 We have a lot of choices to make about our diet. Add to that, doing the right thing when it comes to preventing or treating a chronic disease, fighting a virus, or losing weight, and suddenly our nutrition choices can seem almost overwhelming. Well, I'm here to help. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. Today we take a look at the best way to take care of the largest organ in our body. For skin. In our first story, almonds are put to the test in a randomized controlled trial for facial wrinkles. After my video on dates blew my mind, showing that even just a few dates can significantly reduce the duration of labor during childbirth and improve the progression of labor. But there are some surprising benefits attributed to nuts in randomized controlled trials, like how about a study on the effects of almond consumption on wrinkles? They even come up with the idea. Well, population studies have found that healthy diets are associated with less facial wrinkles, like a meat and junk predominant eating pattern was associated with more wrinkles, whereas a fruit predominant pattern was associated with fewer wrinkles. In terms of single foods, yellow vegetables and soy appeared protective, but wine may make things worse. They're thinking that it might be the antioxidants in healthy foods, decreasing the oxidative stress load or the anti-inflammatory benefits or protection from sun damage or improved collagen production or better DNA repair. I've got videos on most of those topics. The bottom line is that eating healthier may reduce wrinkling, which could actually save lives if people started eating healthier to maintain a more youthful appearance and get all the chronic disease benefits as a happy side effect. Other studies found the same thing, supporting recommendations for more healthy foods like fruits, vegetables and nuts. Here's another study that landed on yellow vegetables and greens as well. In this study, a high intake of vegetables, beans and olive oil were to be protective against spots of pre-cancerous sun damage, whereas a high intake of meat and dairy may make things worse. Prunes, apples and tea seem particularly good, but this is a cross-sectional study, meaning just a snapshot in time, and maybe people who eat more meat are out barbecuing in the sun or people who eat more prunes just use more sunblock. I mean, you can't know for sure if foods actually affect wrinkling until you put them to the test, but we had no such studies until now. Why study almonds? Because it was paid for by the Almond Board, of course. The researchers didn't know who was in the nut group, though, and who was in the control group when they were looking at the results. The nut group were given two ounces of nuts a day, like two palmfuls of nuts, and the control group was instead given nut-free snacks to eat instead, like nut-free granola bars or pretzels. Before and after, they got high-res facial photographs to quantify facial wrinkled depth and severity using a computer-based photographic analysis, and boom! The almond group had significantly decreased wrinkle severity compared with the control group by the end of the 16-week study. The paper concludes, our study demonstrates that daily almond consumption may reduce wrinkle severity. Now, they used a relatively large dose of two ounces a day, whereas you can get cardio-protective benefits of nuts from even less than a half an ounce, so who knows? Maybe they could have gotten away with using less. Here's the low-dose nut study they referenced, showing a significant drop in LDL cholesterol within six weeks, eating just a few almonds a day. Ten grams is just like eight almonds a day. That's the nice thing about healthy foods, they just have good side effects. So global disease prevention strategies might benefit from emphasizing that a healthy diet is also linked to less facial wrinkling, and maybe vanity will help us prevent a few heart attacks in the bark. In our next story, we discover how some foods appear protective against the development of skin wrinkles while others may make them worse. The skin is the largest organ in the body, about 20 square feet, and the most vulnerable organ in the body exposed to both the oxidizing effects of UV radiation from the sun, and the oxidizing effects of oxygen in the air. And years of oxidant stress can take a toll. Over the years, skin becomes thinner, more easily damaged, loses volume, elasticity, and can sag and wrinkle. What can we do about it? Skin wrinkling, can food make a difference? They measured healthfulness of skin using a microtopographic method. It's cool, they make a mold of the back of your hand with a silicone rubber, peel it off, and then look at it under a microscope. But then as we age, our skin can get all coarse and flaccid. How can we stop it? Well, three things contribute to the aging of skin. Oxidative stress induced by sun damage, inflammation, and ischemia, lack of adequate blood flow. Oxidative stress means we need anti-oxidants. Under these circumstances, many skin antioxidants undergo depletion, must be replaced continuously in order to delay the otherwise inevitable deterioration, which would lead to skin aging. So, plant foods would presumably help. And then inflammation and lack of blood flow. And so one might predict saturated fat, inflammation, and cholesterol ischemia might be associated with adverse effects on our skin. Let's see if our predictions hold up. In particular, a high intake of vegetables, beanspeed lentil soy, and olive oil appeared to be protective against skin wrinkling, whereas a high intake of meat, dairy, and butter appeared to have an adverse effect. Prunes, apples, and tea appeared especially protective. A recent study, for example, found that green tea phytonutrients were able to protect skin against harmful root UV radiation, help improve skin quality of women. After a few months on green tea, there was a 16% reduction in skin roughness and a 25% reduction in scaling, as well as improved skin elasticity and hydration. Finally today, we ask the question, instead of treating sensitive skin topically with lotions and creams, why not treat it from the inside out with diet? About half of the American population says they have sensitive skin defined loosely as tingling, chafing, burning, itching sensations when exposed to various environmental factors. A similar high prevalence has been reported throughout Japan and Europe, especially in women. Often there are no obvious signs, and so it's often dismissed by the medical community as a princess in the pee phenomenon, a mindset that has hindered the investigation of this problem. But now it's largely recognized as a genuine phenomenon of physiological origin, thought to arise from an alteration of the skin barrier, allowing potentially irritating substances to penetrate the skin and generate an inflammatory reaction. Okay, so what can we do about it? Well, recently supplementation of flaxseed oil was found to diminish skin sensitivity and improve skin barrier function and condition. In a randomized, double-blind, 12-week study, women were given about a half teaspoon of flaxseed oil a day internally versus safflower oil as a control. That's the amount of oil found in about a teaspoon and a half of flax seeds. After three months, there was a significant decrease in skin reddening in the flax group compared to the safflower group when an irritant chemical was painted on their forearms to measure skin sensitivity. Their skin also ended up significantly better hydrated, had significantly better barrier function as evidenced by lower transepidermal water loss, skin that's less rough, less scaly, and smoother. You can actually see the changes in a close-up view of the skin. Skin looked pretty much just as dry and scaly before and after the safflower oil intervention, but significantly improved after the flaxseed oil. Sensitive skin is typically treated by topical application of lotion and creams, but why not treat it from the inside? This study showed that daily supplementation with flaxseed oil improved skin appearance and led to a decreased skin sensitivity by improving epidermal barrier function and decreasing inflammation. The best source of flaxseed oil is within the flaxseed itself. Then you get all the nutrition of the whole food and it's cheaper and more stable. Unlike the oil, you can bake with the seeds without destroying the omega-3s and even store ground flaxseed for a month at room temperature without spoilage or oxidation. 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 be able to share it on 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, audio book, or the hard copy of my latest book, How to Survive a Pandemic, or go to your local public library for that matter. For more 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 of course, all the proceeds I received from all the sales of my books go to charity. NutritionFacts.org 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 are no ads, no corporate sponsorships, no kickbacks, it's strictly non-commercial. Not selling anything. I just put it up as a public service, a labor of love as a tribute to my grandmother, whose own life was saved with evidence-based nutrition.