Connect with us

NewsMakers

Your sense of smell may be the key to a balanced diet

The food you ate just before your walk past the bakery may impact your likelihood of stopping in for a sweet treat – and not just because you’re full.

Published

on

Photo by Otto Norin from Unsplash.com

Walking past a corner bakery, you may find yourself drawn in by the fresh smell of sweets wafting from the front door. You’re not alone: The knowledge that humans make decisions based on their nose has led major brands like Cinnabon and Panera Bread to pump the scents of baked goods into their restaurants, leading to big spikes in sales.

But according to a new study, the food you ate just before your walk past the bakery may impact your likelihood of stopping in for a sweet treat – and not just because you’re full.

Scientists at Northwestern University found that people became less sensitive to food odors based on the meal they had eaten just before. So, if you were snacking on baked goods from a coworker before your walk, for example, you may be less likely to stop into that sweet-smelling bakery.

The study, “Olfactory perceptual decision-making is biased by motivational state,” was published August 26 in the journal PLOS Biology.

Smell regulates what we eat, and vice versa

The study found that participants who had just eaten a meal of either cinnamon buns or pizza were less likely to perceive “meal-matched” odors, but not non-matched odors. The findings were then corroborated with brain scans that showed brain activity in parts of the brain that process odors was altered in a similar way.

These findings show that just as smell regulates what we eat, what we eat, in turn, regulates our sense of smell.

Feedback between food intake and the olfactory system may have an evolutionary benefit, said senior and corresponding study author Thorsten Kahnt, an assistant professor of neurology and psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine.

“If you think about our ancestors roaming the forest trying to find food, they find and eat berries and then aren’t as sensitive to the smell of berries anymore,” Kahnt said. “But maybe they’re still sensitive to the smell of mushrooms, so it could theoretically help facilitate diversity in food and nutrient intake.”

Kahnt said while we don’t see the hunter-gatherer adaptation come out in day-to-day decision-making, the connection between our nose, what we seek out and what we can detect with our nose may still be very important. If the nose isn’t working right, for example, the feedback loop may be disrupted, leading to problems with disordered eating and obesity. There may even be links to disrupted sleep, another tie to the olfactory system the Kahnt lab is researching.

Using brain imaging, behavioral testing and non-invasive brain stimulation, the Kahnt lab studies how the sense of smell guides learning and appetite behavior, particularly as it pertains to psychiatric conditions like obesity, addiction and dementia. In a past study, the team found the brain’s response to smell is altered in sleep-deprived participants, and next wanted to know whether and how food intake changes our ability to perceive food smells.

According to Laura Shanahan, a postdoctoral fellow in the Kahnt lab and the first and co-corresponding author of the study, there’s very little work on how odor perception changes due to different factors. “There’s some research on odor pleasantness”, Shanahan said, “but our work focuses in on how sensitive you are to these odors in different states.”

Pizza and pine; cinnamon and cedar

To conduct the study, the team developed a novel task in which participants were presented with a smell that was a mixture between a food and a non-food odor (either “pizza and pine” or “cinnamon bun and cedar” – odors that “pair well” and are distinct from each other). The ratio of food and non-food odor varied in each mixture, from pure food to pure non-food. After a mixture was presented, participants were asked whether the food or the non-food odor was dominant.

Participants completed the task twice inside an MRI scanner: First, when they were hungry, then, after they’d eaten a meal that matched one of the two odors.

“In parallel with the first part of the experiment running in the MRI scanner, I was preparing the meal in another room,” Shanahan said. “We wanted everything fresh and ready and warm because we wanted the participant to eat as much as they could until they were very full.”

The team then computed how much food odor was required in the mixture in each session for the participant to perceive the food odor as dominant. The team found when participants were hungry, they needed a lower percentage of food odor in a mixture to perceive it as dominant – for example, a hungry participant may require a 50% cinnamon bun to cedar mixture when hungry, but 80% when full of cinnamon buns.

Through brain imaging, the team provided further evidence for the hypothesis. Brain scans from the MRI demonstrated a parallel change occurring in the part of the brain that processes odors after a meal. The brain’s response to a meal-matched odor was less “food-like” than responses to a non-matched meal odor.

Applying findings to future sleep deprivation research

Findings from this study will allow the Kahnt lab to take on more complex projects. Kahnt said with a better understanding of the feedback loop between smell and food intake, he’s hoping to take the project full circle back to sleep deprivation to see if lack of sleep may impair the loop in some way. He added that with brain imaging, there are more questions about how the adaptation may impact sensory and decision-making circuits in the brain.

“After the meal, the olfactory cortex didn’t represent meal-matched food odors as much as food anymore, so the adaptation seems to be happening relatively early on in processing,” Kahnt said. “We’re following up on how that information is changed and how the altered information is used by the rest of the brain to make decisions about food intake.”

NewsMakers

Maintaining a healthy heart may require regular doses of positivity

The findings of this study further point to the importance of attending to mental and behavioral health for cardiovascular disease prevention and cardiovascular health optimization.

Published

on

Positive psychology interventions such as mindfulness, gratitude journaling and optimism training can consistently improve blood pressure, inflammation markers and other cardiovascular disease risk factors within a matter of weeks, a recent study found. However, since these benefits are associated with lifestyle changes such as eating healthier and greater physical activity, the researchers suggested that ongoing reinforcements may be needed to stay on course long term.

Rosalba (Rose) Hernandez, a professor of social work at the University of Illinois Urbana-Champaign, led a team that analyzed the findings of 18 randomized controlled trials that used positive psychological and mindfulness interventions to enhance mental or physical health.

The programs that the team reviewed included individual methods — such as structured telephone sessions, journaling with brief check-ins and digital platforms such as apps and text messaging — and interactive in-person group sessions, as well as hybrid formats that blended these with online tools and virtual meetings. Most of the programs consisted of weekly sessions and at-home activities that reinforced the skills taught, with the majority of programs lasting from six to 12 weeks, the team found.

In general, the programs included 50-200 adults with elevated cardiovascular risk factors such as uncontrolled hypertension, heart failure or other conditions. Typically, the participants were in their late 50s to mid-60s, and women comprised 35-55% of the samples across those studies that reported their participants’ gender, according to the researchers.

“In hypertension and postacute coronary syndrome cohorts, mindfulness-based programs delivered over an eight-week period reduced systolic blood pressure and lowered inflammatory markers such as high-sensitivity C-reactive protein and fibrinogen,” said Hernandez, who is a Fellow of the American Heart Association. “A 12-week spirituality-based digital intervention achieved one of the largest reductions — reducing systolic blood pressure measured with a standard cuff by 7.6 points, and central systolic pressure — which is measured in the aorta as it leaves the heart — by 4.1 points.”

In prior research on positive psychology interventions, scientists seldom defined the dose that was needed to obtain the beneficial effects, Hernandez said. She and the team members sought to clarify the frequency and duration that was most likely to improve individuals’ cardiovascular health.

Programs that had more frequent contact with their participants yielded the most consistent physiological benefits, underscoring the opportunity to embed positive psychological strategies into long-term cardiovascular care, Hernandez said.

The team found that the strongest behavioral improvements were achieved by an eight-week program delivered over WhatsApp that combined weekly sessions with daily microtasks, motivating participants to engage in greater physical activity, eat a healthier diet and take their medication as prescribed. A program that included motivational interviewing succeeded in increasing cardiac patients’ levels of physical activity by 1,800 steps a day and their medication adherence, while the mindfulness programs improved participants’ activity levels and diets only, according to the study.

“The therapeutic dose that was most consistently linked with improvements in blood pressure, inflammation and endothelial function was daily practice reinforced by weekly sessions over eight to 12-week periods,” Hernandez said. “Therapeutic dosing typically involved high-frequency dosing over this time period to obtain short-term physiologic benefits, while ongoing less-intensive contact may be needed to sustain behavioral change.”

Published in the journal Cardiology Clinics, the study was co-written by University of South Florida social work professor Soonhyung Kwon; Alyssa M. Vela, a professor of surgery and of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine; and Katharine S. Edwards, a professor of cardiovascular medicine and of psychiatry and behavioral medicine at Stanford Medicine.

“The findings of this study further point to the importance of attending to mental and behavioral health for cardiovascular disease prevention and cardiovascular health optimization,” Vela said. “This speaks to the need for routine screening and integration of cardiac behavioral medicine to allow for access to important interventions.”

The current study adds to a growing body of research linking psychological well-being — including traits such as optimism, positive affect and gratitude — with cardioprotective benefits.

Continue Reading

NewsMakers

Heart disease risk may start in the womb, study finds

Young adults whose mothers had high blood pressure during pregnancy — either pregnancy-associated hypertension, pre-eclampsia or eclampsia — had more signs of early arterial injury, higher blood pressure, higher body mass index and higher blood sugar than peers.

Published

on

A child’s future heart health may be partially shaped before they are born, reports a new Northwestern Medicine study that found pregnancy complications are linked to poorer cardiovascular health in offspring more than 20 years later.

The study found that young adults whose mothers had high blood pressure during pregnancy — either pregnancy-associated hypertension, pre-eclampsia or eclampsia — had more signs of early arterial injury, higher blood pressure, higher body mass index and higher blood sugar than peers.

The authors said the study adds to growing evidence that cardiovascular risk may be transmitted across generations through a combination of biological, environmental and behavioral factors.

“That means we must make sure people maintain good health from childhood into young adulthood, so that if or when someone becomes a parent, they pass on the best opportunity for good health to their children,” said study senior author Dr. Nilay Shah, assistant professor of medicine in the division of cardiology at Northwestern University Feinberg School of Medicine.

How the study was conducted

Shah and colleagues evaluated nearly 1,350 mother-child pairs from the Future of Families and Child Well-Being Study, which enrolled mothers and children at birth between 1998 and 2000 across 20 U.S. cities. The children were then followed into adulthood.

Using delivery hospitalization records, the Northwestern scientists first identified whether mothers experienced pregnancy complications, including high blood pressure during pregnancy, gestational diabetes (high blood sugar during pregnancy) or preterm birth (before 37 weeks of pregnancy).

The three pregnancy complications are on the rise, and affect almost one in four pregnancies in the U.S.

The research team then analyzed cardiovascular health of offspring at age 22, using blood pressure measurements, blood testing, body mass index assessments and carotid artery ultrasounds to look for signs of artery injury.

Finally, the scientists compared participants with and without exposure to each pregnancy complication and adjusted for factors like income, education, difference in birth weight and smoking during pregnancy.

Key findings

At around age 22, participants whose mothers had high blood pressure during pregnancy had:

  • Higher body mass index (+2.8 BMI points)
  • Higher diastolic blood pressure (+2.3 mm Hg)
  • Higher blood sugar levels (+0.2% HbA1c)
  • Thicker artery walls (~0.02 mm)

While the difference in artery wall thickness may seem small, the study authors said it corresponds to roughly three to five years of additional vascular aging. That means arteries looked older and less healthy than expected, which raises the risk of future heart disease.

Other pregnancy complications also showed some long-term effect:

  • Exposure to gestational diabetes was linked to worse blood pressure and some evidence of artery thickening
  • Being born preterm was associated with higher blood sugar levels

‘Most heart disease is preventable’

With pregnancy complications on the rise in the U.S., Shah said the study provides compelling evidence that improving health before and during pregnancy could help reduce heart disease risk in the next generation.

“There is evidence that both parents’ health at the time of conception and during pregnancy influences a child’s health,” he said. “So, promoting health from an early age, like exercising regularly, eating healthfully, never smoking and getting enough sleep, is not just meant for an individual, but doing so may help future generations be healthier, too.”

Shah also emphasizes that risk is not destiny.

“The good news is that most heart disease is preventable,” he said. “If you experienced high blood pressure or high blood sugar during pregnancy, or your child was born early, it does not absolutely mean that your child will have worse health as adults. But I would encourage you to pay attention now to your child’s health behaviors.

“What children learn in childhood sets the stage for their health across their lives. If you are wondering whether your children’s behaviors are healthy, or are considering making a change, please speak with your child’s pediatrician for advice and guidance.”

Other Northwestern co-authors include Emily Lam, Abigail Gauen, Dr. Sadiya Khan, Alexa Freedman and Norrina Allen.

Continue Reading

NewsMakers

Viagra could hold key to halting Peyronie’s disease

Combining two widely prescribed drug classes could provide the first effective treatment for early-stage Peyronie’s disease.

Published

on

Combining two widely prescribed drug classes could provide the first effective treatment for early-stage Peyronie’s disease, according to a study published in The Journal of Sexual Medicine.

Peyronie’s disease (PD) is caused by the development of fibrotic scar tissue within the penis, leading to pain, curvature, sexual dysfunction and, in many cases, significant psychological distress. It affects an estimated 10 per cent of men during their lifetime, but despite its prevalence, treatment options are limited, particularly in the early phase of the condition.

The study, carried out by Anglia Ruskin University (ARU) and University College London Hospital (UCLH), found that combining phosphodiesterase type 5 (PDE5) inhibitors such as sildenafil (Viagra) and tadalafil (Cialis) with selective oestrogen receptor modulators (SERMs), including tamoxifen, may slow or even stop disease progression when given early.

The clinical study, carried out by Professor David Ralph of UCLH, evaluated outcomes in 133 men diagnosed with acute Peyronie’s disease who were treated with the drug combination for three months. Their results were compared with a smaller group of patients receiving standard care, which included giving vitamin E or no treatment at all. Standard care did not include surgery.

The study found 43 per cent of patients on the combination experienced an improvement in penile curvature, almost three times higher than in the standard‑care group (15 per cent).

At the start of treatment, 65 per cent of patients in the combination group reported pain during erections. After three months, that figure had fallen to just 1.5 per cent. By comparison, pain prevalence in the standard‑care group fell from 50 per cent to 27 per cent.

The clinical findings build on earlier laboratory work led by Professor Selim Cellek at ARU’s Fibrosis Research Group. Over the course of several years, Professor Cellek’s team screened 1,953 FDA‑approved drugs to identify compounds capable of blocking the transformation of fibroblasts into myofibroblasts, the key cells responsible for fibrosis. PDE5 inhibitors and SERMs emerged as particularly effective, and when used together demonstrated an effect greater than either drug alone.

Currently, there are no approved oral therapies proven to prevent early disease progression, forcing patients in the acute phase to wait until the condition stabilises before they can be offered treatments including injections or surgery.

Professor Cellek said: “Positive findings from this pilot clinical study validate our drug‑screening approach in the lab. It shows how repurposing well‑known medicines can accelerate progress in areas of unmet clinical need.

“Because both PDE5 inhibitors and SERMs are already widely used in clinical practice and have established safety profiles, the approach could be readily adoptable if confirmed in larger studies.

“These results suggest that early intervention targeting fibrosis could change how we treat Peyronie’s disease. Repurposing existing drugs may allow us to move from managing symptoms to modifying the disease itself.”

Professor David Ralph, Professor of Urology at UCLH, said: “This paper confirms the basic science research with regards to halting the progression of Peyronie’s disease. In previous papers we have noted that tamoxifen and PDE5 inhibitors inhibit the transformation of fibroblasts into myofibroblasts and therefore contraction of the plaque.

“This has now been put into clinical practice where this paper shows that when tamoxifen and a PDE5 inhibitor are combined, there is statistically less progression of the disease and improvement in curvature compared to the control arm. This is where from bench to clinical practice prevails and hopefully now a prospective clinical trial can be initiated.”

Continue Reading
Advertisement
Advertisement

Like Us On Facebook

Loading...

Most Popular

Copyright ©FRINGE PUBLISHING. All rights reserved.