The acai berry (pronounced “ah-sigh-ee”) is found growing on a tall, slender palm tree mainly in swampy areas in the Amazon rainforests of South America. Acai berries look a lot like blueberries in that they are purple on the outside. They are a little larger than blueberries, however, and inside is primarily composed of a pit (seed) with just a thin layer of edible flesh. They taste a bit like a vibrant blend of berries and chocolate, though they are not as sweet as most berries.
Acai berries have to be harvested and processed very quickly or they will soon spoil. The method of processing acai berries is extremely important. The berries can, of course, be frozen and processed at a later date, but for most applications freeze-drying or other low temperature drying is preferred (see Table 1). Low temperature drying techniques maintain the nutrient content and are preferred over higher temperature methods such as spray drying. These low temperature produced acai powders are more expensive than other dried forms, but you get what you pay for. For example, it takes 10 pounds of berries to make one pound of freeze-dried acai powder. In contrast, spray drying techniques can produce one pound of powder from only four pounds of berries, but that comes with a cost of as much as 60 percent of the antioxidants and other beneficial nutrients because of the higher heat used in the process.
The History of Acai
Acai, of course, has long been a popular food and medicine in South America. The birth of the popularity of acai in North America is attributed to the appearance of renowned physician Nicholas Perricone, MD, on “The Oprah Winfrey Show” in July 2005. But, the truth is that acai was already making its presence known among health conscious consumers around 2000. However, there is no doubt that when Perricone crowned acai as the “Superfood for Age-Defying Beauty” on Oprah’s show, it signaled the arrival of acai in North America.
Acai Berry Benefits
Some of the claimed benefits for acai have sound scientific support while others are simply marketing propaganda. The truth is that the benefits of acai berry are similar to other berries in that most of the health benefits are related to their flavonoid components though the levels of flavonoids and other antioxidants tends to be higher in acai berries compared to blueberries, strawberries, cherries, grapes, and many other fruits.
A powdered preparation of freeze-dried acai fruit pulp and skin contains per 100 g of dry powder approximately 530 calories from 50 g carbohydrates, 8 g protein, and 30 g total fat. The carbohydrate portion is approximately 90 percent dietary fiber. The fat composition is very similar to olive oil in that it contains 56 percent oleic acid. Its vitamin and mineral content is not that significant. The real health benefits are due to its phytochemicals (anthocyanins, phenolic acids, procyanidin, lignans, and stilbenes).
The Antioxidant Effects of Acai
The most widely used method to determine the antioxidant content of food is the oxygen radical absorbance capacity score (ORAC). A wide variety of foods have been tested using this method, with certain spices, berries and legumes rated highly in extensive tables once published by the United States Department of Agriculture (USDA). Because this test is an in vitro (test tube) method its relevance is debated. The thought is that many of the compounds with antioxidant activity via ORAC are either broken down in the digestive process or not absorbed, so while a food or compound may have a high ORAC value in the lab it may have absolutely zero if any antioxidant effects within the body.
There are a lot of charts on the internet misrepresenting the ORAC value of acai compared to other foods. The truth is that the berries themselves are very similar to other flavonoid-rich berries in terms of antioxidant levels and the acai powders may vary considerably in terms of their ORAC value. That said, there is no question that high quality, properly processed freeze-dried acai berry powder has a very high ORAC value.
So, the big question is “How does the ORAC value of acai translate to antioxidant effects in the human body?” Fortunately, there are a few clinical studies that clearly demonstrate that acai berry products can produce significant and important antioxidant effects.
Chief among the antioxidant effects are the ability of acai berry pigments known as anthocyanins and procyanidins to protect the cells that line the blood vessels – the endothelial cells. Damage to these cells is what starts the process of atherosclerosis (hardening of the arteries) that ultimately leads to heart disease and strokes. Endothelial function also plays a role in inflammation, blood clotting, and blood flow. By improving endothelial cell health acai may be producing significant effects in these and other functions. Acai appears to be very helpful in protecting endothelial cells from the damaging effects of high blood sugar levels making it an important consideration in people with type 2 diabetes.
The bottom line is that acai flavonoids appear to offer similar protection compared with other flavonoid-rich extracts such as grape seed or pine bark in the protection against cardiovascular disease. The antioxidant effects may also offer some benefits against other diseases as well similar to what is known with other flavonoid-rich foods like green tea, red wine, and chocolate.
The Weight Loss Effects of Acai
Perhaps one of the most controversial ways in which acai is promoted is as a weight loss aid. Yes, it does possess some effects that are somewhat beneficial in some aspects of weight loss, but the claims have far exceeded the science. What is known is that an acai product was shown to modify some aspects of the metabolic syndrome –a cluster of metabolic risk factors that include:
• Central obesity (excessive fat tissue in and around the abdomen)
• Elevated cholesterol or triglyceride levels.
• Raised blood pressure (130/85 mmHg or higher)
• Insulin resistance (the body can’t properly use insulin or blood sugar)
The metabolic syndrome is a serious issue because people with it are at increased risk of diabetes, heart disease and cancer. It is now estimated that about 60 million U.S. adults meet the criteria for the metabolic syndrome. In addition, about 20 million Americans have type 2 diabetes.
In a clinical trial, 10 overweight individuals with metabolic syndrome took 100 g twice daily of a frozen puree of acai pulp as a smoothie. In the 30-day study period significant improvements were observed in fasting glucose and insulin levels as well as blood glucose levels after a standardized meal. Improvements were also noted in cholesterol and triglyceride levels.
While more research is definitely needed, there is reason to believe that the intake of acai as well as other dietary sources of similar flavonoids (e.g., green tea, chocolate, etc.) does help to address some of the underlying issues of insulin resistance and may therefore be quite helpful as an adjunct for weight loss.
As a supplement, acai is sold in capsules, extracts and powders. There are no known safety issues with acai, but like any food allergic reactions are possible (though none have been reported). Acai is definitely a super fruit, but so are apples, blueberries, cherries and many more. That said, the addition of acai berry powder to smoothies, hot cocoa, yogurt, and other food and beverages is definitely a super way to increase the intake of health promoting phytochemicals. VR