Dear Mark: Superfoods, Plants for Pollution, Raw Liver Danger, and Irradiated ‘tsticles

Superfood: Spoons of various superfoods on wooden backgroundFor today’s edition of Dear Mark, I’m addressing four questions and comments from readers. First up, do I subscribe to the idea of superfoods? If so, what do I like? If no, what do I consider “super”? Next, we know that plants—house plants, garden plants, trees—can absorb pollution and release stress-lowering odors. Is there an optimal arrangement of flora to achieve these goals? After that, I address a reader comment about the dangers of eating raw liver, followed by an intrepid reader who found the reference for the sunbathing testicle study from last week.

Let’s go:

I would like to know what you think about super foods and/ or your favorite superfoods you use?

I don’t generally go for “superfoods.” The goji berries hand-picked by Tibetan lamas and placed in their armpits to salt-cure on a sweaty mountain ascent. The 110%-cacao cacao nibs, the raw maca root you gnaw and try to convince yourself is delicious, the heritage chia seeds cultivated from Moctezuma’s own personal stash.

It’s not that those foods don’t possess some interesting, helpful qualities. They’re generally very nutritious. But you’re not going to eat them that often (who else has a half dozen mostly-full bags of random Navitas Naturals produts in their pantry?), and eating them once in a blue moon won’t give you any superpowers.

I think many foods are super, though. Foods like wild salmon, egg yolks, liver, dark chocolate, purple potatoes, turmeric, fatty fish, aged cheese, various ferments are excellent “supplemental foods” (hat tip to Paul Jaminet)—foods with proven benefits and broad appeal in the kitchen. Even some common staples like garlic, onions, and ginger have incredible support in the scientific literature for their health benefits. These are the “superfoods” you should focus on because they’re time-tested, they’re easy to integrate into your diet, and they actually work. Don’t reject the goji berries and maca, mind you. Just don’t base your diet around them, and don’t think occasional consumption will supercharge your health.

Hi Mark, (not really nutrition, but paleo nonetheless) I would love your take on plants clearing pollution at home (and some details on the best combinations perhaps) and plants that give off plant odours that reduce stress.

This is a two parter. First, which plants reduce pollution?

The easy answer is: probably all of them. One way plants reduce pollution is by trapping it. I mean that quite literally. The major reason trees, grass, and other types of flora reduce airborne particulates is that the particulates attach themselves to the foliage. They become repositories for the pollution. This is different from metabolizing the pollution and rendering it inert. The pollution is still there. It’s just not getting to you.

A recent paper reviewed the determinants of how much particulate matter gets deposited:

  • Conifers can accept more deposits than deciduous trees.
  • Needles accept more than broad leaves.
  • Pine accepts more than yew and ivy, but less than juniper.
  • Leaves with more “hair” and wax accept more deposits.

When we’re talking about airborne chemicals like benzene, formaldehyde, trichloroethylene, xylene, toluene, and ammonia, certain plants actually filter them. Lucky for us, NASA did a comprehensive study to determine the specific detox abilities of various plants. Check the list and see what works for you.

As for the second question, once again, almost everything probably works.

The forest bathing research out of Japan suggests as much. Forest bathing lowers stress, reduces hypertension, improves immune function, and lowers blood sugar whether the forest is cedar, hiba, oak, or beech. And followup studies using cypress oil, cedar wood chips, cedar interior walls (which is relevant, as many Japanese homes are made of cedar) have all found similar effects. You could probably use a sack of cedar mulch from the nursery.

Those are trees, though. It’s not exactly feasible to grow a redwood or cedar tree in your house. What about house plants? This paper (PDF) found that geraniums, chrystanthemums, cyperus, and begonias were all potent sources of phytoncides—the stress-relieving plant odors. Other studies have shown that lavender and rosemary aroma can reduce cortisol and improve free radical scavenging, or that a combo of lavender, rosemary, clary sage, and peppermint aromas reduce perceived stress in university students.

The real key might be interacting with the plant—any plant. In one study, young adults found that simply transplanting house plants from one pot to another reduced physiological and subjective markers of stress by quieting the sympathetic nervous system.

Now, for some loose ends from last week.

Whenever the subject of raw liver consumption comes up, I want to shout THINK TWICE. I contracted campylobacteriosis from adding raw chicken liver to a smoothie. Yes, I’d been regularly consuming raw beef, lamb, and chicken liver for months with nothing but positive, energy-boosting results. Yes, I’d frozen this particular batch of fresh, localyl-sourced liver for a few weeks before consuming it, but this time, the bacteria survived the freeze. I, who hadn’t contracted so much as a cold in years, got very, very ill, and two courses of antibiotics were necessary to wipe out the infection. More than two years later, my digestion is still not 100 percent. Never again for me. Think twice.

Great comment. Thanks for writing it.

It is indeed a risk. While deep freezing is pretty good at killing parasites in fish, it’s mostly ineffective against pathogenic bacteria like e. coli or salmonella. Those are hardy bacteria.

I’ve never had an issue with raw liver. Then again, I don’t eat raw liver on a regular basis (I prefer it cooked), and I get it from the same place each time (a source I trust). For what it’s worth, if I didn’t know the provenance of my liver, I wouldn’t eat it raw.

Here’s the study that you were looking for, Mark:
“Ultraviolet Irradiation and Sex Hormones in the Male” by Abraham Myerson and Rudolph Neustadt
Journal of Nervous & Mental Disease: February 1940 – Volume 91 – Issue 2 – p228

That’s the one. Thank you!

That’s it for today, everyone. Take care, let me know what you think down below, and thanks for reading!

Primal Kitchen Ketchup

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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24 thoughts on “Dear Mark: Superfoods, Plants for Pollution, Raw Liver Danger, and Irradiated ‘tsticles”

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  1. woopsie, ate three turkey livers that had been sitting in the bottom of the bucket at my second-most-trusted butcher in Toronto couple of weeks ago. Then I took about four hours getting home (train/bus/bike). I was distracted and didn’t do my usual test (cutting one open and making sure it burns my finger within three seconds). Barfed all night. I had even read in detail Mark’s warnings about this last year I think. Hadn’t barfed in seventeen years and four months and was scared. And it’s dramatic. But, read on: Next day, seventy-five times from the other end and couldn’t even keep water in me but–are you still with me?–by that night I was fine. I’d read about people taking years to recover (and everyone’s different as Minger would say, so of course mega-sympathy for others) and I was ready for the worst. Wore a diaper on the plane getting down to Tennessee next day, but I was doing handstands in the airport. Felt strong and light. A barf fast! My take on it now is that I’m so healthy from paleo that my body did precisely what it needed to do to get rid of this poison: violent but effective. And already down here in Appalachia I’m into the raw goat milk. I’m still scared of throwing up, but it’s not the terror I had for seventeen years. Off to have half a gallon of raw goat milk.

  2. I’ve eaten raw liver (as well as raw egg, raw milk, raw beef, and raw salmon) off an on for over 4 years now without a problem. As stated there’s always a chance of catching something. But be honest with yourself, you knew that before you did it so don’t put the blame elsewhere. The sickest I personally have ever been from eating something was when I ate some contaminated raw spinach. Spinach is also the world’s leading contaminated crop. So, from a statistical standpoint, eating raw animal flesh is less dangerous then eating raw greens. But hell, I love greens. I eat them raw just about everyday. Ironically food poison probability is one thing that increases when you eat a real unprocessed food diet. Eating a candy bar that’s been highly processed and heated several times poses a relatively low risk contamination, but a relatively high risk of increasing chronic disease. If eating raw meat you need to source it properly and make sure it’s been frozen first. Also, something many people don’t account for, most farmers (or at least mine do) out source their processers. My farmer transports his cattle to a local processer to butcher and wrap the meats and whatnot. So take into consideration that the farmer as well as the processer needs to sterile about everything they do. At the end of the day, you don’t like how it sounds, then DON’T do it. Besides, raw meats shouldn’t be a staple anyways. The cooking process makes the meat more caloric dense. The only advantage to occasionally eating raw meat is nutrient density. Key nutrients like taurine, coq10, vitamin c, and b vitamins are reduced upon cooking, some like vitamin c and taurine are eliminated entirely.

  3. I’d like to suggest adding Jasmine to your list plants with of stress-relieving scents. At least one study suggests that there is some scientific basis to aromatherapy. Here’s an article written for a layperson from The Telegraph describing the GABAergic effects of Jasmine, . This article refers to a publication in the Journal of Biological Chemistry; even the abstract is pretty dense though.

    In addition, here’s a study published in the Asian Journal of Chemistry suggesting pharmacological effects of jasmine extract. Not exactly direct support for the effects of jasmine’s aroma, but doesn’t disprove the aforementioned study either.

  4. The book “How to Grow Fresh Air: 50 Houseplants that Purify Your Home or Office” by Dr. B.C. Wolverton is an excellent resource for plant purifiers. It has a few chapters of introduction, discussing the science of indoor pollution and how plants purify, then most if the book is a description of each plant, how they rank in removal of chemical vapors, also ease of taking care of them, resistance to insects, where they grow best, how to care for them, etc. It’s a great little book with lots of great pictures. The only thing I would add is to make sure you look up toxicity on a plant before you get it if you have pets. A peace lily, for example, is a great purifier and really easy to take care of, but it’s also pretty toxic to cats and dogs.

  5. Of course the liver comment comes after I just jumped back on the raw liver bandwagon! I had some local grass fed beef liver in the freezer for over a month. Just yesterday cut it up and put it back in a ziploc. Had two big chunks of it this am. (My turtle loves it too!) I’ve done it off and on for a few years and always felt great. When I don’t feel like dealing with the raw liver (which really is pretty gross) I like the liver capsules from Vital Proteins. And love all the plant info. I love plants but always just thought of them as air purifiers. Never gave any thought to the stress stuff. Very cool!

  6. oh and lol to the partly used packets of Navitas Naturals. I have a number of them gathering dust. But raw cacao is something I use pretty regularly that I really love. I don’t think there’s anything wrong with them, but it makes me crazy when people talk about the high protein content of something like spirulina. I have never used more than a teaspoon of it at a time. Even if it’s pure protein it’s not making that much of a difference. I’m much more interested in the trace minerals.

  7. Don’t get me wrong, I love me some raw livers… every Wednesday, and every Sunday, I chop up a pound of grass fed beef liver for wife, boys and me. Usually add in a couple of raw pastured yolks, frozen cherries (raw honey for boys) and spring water — blend, drink and wipe face.

    The alternative, if you want to stick with the nourishment of raw, is a freeze dried liver supplement. Freeze drying liver preserves the heat sensitive vitamins and co-factors that make liver so incredibly nourishing — think vitamin A, choline and folate.

    Most of the desiccated liver products on the market use heat processing to remove the moisture… this type of heat dehydration removes 90-95 percent of the moisture content. Some brands (listed below) of desiccated liver are freeze dried using sublimation to remove the moisture… sublimation dehydration removes 98-99 percent of the moisture content. This leaves almost no moisture; since bacteria (nor viruses) can survive without moisture, this allows for a very safe and convenient way to get you liver fix.

    Both brands (listed below) make a higher standard freeze dried liver supplement from grass-fed / grass-finished cows that are pasture raised in New Zealand. In full disclosure, I prefer the Ancestral Supplements brand because… I set out to make a product that I would be proud to give my boys… as close to nature as possible, pure liver, no fillers, no flow agents, no antibiotics, no GMO, no pesticides… that’s right, I am the very proud parent of Ancestral Supplements. And to be fair, I know the other guys make a wonderful product too!

    – Ancestral Supplements
    – Vital Proteins

  8. My wife had serious issues after eating raw chicken liver (which had been frozen). It took 6 weeks to diagnose and treat with antibiotics (which was a big issue as she was still recovering from leaky gut). We still eat liver – but it’s from lamb and it’s cooked. Tip: always buy liver fresh-frozen (it goes bad VERY quickly) and keep frozen (it will begin to thaw very quickly on the journey home).

  9. Love your mention of everyday food superheroes: wild salmon and other fatty fish, pastured-raised eggs with the yolks, liver and other organ meats, garlic, onions, ginger, etc., etc.

    So, so much benefit from making those (rather than the latest pricey superfood trend) part of a regular diet!

  10. Thanks Mark! Great overview of how plants can help, and I agree that probably any plant metabolizes toxins to some degree (just as our livers do..!)

  11. loved the way you discussed about superfood we should use those that are easy for us to get. about the liver now I am not claiming to be an expert so please correct me if I am wrong but if I am correct freezing only stops bacteria from reproducing (they go in sleep mode sort of) the only way to get rid of them is by heating right ? I personally would never eat raw liver even if I knew that my source takes proper care for his products as it takes only one mistake one time that could screw you over am I making sense or all I am saying is outdated stuff I learned in school haha would really appreciate feedback :3

    1. I believe you are correct. Freezing only kills parasites not bacteria. USDA recommends two weeks of freezing. (from the book Nourishing Traditions)

      I’ve been eating raw liver two or three times a week for about seven years and never had a problem. I also undercook meat. For me it works out great. Liver and horseradish is an excellent combination.

      The vast majority of food poisoning comes from green vegetables. So the average American has absolutely nothing to fear. (punchline credit to Conan O’Brien)

      1. love the reference xD, And thanks for clearing that up seems it’s highly unlikely to get sick from it as long as your body does not have specific conditions.

  12. When I started making my own mayo a few years ago, I used to use the microwave to sterilise the yolks, but I learned my chances of getting a bad yolk were 10,000:1 so I just use ’em raw now. I put the risk at about the same as getting sick from sauerkraut or yogurt, which I also make myself. Sometimes you’ve just gotta go for it.

    I guess with other things you might be asking for trouble.

    1. i grew up in France and we eat raw egg (including home made mayonnaise) all the time, my grand parents used to give us kids a raw egg with a hole in it for us to suck it out of the shell (no joke). I never knew you could get sick with raw eggs until i started reading american food articles and blogs. I sounded like eating raw eggs was like playing Russian roulette. i thought it was very weird. But i once read that the chances of getting sick from eggs in the US was much higher than in Europe because of the way eggs are handled (they are washed and disinfected which makes their shell more porous and prone to contamination …..)

  13. I just ate some liver with some fava beans and a nice chianti…

  14. I drink four pounds of raw beef and bison liver each week via shakes and have never been ill on this regimen. However I also prepare the shakes with generous amounts of greens (prebiotic) and good bacteria (kefir and various fermented veg) which surely stacks the deck against pathogens. This was originally to simulate the universal alpha hunter meal of on-the-spot liver and stomach contents, but now I realize it has the additional benefit of girding against contamination. And even if some pathogens slip past the front line, just like our muscular systems need a good struggle, surely our microbiomes need a pitched battle once in a while to keep the war machine humming. Raw ruminant liver is the apex predator’s sine qua non!

    1. OMG – how do your swallow it? My stomach churns just thinking about it. I can only eat thinly sliced liver sauteed with onion and bacon. You must be superman.

      1. Actually it’s incredibly good! I’m drinking one right now after a very long day lifting and hiking. Not a fan of cooked liver, but when it’s raw and mixed with greens, kraut, kefir and berries (gojis and raspberries) it tastes like the most refreshing thing on earth. The way it speeds recovery from intense exercise is almost miraculous. Totally makes sense that liver was revered as sacred by indigenous hunters. There’s nothing else like it!

        If you want to give it a try, start with a tiny amount. It might grow on you!

  15. Cooking doesn’t necessarily make food safe. My husband and I cooked and ate a marinated tri-tip. It was delicious. We were both sick for two days. First time I had had a stomach illness in nearly a decade, I have never felt so bad in my life, the pain in my stomach was horribly intense. There is a bacteria that can live in brine, apparently cooking the food doesn’t help if it’s contaminated, since what makes you ill is the bacterial waste. There is no way to avoid every single illness, even if you observe every single precaution. That said, I par-boil the raw liver I use in my cat’s homemade food. Just 20-30 seconds dipped in boiling water kills most of the bacteria on the outside of the liver.