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Medscape
17 hours ago
- Health
- Medscape
Women's Scent Has Psychological Effects on Men
This transcript has been edited for clarity. Welcome to Impact Factor , your weekly dose of commentary on a new medical study. I'm Dr F. Perry Wilson from the Yale School of Medicine. We live in a world of sight and sound. That is the human experience. But most other mammals live in a very different world, a world of smells. Evolution has atrophied our sense of smell to the point that, in social situations, we don't really think about it unless an odor is particularly offensive. But it turns out that, somewhere deep in the recesses of our brains, we still respond to smell cues from other humans. And, for men at least, certain smells from women can make us more calm and less hostile, and make them seem more attractive. And now, thanks to some rigorous research, scientists may have identified exactly the chemical compounds that have this effect on the male of our species. What chemistry makes up the scent of a woman? Let's find out. The study we're discussing today, appearing in iScience , is not the first to note that smells can have physical and psychological effects on people. But it may be the most detailed. Researchers recruited 21 female volunteers to be scent donors. They used a special silicone material, placed under the armpits, to capture the molecules that, under ordinary circumstances, float through the air and into our nostrils and up to our olfactory bulbs. They did this across the four phases of the female menstrual cycle to figure out if and how scent changes with hormone level changes. Then they exposed 21 men to these samples and asked them to rate them all in terms of pleasantness. You can see the results here. While all the smells were rated slightly less pleasant than a 'no odor' control, the scents collected during ovulation were rated by men to be significantly more pleasant than those during other phases of the menstrual cycle. 'Pleasant' is a rather subjective term, of course. The researchers asked the men to describe the odors across a spectrum that would be familiar to any perfumer or sommelier. During ovulation (labeled "O" here), men described women's scents as more citrus, more 'grassy,' and more 'fragrant,' while being less 'vinegary,' 'musty,' or 'stinky.' But what exactly is making those smells? This is where the study starts to get really interesting. The researchers put those silicone patches through a mass spectrometer to identify all the volatile compounds present. They then identified compounds that were more uniquely present during ovulation compared with other times during the cycle. In this case, there were three big hits. These three chemicals are the likely candidates for those pleasant aromas that men reported from the first set of experiments: (E)-geranyl-acetone, tetradecanoic acid, and (Z)9-hexadecanoic acid. These are really interesting compounds. (E)-geranyl-acetone is formed by the breakdown of squalene, which is a substance on our skin. It is described as having a green or floral quality, similar to what the men in the first set of experiments described. You can find it in tomatoes, mint, citronella, passionfruit, and quite a few other places. Tetradecanoic acid (myristic acid) has a waxy or creamy odor. In humans, you find this in breast milk, amniotic fluid, and saliva, in addition to the skin. Human babies will actually start a suckling reflex when exposed to tetradecanoic acid. In the natural world, the richest source of tetradecanoic acid I could find was in nutmeg butter, but despite being from the Nutmeg State, this is one foodstuff that has not yet graced my table. Still, the picture of exactly what makes the pleasant scent of a woman pleasant is becoming more clear. We have green grass, we have citrus, and something creamy that — perhaps — evokes breast milk. But the third compound was a bit harder to understand. (Z)9-hexadecanoic acid is also known as palmitoleic acid. It is, apparently, odorless. It does, however, break down into (E)-2-nonenol which is a compound known to carry that 'old age' smell that you sometimes hear about. I am unclear how this precursor to an old-age smelling compound plays into the bouquet we are describing, but it is there. Data don't lie. Here's where the study gets cool. With these three compounds isolated, the scientists created their own version, a mix of the three, perhaps the most scientifically based perfume in history. Men were brought into a room and given a headset with a microphone. Unbeknownst to them, the microphone cover had been dosed with either nothing or one of three scents: the ovulation cocktail, the 'baseline' armpit smell, or a combination of these two scents. Then the men were asked to take some surveys. Nothing about smell this time; they were about mood. Unaware of what scent they were smelling, the men were not even aware they were supposed to be smelling something. The men exposed to the ovulation cocktail reported less feelings of hostility, increased 'liveliness,' better concentration, and less boredom. The researchers stop short of calling this 'signaling via pheromone,' but it is hard not to conclude that a simple scent, in this case a purely synthetic one, can induce specific feelings in men. The experiments didn't stop there. They next had the men rate faces of various women. Shown a face, they were asked to rate them in terms of whether the person was beautiful, elegant, and intellectual, someone they want to spend time with, and someone they want to keep gazing at. These four categories were all quite correlated, actually. It turns out that if a man thinks a face is beautiful, he also thinks he wants to spend time with that woman. In any case, for women rated very high on the attractiveness scale, the scent didn't seem to make a difference; they always scored well. But for women who, overall, were rated lower on the attractiveness scale, they scored better when the men doing the rating were exposed to that ovulation cocktail. It's sort of crazy to me to think of how our perceptions can be influenced by sensations we aren't necessarily fully conscious of. And, of course, this research leads to some very interesting questions. Probably the first on people's minds is: Does any perfume have these compounds in it? And the answer is, yes, absolutely, but since perfume ingredients are not always listed, I have no idea which one. If you're looking, aim for something that has notes of nutmeg, citrus, and tea, perhaps. Of course, as a man, I wonder if this works the other way. We don't have hormonal cycles with quite as profound physiologic ramifications as women do, but I do wonder if there are compounds in our natural body odor that might affect the feelings or thoughts of the fairer sex. This study reminded me of an embarrassing period in high school when a relationship with my then girlfriend felt like it was on the skids and, desperate to hold things together, I changed my cologne. It turned out, as you might expect, that that was not the secret to long-lasting happiness. This research won't unlock that secret either. But what we see here is the way in which we are starting to decode a new language, the language of smells, one that many thought humans were no more capable of speaking than dogs are of speaking English. But perhaps, like a dog recognizing the word 'walk,' somewhere, in the recesses of our brains, we still understand the language of scent. Sorry for being nosy.
NDTV
6 days ago
- Health
- NDTV
COVID-19 May Trigger Alzheimer's-Like Protein Buildup In Brain And Eyes, Study Finds
New research suggests that COVID-19 can lead to protein build-up similar to that seen in Alzheimer's patients, not just in the brain but also in the eyes. Elevated amyloid beta levels were found in the retinal tissue of people who had COVID-19, similar to Alzheimer's-like retinal conditions. Notably, Amyloid beta buildup is associated with Alzheimer's disease. Researchers analysed two proteins, neuropilin-1 (NRP1) and angiotensin-converting enzyme 2 (ACE2). The NRP1 protein may serve as an entry point for viruses into human eyes and brains. Researchers found that introducing an NRP1 inhibitor countered the amyloid beta increase caused by COVID-19's spike protein. The study, led by Yale University and published in Science Advances, sheds light on COVID-19 brain fog, which was a commonly reported symptom following infection. The researchers believe that amyloid beta may act as a bodyguard for the brain, indicating underlying danger. "There is growing evidence linking COVID-19 and brain fog, a commonly reported symptom following infection," senior author Brian Hafler, ophthalmologist at Yale School of Medicine, said as quoted by Science Alert. "While the mechanisms of brain fog after COVID-19 are not fully understood, scientists have found that SARS-CoV-2 can induce amyloid beta accumulation in the central nervous system." The research team is conducting clinical studies to determine if COVID-19 increases the long-term risk of developing Alzheimer's disease, to explore NRP1 inhibitors as potential therapeutics. The involvement of NRP1 in amyloid beta aggregation provides a specific molecular target for future investigation. Other viruses may trigger similar amyloid beta buildups, as there's a need for further research. This study contributes to understanding the complex relationship between COVID-19 and neurological health. "Our study showed that exposure to SARS-CoV-2, in particular spike protein, can lead to the formation of amyloid beta aggregates in both human retinal tissue and retinal organoids," Hafler says.
USA Today
19-07-2025
- Health
- USA Today
What are the symptoms of celiac disease?
If you've ever felt bloated or fatigued after eating a slice of pizza or a toasted bagel, it could be more than indigestion alone. Celiac disease is an underdiagnosed and serious chronic condition that affects some 2 million people in the U.S. each year and millions more across the globe. For the individuals dealing with it, avoiding gluten is anything but a "fad" diet; it's a medical necessity. "Celiac disease is an autoimmune disorder in which eating the gluten that's found in wheat, barley and rye leads to the body's immune cells attacking the lining of the small intestine," explains Dr. Marie Robert, a surgical pathologist at Yale School of Medicine New Haven Hospital. This can cause a wide variety of unwanted symptoms in both adults and kids alike. "While in the past celiac disease was thought to mainly affect children, it is now clear that it can occur at any age," says Dr. Alessio Fasano, a professor of nutrition at Harvard T.H. Chan School of Public Health and the pediatrics director of the Center for Celiac Research and Treatment at Massachusetts General Hospital. Here's what the most common symptoms of celiac disease are, what causes it and how it is usually treated. What are the symptoms of celiac disease? Celiac disease is a notoriously elusive condition because its symptoms vary in severity and can look different from one person to the next. Digestive issues are the most common symptom, and include "bloating, stomach pain and diarrhea," says Dr. Runa Watkins, a division chief in the pediatric gastroenterology and nutrition division at the University of Maryland School of Medicine. But because "there is no tissue or organ that's spared by the inflammatory process started by celiac disease," Fasano explains, many people with the disease also have non-gastrointestinal symptoms. These symptoms may include fatigue, anemia, joint pain, skin rashes and neurological symptoms like depression, brain fog, mood swings or headaches. "Reproductive issues such as infertility are also not uncommon,' adds Robert. Kids with celiac disease may also experience growth delays and short stature. 'Growth failure in children is another common sign of the disease,' says Dr. Peter Green, a physician and professor at the Celiac Disease Center at Columbia University. And when celiac disease goes untreated or undiagnosed – as it commonly does – the condition can lead to more serious complications such as other autoimmune diseases and osteoporosis. There's also a potential for increased risk of cancerous tumors and fractures due to chronic nutrient deficiencies. Due to all such factors, 'those with celiac disease face a higher mortality rate than the general population," says Green. Did you know? Acid reflux impacts about 20% of American adults. What causes it? What causes celiac disease? While the exact cause of celiac disease is not always known, Watkins says it's usually driven by a mix of genetic and environmental factors. When it comes to genetic associations, research shows that the strongest link is someone having what are known as the HLA-DQ2 or HLA-DQ8 gene variants. 'Because of these genes, up to 10% to 15% of first-degree relatives of celiac disease patients are affected,' says Fasano. As for environmental factors, eating gluten is what most commonly triggers symptoms in people with celiac disease, but "changes in the gut ecosystem – often caused by an infection (especially during childhood), surgery or stress – can also start the march from genetic predisposition to clinical outcome," explains Fasano. Need to avoid gluten? Here's what foods have gluten and more on hidden sources of gluten How is celiac disease treated? As of now, the only treatment for celiac disease is a strict gluten-free diet. 'Even small amounts of gluten, like crumbs from a toaster, can cause damage and symptoms,' says Watkins. But once gluten is eliminated completely, many patients feel better within weeks – though recovery may take longer for some people. Most of these patients work with a medical provider or dietitian to identify and eliminate food sources that contain gluten and to get recommendations on how to make up for nutritional deficiencies. This can be easier said than done though as, in addition to being a protein naturally found in many grains, gluten is "often added to processed foods as a filler," says Fasano. "Sauces, candies and even some meats may contain it." And for a small number of patients, even committing wholly to a gluten-free diet won't be enough to stave off symptoms. This is due to a rare condition called refractory celiac disease, which requires specialized treatment. For these and all patients with celiac disease, "there are numerous clinical trials attempting to find medicines that will prevent the associated inflammatory response," says Robert. "Hopefully, it's only a matter of time before there will be medicines that can make living with celiac disease easier."
Time of India
19-07-2025
- Health
- Time of India
AI expands usefulness of common heart test
London: Artificial intelligence (AI) can turn a common doctor's office test into a screening tool for detecting structural problems in patients' hearts, researchers reported in Nature. Their publicly available AI tool, called EchoNext, analyzes ordinary electrocardiogram (ECG) data to identify patients who should have an echocardiogram - a noninvasive ultrasound exam - to look for valve diseases, thickening of the muscle tissue, and other structural defects that can impair heart function. "We were all taught in medical school that you can't detect structural heart disease from an electrocardiogram," study leader Pierre Elias of Columbia University Vagelos College of Physicians and Surgeons said in a statement. "We think that ECG plus AI has the potential to create an entirely new screening paradigm." EchoNext uses the cheaper ECG to figure out who needs the more expensive ultrasound, he said. When 13 cardiologists reviewed a total of 3,200 ECGs, they detected structural heart problems with an accuracy rate of about 64%, compared to a 77% accuracy rate for EchoNext, the researchers found. They next used the tool to review ECGs obtained in the past from nearly 85,000 patients. Based on those ECGs, the patients' doctors had sent 4,100 of them to get echocardiograms, which found structural problems in roughly 3,000. But EchoNext identified an additional 3,400 patients as being at high risk and needing the ultrasound exam. Because AI was unavailable when those ECGs were obtained, many of the additional patients may have had potentially serious structural heart disease that went undiagnosed, the researchers said. "You can't treat the patient you don't know about," Elias said. "Using our technology, we may be able to turn the estimated 400 million ECGs that will be performed worldwide this year into 400 million chances to screen for structural heart disease and potentially deliver life-saving treatment at the most opportune time." Worldwide, structural heart disease impacts 64 million people with heart failure and 75 million with valvular disease, with costs in the U.S. alone exceeding $100 billion annually, the researchers said. SOME BRAIN CELLS HAVE BACKUP BATTERIES Neurons, the nerve cells that transmit information to and from the brain, are equipped with "backup batteries" that kick in to keep the brain running during periods of metabolic stress, researchers have discovered. Traditionally, it was believed that brain cells called glial cells served as "energy warehouses" for the neurons, storing a form of sugar known as glycogen and supplying it as needed for fuel. "But we now know that neurons themselves store glycogen and can break it down when the pressure is on," study leader Milind Singh of the Yale School of Medicine said in a statement. "It's like discovering that your car is a hybrid - it's not just reliant on gas stations, it's been carrying an emergency battery the whole time." Their discovery was made during experiments with a microscopic roundworm called C. elegans and a fluorescent sensor that glows when cells break down sugar for energy. The findings could shape new treatments for neurological conditions in which energy failure plays a role, such as stroke, neurodegeneration, and epilepsy, the researchers said in PNAS. The team found the neuron's glycogen-dependent energy production is especially important when their mitochondria - their primary energy factories - are impaired, such as when the oxygen supply is limited. Under these conditions, glycogen serves as a rapid-access fuel source, helping neurons stay active when other systems might stall, the researchers said. "That flexibility might be crucial for how the brain maintains function and responds to stress," senior researcher Daniel Colon-Ramos, also of Yale, said in a statement. "This research reshapes our understanding of brain energy metabolism and opens new avenues for exploring how to protect and support neuronal function in disease." (To receive the full newsletter in your inbox for free sign up here)
National Geographic
18-07-2025
- Health
- National Geographic
This underdiagnosed vein disorder affects 4 in 10 Americans
A nurse practitioner examines a patient with chronic venous insufficiency (CVI), a vascular condition in which damaged leg veins impair blood flow back to the heart. CVI can lead to symptoms such as swelling, skin changes, and venous ulcers if left untreated. Photograph by Michael Macor, The San Francisco Chronicle via Getty Images From tingly legs to bulging veins, these warning signs may point to chronic venous insufficiency—a widespread circulatory issue doctors say is on the rise. Swelling, aching calves, tingling, or bulging veins might seem like everyday discomforts, but they could point to a hidden problem in your circulatory system. A surprisingly common yet underrecognized condition called chronic venous insufficiency is behind a growing number of cases—and scientists say it's far more widespread than most people realize. Here are five things to know about this painful and underdiagnosed vascular disorder. What is chronic venous insufficiency? Chronic venous insufficiency (CVI) occurs when the valves in your leg veins become weak or damaged and begin leaking. 'Because veins carry blood back to the heart, these leaky valves can allow blood to flow backward or pool in the leg,' says Raul Guzman, division chief of vascular surgery and endovascular therapy at Yale School of Medicine, New Haven Hospital. Over time, this backward flow and pooling increases pressure within the veins, leading to inflammation and damage to surrounding tissues. Left unchecked, the condition can trigger a chain reaction that affects both the skin's surface and the deeper structures of the leg. Early signs and symptoms of CVI Early signs of CVI can be as subtle as a tight feeling in your calves, cramping, or especially heavy or tired legs after a long day. But as the condition progresses, symptoms often intensify and include 'pain or discomfort in the leg, swelling, and skin damage,' explains Guzman. The skin may take on a discolored or leathery appearance, become itchy or cracked, and develop slow-healing wounds or ulcers. (Scientists are unraveling the mysteries of pain.) Due to the pooling blood, varicose and bulging veins are another hallmark sign, though not everyone with CVI has them. Left untreated, CVI can lead to increased venous pressure, more serious conditions, and even blood clots. Who is most at risk for CVI? Despite its low profile, chronic venous insufficiency affects an estimated 40 percent of Americans, according to the Society for Vascular Surgery. It's especially common in women over 50 and those who are pregnant. But men aren't immune, particularly if they lead a sedentary lifestyle or are living with obesity. It's also prevalent in individuals with a history of deep vein thrombosis or other venous diseases. 'We know that there is a hereditary component to CVI,' says Guzman. (Why heart attacks are rising in young adults—and what to watch out for.) Smoking and high blood pressure can also contribute to the condition. So can jobs that require prolonged standing or sitting because 'may cause blood to pool in the legs, increasing pressure on your veins,' says Marie Robert, a surgical pathologist at Yale School of Medicine, New Haven Hospital. Why CVI is often misdiagnosed One of the biggest challenges with CVI is that its symptoms are frequently misinterpreted. Swollen legs may be attributed to aging or fluid retention. Varicose veins are often seen as purely cosmetic, and skin changes may be mistaken for eczema or unrelated irritation. But ignoring these signs can allow the condition to worsen, Guzman says—sometimes even resulting in irreversible damage. That's why it's essential to consult a healthcare provider, such as a vascular specialist, if even minor symptoms persist or worsen. Robert says that a simple physical exam and either an magnetic resonance angiogram (MRA) or ultrasound are usually all that are needed to determine whether CVI is present and what treatment may be required. The good news is that CVI is highly treatable, especially when caught early. Doctors often begin with conservative approaches, such as suggestions to elevate your legs above your heart during the day and using compression garments to improve blood flow. 'The first method of treatment involves the use of elastic compression stockings,' says Guzman. (The ability to reverse damage to your lungs and heart is tantalizingly close.) Lifestyle changes, such as weight loss, improving diet, regular exercise, and avoiding prolonged periods of sitting or standing, are also frequently recommended. All such recommendations 'help ease swelling, improve circulation, and relieve symptoms,' says Robert. Medications such as blood thinners or diuretics may also be prescribed to reduce swelling or improve blood flow. 'And there are several surgical procedures and more advanced medical interventions that can be performed,' adds Guzman. These include sclerotherapy (an injected solution that causes the affected veins to collapse and fade), vein stripping, angioplasty and stents, endovenous ablation (a minimally invasive procedure using heat or laser to close off the affected veins), or surgical removal of malfunctioning veins. 'Use of these treatments depends on the location of the involved veins and the degree of the problem,' says Guzman. As awareness of chronic venous insufficiency grows, so do opportunities for earlier detection and more effective management. 'For many people, CVI is annoying and uncomfortable—but not usually life-threatening,' says Robert. 'It's a condition that can be helped by a variety of lifestyle changes and mild interventions.'
