A while back, ERV had a post about the tenuous link between Vitamin D and all sorts of effects on health (and I shamelessly co-opted her title). Then, PalMD dissected the spurious link between Broccoli and cancer. Now it’s my turn:

A new study has revealed that naturally occurring chemicals found in the skin of the nut boost the immune system’s response to such infections.
Researchers found almond skins improved the ability of the white blood cells to detect viruses while also increasing the body’s ability to prevent viruses from replicating and so spreading inside the body.

Oh Guardian, I thought you were better than this[Telegraph – my bad]. Let’s see what the actual paper showed.

The setup

They took human peripheral blood mononuclear cells (PBMC’s) – that’s basically all lymphocytes (T-cells and B-cells) plus monocytes, any circulating macrophages, and a few others – and incubated them with different components of almonds. Natural skins (NS), boiled skins (BS) and these same skins that have been treated with various types of in vitro digestion using gastric or intestinal enzymes. Then they infected these cells with a virus for 24 hours, and looked how much virus came out.

The results

Almonds and viruses.png

On the x-axis, you have the various almond parts, and the y-axis shows “plaque-forming units” (PFU’s) of virus, which is just a measure of infectious virus extracted after infection. The difference between the first bar (the PBMC’s treated with almond skins) and the last bar (untreated cells) doesn’t look that impressive, but it’s plotted on a log scale, which means there’s almost 10 times less virus with the almond skins – so far so good. But… (there’s always a but)

The Problems

There are so many. First off, the digested almonds didn’t do anything. This is all in vitro (in a tissue culture dish), so you’d have to take any result with a tablesoon of salt, but even the most relevant in vitro condition was completely ineffective. So unless you’re planning on grinding up almond skins and injecting them directly into your blood-stream (DON’T DO THIS!), this study doesn’t acutally show anything.

Second, the mechanism of action seems pretty straightforward – the undigested skins induced inflammation. They measured cytokine production from their PBMC’s, and a bunch of cytokines, especially IFNγ, TNF, and especially type-1 interferons were produced. Lots of things cause inflammation, and those would all restrict viral replication in this assay. But systemic inflammation is generally bad. So if you actually did grind up almond skins and inject them into your blood-stream (again, DON’T DO THIS), presuming you don’t die because of almond particles clogging up your capillaries, the best you can expect is a fever, and some tissue damage all over your body. You might decrease your chance of getting a cold, but it’s probably not worth it.

Finally, this study was funded by the Almond Board of California. I suppose it’s no wonder that the conclusions were wildly over-blown.

Arena, A., Bisignano, C., Stassi, G., Mandalari, G., Wickham, M., & Bisignano, G. (2010). Immunomodulatory and antiviral activity of almond skins Immunology Letters, 132 (1-2), 18-23 DOI: 10.1016/j.imlet.2010.04.010


  1. #1 Richard Jefferys
    November 2, 2010

    The almond-industrial complex is at it again. Immunology Letters has always seemed pretty off the wall to me, they used to publish papers from the people who promoted DNCB as an HIV treatment. The nutty press article is actually in the Daily Telegraph, not the Guardian.

  2. #2 Kevin
    November 2, 2010

    Good point – fixed. You know all those “” websites look alike.

  3. #3 SimonG
    November 2, 2010

    Medicines are nasty. Almonds are lovely, (especially when coated with sugar and/or chocolate), therefore they can’t be medicines.

    If someone were to tell me that banannas are medicinal, that I could believe.

    The only medicine I can recall which was at all pleasant was Owbridges, which went off the market years ago.

  4. #4 Elizabeth Munroz
    November 3, 2010

    Who thinks up the boiling almond skins thing? And I wonder how much money Arena et al received to come to these conclusions.

  5. #5 Kevin
    November 3, 2010

    I think the boiling thing was because that’s a common way to prepare them (bleaching – it basically removes the skins). In my opinion, everything in this paper could be explained if their almond skins were contaminated with bacteria. Boiling would kill them, the digestion procedures would kill them, but putting them in culture medium alone would allow them to replicate and activate inflammation.

    To be fair, I sincerely doubt the researchers were actually paid directly. But they wouldn’t have reported anything if the almonds did nothing (nor would any scientist – no one likes a negative result), and I imagine that the source of their funding could have caused them to be a bit over-zealous with their findings and forget to do the right controls.

  6. #6 Scottie
    November 8, 2010

    Thank you for the information you have shared on your post. This post caught my eye because recently, my dad has started eating almonds a lot, and has switched over from peanut butter to almond butter (which is quite good). He has done this to help regulate his diet, despite being one of the healthiest eaters I know. I understand, though that the point you are making in your post talks of a different topic, that of the immune system, not of the healthiness of almonds, but I was wondering, is there any other food/nut that has been proven to help the immune system if the almond is falsely portrayed as being a “virus fighter”? I really think you did a great job of distinguishing the fact as to why the almonds aren’t necessarily affective, which is because they were only tested in an undigested manner, which is never how they are actually used. It makes one wonder, then, how accurate are the facts that the media gives us, or the FDA gives us, that say a certain food can reduce the risk of “x” disease or can help fight “y” virus. This is an interesting point you have made in your blog post, and I think it’s important to promote these kinds of foods, or reveal the truth about them, so that the nation can avoid bad products, and increase their consumption of the better food. This awareness is what will help create a healthier world, and one with less illness and unfortunate disease.

  7. #7 Kevin
    November 8, 2010

    The FDA usually base their recommendations on a substantial amount of scientific data. Of course, sometimes the science can be wrong or (more frequently) incomplete, but those recommendations are generally far more reliable than stuff you might read on a supplement label or on the internet.

    Having a good diet is good for the immune system, and nuts are generally pretty healthy, but I would be extremely skeptical of anything that says, “this nut has been proven to fight this disease.”

  8. #8 Kevin
    November 8, 2010

    This is very interesting. My family and I eat almonds on a regular basis. Unfortunately we don’t grind them up and inject them into our blood stream. If they could find a safe way to do this it would be great because it’s a natural way of preventing colds. I wonder why the skin of the almonds helps improve the ability of white blood cells. If they could find other foods like this it would be very helpful because it would be a natural way of preventing colds.

  9. #9 Kate
    November 8, 2010

    This post caught my eye because I find it interesting how many topics such as this one, relating food to health related cures, are sometimes very much exaggerated. Yes nuts are better for you than candy, but there is no need to over play their role. Of course they could provide you with a good nutritional value, but it isn’t that likely that they can replace the role of a flu shot. It is just like the link that you posted about Vitamin D. In the blog post about Vitamin D it explains that we are already getting enough Vitamin D in our diet, but just because there is a need for it in our body we feel that we need to over supply ourselves with it. This is the idea that many people miss; we already get most of our nutritional needs if we consume the right foods. By getting more than enough of a certain vitamin people think that it is very good for them when honestly the effect is pretty much the same. The reason I say this is that I’ve had this idea explained to me when I was at the doctor for a check-up, and what I was told was that if I make the right food choices I will get enough of all the vitamins and minerals, but they wont however prevent disease, it can however strengthen my immune system. I feel that this is a very good topic to discuss; the post really got me thinking.

  10. #10 Cyndi
    November 9, 2010

    This post is very interesting. In my house, my mom always tells me to eat nuts especially almonds. She said they were good for you but I didn’t know why. But this article just proves that they don’t necessarily help our bodies. I agree that they are better to eat than junk food but there isn’t a medical reason saying that almonds prevent viruses in your body.In the comment above Kate said that food relating to health related cures is sometimes very much exaggerated. I am a strong believer in that because whenever something is found out about a food like that it lowers some risks there is always an article that comes out later saying here are the risks for consuming this on extreme levels. So basically you would need to get the perfect amount of that food, but we are humans and nothing is perfect. I truly believe that we just need to let our bodies do the work for us. I don’t understand why parents these days are making their children eat vitamins every morning. I think as long as we eat right and exercise we will be fine. But I am still a teenager, so I will probably choose junk food over almonds anyday.

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