Apples contain prebiotics . 20 Prebiotics can cause specific changes in the composition and / or metabolism of gastrointestinal microbiota . 20 Polyphenols from apples reach the colon intact . Here they interact with the gut microbiota . 12 This is a reciprocal or interchange process where the commensal bacteria transform polyphenols into simple aromatic metabolites , while polyphenols can reciprocate via the ability to modulate the gut microbiota composition . 12 This includes inhibiting some bacterial populations and stimulating others . 12
Apple cider vinegar and health
Apple cider vinegar is one of the most commonly available vinegars . 14 , 15 It is widely used as a flavouring , a dressing , and a preservative in foods . 16 Apple cider vinegar is also known for its usefulness as a surface disinfectant of fruits and vegetables and as a natural preservative for inhibiting the growth of foodborne pathogenic microorganisms in food . 26 Apple cider vinegar is produced by the fermentation of apples . 14 , 27 It is produced from apples that go through a very restricted treatment process . 15 During
Epidemiological studies support the association
between frequent apple consumption and reduced risk of chronic diseases , such as cardiovascular disease , 12 , 13 type 2 diabetes , 12 and some specific cancers . 7
the first stage of the process , the sugars from apples are fermented by yeasts to cider . The produced ethanol is used as a substrate by acetic acid bacteria in a second separated bioprocess . The ethanol oxidation to acetic acid is initiated by native microbiota that survived alcohol fermentation . 15 Research has shown that bacterial microbiota for the industrial production of organic apple cider vinegar is clearly more heterogeneous than the bacterial microbiota for the industrial production of conventional apple cider vinegar . 15
A key factor in the quality of apple cider vinegar is the microbiota converting the main substrate , ethanol , into acetic acid , and producing by-products that influence the chemical composition . 15 Apple cider vinegar contains acetic acid , 27 , 28 organic acids , 26 phenolic compounds ( gallic acid , chlorogenic acid , caffeic acid ), 26 polyphenols , 28 , 29 14 , 26 , 28 , 29
flavonoids , catechins , 14 , 26 epicatechins , 26 caffeic acid , 14 ferulic acid , 14 alkaloids , 29 tannins , 26 carotenoids , 26 anthocyanin , 26 quercetin , 26 vitamins , and minerals . 28 It has relatively low acidity ( 5 % acetic acid ). 28
In-vitro research has found that apple cider vinegar has antioxidant , 29 antiinflammatory , 27 antibacterial , 28 and antimicrobial effects , 27 , 30 and antifungal properties against Candida spp . 31 Invitro anti-microbial effects directly on resistant Escherichia coli ( E . coli ) and methicillin resistant Staphylococcus aureus ( MRSA ). 27 Additionally , in-vitro studies found that apple cider vinegar can inhibit the nucleation , growth , and aggregation of calcium oxalate crystals , potentially benefiting the reduction and prevention of kidney stones . 29
Research in animals has shown that apple cider vinegar has a variety of pharmacological functions , including antioxidant , anti-inflammatory , lipid lowering , and antihypertensive properties . 14 A systematic review and meta-analysis found that consumption of apple cider vinegar may beneficially affect glycaemic status and lipid parameters in adults . 14 A significant improvement in HDL-C has been found among non-diabetic participants . 14 Apple cider vinegar may reduce serum total cholesterol concentrations . This effect of apple cider vinegar on lipid profiles may be attributed to its stimulation of acid bile excretion , increasing lipolysis , and decreasing lipogenesis . 14 A subgroup analysis indicated a greater beneficial effect on both total cholesterol and triglyceride levels among type 2 diabetic patients . 14 The effect on triglycerides and total cholesterol was more significant when interventions lasted greater than 8 weeks with a daily consumption greater than 15 mL per day . 14 Studies showed that the consumption of apple cider vinegar improved serum levels of fasting plasma glucose . 14 Topically , it is used for its antimicrobial effects for cleaning and treating nail fungus , head lice , and warts . 26
Apple cider vinegar may benefit weight management . A randomised clinical trial was performed to examine whether apple cider vinegar at 30 mL per day for 12 weeks had beneficial effects on the management of body weight and metabolic profiles in overweight or obese
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