Açaí vs. Wild Blueberries for Artery Function

“Plant-based diets…have been found to reduce the risk of cardiovascular disease” and some of our other leading causes of death and disability. “Studies have shown that the longest living and least dementia-prone populations subsist on plant-based diets.” So why focus on açaí berries, just one plant, for brain health and performance?

Well, “foods rich in polyphenols…improve brain health,” and açaí berries contain lots of polyphenols and antioxidants, so perhaps that’s why they could be beneficial. If you’re only looking at polyphenols, though, there are more than a dozen foods that contain more per serving, like black elderberry, regular fruits like plums, flaxseeds, dark chocolate, and even just a cup of coffee.

As you can see at 1:02 in my video The Benefits of Açaí vs. Blueberries for Artery Function, in terms of antioxidants, açaí berries may have ten times more antioxidant content than more typical fruits, like peaches and papayas, and five times more antioxidants than strawberries. But blackberries, for instance, appear to have even more antioxidants than açaí berries and are cheaper and more widely available.

Açaí berries don’t just have potential brain benefits, however. Might they also protect the lungs against harm induced by cigarette smoke? You may remember the study where the addition of açaí berries to cigarettes protected against emphysema—in smoking mice, that is. That’s not very helpful. There is a long list of impressive-looking benefits until you dig a little deeper. For example, I was excited to see a “[r]eduction of coronary disease risk due to the vasodilation effect” of açaí berries, but then I pulled the study and found they were talking about a vasodilator effect…in the mesenteric vascular bed of rats. There hadn’t been any studies on açaí berries and artery function in humans until a study published in 2016.

Researchers gave overweight men either a smoothie containing about two-thirds of a cup of frozen açaí pulp and half a banana or an artificially colored placebo smoothie containing the banana but no açaí. As you can see at 2:26 in my video, within two hours of consumption of their smoothie, the açaí group had a significant improvement in artery function that lasted for at least six hours, a one or two point bump that is clinically significant. In fact, those walking around with just one point higher tend to go on to suffer 13 percent fewer cardiovascular events like fatal heart attacks.

As I show at 2:52 in my video, you can get the same effect from wild blueberries, though: about a one-and-a-half-point bump in artery function two hours after blueberry consumption. This effect peaks then plateaus at about one and a half cups of blueberries, with two and a half cups and three and a half cups showing no further benefits.

What about cooked blueberries? As you can see at 3:12 in my video, if you baked the blueberries into a bun, like a blueberry muffin, you get the same dramatic improvement in artery function.

Cocoa can do it, too. As shown at 3:30 in my video, after having one tablespoon of cocoa, you gain about one point, and two tablespoons gives you a whopping four points or so, which is double what you get with açaí berries.

One and a quarter cups’ worth of multicolored grapes also give a nice boost in artery function, but enough to counter an “acute endothelial insult,” a sudden attack on the vulnerable inner layer of our arteries? Researchers gave participants a “McDonald’s sausage egg breakfast sandwich and two hash browns.” They weren’t messing around! As you can see at 3:56 in my video, without the grapes, artery function was cut nearly in half within an hour, and the arteries stayed stiffened and crippled three hours later. But when they ate that McMuffin with all those grapes, the harmful effect was blunted.

Eat a meal with hamburger meat, and artery function drops. But if you eat that same meal with some spices, including a teaspoon and a half of turmeric, artery function actually improves.

What about orange juice? Four cups a day of commercial orange juice from concentrate for four weeks showed no change in artery function. What about freshly squeezed orange juice? Still nothing. That’s one of the reasons berries, not citrus, are the healthiest fruits.

For a beverage that can improve your artery function, try green tea. Two cups of green tea gives you that same effect we saw with cocoa, gaining nearly four points within just 30 minutes. And, as you can see at 5:05 in my video, that same crazy effect is also seen with black tea, with twice as powerful an effect as the açaí berries.

So, why all the focus on just that one plant? Why açaí berries? Well, the real reason may be because the author owns a patent on an açaí-based dietary supplement.


How do the antioxidant effects of açaí berries compare to applesauce? See The Antioxidant Effects of Açaí vs. Apples.

What about the effects of other foods on artery function? Coronary artery disease is, after all, our leading cause of death for men and women. See:

What else can blueberries do? Check out:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

In Late Pregnancy Moderate the Intake of Powerful Anti-inflammatory Foods

The right side of the heart pumps deoxygenated blood from the body to the lungs, where it can fill up with oxygen, and then the left side of the heart pumps oxygen-rich blood from the lungs to the rest of the body. So, blood travels from the body to the right side of the heart to the lungs to the left side of the heart and back to the body.

But what happens in the womb? Fetuses’ lungs don’t work because they’re filled with fluid. How does the heart bypass the lungs and spread the oxygen-rich blood coming in through the umbilical cord to the rest of the body? Before we’re born, we have an extra blood vessel—the ductus arteriosus—that directly connects the right side of the heart with the left side of the heart, bypassing the fluid-filled lungs. When the baby is born and takes a first breath, this blood vessel closes. In about 1 in 10,000 births, though, the blood vessel closes prematurely before the baby is born, necessitating an emergency C-section, as I discuss in my video Caution: Anti-inflammatory Foods in the Third Trimester.

Most cases for which there’s a known cause are thought to be related to taking anti-inflammatory drugs such as aspirin or ibuprofen. This is because the way the body keeps this blood vessel open is with a class of inflammatory compounds called prostaglandins. If you take an anti-inflammatory drug, you can undermine your body’s ability to keep it open, and it could constrict closed prematurely. That’s why most authorities recommend that these nonsteroidal anti-inflammatory drugs (NSAIDs) be avoided in the third trimester. The likelihood that anything bad will happen is extremely remote, but it’s better to be safe than sorry.

Sometimes this premature constriction happens even when women are not taking drugs, so-called “idiopathic” cases, which is doctorspeak for “we have no idea what causes it.” If anti-inflammatory drugs can cause it, though, what about anti-inflammatory foods? A few years ago, in my video Chamomile Tea May Not Be Safe During Pregnancy, I profiled two incidents apparently caused by pregnant women drinking chamomile tea. One of which reversed in that the ductus opened right back up once the tea was stopped, but, in the other case, the other baby had to come right out. Since then, there have been other case reports of this occurring––for example, when a woman had been drinking a few ounces of an acai berry drink every day and when another woman had been drinking prune juice and a violet vegetable juice containing a blend of fruits and veggies. Pregnant women should, therefore, take special care when consuming lots of these powerful anti-inflammatory berry nutrients.

What about berries themselves, green tea, and all the other wonderful anti-inflammatory foods and beverages out there? A group of researchers in Brazil compared ultrasounds of the hearts of third-trimester babies whose moms ate a lot of these anti-inflammatory foods with those whose moms ate less, and they could tell a difference. The speed of blood through the ductus in the moms consuming the anti-inflammatory diet was higher, suggesting it was narrower, just like when you pinch the opening of a hose closed and can make water shoot out faster. Also, the right sides of the hearts of the babies whose moms were consuming the anti-inflammatory diet were larger than their left sides, suggesting some blood backup, again an indicator of a tighter ductus. The researchers suggested changes in late pregnancy diets may be warranted, but critics replied that the differences they noted might not have any clinical relevance, meaning it may not matter if the vessel is a little more open or closed. We don’t want to alarm women because many of these anti-inflammatory foods may be beneficial––such as cranberries, for example, which may be useful in preventing urinary tract infections, which can be a risk factor for premature birth. Consuming cranberries is attractive from a public health and cost standpoint if it can prevent some premature births.

Before cutting down on a healthy food such as cranberries, we’d want some stronger evidence that they’re potentially harmful. What about confounding factors? For example, women who ate lots of anti-inflammatory foods might have had other characteristics that could affect fetal blood flow. What we needed was an interventional trial in which pregnant women change their diets and see what happens, but we didn’t have such studies… until now.

A study has shown that cutting back on anti-inflammatory foods such as tea, coffee, dark chocolate, grapes, and citrus for a few weeks during the third trimester did indeed seem to open up the ductus during normal pregnancies. In women whose fetuses had abnormally constricted vessels, a few weeks of eliminating polyphenol-rich foods reversed the ductal constriction in 96% of cases. Importantly, researchers didn’t follow these babies after birth to see if it made any difference. That complete closure only happens in 1 in 10,000 births; we’re not sure what effects relative levels of constriction may have, so it’s too early to be instituting a ban on dark chocolate for pregnant women.

At this stage, what we’re left with is a note of caution. During the rest of your life, I recommend eating healthy foods such as berries and cocoa powder, but from about 28 weeks until birth, pregnant women may want to cut back until we know more.


In Chamomile Tea May Not Be Safe During Pregnancy, I profile those two case reports I mentioned above. As I noted in Anti-inflammatory Antioxidants, highly antioxidant foods are, in general, highly anti-inflammatory foods.

For comparisons between the strength of anti-inflammatory foods and drugs, see Watermelon for Sore Muscle Relief, Anti-inflammatory Life Is a Bowl of Cherries, and Which Spices Fight Inflammation?

The videos provide more information about healthy (and unhealthy) diets in pregnancy:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: