Triple Threat: Maqui Berry Supports Glucose, Eyes, and Heart
Aristotelia chilensis is a species of tree that is native to the rainforests of Chile and southern Argentina. Its fruit is known as Chilean wineberry or maqui, which is used as food or consumed as a dietary supplement, primarily because of its high anthocyanin content.1
Along with açaí and goji berries, maqui berries are considered by many to be a “superfruit.” An analysis of the oxygen radical absorbance capacity (ORAC, a measure of a food’s antioxidant property) of over 120 species and varieties of fruit produced within the south Andes determined that maqui along with two other fruits “largely outscored” all others.2
Research has revealed a better ability for Maqui berry to trap free radicals in comparison with other commercial berries.3 The juice of the berry inhibited copper-induced oxidation of low-density lipoprotein (LDL), which can react with the lining of the blood vessels and cause inflammation and atherosclerosis. Additionally, maqui juice protected human endothelial cells from hydrogen peroxide-induced intracellular oxidative stress. “These results show that Aristotelia chilensis is a rich source of phenolics with high antioxidant capacity and suggest that it may have antiatherogenic properties,” S. Miranda-Rottmann and colleagues conclude.
A double-blind trial that included 42 middle-aged participants who received an extract of maqui berry or a placebo three times per day for 4 weeks resulted in a decrease in oxidized LDL levels in the plasma and F2-isoprostanes (a marker of oxidative stress) in the urine.4
The leaves of Aristotelia chilensis also contain antioxidant polyphenol compounds and have been shown to have the ability to inhibit alpha-glucosidase, an enzyme that breaks down carbohydrates so that they can be absorbed.5 (Alpha-glucosidase inhibiting drugs are used in the treatment of diabetes.)
In a mouse model of diabetes, an anthocyanin-rich formula from maqui berry improved fasting blood glucose.6 The formulation also lowered glucose production in rat liver cells and stimulated glucose uptake in rat muscle cells. Similar benefits were observed after the administration of delphinidin 3-sambubioside-5-glucoside (D3S5G), an anthocyanin isolated from maqui berry, leading the researchers to conclude that the compound is at least partly responsible for maqui berry’s antidiabetic properties. (Delphinidins are anthocyanins that have a significant presence in maqui.)
A double-blind, placebo-controlled trial involving 10 participants with moderate glucose intolerance resulted in lower blood glucose and insulin when an extract of maqui berries standardized to at least 25% delphinidins and at least 35% total anthocyanins was consumed prior to food.7 In diabetic rats, daily intake of the extract over a four-month period reduced fasting glucose levels to those that were indistinguishable from nondiabetic rats.
In a study that tested the effects of a delphinidin-rich extract of maqui berry in 43 prediabetic participants, varying doses of the extract administered an hour before glucose consumption resulted in lower blood glucose and insulin in oral glucose tolerance tests compared to test results obtained without pretreatment.8 The authors of the report suggest that the extract could be acting through three mechanisms: inhibition of intestinal glucose transporters, an incretin-mediated effect, or improvement of insulin sensitivity.
Inflammation, Eye Health, and more
In an article titled “Anti-Inflammatory Diets,” Barry Sears, PhD, author of The Zone and other books, notes that, “Chronic disease is driven by inflammation […] To overcome silent inflammation requires an anti-inflammatory diet (with omega-3s and polyphenols, in particular those of Maqui).”9 In immune cells known as macrophages stimulated with proinflammatory lipopolysaccharides, maqui extract lowered the production of prostaglandin E2 and the expression of cyclooxygenase-2 (COX-2), both of which are involved in inflammation.10
A study that evaluated maqui berry fractions and extracts found strong anti-inflammatory and antioxidant effects for the extract as well as several subfractions, mixtures and the compounds quercetin, gallic acid, luteolin and myricetin in lipopolysaccharide-treated mouse macrophage cells.11 “Thus, the phenolics (anthocyanins, flavonoids, and organic acids) as the fractions and mixtures may provide a potential therapeutic approach for inflammation associated disorders and therefore might be used as antagonizing agents to ameliorate the effects of oxidative stress,” authors C. L. Cespedes and colleagues conclude.
Maqui has been associated with benefits to the eye, which may be the result of its high delphinidin content. “Delphinidins represent the most potent antioxidant anthocyanin species owed to largest number of hydroxyl groups in the B-ring,” write R. R. Watson and F. Schönlau in a 2015 review. “The richest known natural source of delphinidins is the maqui berry (Aristotelia chilensis).”12 Maqui’s delphinidins D3S5G and D3G5G have shown the ability to protect the photoreceptor cells of the eye from cell death induced by light exposure.13 Standardized maqui berry extract given to participants with moderately dry eyes resulted in a significant increase in tear production after 30 days.14 While a 30 milligram dose proved to be effective, 60 milligrams daily was associated with a superior benefit.
The Bottom Line
“Many qualities make the maqui berry the undisputed sovereign of the family of so-called ‘superfruits,’ as well as a valuable tool to combat cellular inflammation of bones and joints,” remark Valeria Romanucci and colleagues in a recent review. They note that maqui’s properties include “antioxidant activity, inhibition of visible light-induced damage of photoreceptor cells, inhibition of alpha-glucosidase, inhibition of pancreatic lipase, antidiabetic effects, anti-inflammatory effects, analgesic effects, anti-diabetes, effective prevention of atherosclerosis, promotion of hair growth, anti-photo aging of the skin, and inhibition of lipid peroxidation.”15
While this superfruit may be hard to find in the Northern hemisphere, maqui extract is contained in a number of nutritional supplement formulas that are readily available in the U.S.