More on Anthocyanins

How well are anthocyanins absorbed? Early research suggests that absorption of anthocyanins may be low, but recent studies are more encouraging. In 2005, researchers sought to evaluate the bioavailability of anthocyanins (how much gets into the blood and tissues after it’s been ingested) and to find out what impact, if any, an anthocyanin-rich diet has on antioxidant levels in rats. While depriving the animals of vitamin E (an important antioxidant), but instead giving them bilberry (Vaccinium myrtillus L.), supplements rich in anthocyanins, the researchers observed significantly enhanced antioxidant capacity compared with animals fed a normal diet with no intervention. Although much of the anthocyanins were eliminated unchanged, they nevertheless exerted a positive effect on antioxidant capacity in the test animals.

Anthocyanin and Antioxidants

To predict how a substance will behave when ingested by humans, and to quantify the activity of anthocyanins and other naturally occurring antioxidants in the body, scientists have developed a number of laboratory tests and models. One method that is gaining in popularity was developed in the mid-1990s by scientists working at the National Institute on Aging in Baltimore, Maryland. Known as oxygen-radical absorbance capacity (ORAC), this method uses an indicator protein, a powerful oxidant radical generator, and a control substance called Trolox (similar to vitamin E) to measure the ability of a test substance to absorb damaging oxygen radicals.

Early research from the Human Nutrition Research Center on Aging (the chief scientific agency of the U.S. Department of Agriculture) suggests that eating an abundance of high-ORAC fruits and vegetables may help slow the processes associated with aging in both body and brain. High-ORAC fruits and vegetables raised the antioxidant power of human blood 10 to 25 percent, prevented some loss of long-term memory and learning ability in middle-aged rats, maintained the ability of brain cells in middle-aged rats to respond to chemical stimuli, and protected rats’ capillaries (tiny blood vessels) against oxidative damage.

According to the USDA, natural fruits typically score between 500 and 900 ORAC units per 100 grams (3.5 ounces). The FDA has recently suggested that Americans should increase their consumption of antioxidants to 7,000 ORAC units daily. It would require nearly twelve servings of ordinary fruit to achieve this level of protection. Unfortunately, most of the ORAC values of acai have been generated by industry, and not published in scientific journals. To make matters worse, inconsistency in units of measurement used to report the ORAC activity of acai has made comparisons between different products very challenging. The best information available suggests that high-quality acai might provide somewhere between 40,000 and 60,000 ORAC units per 100 grams. These are exceptionally high ORAC scores, even when compared with other anthocyanin-containing compounds, indicating powerful free-radical- scavenging capacity.

Anti-inflammatory Relief

Researchers investigated the therapeutic efficacy of anthocyanins, primarily C-3-G, in an experimental model of lung inflammation in rats. After inducing an inflammatory response in the lungs (characterized by fluid accumulation containing a large number of white blood cells) as well as oxidative effects, researchers administered anthocyanins, which exerted “multiple protective effects” against lung inflammation and pleurisy.

Do they Protect the Brain

The brain-protective effects of anthocyanins and other flavonoids is the subject of intense scientific interest and a growing amount of research. In order for the powerful antioxidant effects of anthocyanins to protect the brain directly, these compounds must be able to cross the blood-brain barrier, a special membrane that limits the passage of substance from the blood into the central nervous system. A 2003 study explored the potential of anthocyanins and their metabolites to cross the blood-brain barrier and enter the brain’s cells. Their research showed that several flavonoids, including cyanidin-3-rutinoside, were taken up by brain cells in mice and rats.

Prevention of Ulcers

Researchers have studied the effects anthocyanins, with and without the antibiotic clarithromycin, on Helicobacter pylori, the organism thought to be a primary cause or contributing factor to most stomach and small intestinal ulcers. Since H. pylori can become resistant to clarithromycin and other antibiotics, alternative treatments are desirable. In one study, anthocyanin-rich berry extracts significantly inhibited H. pylori and also increased susceptibility of the organism to clarithromycin.

Cancer Fighting Results are Strong

Anthocyanins present in many edible berries possess a wide spectrum of therapeutic and cancer-fighting properties. These natural antioxidants repair and protect the integrity of DNA. As we age, the cumulative effects of oxidation take their toll on our bodies, and this is seen in many of the telltale signs of aging, but also in an incidence of various cancers. Cancer prevention is one of the more exciting and well-studied areas of research on anthocyanins. Several different body systems and cancer types have been studied in this regard, and anthocyanins are yielding very exciting results on almost all fronts.

In animal and test-tube studies, anthocyanins are proving to be potentially powerful allies in the fight against colon cancer. (Other than skin cancer, colorectal cancer is the third most common cancer found in men and women in the United States.) In test-tube studies, anthocyanins were more effective than other flavonoids at inhibiting the growth of human intestinal carcinoma cells. In another study, colon cancer cells were inhibited by anthocyanin-containing berry extracts.

In animal research, tart cherry extracts, rich in many of the same anthocyanins as are found in acai, inhibited development of intestinal tumors in mice, suggesting that anthocyanins may reduce the risk of intestinal cancer. Freeze-dried black raspberries, purple corn, purple sweet potato, and purple cabbage have all been shown to inhibit chemically induced colon tumors in rats. In other research, the anthocyanins appeared to specifically target cancerous cells, but left noncancerous cells alone.

How Does It Do It

Little is known about the anticancer mechanisms of action of anthocyanins. However, two mechanisms have been elucidated in recent research: protection of DNA and inhibition of angiogenesis (new blood vessel formation). By protecting DNA from oxidative damage, antioxidants (and anthocyanins in particular) halt one of the initiating processes in the cascade of cellular dysfunction that leads to cancer. The effects of several anthocyanins against experimentally induced DNA damage were evaluated in a liver cancer study of rats. Anthocyanins were found to be protective against cellular toxicity, DNA strand breaks, and oxidative damage. In another study, rats were maintained on vitamin E-deficient diets for twelve weeks in order to enhance susceptibility to oxidative damage and were then given rations containing a highly purified anthocyanin-rich extract. Consumption of the anthocyanin-rich diet significantly improved blood antioxidant capacity and decreased damaging products of oxidation in the liver.

Angiogenesis is the growth of new blood vessels from preexisting vessels, which is a normal part of wound healing and growth and development in general. However, angiogenesis is also a key step in the transition of tumors from a dormant state to a malignant state. Inhibition of abnormal angiogenesis is thus emerging as one of the more important therapeutic tools of cancer prevention now being explored in pharmaceutical and nutraceutical studies. Many botanical and nutritional agents have been tested for their anti-angiogenic capacity, including anthocyanins. In 2004, researchers at Creighton University demonstrated that berry anthocyanins prevent angiogenesis. This research, together with at least four earlier studies, suggests that angiogenesis inhibition is one of the important mechanisms by which anthocyanins fight cancer.

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Power of Acai Berry

The main type of antioxidant in acai is anthocyanin. Anthocyanins are a class of bioflavonoids that form the dark red to purple and blue-black pigments found in certain plants and flowers. The word anthocyanin derives from the Greek, anthos, meaning flower, and kydneos, meaning purple—hence “purple flower.” The blue to red color imparted by anthocyanins depends mainly upon the acidity or alkalinity of the medium in which they occur.

Anthocyanins are widely consumed by humans: It has been estimated that a typical daily intake is around 180 mg, which comes mainly from fruits and red wines. Most anthocyanins are potent antioxidants and free-radical scavengers. They are also able to absorb radiation, including ultraviolet (UV) light and ionizing radiation. Published studies have examined the antioxidant activity of anthocyanins as well as their ability to suppress tumor formation. Foods rich in anthocyanins include bilberry, elderberry, strawberry, blackberry, blueberry, black raspberry, beet root, black currant, blood orange, tart cherry, purple corn, purple sweet potato, purple cabbage, red wine, and, of course, acai. In fact, acai is one of the world’s richest natural sources of anthocyanins. For this reason, it may also be one of the most powerful naturally occurring antioxidants. The most abundant anthocyanins in acai are cyanidin-3-glucoside (sometimes called kuromanin) and cyanidin-3-rutinoside, but it contains many others as well. The beneficial effects of anthocyanins in the body are numerous.

Real Antioxidants – Real Benefits

The main anthocyanin in acai, cyanidin-3-glucoside (C-3-G), has been shown to inhibit oxidative damage to blood fats (such as LDL cholesterol), one of the critical early factors in the development of cardiovascular disease. The extent of antioxidant protection by C-3-G has been found to be significantly greater than for resveratrol (the main antioxidant responsible for the health-promoting properties of red wine) or vitamin C. This anthocyanin is also a highly efficient oxygen free-radical scavenger and should be considered as one of the most effective antioxidants from plants. In another study, acai juice added to yogurt was found to exert antioxidant effects similar to those of bilberry.

Natural Protection Against Ultra-Violet Rays

Ultraviolet radiation from the sun causes damaging oxidation in the body, generating what are known as reactive oxygen species (ROS). ROS can cause extensive cellular damage and even cell death. In 2005, researchers examined the protective effects of C-3-G against UV-induced cell death and DNA damage in human skin cells. Treatment of the cells with C-3-G before UV exposure prevented cell death and DNA damage. The cyanidin appeared to specifically protect the cell membrane, and the researchers concluded that anthocyanins are novel agents that protect the skin from exposure to UV radiation.

Acai Fights Obesity, High Blood Sugar, and Diabetes

Certain anthocyanins have been studied for their effect on obesity-related disorders. One anthocyanin, known as pelargonidin and also present in acai, demonstrated an antidiabetic effect in rats. In fact, several anthocyanin-containing extracts have been shown to suppress the increase in after-meal blood sugar levels from starchy foods. In another study, C-3-G was reported to reduce insulin resistance, high blood sugar, high blood levels of insulin, and high cholesterol in mice fed a high-fat diet. These results could have important implications for acai’s potential to prevent diabetes, heart disease, and related disorders. Recent studies have also shown that C-3-G exerted beneficial effects on the genes that control the activity of fat cells and also on genes involved in fat metabolism. Anthocyanins have also been shown to support healthy insulin release from the cells in the pancreas where insulin is produced (islets of Langer-hans). Cyanidin-3-glucoside was among the most effective.

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