 What if just one lifestyle change could help you avoid getting cancer? Or diabetes? Or heart disease? Or high blood pressure? This one change could cut your risk of chronic disease and add years to your life. Well, the simple solution to so many of these problems is to eat a healthy diet. In other words, one centered around whole plant foods. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. Today, we look at a problem that many men experience from time to time, erectile dysfunction, and we start by looking at the nuts. I'm talking about walnuts, almonds, hazelnuts, here's the story. In 2013, I can't believe it's already been so long, I posted a video based on this study that found that three weeks of pistachios resulted in a significant improvement in erectile function in men. It's always nice to see a whole food intervention have clinical effects, and I was curious to revisit the topic to see what's been published since. Even if you ignore all the lab animal studies on how much hazelnuts improve the function of retesticles, you still never know what you'll find searching the medical literature for nuts and sexual function. Like this case of penile strangulation with a metal hex nut. I guess nuts can sometimes make things worse if you can't remove them. They used the Dundee technique, which involves creating 20 puncture holes to relieve the pressure, but that didn't work so well. Diamond disc cutter was used to saw through it, and they slipped a few times. Well, that got me curious. Evidently, penile entrapment is so common there's an entire grating system that emergency room docs can use. If a drill is not available, these surgeons advise a hammer and chisel may be used. A drill? Oh, a dental drill. I like how they brag about the precisely cut edges to preserve the penis from a fatal outcome. That's a strange way to put it. Urologists should be aware of all the available armamentarium, and if you don't know how to operate the saw, you can always call in your local blacksmith. Yeah, but how are you going to remove a barbell or steel sledgehammer head? A heavy-duty air grinder provided by the fire department requiring six hours of cutting with the patient protected from the sparks with firecoats, whatever it takes, hacksaw, cement eater, the silk winding method, but anyway, back to the task at hand. Consumption of at least one serving of vegetables a day and more than two serving of nuts a week was associated with more than a 50% decrease in the probability of erectile dysfunction in a snapshot-in-time cross-sectional study, but such observational studies can't prove cause and effect. It's like finding that men who eat more healthfully have better swimmers. Maybe men who eat nuts are just health nuts, and the improvement is due to some other factor like exercise. What we need is an interventional trial, and here we go. The effect of nut consumption on semen quality and functionality, a randomized controlled trial, a standard American diet with or without a handful of walnuts and a half-handful of each almonds and hazelnuts. And the nut group experienced significant improvements in their total sperm count, vitality, motility, and shape, perhaps because those in the nut group showed a significant reduction in SDF. Sperm DNA fragmentation. The nuts appeared to protect their sperm DNA. Too bad while they're at it, they didn't measure the guy's erectile and sexual dysfunction. Oh, but they did! The effect of nut consumption on erectile and sexual function from the same study, the researchers report that those in the nut group saw a significant increase in orgasmic function and sexual desire, but what about erectile function? Anytime you see this kind of selective glass half-full reporting, you suspect some kind of industry funding, and indeed that was the case here. Yes, there was a marginal increase in orgasmic function and sexual desire of questionable clinical significance, but no improvement in erectile function, intercourse satisfaction, or overall satisfaction. And with so many comparisons, even the so-called significant findings may not even be statistically significant. But why did the pistachios I talked about back in 2013 work while these other nuts didn't? Well, if you remember, the original study was done on men in their 40s and 50s, who already had chronic erectile dysfunction, whereas the average age in the new study was 24 years old. So they may have started out with near-maximum circulation, but not leaving much room for the nuts. In our next story, we'll look at how men eating pistachio nuts experienced a significant improvement in blood flow through the penis, accompanied by significantly firmer erections. Here's the story. Erectile dysfunction is considered an important cause of decreased quality of life in men. In fact, so much so that one early theory suggested they explained the link between impotence and heart attacks. Depression is a risk factor for coronary heart disease, and the thought was that men who couldn't get it up became so depressed that they liked to die of a broken heart. But now we know that erectile dysfunction and heart disease can be two different manifestations of the exact same root problem— diseased arteries. Inflamed oxidized cholesterol clogged blood vessels. So no wonder a diet chock full of anti-inflammatory, and cholesterol-lowering plant foods would improve sexual functioning in both men and women, as well as reduce risk of heart disease. But why go low risk when you can shoot for no risk? A totally plant-based diet can even stop and reverse our number one killer. Of all the plant foods individually examined so far, nuts are among those most tied to longevity. Just two handfuls and nuts a week may extend a woman's life as much as jogging four hours a week. So if nuts reduce the risk of heart disease, might they also help with sexual function? Well, men, eating three to four handfuls of pistachios a day for just three weeks, experienced a significant improvement in blood flow through the penis, accompanied by significantly firmer erections. This may not be surprising. Remember how antioxidant-rich foods have a viagra-like effect of boosting nitric oxide production? Well, pistachios are certainly rich sources of antioxidants. And remember how the citrulline and watermelons helped with erection firmness by boosting arginine, which is what our body makes nitric oxide out of? Well, pistachios have a bunch of arginine, which may help explain the improvement in blood flow. And we know that cholesterol is an important predictor of sexual dysfunction in both men and women. And after just three weeks on all those pistachios, there were significant improvements in cholesterol. And like other studies that piled on hundreds of calories of nuts a day, there was no weight gain. Conclusion, just three weeks of pistachios resulted in a significant improvement in erectile function with additional improvement in cholesterol without any side effects. Note the two important differences between diet and drugs, just taking drugs like viagra to poison this enzyme and artificially boost nitric oxide signaling is just covering up the symptoms of the underlying problem on healthy arteries. Whereas eating whole healthy plant foods like nuts actually helps attack the root cause, cholesterol, oxidation, and inflammation, and only has good side effects. This enzyme that viagra-like drugs muck with is primarily found in two places in the body, the erectile tissue of the penis, and the retina of the eye. That's why the FDA encourages people to stop taking drugs like viagra and call a doctor right away if you experienced sudden loss of vision. Of course you can still find your phone. Though the harms tend to be self-limited and reversible, such as cyanopsia, in which your vision suddenly becomes tinted blue, why risk side effects at all when the problem can be reversed, cured in the first place, improving the quality and quantity of our lives. Improvement of sexual function in men and women should be added to the growing list of clinical benefits brought about by healthy lifestyles in human beings. Did you know that dioxins, endocrine disrupting pollutants, heavy metals, saturated fat, and steroids in the meat supply may be affecting sperm counts, semen quality, and the ability of men to conceive? Infertility affects 10 to 15% of couples attempting to conceive, and about half the cases a problem is found in the man. A recent Harvard study found that increasing saturated fat intake, just 5%, was associated with a 38% lower sperm count. But why? I've talked about the role of xenoestrogens, endocrine disrupting industrial pollutants that build up in animal fat, particularly fish. But male fertility is not just about sperm count, the number of sperm, but about how well the sperms themselves work. A recent study found that successful pregnancy and fertilized egg implantation outcomes are decreased in patients reporting a more frequent intake of meat. This finding is consistent with poor semen quality associated with a higher intake of products that may incorporate these chemicals and steroids. The use of these compounds in the food industry results in an increased total level of xenoestrogens and sex steroids in processed foods, such as meat or milk, whose intake contributes significantly to daily exposures. Xenoestrogens are highly lipophilic substances that can accumulate in fat-rich foods, such as meat, and may be suspected as partially responsible for the decline in semen quality. Conclusion. Couples having trouble conceiving must be advised about the drastic effect of both the male and female lifestyles on infertility treatment success. This is consistent with previous findings that frequent intake of fat-laden foods, like meat products and milk, may negatively affect semen quality in humans, whereas some fruits or vegetables may maintain or improve semen quality. Vegetable consumption was also found protective of a new study, which may be because of the antioxidant and nutrient content of these plant foods. The adverse effects of meat could be from other pollutants as well. Exposure, even as an infant, to low levels of dioxin can permanently reduce sperm quality. The general consensus is that human sperm quality has declined over time in different areas. We're still not sure why, but dioxins may be playing a causal role. The reason why maternal beef consumption may alter a man's testicular development and adversely affect his future reproductive capacity is thought to be due to the anabolic steroids implanted into the animals. But as the accompanying editorial points out, the steroids could also be interacting with other xenobiotic, meaning industrial chemicals present in meat, such as pesticides and dioxin-like pollutants and even chemicals that may be present in the plastic wrap. Heavy metals may also play a role. Lead and cadmium exposure, as measured in the bloodstream, was associated with significantly longer time to conceive. Where might exposure be coming from? Well, common types of seafood, right? Out of fish markets and supermarkets, were sampled. The highest cadmium levels were found in tuna, highest lead levels found in scalps and shrimp. The greatest risk from different metals resided in different fish, some of which got really high. Thus, the risk information given to the public, and mainly about mercury, does not present a complete picture. There are other toxic metals in fish as well. The largest and oldest fish had some of the highest levels, and we see that with other animals as well. For example, contamination of beef by cadmium and lead, clearly dependent on the age of the animal. The only beverage associated with infertility in women was soft drinks, though this may be from an indirect route, with soda linked to obesity, and then obesity then linked to reduced fertilization rates. Though there has been a study on one really direct route, the effectiveness of Coca-Cola as a spermacidal agent in vaginal douching. Diet Coke apparently had the strongest effect. Harvard researchers publishing in the New England Journal of Medicine. What about Coke versus Pepsi? Taxpayer money-hearted work for this head-to-head test, and neither of them really worked. Coke nor Pepsi. Though they explained their methods for preparing the sperm-Cola mixtures differed from the Harvard group, bottom line, soda probably isn't good for you going into any more of this. 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 to each of these topics. My latest two books are How to Survive a Pandemic, Available on e-book, audio book, or actual book, and the How Not to Diet cookbook with more than 100 recipes for delicious and nutritious meals. All proceeds I receive from 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'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.