 I know you work hard to make the best lifestyle choices, so you can improve your health, destiny, and longevity. And there's lots of information out there on how to do just that. So where do you start? Well, we start with the facts. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. My job is to bring you the latest peer-reviewed nutrition and health research, and share it with you here. Today, it's all about those pesky skin bumps and blemishes that always seem to show up at the worst possible time. We start out with a kind of unusual question. Do sunflower seeds cause acne? Let's find out. A recent observational study on acne reported a statistically significant relationship between acne severity and dietary factors such as chocolate and dairy products but this surprised me. Sunflower seed consumption? When I think sunflower seeds, I just think good whole food source of nutrition found to lower cholesterol levels as much as almonds, which is pretty good. There are, however, right and wrong ways to eat them. If you sit down and eat a pound of unshelled sunflower seeds, just eat them with the shell still on, you can end up corked with a fist-sized mass of shredded sunflower seed shells. How could a doctor diagnose such a thing? By the colonic crunch sign, of course. Sounds like a breakfast cereal served in hell, but rather when you pop eat a large, crunchy rectal mass. You can end up a sharp, thorny mass, which is why the so-called sunflower seed syndrome has been described as a prickly proctological problem, lamenting that people who consume health foods occasionally fall into the trap of believing if some is good, more is better. It's not the amount, though, it's how they're eating them with the shells still on. That's why the syndrome is uncommon unless the patients or children who don't know any better or adults who are either impaired or have no experience with eating sunflower seeds. Most cases involve younger children, but here researchers describe a psychologically sound 13-year-old stressing the importance of the role of the parents to guide their children about the potential problems associated with the ingestion of too many unshelled seeds. You can overdo even shelled seeds, though, because of just the nature of some flowers. They're good at drying up the naturally-occurring heavy metal cadmium out of the ground, so they'll end up with higher levels than most foods, even if grown in relatively uncontaminated soil. The people who consume large amounts of sunflower seeds don't seem to suffer any untoward effects, or even end up with detectably higher cadmium levels, and here they define large amounts as greater than an ounce a week, which is like a handful, about 150 seeds. The World Health Organization recommends staying below about 490 micrograms of dietary cadmium a week. I mean, if you ate a handful a day, you'd be well below that, but you may get as much as 36 a day from the rest of your diet, so I think one handful a day is a reasonable safe upper limit. Yeah, but will it give us acne? You don't know, until you put it to the test. Yeah, but who's going to do a randomized control trial of some flower seeds in acne? Nobody. Until now. After all, consuming sunflower seeds is a very enjoyable way of participating in a clinical trial. 50 young adults were randomized to eat sunflower seeds or not for a week. In the control group, the acne severity index stayed about the same, but in the sunflower seed group, they got worse. This translates into about three extra pimples in the sunflower group, versus about one extra in the control group. They conclude that sunflower seed intake appears to aggravate acne. However, further evidence may be needed before banning sunflower seed intake in patients with acne. In our next story, we learn how dairy is considered a major cause of the acne epidemic. Here's the latest update published in 2011. Evidence for the acne-promoting effects of milk. Though acne is an epidemic, skin disease in Western countries, afflicting more than 85% of adolescents, acne is absent in non-Western populations, which do not consume milk and dairy products. They go on to review all the studies which I've already talked about. By million years of evolution, they conclude, the growth signaling system of mammalian milk is exclusively and physiologically provided to the newborn only during the nursing period. The chronic abuse of this mammalian postnatal signaling system by widespread cow milk and dairy consumption in humans of industrialized societies has been proposed to be the major cause of the acne epidemic, and the more serious chronic Western diseases. There's lots of diseases associated with unrestricted growth. So, what should we do? There are two solutions to this problem. The restriction of milk protein consumption, or we somehow engineer milk that doesn't have these effects. Either way, both restriction of milk consumption or the generation of less insulin-affecting milk will have an enormous impact on the prevention of epidemic Western diseases like obesity, diabetes, cancer, neurodegenerative diseases, and acne. Finally today, a 5% tea tree oil gel is pitted head to head against the leading over-the-counter treatment for pimples. Acne remains one of the commonest diseases to afflict humanity. If you do online surveys, tea tree oil appears to be the second most commonly used topical treatment after benzoyl peroxide. Though crowdsourcing may be a novel research method for evaluation of acne treatments, before getting too enamored with popular wisdom, you should know that there's stuff like this circulating on the internet, the facial application of urine as a home remedy for acne. Urine therapy advocates cite historical use as proof of its therapeutic potential as a free cure for many systemic diseases, apparently forgetting all the god-awful crazy skeletons crowding the closets of medical history. While recycling what the body intentionally removes may seem counter-intuitive to good health, what about premarin? The best argument this author could come up with for putting urine on your face is, hey, women after all swallow pills made from pregnant horse pee, not exactly following the logic there. Of course there's drugs for acne, there's always drugs, though along with drugs comes drug side effects. Antibiotics that suppress the bacteria that cause acne are the standard treatment for acne, but are becoming less effective, presumably because of the emergence of antibiotic-resistant strains. The prevalence of resistant strains has apparently grown rapidly, such that antibiotics for acne are no longer recommended just by themselves, with reevaluations advised every six to eight weeks. Well, the bacteria do seem to be susceptible to tea tree oil in a petri dish, but these kinds of studies were performed with free-floating bacteria, whereas in pimples, the bacteria form what's called a biofilm, which makes them generally more difficult to eradicate. The bacteria form like glue that plugs up the follicle, so petri dish studies can only tell you so much. I mean, even if tea tree oil couldn't kill off the bugs, though, it has been shown to suppress skin inflammation, like if you inflame people's skin with an allergen and then try to calm it down. Tea tree oil did a decent job compared to an over-the-counter ointment or moderate potency prescription steroid cream. So potentially tea tree oil could help with acne via an antibacterial mechanism or from an anti-inflammatory standpoint, but you don't know until you put it to the test. A 20% tea tree oil gel applied twice a day and a beautiful drop in acne lesions, after one, two, three months. About 24 pimples down to about 11. They conclude that the study showed that tea tree oil could significantly improve mild to moderate acne. But who can tell me the study's fatal flaw? Right, there was no control group. How do we know they wouldn't have healed even faster without it? In this systematic review of randomized clinical trials on tea tree oil, their most striking finding is that they could hardly find any. Given the widespread use of tea tree oil, this is both disappointing and important to note. But finally, a randomized double-blind placebo-controlled trial of a 5% topical tea tree oil gel in mild to moderate acne. After six weeks in the tea tree oil group, 40% drop in whiteheads and blackheads, a 40% drop in red and tender acne bumps, and a 47% drop in pus-filled pimples, compared to comparatively little change in the control group. Overall, in terms of total lesion count, the tea tree oil gel was three and a half times more effective than placebo, three and a half times more effective than essentially doing nothing. But most teens don't do nothing for their pimples. How does tea tree oil compare to the gold standard, benzoal peroxide? We'll find out right now. Benzoal peroxide is by far the most popular over-the-counter acne therapy, despite its side effects. It can be irritating, causing redness, dryness, peeling, stinging, burning. However, the prescription option, the long-term use of topical or oral antibiotics, is discouraged to the development of spread of antibiotic resistance. As a result, attention has turned to non-antibiotic products such as tea tree oil. The benzoal peroxide did cause more side effects, dryness, itching, stinging, redness, burning, but it worked better too, cutting the number of inflamed pimples by two-thirds within three months, versus only by half in the tea tree oil group, though the most recent study found them to be more comparable. Putting all the studies together, and tea tree oil products not only beat out placebo, but approximate more standard regimens like benzoal peroxide or topical antibiotics, suggesting tea tree oil products may be an appropriate option for treating mild to moderate acne. We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to nutritionfacts.org slash testimonials. We may share it on our social media to help inspire others. To see any graphs, charts, graphics, images, or studies mentioned here, please go to the nutrition facts podcast landing page. There you'll find all the detailed information you need, plus links to all the sources we cite for each of these topics. For a vital, timely text on the pathogens that cause pandemics, you can order the e-book, audiobook, or the hard copy of my last book, How to Survive a Pandemic. For recipes, check out my new How Not to Diet Cookbook. It's beautifully designed with more than 100 recipes for delicious and nutritious meals. And all proceeds I've received from the sales of all my books goes to charity. NutritionFacts.org itself is a non-profit, science-based public service where you can sign up for free daily updates on the latest in nutrition research via bite-sized videos and articles. Everything on the website is free. There's no ads, no corporate sponsorship. It's strictly non-commercial. I'm not selling anything. I just put it up as a public service, as a labor of love, as a tribute to my grandmother, whose own life was saved with evidence-based nutrition.