. The concentrations of various molecules in exhaled breath were examined for potential use as biomarkers of liver function. Subjects with chronic liver diseases could be differentiated from those with normal liver function by comparing levels of breath carbonyl sulphide, carbon disulphide and isoprene; these differences were confirmed and correlated by comparing the levels with standard clinical blood markers of liver damage. The presence of chronic liver failure can thus be detected with sensitivity and specificity by quantifying sulphur-containing compounds arising from the abnormal metabolism associated with liver disease. The breath test we have developed appears to distinguish between hepatocellular and biliary tract aetiologies, and allows staging for severity. This approach may provide the clinician with a simple, non-invasive technique for use in the screening of large populations and follow-up for patients with chronic liver disease.

Postnatal changes in maternal and neonatal plasma antioxidant vitamins and the influence of smoking

OBJECTIVE

To study the postnatal changes in the plasma concentrations of fat soluble antioxidant vitamins and malondialdehyde (MDA) in mothers and their newborns and their relation to smoking.

DESIGN

Prospective cohort study.

SETTING

Tertiary perinatal centre.

SUBJECTS

Eighteen non-smoking and 14 smoking mothers and 33 infants.

MAIN OUTCOME MEASURES

Plasma concentrations of vitamins E, A, and beta-carotene and MDA were measured in mothers and infants at delivery and on day 4 post partum.

RESULTS

Neonatal plasma levels of vitamins E, A, and beta-carotene were significantly lower than maternal levels both at delivery and on day 4 in both groups. There was a significant postnatal increase in plasma vitamin E levels in smoking mothers and neonates of both groups. A significant postnatal increase in maternal, but not neonatal, plasma vitamin A was noted in both groups. Cord plasma vitamin E levels were significantly lower in infants of smoking mothers (mean 4.7 v 6.5 micromol/l, p = 0.041). Plasma MDA was paradoxically lower in smoking mothers at delivery (3.19 v 4.01 micromol/l, p = 0.03) and on day 4 (1.37 v 3.29 micromol/l, p = 0.005) and in infants of the smoking group on day 4 (2.18 v 3.12 micromol/l, p = 0.014). Also, there was a significant postnatal fall in plasma MDA levels on day 4 in mothers and infants in the smoking group.

CONCLUSIONS

The postnatal changes in plasma vitamin E were more pronounced in the smoking group. The postnatal changes in plasma vitamins A and beta-carotene were similar in both groups. The rapid decline in plasma MDA in smoking mothers and their infants suggests withdrawal of oxidative stress from smoking around delivery. This coincided with the increase in plasma vitamin E.

Maternal smoking and reduced duration of breastfeeding: a review of possible mechanisms

AIM

To systematically review the possible mechanisms by which maternal smoking affects lactation.

METHODS

Databases (Medline, CINAHL, Current Contents, Psychinfo, Sociological Abstracts and the Cochrane Library) were searched for smoking and breastfeeding or infant feeding. The Journal of Human Lactation and Birth were hand-searched, searches were also conducted at NMAA's Lactation Resource Centre and references cited were located where appropriate. Articles were divided into the various ways that smoking could affect breastfeeding and were tabulated.

RESULTS

Most studies were conducted on small samples of animals or humans; the majority were prior to 1985. Most animal studies exposed the animals to much greater levels of nicotine than those to which humans are exposed. Most studies did not examine if breastfeeding behaviour was similar in smokers and non-smokers, and did not consider that any physiological difference found could be the result of poor lactation practices, rather than the cause of poor lactation in smokers. The definition of breastfeeding infants was also problematic in many studies. The effect of smoking on oxytocin in women was only examined in one study, and no effect was found, yet a negative effect of smoking on oxytocin release is reported in the breastfeeding literature.

CONCLUSION

Although there is consistent evidence that women who smoke breastfeed their infants for a shorter duration than non-smokers, the evidence for a physiological mechanism is not strong.

Clinical application of breath biomarkers of oxidative stress status

Isolation and quantification of volatile breath biomarkers indicative of relevant alterations in clinical status has required development of new techniques and applications of existing analytical chemical methods. The most significant obstacles to successful application of this type of sample have been reduction in required sample volume permitting replicate analysis (an absolute requirement for all clinical studies), separation of the analyte(s) of interest from background molecules, water vapor and other molecules with similar physical properties, introduction of automation in analysis and the use of selective detection systems (electron impact mass spectrometry, flame photometric, thermionic detectors), and automated sample collection from the human subject. Advances in adsorption technology and trace gas analysis have permitted rapid progress in this area of clinical chemistry.

Possible antioxidant effect of vitamin A supplementation in premature infants

BACKGROUND

Increased lipid peroxidation caused by oxygen free radicals is thought to be one of the common pathogenetic mechanisms for the so-called oxygen radical diseases of prematurity. Since in vitro studies have shown that various forms of vitamin A can exert antioxidant effects that are more potent than those of vitamin E (treatment with which has been ineffective in these diseases), the purpose of this prospective, controlled study was to determine whether administration of supplemental vitamin A to premature infants deficient in this vitamin would have an antioxidant effect in vivo.

METHODS

Fourteen infants (1181 +/- 35 g; gestational age 29 +/- 0.04 weeks) with a serum retinol concentration at 7 +/- 2 days of age in the deficient range, lower than 0.7 mumol/l (< 20 micrograms/dl), were enrolled in the study. Infants were randomized to receive the standard amount of vitamin A or standard plus supplemental (2.6 mumol/l [2500 IU] orally each day) vitamin A, beginning at 1 week of age. Antioxidant effects of supplementation were assessed by a decrease in lipid peroxidation, quantified by the ethane content of expired air.

RESULTS

Three weeks after study enrollment, total daily vitamin A intake in the infants receiving supplements was 4.565 +/- 0.236 mumol (4354 +/- 225 IU) versus 1.879 +/- 0.317 mumol/l (1792 +/- 302 IU) in infants receiving standard amounts of the vitamin. In spite of the difference in intake of vitamin A, 3 weeks after study enrollment, serum retinol concentrations did not differ between the infants given supplements and those receiving standard amounts of vitamin A, 0.70 +/- 0.21 versus 0.66 +/- 0.07 mumol/l (20 +/- 6 micrograms/dl versus 19 +/- 2 micrograms/dl, respectively). In the infants receiving supplemental vitamin A, breath ethane values declined from baseline values. There was an inverse correlation between the number of weeks of supplementation and breath ethane values, whereas there was no significant correlation between the duration of the study and breath ethane values in the infants not given supplements.

CONCLUSIONS

Our data suggest that supplementation with vitamin A in a small group of vitamin A-deficient preterm infants was associated with an antioxidant effect. Although no immediate clinical benefits were associated with supplementation, the data provide the rationale for future investigations of possible antioxidant effects of (larger amounts?) of vitamin A in higher risk premature infants born with subnormal serum retinol concentrations.