Deodorize from the Inside Out

**Michael Greger** (0:00)
I'm often asked my opinion about the cause or treatment of some medical condition, but the question to instead ask is what does the science say? What does the best available balance of evidence published in the peer-reviewed medical literature have to say right now? Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. Today, what our body smells can tell us about the food we eat, and we start with how to treat body odor with diet. Vision is not the only sense associated with physical attractiveness and partner preference. Body odor signals a variety of information on matters such as eating habits, hygiene, health, and more. Based on a survey of hundreds of college students, men rated visual and smell information as being equally important for selecting a lover, while women considered to have their potential mate smell to be the single most important variable. In other words, women ranked body odor as more important for attraction than looks. I've talked about the concern around aluminum-containing antiperspirants. What can we do to make ourselves smell better? Clinical studies dating back to the 1950s show that chlorophyll can be used to improve body odors. This led to a wave of commercial chlorophyll deodorant products. But, as one chlorophyll scientist lamented, because of the unfounded, fantastic, and sometimes completely idiotic claims made for chlorophyll by the promotion and advertising men, the buying public, as well as the scientist, will remain skeptical, and rightly so. To be an effective deodorant, chlorophyll has to be taken internally at doses that far exceed those found in so-called deodorizing chewing gums and lozenges. Studies showing the elimination of detectable underarm odors use doses on the order of 100 milligrams a day. In other words, the amount of chlorophyll one could get in about a third of a bunch of raw spinach. So before slathering aluminum onto your skin, I recommend first trying to deodorize from the inside out by eating a big salad every day, which may improve your body odor two ways, hitting the chlorophyll threshold and improving your health. There is a scent to disease. Some diseases result in a characteristic odor emanating from sick individuals. For example, tuberculosis of the throat makes you smell like stale beer. Typhoid makes you smell like baked bread. That doesn't sound so bad. Though, yellow fever makes you smell like a butcher's shop. But it's not just infection. I mean, evolutionarily, wouldn't it be advantageous if you could smell the first signs of inflammation, immune system activation, to stay away from people before they become contagious? What this team of researchers did was inject people with endotoxin, which is a highly inflammatory component of certain bacterial cell walls, and caused a big spike of internal inflammation. And the question is, could you smell it on people? Within just a few hours, endotoxin-exposed individuals had a more aversive body odor relative to when they were exposed to a placebo, a significantly less pleasant body odor within hours. Moreover, the more inflamed they got, the worse they smelled, providing the first experimental evidence that we can smell inflammation on people. And guess where endotoxins are found in the food supply? Where bacteria are found in meat. And they're not destroyed by cooking. I have a whole series of videos about that. We know meat causes inflammation, so does that mean it makes people smelly?
You don't know, until you put it to the test. The effect of meat consumption on body odor attractiveness. Not just body odor, but body odor attractiveness. For two weeks, male odor donors were placed on a diet that included meat or excluded meat, a no-meat diet. And then during the final 24 hours, they had pads taped into their armpits to collect their body odor. Then the researchers just needed some judges to sniff the pads from each of the men. So fresh odor samples hot off the pits, less than an hour old, were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women. A month later, the study was repeated with the same guys, but now following the other diet. The same poor women were used as judges. The men, incidentally, were paid $2,000 in check currency for their time and potential inconvenience caused by the prescribed diet. But the women who had to sniff all those armpit pads? The raiders were not paid for their participation, though did get a chocolate bar after the second session. So, who had the most pleasant, the most attractive body odor? The results showed that the odor of donors when on the non-meat diet was judged as significantly more attractive, more pleasant, and less intense. No difference was noted for masculinity. The researchers concluded that meat may have a negative impact on perceived body odor hedonicity. In other words, those eating more plant-based evidently smell significantly more pleasurable. In our next story, we look at how shaving, before applying antiperspirants, can increase aluminum absorption and also the risk of breast cancer. A famous case report called The Mortician's Mystery in the New England Journal of Medicine back in the 80s described a man whose testicles started shrinking and breasts started growing. Turns out he failed to wear gloves as he massaged embalming cream onto his corpse. They conclude there must have been some estrogenic compound in the cream that got absorbed through his skin into his body, one of the first such cases described. This case was cited as inspiration by a group of researchers that came up with a new theory to explain a breast cancer mystery. Why do most breast cancers occur in the upper outer corner of the breast? The standard explanation was simply because that's where most of the breast tissue is located, as the so-called tail of the breast extends up into the armpit. But that doesn't explain this. It didn't always used to be that way. There's been a shift towards that upper corner. And it doesn't explain this. Greater genomic instability, chromosome abnormalities that may signal precancerous changes. There definitely seems to be something happening to that side of the breast. And something relatively new, just in the last 50 years or so. Is it possible that the increasing use of underarm antiperspirant, which parallels increasing breast cancer incidence, could be an explanation for the greater number of tumors and the disproportionate incidence of breast cancer in the upper outer quadrant of the breast, near where the stick, spray, or roll-on is applied? There is a free flow of lymph fluid back and forth between the breast and the armpit, and if you measure aluminum levels in breasts removed after mastectomies, the aluminum content of breast tissue in the outer regions near the armpits was significantly higher, presumably due to closer proximity to the underarm region. This is a concern because in a Petri dish, at least, it has been demonstrated that aluminum is a so-called metalloestrogen, having proestrogenic effects on breast cancer cells. Long-term exposure of normal breast tissue cells in a test tube to aluminum concentrations in the range of those found in the breast results in precancerous type changes. And then once the cells have turned, those same concentrations can increase the migratory and invasive activity of human breast cancer cells in a petri dish. This is important because women don't die from the tumor in the breast itself, but from the ability of the cancer cells to spread and grow at distant sites like the bones, lungs, liver, or brain. But we don't care about petri dishes. We care about people. In 2002, a paper was published in the Journal of the National Cancer Institute, in which the underarm antiperspirant habits of 800 breast cancer survivors was compared to women who never got breast cancer, the first study of its kind, and they found no indication of a link between the two. Based on this study, Harvard Women's Health Watch assured women that antiperspirants do not cause breast cancer. Women who are worried that antiperspirants might cause breast cancer can finally rest easy.