Does Elderberry Boost Your Immune System?

Around this time of year, there is often increased interest in supplements to boost the immune system. Of course, that has never been more true than now, as most of the world is now under varying levels of lockdown, preoccupied with the growing threat of the novel coronavirus.

The idea of taking a supplement to help your immune system be at its strongest is understandably enticing, especially at a time like this. We are all stuck in an unprecedented situation, where we have little control. Many of us are longing for something to do, some way to protect ourselves. We naturally crave to take action. And there is a veritable cornucopia of products out there that offer to fill that void.

One supplement that often pops up in these discussions is elderberry. Now, when a lot of us think of elderberries, this might be the first thing that comes to mind (or at least, it is for me).

Okay, but the second thing that likely occurs to you, with respect to elderberries, is a purported ability to “boost immunity.”

Elderberry is a common name for various species of flowering plants belonging to the genus Sambucus. Parts of these plants have been used for thousands of years by Native Americans and people of the Mediterranean basin. Indeed, medicinal and dietary applications of elderberries date back at least to the Ancient Egyptians. But what does the research today tell us about elderberry?

Research on Natural Products

First, before I get into elderberry specifically, I need to make a general caveat.

With natural therapeutics, it’s very uncommon to have the same amount and quality of evidence that we can find with pharmaceuticals. And as you have heard us discuss before, the term “quality of evidence” can be confusing.

Sure, that term can be used to refer to a study that was conducted poorly, but the quality of evidence is actually better thought of synonymously with “confidence in the evidence.”

So, many studies with natural products could have been conducted impeccably well, but because of budgetary limitations, natural-product research protocols don’t often break into the echelon of rigor that gives us high confidence that an effect is real.

Furthermore, studies on natural products are frequently conducted with funding by a supplement company that stands to profit from a positive outcome. This doesn’t automatically mean that the research is invalid, but the sponsorship of a study is certainly a factor that needs to be considered, especially because there is an incentive to not submit the studies that show null or negative results.

This is essentially the world we live in when it comes to natural product research. That is not to say that there aren’t real effects occurring with these compounds, it’s just harder to know for sure what’s real and what is hype.

Elderberries and Respiratory Illness

With elderberry, we do have, relatively speaking, a hefty amount of research to look at. There are many smaller studies testing various concoctions of elderberry, sometimes in people but often in animal models or in cell cultures. Unfortunately, there are no large-scale studies testing the effects of elderberry extract or juice on immune function or disease symptoms in human subjects. Nevertheless, there have been a few high quality trials, which merit our consideration.

A recent meta-analysis quantified the effects of elderberry supplementation on upper respiratory symptoms for the very first time, and it frankly could not be more timely. Let’s take a quick look.

Methods

In this analysis, the researchers narrowed their focus to randomized controlled clinical trials using human participants, with the primary outcome of interest being upper respiratory symptoms. Studies using primates or rodents or other critters were thrown out.

The researchers also limited their search to studies that used pure elderberry (either as a syrup or pill) as a primary intervention, without any other substances being used. It’s not uncommon for these sorts of studies to use a blend of ingredients, but you can imagine that adding other active constituents might make it tricky to tell if it’s the elderberry or if it’s something else.

The initial search revealed 137 studies. After evaluating these papers for inclusion criteria, a total of four studies were included in the meta-analysis. Yes, four. So, this evidence meets a high standard of rigor, but there simply isn’t very much of it to work with.

These studies were generally pretty similar. They all randomly assigned participants to take either some form of elderberry extract or placebo, and then relied upon self-reporting instruments to measure upper respiratory symptoms. Symptoms were measured at baseline and at least once per day while symptoms were present. Total duration of upper respiratory symptoms were the outcomes being evaluated.

Just as an example, one of the papers tested the effects of a standardized elderberry extract supplement in economy class passengers traveling from Australia to an overseas destination. Cold episodes, cold duration, and respiratory symptoms were noted in a daily diary, and participants also completed three surveys containing questions regarding upper respiratory symptoms just before travel and at 4-days after travel.

In the analysis, effect sizes were calculated from the symptom duration and the severity.

Results

The final analysis included results from 89 participants in the elderberry groups, and 91 participants in the control groups, for a total of 180 participants.

The data showed that the elderberry actually had a large and significant effect here (1.717 (SE=0.447; 95% CI: 0.840-2.593), p = <.001). Elderberry supplementation reduces upper respiratory symptoms from both viral infections but was much more effective at reducing the duration and severity of upper respiratory symptoms associated with influenza, rather than the common cold. However, this disparity should probably be taken with a grain of salt, since only one of the studies in the analysis looked at elderberry for common cold.

So, the findings of this meta-analysis suggest that supplementation with elderberry may substantially reduce the duration of upper respiratory symptoms.

Sounds great! But before you start loading up on elderberries, there are a few things you need to keep in mind.

Important Caveats

Elderberries must be properly prepared.

The raw berries, flowers, bark, and other parts of Sambucus plants produce cyanogenic glycosides, which are hydrolyzed to hydrogen cyanide in the gastrointestinal tract. Yikes! Fortunately, the risk of toxicity is eliminated when the berries are exposed to heat, combined with evaporation to release the dangerous compounds. If you insist upon using elderberries that you have grown or foraged yourself, make sure you have correctly identified the plant, removed any bark or leaves, and carefully cooked them.

Homemade formulas are also unlikely to achieve the potency found in commercial products. The safest bet is to stick to commercial products from companies that have expertise in natural-product preparation.

The actual content and efficacy of commercially available elderberry products may vary tremendously.

The content of supplements isn’t tightly regulated by the FDA. This means that it can often be hard to know if the pill that you are taking actually contains what the label claims. Elderberry is no exception to this phenomenon.

Furthermore, there does not appear to be a standardized method for measuring the number of bioactive components, like anthocyanins, in these sorts of products. One study showed that a supplement could claim to contain 762 mg/L but really only contain 4 mg/L, depending on the method used to measure anthocyanins. Therefore, determining the effects of currently available products may be difficult.

So what can you do? When you buy any supplement, including but not limited to elderberry, you need to look for products that have been verified by independent organizations, like NSF or USP. Just as one example, the brand Nature Made is extremely easy to find in stores in the US (you can even get it at Wal-Mart), and the USP verified mark appears on most its products.

You can also consult ConsumerLab.com, which lab-tests supplements and publishes results on their website. In their report for elderberry, they found that doses of anthocyanosides in elderberry products varied immensely, by as much as 2000-fold. So again, it’s worth it to do your research and be picky here.

Key Takeaways

Here’s what we know: A few small, industry-funded, randomized controlled trials show that supplementation with a standardized elderberry extract appears to significantly reduce total duration and severity of upper respiratory symptoms associated with influenza.

There isn’t strong evidence suggesting elderberries can prevent infection in the first place, though there is some preliminary research suggesting that compounds in elderberry may generally improve the function of the immune system in response to infectious threats.

Please note, the studies that we do have are testing elderberry extract in relation to symptoms associated with influenza. We do not know this applies specifically to SARS-CoV-2. We do know our cells respond quite differently to the virus that causes COVID-19, compared to other respiratory illnesses, so we can’t necessarily extrapolate findings related to influenza to this novel coronavirus.

For now, continue to focus on handwashing, social distancing, and taking medical advice from your doctor. Also, continue to follow us here as we detail other important factors related to immune system health and support interventions. If you haven’t see this yet, please be sure to check out our article on sleep and immunity here.