Applied nutritional investigationEffects of alcohol-free beer on lipid profile and parameters of oxidative stress and inflammation in elderly women
Introduction
Atherosclerosis is the single most important contributor to the growing burden of cardiovascular, cerebrovascular, and peripheral arterial diseases. It has been shown that atherosclerosis is an inflammatory disease that develops from complex interactions among leukocytes, platelets, and cells of blood vessel walls [1], [2]. Activated neutrophils and macrophages produce free radicals that can attack plasma low-density lipoprotein (LDL). This modified, oxidized LDL (ox-LDL) is essential to the development of atherosclerosis, because it leads to the attraction of blood monocytes beneath the endothelium, generates the accumulation of lipids, and facilitates the fibrous degeneration of arteries [3]. Thus, oxidative stress is the initial step in atherosclerotic disease pathogenesis.
There is mounting evidence from animal models and observational studies that consumption of certain foods results in a reduction of oxidative stress [4]. Moderate consumption of alcoholic beverages has been significantly and positively correlated with cardiovascular disease protection. Moderate alcohol consumption affects lipoprotein metabolism by elevating plasma high-density lipoprotein cholesterol (HDL-C) concentrations [5] and by mediating an increase in the total antioxidant capacity of plasma [6]. Changes in hemostatic and fibrinolytic parameters, which can contribute to alcohol's protective properties, have also been reported [7], [8]. The protective effect of alcoholic beverages has often been shown to be independent of the type of drink [9], and it has been suggested that components other than the alcohol in the beverages, such as flavonoids, might also be implicated in the protective mechanism. It must be noted that alcohol consumption has not only beneficial but also adverse effects. There are gender-related differences in alcohol's adverse effects, resulting in increased susceptibility to these adverse effects in female subjects.
Beer is a drink made of fermented barley malt and flavored with hops. It has more than 2000 chemical components, including folic acid, B-complex vitamins (B1, B2, B12), and polyphenols, which are essential in shaping the taste and maintaining the foam of this drink [10]. This complexity illustrates that, in addition to its nutritional value, beer's functional properties, in particular its antioxidant activity, are very important. This antioxidant activity comes from phenolic compounds, most of which come from the barley and hops, and from melanoidins produced by heat treatment during beer production [11], [12]. Non-alcoholic beer is a relatively new product on the market that satisfies the needs of consumers who want a refreshing drink without the alcohol content. There have been very few human studies of the benefits of diet supplementation with non-alcoholic beer. To address this lack of knowledge, we designed a study to assess the effects of supplementing a normal diet with alcohol-free beer on blood lipid profile and markers of oxidative metabolism and inflammation. We chose a population of subjects at risk for atherosclerotic disease who present certain characteristics that made them particularly well suited to this type of study: middle-age and older nuns residing in a closed convent with a disciplined, clean, regular, and homogeneous lifestyle.
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Subjects
The study population was recruited from a group of 50 nuns living in a closed Catholic convent. Nuns were included if they voluntarily agreed to participate in the protocol, gave written informed consent, and were medically healthy women, as indicated by a general medical questionnaire and physical examination. Nuns were excluded if they presented hypertension, diabetic mellitus, or neoplastic or acute infectious diseases. They were also excluded if they took medications thought to have
Results
No significant differences in daily mean energy and nutrient intake were observed between the onset and the end of the supplementation period (1670 ± 113 versus 1725 ± 120 kcal/d, 81.7 ± 13.3 versus 82.1 ± 15.2 g/d of protein, 58.8 ± 12.2 versus 59.1 ± 11.2 g/d of fat, and 205.4 ± 43.6 versus 210.9 ± 38.5 g/d of carbohydrates). The mean body weight was slightly greater after the supplementation period (61.8 ± 6.2 kg), but no significant differences were observed with respect to the basal
Discussion
We have shown that consumption of 500 mL/d of alcohol-free beer with meals resulted in changes in specific oxidative metabolism parameters. It also enhanced the antioxidant defense by increasing plasma levels of α-tocopherol and levels of the endogenous antioxidant glutathione in the women participating in the study. These findings may have beneficial effects for diseases related to oxidative stress. Increased reactive oxygen species are implicated in the genesis of endothelial dysfunction and
Conclusion
Daily ingestion of 500 mL of alcohol-free beer for 45 d reduced parameters of oxidative stress as TBARS and CG and enhanced antioxidants as α-tocopherol and glutathione. However, mediators of inflammatory processes that could have potential effects on vascular endothelial function were not modified. Therefore, alcohol-free beer could be included in the diet of the population as a possible protective factor for diseases related to oxidative stress but prospective observational studies are also
Acknowledgments
The authors thank the Mother Superior and all the nuns who generously and enthusiastically participated in the study.
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This work was supported in part by a grant from the Centro de Información Cerveza y Salud, Cerveceros de España.