By Michael Downey
Consumers hear a lot today about “healthy foods” that are shown to prevent disease.
Missing from news broadcasts are details about how to benefit from specific plant components that published studies document help protect against degenerative disorders.
In seeking to clarify their knowledge base, scientists are focusing a lot of research on compounds known as anthocyanins, which provide berries and other plants with their rich deep red and purple colors and have been proven to combat multiple pathways of disease.1,2
In this report, we provide you with research findings about various anthocyanin-rich plants and how you can access their disease prevention benefits.
Hidden in berries and other plants are diverse bioactive compounds that provide broad-spectrum protection against cognitive decline, diabetes, cancer, and heart disease.1-4
According to the National Institutes of Health, “There is accumulating evidence that much of the health-promoting potential of berries may come from phytochemicals, the bioactive compounds not designated as traditional nutrients.”5
What the National Institutes of Health is saying is that the disease prevention properties of healthy plants extends beyond the vitamins and minerals they naturally supply.
Anthocyanins: Powerful Antioxidant Protection
Extensive research confirms that the most powerful antioxidant berries are those that contain a class of polyphenols known as anthocyanins. These nutrients create the deep red, blue, and purple pigments found in plants such as blueberries, elderberries, blackberries, and açaí.1,6-8 Berry anthocyanins strongly combat oxidative stress, a causative factor in the pathogenesis of many major diseases1 such as Parkinson’s disease,9 Alzheimer’s disease,10 amyotrophic lateral sclerosis (ALS),11,12 cancer,13 and allergic disorders.14
In a new development, scientists are suggesting that superior free-radical defense is just part of the berry benefit story.
Mechanisms: Beyond Antioxidant Activity
Recent evidence indicates that anthocyanin-rich foods exert their effects through multiple mechanisms that go far beyond berries’ well-known antioxidant activity. These underlying pathways have been shown to:
- Enhance glucose metabolism and reduced glucose absorption.15-17
- Reduce the formation and enhance immune system clearance of amyloid protein, the hallmark protein seen in the brain of individuals with Alzheimer’s disease.18
- Inhibit LDL oxidation16 and improved lipid profiles.17,19
- Induce cancer apoptosis (programmed cell death) in several cancer cell lines.20-23
- Possesses antiviral,24 antibacterial,25 and antiparasitic26,27 activity.
- Inhibit DNA damage.5,28
- Inhibit inflammatory gene expression and reduce inflammation.5,16
- Reduce capillary permeability and fragility.2
- Boost nitric oxide, an important cell signaling molecule.2,16
- Improve neuronal cellular communication.29
- Inhibit pathways that lead to tumor cell resistance to chemotherapeutic agents.30
- Metabolize carcinogens and xenobiotics.30
Next, we’ll examine the anthocyanin sources considered by scientists to be the most potent.
A wealth of studies has validated that each of the following food sources provides superior benefits against aging and age-related diseases.
A standard index for determining the antioxidant value of various organic compounds is known as oxygen radical absorbance capacity, or ORAC.31 Of all fruits and vegetables—açaí berries have one of the highest reported total ORAC scores of any fruit or vegetable.32
In lab studies, açaí extracts inhibited proliferation of human colon cancer cells by up to 90.7%33 and proliferation of human leukemia cells by 56-86%.34
As a major cardiovascular protector, animal studies showed that Açaí induces long-lasting arterial wall relaxation (endothelium-dependent vasodilation),35 and reduces total and non-HDL cholesterol.36
With implications for treatment of neurological disorders such as Alzheimer’s disease and Parkinson’s disease, açaí-treated brain tissue showed decreased reactive oxygen species-induced damage to the lipids and proteins in the tissue, regardless of the area of the brain from which it was taken.37 And studies using freeze-dried açaí fruit pulp have shown it to have beneficial anti-inflammatory action—an important finding since inflammation underlies many chronic diseases of aging.38
In an uncontrolled 2011 pilot study, consumption of açaí fruit pulp reduced levels of selected markers of metabolic disease in ten overweight humans. In just one month, açaí reduced fasting glucose, insulin, and total cholesterol levels, and ameliorated the increase in plasma glucose following a standardized meal.39
Also known as chokeberries, aronia berries have been found to yield very high ORAC values.32 Aronia has been shown to decrease lipid peroxidation,16 as well as oxidative stress.40 In vitro research found an anti-clotting effect.41 Drinking aronia berry juice reduced exercise-induced oxidative damage to red blood cells.42
In animals with experimentally induced high cholesterol, scientists observed that aronia exerted a significant cholesterol-lowering effect.43 Animal studies have demonstrated that aronia extracts have a protective effect on the liver,44 and, in diabetic rats, can help return the blood levels of both glucose and cholesterol to normal levels.45
Human intervention studies showed improvements in lipid profiles, glucose metabolism, and reduced LDL oxidation.16,40
In a host of studies, aronia compounds inhibited proliferation of human cervical tumor cells,46 killed malignant brain tumor cells,47 reduced biological markers of colon cancer,48 and helped prevent gastric ulcers.49
Bilberry, a relative of the blueberry, promotes frontline prevention against cardiovascular disease by significantly inhibiting angiotensin-converting enzyme (ACE), which contributes to hypertension by promoting narrowing of the arteries (vasoconstriction).50
Bilberries improve insulin sensitivity, which may help ward off diabetes.51 They also enhance short-term memory in animal models, suggesting the potential to help prevent Alzheimer’s disease.52
These berries inhibit proliferation of breast cancer cells and induce apoptosis in animal models,53 and bilberry extract defends against intestinal cancer.54-56
Extract of bilberry helps increase enzymes that inhibit oxidative stress in the eyes, suggesting it protects against age-related eye disorders, such as macular degeneration.57 In 2012, a study found that bilberries may prevent the early, gene-related changes that precede obesity- and diabetes-related visual impairment.58
Extracts of blackberry show the potential, in lab studies, to inhibit the growth of human cancer cells of the colon, breast, and prostate.59,60
Compounds found in blackberries have been shown to be anti-inflammatory,61 antibacterial,62 and significantly antioxidative.31 They were found to be as effective as the drug metronidazole (Flagyl®) in treating a parasite and common cause of diarrhea known as Giardia duodenalis.27 And in 2012, scientists reported that blackberries appear to be a promising therapy for periodontal (gum) disease.63
They are particularly rich in an anthocyanin called cyanidin-3-O-beta-D-glucoside (C3G), which holds a higher ORAC value than many other tested anthocyanins.28 C3G has been shown to inhibit free radical damage induced by ultraviolet (UV),64 defend against oxidative effects in the liver,65 protect blood lipids against lipid peroxidation,66 and protect blood vessels.67 C3G plays an important role in protecting retinal tissue and retinal pigments from oxidative damage. It stimulates regeneration of the retinal pigment called rhodopsin.68 Rhodopsin is particularly vital to vision under dim light conditions. When rhodopsin levels are depleted, more time is needed for the remaining pigment to return to its normal, light-sensitive state. C3G increases the restoration of rhodopsin levels.69,70
Additionally, C3G protects retinal cells from harmful oxidation that is triggered by light and reduces the age-associated accumulation of a fluorescent pigment called A2E that interferes with normal function of the retina.71
Studies demonstrate that blackcurrants relax the aorta by enhancing the synthesis of nitric oxide,72 improving the functioning of blood vessels,73 and reducing susceptibility of low-density lipoprotein (LDL) to oxidative stress, resulting in cardioprotective benefits.71 Blackcurrant anthocyanins improve blood flow in the human forearm and have been shown to reduce muscle fatigue and stiffness.74
One study found that black currant extract improved volunteers’ ability to adapt to darkness and decreased symptoms of tired eyes.75
A scientific review published in 2012 noted the therapeutic potential of blackcurrants against cardiovascular-associated illnesses, neurodegenerative and ocular diseases, kidney stones, and diabetic neuro-pathy.76
Blackcurrant has also been shown to stop the growth of certain harmful bacteria,62,77 provide potent anti-viral activity,78 and alleviate allergy-driven airway inflammation, a major cause of asthma.79 And in lab studies, mice given blackcurrant juice were shown to live longer.80
Abundant in polyphenols that can cross the blood-brain barrier, blueberries are well known for their enhancement of cognitive performance and their protection against age-related decline of memory and brain function.81-83
Blueberries have been shown not only to improve cognition in animal models of Alzheimer’s disease, but to decrease aggregation and enhance immune system breakdown removal of amyloid beta plaques in the brain.18 Blueberries help protect the aorta84,85 and the myocardium, and may prevent heart failure following myocardial infarction.86 They lower blood pressure and lipid peroxidation.87 They have also been found to improve insulin resistance and glucose control in pre-clinical models.87,88
In the laboratory, blueberry induced self-destruction among oral, breast, colon, and prostate cancer cells.60
Other beneficial effects of blueberries include activity against colitis (when taken with probiotics),89 liver injury,90 prevention of collagen breakdown in bone,91 inflammation,92 and neurodegeneration.92
Both sweet and tart varieties of cherry have exhibited potent cardiovascular and antidiabetic effects.
Traditionally associated with the soothing of arthritis and gout, cherries have been found to block inflammatory pathways associated with these diseases;93-95 and a 2012 study found cherry intake reduced gout attacks by 35%.96 These berries and their extract also inhibit the inflammatory processes involved in heart disease.94,95,97
Rat studies using whole tart cherry powder suggest a protective role against both heart disease and diabetes, through an ability to reduce blood levels of triglycerides, cholesterol, glucose, and insulin, as well as the amount of cholesterol stored in the liver.98 Tart cherries have also been found effective in suppressing inflammation-induced pain.99
Cherries are rich in a phytonutrient—perillyl alcohol—shown to prevent development, or limit progression, of several cancer types.100-103And when anthocyanins and cyanidin supplements from cherries were fed to mice with a genetic susceptibility to colon cancer, they developed fewer tumors than those who did not receive the cherry-based supplement.104
Anthocyanins and other exceptionally active antioxidants are not limited to berries.
Blue corn, also known as purple corn, is botanically identical to yellow corn but with one important difference. Its deep blue-purple color is the result of its rich anthocyanin content—with a concentration equal to, or greater than, the anthocyanin concentration of blueberries.105
Blue corn possesses anti-mutagenic effects, reducing expression of genes involved in the proliferation of tumor cells,106,107 as well as suppressing the development of colon cancer cells in rats.108
Scientists studied rats on a high-fat diet, and divided them into two groups. The test group’s diet was supplemented with purple corn pigment, and these subjects were found to be less likely to develop early signs of obesity and diabetes than the controls.15
Cranberries provide powerful protection against oxidative damage—they were shown in an 8-week, double-blind, placebo-controlled trial involving 65 healthy women to significantly reduce blood levels of advanced oxidation protein products.109
But cranberries and cranberry juice are probably best known for their ability to help prevent urinary tract infections,110,111 and are believed to work by inhibiting the adherence of E. coli to the urethra and bladder wall, making it easier for the body to flush them out.112,113 Similarly, they may protect against gastric ulcers by preventing Helicobacter pylori, the bacterium implicated in this condition, from adhering to the stomach lining.114,115
Cranberries also display anti-proliferative activity in vitro and in vivo, against cancer cells of several different types: gastric,116 esophageal adenocarcinoma,117 breast,118 prostate,118 colon,118 and lung.118
Evidence indicates that cranberry compounds may protect cardiovascular health through various mechanisms, including modulation of blood pressure, inhibition of platelet aggregation, and reduction of inflammation.87,119
Elderberries have natural anti-viral activity. A standardized elderberry product was shown in placebo-controlled, double-blind, human studies to reduce the duration of illness from seasonal influenza to as little as 2-4 days.120,121 In lab studies, elderberry anthocyanins were also found to bind to H1N1 swine flu virus, blocking its ability to infect host cells—exhibiting certain activity comparable to that of oseltamivir (Tamiflu®).122 Elderberry has been shown in cell culture studies to be effective against at least10 different strains of influenza.120,121
Elderberry also delivers cardioprotective benefits by reducing lipid peroxides,123 neutralizing lipid peroxyl radicals,123 inhibiting LDL oxidation,123 and significantly protecting endothelial cells against oxidative stress.124 A remarkable recent study found elderberry extract reverses hyperlipidemia (high cholesterol) and lipid peroxidation.125
Grapes and grape seeds have been shown in the lab to block the proliferation of prostate, colon, leukemia, and other cancer cells.126-130 A 2012 study concluded that grape seed proanthocyanidins may be a promising cancer therapy for head and neck squamous cell carcinoma.131
Evidence indicates that the highly active compounds in grapes and grape seeds protect cardiovascular health by helping to prevent platelet aggregration,132 LDL oxidation,133 high blood cholesterol,134 reduce fatty streaks in the aorta,134 minimize inflammation,135 and prevent decreased blood flow to the brain.136
Grapes may help combat Parkinson’s, Alzheimer’s, and other neurodegenerative diseases.137,138 Polyphenol extracts from grape seeds have the ability to potently inhibit the production of neurofibrillary tangles, a primary marker for Alzheimer’s disease.137 In a model of Parkinson’s, whole grape extract was shown not only to preserve motor functions, but to extend the life span of fruit flies.138
Extracts of pomegranate have shown promise in reducing the risk of metastasis in breast cancer.139 They initiate apoptosis (programmed cell death) and inhibit the proliferation of prostate, lung, colon, and other cancers.140-142 In both mice and humans with prostate cancer, consuming pomegranate slowed the rising levels of prostate-specific antigen (PSA), which is a marker of disease progression.143,144
Pomegranate juice has been shown in human studies to help protect cardiovascular health by significantly reducing both arterial plaque,145 lowering blood pressure,146 and improving blood lipid profiles.147 Pomegranate-derived compounds help reduce the adverse effects caused by metabolic syndrome.147
This fruit has been shown to reduce inflammation in colitis,148 enhance drug antibacterial activity,149 and suppress inflammation and joint damage in rheumatoid arthritis.150 There is even evidence that pomegranate supports the skin’s underlying structure and lowers the production of collagen-degrading enzymes, resulting in younger-looking skin.151
Nutritional and lifestyle factors can reduce the risk of osteoporosis. According to a 2011 review, the prune is the fruit that is the most effective at both preventing and reversing bone loss in part due to suppressing the rate of bone turnover.152
In rats, prune consumption produced changes in the bowel that suggest a protective effect against colon cancer.153 In obese rats, extract of plum also reduced blood levels of glucose and insulin, and increased insulin sensitivity, clearly suggesting they might be effective against type II diabetes.154
Prunes have also been shown to improve the body’s ability to absorb iron.155
Raspberries are a rich source of ellagitannins, which are converted in the body to ellagic acid,156 a well-known antioxidant.157 Scientists recently established that ellagic acid—by suppressing oxidative stress and inflammation—may provide a useful dietary supplement to decrease the characteristic changes associated with metabolic syndrome, induced by a high-fat, high-carbohydrate diet.158
In vitro, raspberries protect against DNA damage159 in colon cancer cells, and inhibit colon cancer invasion.160 Raspberry and raspberry seed extracts have shown efficacy against oral, breast, cervical, and prostate cancers in the lab.60,161,162 Raspberries have been shown, in vitro, to stimulate apoptosis in human cancer cells20,60
Also, findings suggest that moderate consumption of raspberry juices helps prevent the development of atherosclerosis through improved antioxidant status and serum lipid profiles.163
Black Soybean Hull
Although not a fruit, black soybean hull is rich in anthocyanins, and notably, in C3G (cyanidin-3-O-beta-D-glucoside), as discussed in the section on blackberries.164
Substantial experimental findings reported that black soybean offers promise in fighting colon cancer165 and insulin resistance.166 It also promotes wound healing in skin cells and reduces inflammation in endothelial cells.167 And research showed that black soybean helps protect human LDL cholesterol against oxidation, which might inhibit processes that lead to atherosclerosis.168
Then, in 2012, scientists published a study reporting “potent health benefits of black soybean seed coat anthocyanins in neuroprotection,” mediated through the modulation of a number of genetic signaling pathways.169
Strawberry extracts are impressive cancer fighters. They’ve been shown to inhibit the growth of oral, colon, prostate, liver, and breast cancers.60,170,171
A diet high in strawberries was found effective in protecting animals from age-related deficits in learning and memory.81 Researchers confirmed in 2012 that, although eating more berries may reduce cognitive decline in elderly humans, “flavonoid-rich blueberries and strawberries offer [the] most benefit.”83
In experimental studies, strawberries have also been found to deliver substantial cardiovascular benefits. They reduce the formation of unwanted blood clots, which may help prevent heart attack and stroke,172 lower total and LDL cholesterol,87 improve lipid peroxidation,173 and decrease biomarkers of atherosclerosis (malondialdehyde and adhesion molecules).87
Strawberries favorably affect postprandial inflammation and insulin sensitivity. In a compelling study, overweight humans were given either a strawberry drink or a placebo drink following a high carbohydrate, moderate fat meal. The strawberry group showed lower levels of biomarkers for inflammation and a reduction in postprandial insulin response.174
Every cell in the human body is hit by an estimated 10,000 individual strikes by free radicals each day—a factor in aging and degenerative disease onset.175
Scientific research suggests that berries and other dark-pigmented foods that are rich in anthocyanins provide frontline defense against multiple diseases of aging.
In addition to strong antioxidant protection, these plant compounds favorably regulate vital genes, signaling compounds, enzymes, metabolic factors, and other vital pathways.
Standardized extracts provide the concentrated anthocyanins—and other polyphenols—to ensure that your tissues derive their multiple benefits.
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