Aloha Acai! Understanding The Superfood
What is Acai?
Acai fruits are globose drupes with a diameter of 1 to 2cm. A glossy dark red to purple skin and a very thin purple pulp surround a large single seed that makes up about 80% of the fruit.
The swampy floodplains and riverbanks throughout the Amazon lowlands of northern South America are where Acai palms originated. The trees grow up to 20-30m tall, and have multiple slender stems and pinnate leaves. Tiny brownish and purple flowers adorn their pale yellow racemes that grow up to 1m long (Blancke, 2016).
Fun Fact!
Acai and Sustainability
Hard and insect-resistant, the wood of the Acai palm is suitable for general construction purposes. The tree continues to give through its leaves, which can thatch houses and become hats, baskets and mats (Blancke, 2016). Acai has a potential for sustainable production, which will hopefully be realized through virtuous management!
Acai Today
When the Health and Wellness industry granted the berry its "Superfood" recognition somewhere around 2008, attention to Acai rocketed beyond Brazil.
But what has made the fruit super, and is it really the hero to our health?
Scroll on for:
Fun Fact!
Not All Acai Berries are Made Equal
Did you know that two species of Euterpe (a genus of palm tree) can produce the Acai fruit?
Euterpe Oleracea and E. Precatoria are endemic from different Amazonian regions, and do not share the same chemical composition and pharmacological properties (Yamaguchi et al., 2015). Through cell-based assays, E. Precatoria has been evaluated to have superior antioxidant, anti-inflammatory activities and also a much higher level of carotenoids (Kang et al., 2012).
Acai Claims
Acai is one of the relatively new fruits to catch the eye of today’s global Health and Wellness industry. The berry’s pulp is often celebrated for its superiorly high content of minerals, antioxidants and flavonoid-like compounds.
The fruit has been narrated to boast 10 times the antioxidant benefits of grapes and twice that of blueberries (Dean, 2020). Research has similarly demonstrated Acai to not only possess the highest antioxidant capacity among other exotic berries, but to also hold the highest content of polyphenolic compounds (Nowak et al., 2018).
Continuing the fruit’s nutritional superiority is an evaluation of freeze-dried Acai against different assays with various free radical sources.
Through a superoxide scavenging (SOD) assay, Acai was found to hold the highest activity against superoxide and peroxyl radical. Among all fruits or vegetables tested to date, the berry also held the highest SOD of 1,614 units/g (Schauss et al., 2006).
The promising makeup of Acai has naturally brought forward claims, particularly benefits to:
Weight loss,
Diabetes,
Sexual disorders,
Ageing, and
Cancer.
(Blancke, 2016; Hanekamp, 2017; Perricone, 2002)
Why Do We Need Antioxidants?
An inadequacy of our biological systems to neutralize excessive free radical production causes oxidative stress. The stress can be partly responsible for:
Human diseases and aging,
Cardiovascular disease,
Neurodegenerative disease,
Obesity and Insulin resistance, and
Immune system dysfunction.
Antioxidants protect us from that!
(Jensen et al., 2008)
Acai Nutrition
Acai Basic Nutritional Information
Acai Antioxidants Information
Acai is rich in antioxidants, of which Anthocyanins, Flavonoids and Mono/Polyphenols are of particular interest. However, their compositions can all become quite different after being processed! The table below shows the chemical composition and bioactive properties of different Acai berries.
Repeatedly, Acai's nutritional profile has been compared with other foods. Blueberries are one of the most commonly compared fruits. Here is a comparison of both!
Acai Against Blueberry
Literature Review: How effective are Acai Antioxidant Compounds?
Numerous animal studies have inquired into the functionality of Acai’s antioxidants, and most of them validate the berry’s antioxidant capacity.
One of the studies has found that rat tissues pre-treated with Acai presented a lower level of H202-induced damage. An observed negative correlation between Acai’s polyphenol content and levels of lipid and protein damage suggests that the fruit’s antioxidants can potentially prevent age-related neurodegenerative diseases (Spada et al., 2009).
Positive antioxidant activity is similarly resounded in human studies, where Acai-fed women revealed increased total antioxidant capacity and decreased reactive oxygen species such as oxidized LDL and neutrophil ROS, after 28 days (Barbosa et al., 2016).
A separate study of junior athletes examined blood antioxidant status and lipid profile. After 42 days of consumption, subjects’ plasma revealed a marked increased antioxidant capacity and a significant improvement of serum lipid profile. Additionally, there was an attenuation of exercise-induced muscle damage (Sadowska-Krępa et al., 2014).
While Acai definitely appears to boost general health, do the berries’ antioxidants hold up to claims of Weight Control, Cancer and Cholesterol?
Acai and Weight Control
A study investigating hot-water extract of Acai berry found every 100g to contain:
35.04g of polyphenol,
26.13g of flavonoid,
36.82g of sugar.
It went on to reveal, through cell models, that Acai compounds had regeneration effects against oxidative stress and suppressed adipocytes (fat cells) differentiation. This in turn reduced lipid accumulation and increased glucose uptake, leading the researchers to conclude that Acai juice has not just antioxidants but anti-obesity activities as well (Gu & Hong, 2020).
The berry’s antioxidant and anti-obesity capacity is echoed in a similar study of juice blend (Jensen et al., 2008), whereby Acai was the predominant ingredient. Through an in-vitro study, the fruits’ antioxidant compounds again showed themselves to protect cells from oxidative damage and inspire serum lipid peroxidation (ie. oxidative degradation of fats).
Acai and Weight Loss: Human Studies
Although there exists little research on Acai and Weight loss, there is a published pilot study involving 10 overweight individuals that assessed Acai’s effects on metabolic syndrome parameters.
After 30 days of daily 200g acai pulp intake (with no other changes to their diets), the study group observed significant differences in their levels of fasting glucose, insulin production, serum LDL and total cholesterol as compared to before (Udani et al., 2011).
Acai and Cancer
Acai’s antioxidative compounds (specifically Anthocyanidin and Catechin) have been studied for any potential functionality in cancer prevention.
Growth rates of rat brain tumor cancer cells and human breast cancer cells were monitored after exposure to Anthocyanin. It was observed that Acai held the most potent suppressive effect on rat brain tumor cancer cells, with only 38% of the cells surviving at 200 μg/ml of acai antioxidant (as compared to other antioxidant rich products such as blueberry and wolfberry). However, the hypothesized apoptosis (ie. programmed cell death) was not observed on human breast cancer cells (Hogan et al., 2010).
A similar study of Anthocyanin was conducted on Leukemia cancer cells, this time comparing Anthocyanin-treated cells and untreated cells for their respective cell death rate and cellular caspase-3 activity (capase-3 is an enzyme with an essential role in coordinating cell death).
At the highest dose of 10.7 μM, a 56 to 82% cell death rate was observed. Effects also appeared to be the most pronounced after 3 hours, but completely ineffective after 6 hours. Depending on the dose of Acai, Caspase-3 activity varied between a 5-fold and 8.2-fold increase (Del Pozo-Insfran et al., 2006).
Anthocyanidin and Catechin: Human Studies
For a more realistic understanding of antioxidants’ absorption and availability in human bodies, a study compared antioxidant intake along with the subsequent concentration of those antioxidants in subjects’ plasma and urine. Although this research did not study the Acai berry directly, it investigated compounds (ie. Anthocyanidins and Catechins) that the berries are rich in.
The study observed that Anthocyanidins and Catechins were one of the most poorly absorbed compounds. Absorption rate of Anthocyanidins also varied greatly according to food source, with the highest absorption from black currant juice and the lowest from grape juice (Manach et al., 2005).
Acai and Cholesterol
Utilizing an animal model of dietary-induced hypercholesterolemia (ie. high blood cholesterol), a study aimed to investigate Acai’s antioxidant potential and hypocholesterolemic (ie. cholesterol lowering) effects. The berry presented itself to reduce total and low density lipoprotein cholesterol (ie. LDL/ “bad” cholesterol) as well as decrease plaques on arterial walls. This led researchers to the conclusion that Acai consumption improves antioxidant status and has a hypocholesterolemic effect (de Souza et al., 2012).
Acai and Cholesterol: Human Studies
To investigate Acai’s functionality in cardiovascular health, forty women were fed 200g of Acai pulp for 28 days. Blood samples from the beginning and end of the study revealed no significant changes in various metabolic biomarkers (ie. fasting glucose, fasting insulin, LDL and HDL cholesterol, apolipoprotein B and fasting triglycerides). However, an in-vitro assay within the study determined that greater amounts of phospholipids and cholesteryl esters moved into the HDL (ie. “Good” cholesterol) fraction of the patient serum in-vitro. The improved functionality in post-Acai HDL suggests that the berry may indirectly improve overall cardiovascular health, even if not directly (Barbosa et al., 2016).
In-vitro Studies and Reality
While Acai in-vitro studies communicate valuable information about the fruit’s potential, they can often be heavily manipulated (eg. Compound fractions and isolation), studied at unrealistic doses, and do not account for other variables that may nullify the proposed pro-apoptotic effects (eg. Interactions with other foods). Furthermore, processes such as the crossing of antioxidants through the endothelium of our small intestines can also alter their forms, resulting in negated benefits (Manach et al., 2005).
So far, some of the results of human studies (eg. Acai compounds’ low percentage absorption) seem to dispute some of the claims from in-vitro studies. The latter, along with media claims, should still be approached critically.
The Bottom Line
Acai definitely promises a health boost to our bodies. But to claim it a miracle fruit that is the prevention and cure to diseases and ageing is to me an exaggeration of its functionality.
Surely it can prevent health complications - but don’t all healthy, nutritious foods do that? How stark is the difference between Acai and an Avocado, Acai and Spinach, or other whole foods...? I’m also still confused about Acai’s bioavailability and nutritional profile, since studies I've read seem to conflict one another.
All in all, nothing about Acai’s nutritional profile particularly stands out to me. Furthermore, its antioxidant content is still comparable with other Brazilian fruits (Heinrich et al., 2011 ; Schauss et al., 2006). Thus I can’t help but feel that Acai’s goodness, like most other health foods, has become inflated by corporations...!
However I do appreciate the berry's taste, history, exoticness and the fact it makes for an excellent frozen treat. I too hope that the Aaci trade has improved the lives of farmers and also the Brazilian economy.
Different foods pack different nutrients - and a balanced diet is still the most effective. Acai won’t hurt me - and I think that’s all that matters!
How to enjoy Acai
Nutrition
Reach for the pulp if you’re nutritionally concerned! A human consumption trial vis-a-vis Acai reveals that while Acai juice increased plasma antioxidant capacity up to 2.3-fold, the pulp did so by up to 3-fold (Mertens-Talcott et al., 2008).
Preparation
In Brazil, Acai pulp is often consumed in dark purple beverages. The juice is commonly mixed with cassava flour, or enjoyed in wine and liqueurs forms. The tree is not forgotten as well - locals consider the palm hearts a delicacy and use them in salads and meat dishes (Blancke, 2016).
Internationally, Acai pulp is recognized more in its beloved smoothie form. Due to the berry’s high level of omega fats and high-speed fermentation, the fruits have to be processed fast upon harvest to avoid spoilage (Herder, 2016 ; Oksanen, 2020). As such, the berries mostly leave the country in frozen, powdered, juiced or other processed forms. Frozen pulp is one of the easiest, tastiest and freshest ways to enjoy the fruit. That explains the popularity of Acai bowls and smoothies!
How to make your own Acai Bowl
To make an Acai bowl, all you require is frozen Acai pulp, frozen fruits, some liquid and a blender. Following a personal attempt, I realized it is so much easier than most people would imagine!
After combing through multiple online recipes, I decidedly tweaked one to my own preference. Simple, safe, unsweetened and an opportune moment to relish in oat milk… was basically what I was scouring for. (ˊ•͈ ◡ •͈ˋ)
Recipe
Ingredients
100g of Frozen Acai Pulp (I got the unsweetened one from Gratefood),
1 Handful of Frozen Berries
1 Frozen Banana
⅙ Cup of Oat Milk
Steps
Defrost the pulp packet under running water and crack into pieces, or just let it sit out for a minute or two.
Add all ingredients into a blender or processor and blend.
Top your smoothie, voila! My top Acai toppings: Chopped apple, Squeezed lime, Pumpkin seeds and Cacao powder.
And here is a video of me first try at homemade Acai! The recipe portions were doubled because I wanted to share it with my family.
Can I use any other fruits?
Acai pulp, by itself, is earthy, tangy and tart. Sweeter fruits like banana, blueberries, strawberries help to balance and round out its flavor. I wonder how it would taste if blended with mangoes, figs or avocados! Unfortunately, there was and is insufficient YOLO-ness in me to make my first homemade Acai experience an adventure.
However, I’ve just bought more frozen Acai pulp (this time from Sambazon), and can’t wait to try a few more combinations next time!
Where to Purchase Frozen Unsweetened Acai
I got my Gratefood Unsweetened Acai from Cold Storage (Nex), and my Sambazon Unsweetened Acai from Redman. I’ve actually also encountered Sambazon at Fairprice (Nex), but only the “Original Blend” aka sweetened version.
Gratefood Unsweetened Acai is quite readily available in a number of retailers (click