Meta-analysesThe effects of cranberry on cardiovascular metabolic risk factors: A systematic review and meta-analysis
Introduction
Cardiovascular disease (CVD) is the leading cause of death among non-communicable diseases, and affects millions of people in both developed and developing countries [1]. Despite the reducing CVD mortality rate, it is still one of the main problems faced by healthcare systems, and can lead to serious social distress, as well as imposing substantial health economic burdens on a global scale over the past few decades [2], [3]. For this reason, healthcare service studies should try to find better solution for the prevention and/or treatment of CVD [4], [5]. Multiple factors and diseases have been suggested as being associated with CVD development. Certain associations between CVD and many diseases are well-documented [6], [7], [8], and several metabolic risk factors including hyperglycemia and dyslipidemia have been suggested as playing substantial roles in the onset and progression of CVD [9], [10], [11]. Cardio-metabolic risk factors are modifiable, and CVD can be prevented through strategies which can beneficially amend them. In this regard, many strategies are recommended in terms of focusing on CVD risk factor management, such as diet modification, physical activity, and pharmacological therapy [12], [13]. Current drug therapy, including blood pressure-lowering agents and lipid profiles-modulators, are frequently and effectively used for CVD risk factor management [14], [15]. However, there is a concern about their undesirable side-effects [16], [17], [18]. Beside the pharmacological approach, complementary medicine can offer novel, safe and cost-effective options. It is thus not surprising that many researchers are exploring substitution or adjutant therapy for CVD metabolic risk factor management in parallel with pharmacological agents [19], [20], [21].
Cranberry (Vaccinium macrocarpon Ait Ericaceae), belonging to the Ericaceae family, is widely consumed in many countries in the forms of fresh and dry fruits, juice and encapsulated powders [22]. Cranberries have been highly ranked in terms of their antioxidant capacity, and are known as a rich source of phenolic compounds. It has been used for a long time in traditional folk medicine, especially for the treatment of bladder and kidney ailments [23]. Cranberry also has several putative health benefits for the prevention and/or treatment of cardiovascular disease [24], urinary tract infections [25] and cancer [26]. The CVD protective properties of cranberry have been investigated in animal [27], [28] and human studies [29], [30]. However, results from human studies have remained inconclusive. To summarize the evidence and clarify these inconsistencies in the results of human trials, the current systematic review and meta-analysis was conducted to systematically identify and quantitatively assess the efficacy of cranberry supplementation on CVD metabolic risk factors in adult populations.
Section snippets
Materials and methods
The present systematic review and meta-analysis was reported in accordance with the PRISMA guidelines [31].
Results
Figure 1 shows a flowchart of the study selection process and reasons for excluding articles. The primary literature search yielded 1892 publications from the aforementioned electronic databases. After excluding duplicate studies, a total of 1619 publications were reviewed by title/abstract, and 1603 were excluded which did not meet the inclusion criteria. 16 articles were retrieved and scrutinized by full-text. Of those, 4 studies were discarded for the following reasons: cranberry was
Discussion
The results of the present systematic review and meta-analysis suggested that cranberry supplementation might have favorable effects on blood pressure and weight loss. However, the results did not support any benefit from cranberry on lipid profiles, glycemic status markers, and inflammatory markers. The stratified analysis indicated that cranberry increased TG in the subgroup in which cranberry was administrated in the form of juice. While no significant change was observed in serum TG levels
Conclusion
In conclusion, the current meta-analysis on available trials suggested that cranberry may have beneficial effects on reducing SBP and BMI. This SBP-lowering effect is robust in people >50 years old. Also, the results showed that cranberry might be effective in terms of increasing HDL levels in adults <50 years old. However, these findings are incomplete due to the paucity of studies, and more studies are needed in this field to confirm these results, as well as to clarify other aspects of the
Authorship
M.P. and A.H. carried out the concept, design and drafting of this study. A.N., A.H., and F.J. searched databases, screened articles and extracted data. M.P. performed the acquisition, analysis, and interpretation of data. F.M-G. critically revised the manuscript. All authors approved the final version of the manuscript. F.M-G. and F.J. are the guarantors of this study.
Funding
None.
Conflicts of interest
None.
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