red wine vinegar is 95% water, with no fat or protein. In a reference amount, distilled vinegar supplies of food energy and no micronutrients in significant content. The composition (and absence of nutrient content) for red wine vinegar and apple cider vinegar are the same, whereas balsamic vinegar is 77% water with 17% carbohydrates, per 100 mL, and contains no fat, protein, or micronutrients. In folk medicine Since antiquity, folk medicine treatments have used vinegar, but no conclusive evidence from clinical research supports health claims of benefits for diabetes, weight loss, cancer, or use as a probiotic. A systematic review and meta-analysis later suggested it could help type 2 diabetics reduce insulin and glucose after meals. Some treatments with vinegar pose risks to health. Esophageal injury by apple cider vinegar has been reported, and because vinegar products sold for medicinal purposes are neither regulated nor standardized, such products may vary widely in content and acidity. Cleaning White vinegar is often used as a household cleaning agent. For most uses, dilution with water is recommended for safety and to avoid damaging the surfaces being cleaned. Because it is acidic, it can dissolve mineral deposits from glass, coffee makers, and other smooth surfaces. Vinegar is known as an effective cleaner of stainless steel and glass. Malt vinegar sprinkled onto crumpled newspaper is a traditional, and still-popular, method of cleaning grease-smeared windows and mirrors in the United Kingdom. Vinegar can be used for polishing copper, brass, bronze or silver. It is an excellent solvent for cleaning epoxy resin as well as the gum on sticker-type price tags. It has been reported as an effective drain cleaner. Herbicide and sting relief Twenty percent acetic acid vinegar can be used as a herbicide, but acetic acid is not absorbed into root systems so the vinegar will only kill the top growth and perennial plants may reshoot. Applying vinegar to common jellyfish stings deactivates the nematocysts, although not as effectively as hot water. This also applies to the Portuguese man o' war, which, although generally considered to be a jellyfish, is not (it is a siphonophore). Reactions, byproducts, and regulation Most commercial vinegar solutions available to consumers for household use do not exceed 5%. Solutions above 10% require careful handling, as they are corrosive and damaging to the skin. When a bottle of vinegar is opened, mother of vinegar may develop. It is considered harmless and