Medical Bulletin 03/ June/ 2024

Achieving a healthy work-life balance is getting harder. Longer work hours, the expectation to always be available, and blurred lines between work and personal life are causing workplace stress to spill over at home. This spillover negatively affects mental health and work productivity.

In a study published in the Journal of Psychosomatic Research, researchers discovered that work-life imbalance is linked to biomarkers that signal cardiovascular risk and diseases.

According to the World Health Organization (WHO), 17.9 million people die from cardiovascular diseases each year and poor work-life balance can severely impact an individual's health, particularly cardiovascular health.

Constant stress from long working hours and the inability to disconnect from work increases stress hormones like cortisol, which can lead to high blood pressure, inflammation, and other cardiovascular problems. This chronic stress can contribute to heart disease, stroke, and other serious health issues.

The study, led by Andree Hartanto, Assistant Professor at Singapore Management University, involved 1,179 working or self-employed adults, with an average age of 52.64 years. Participants worked an average of 41 hours per week.

A four-item scale measured negative work-to-family spillover. During data collection, participants stayed overnight at a clinical research centre and underwent a physical exam, including fasting blood samples for cardiovascular risk biomarkers.

The five biomarkers—high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, interleukin-6, and C-reactive protein—indicate cholesterol levels, artery hardening, and heart inflammation, all of which are markers for cardiovascular diseases.

The results showed that work stress spilling over into home life significantly affected two key health bio-markers: higher triglycerides, which can lead to hardening of the arteries, and lower HDL, which can raise cholesterol levels.

The findings suggested that stress from work can cause physical changes that increase the risk of heart disease. The study also found a link between work stress and inflammation markers, such as interleukin-6 and C-reactive protein, which are associated with heart inflammation.

Reference: Andree Hartanto, K.T.A. Sandeeshwara Kasturiratna, Meilan Hu, Shu Fen Diong, Verity Y.Q. Lua; Negative work-to-family spillover stress and heightened cardiovascular risk biomarkers in midlife and older adults; Journal of Psychosomatic Research; Volume 178; 2024; https://doi.org/10.1016/j.jpsychores.2024.111594.

In a new study, published in the journal JAMA, Investigators from Brigham and Women’s Hospital identified and assessed underlying mechanisms that may explain the Mediterranean diet’s 23 percent reduction in all-cause mortality risk for women.

The health benefits of the Mediterranean diet have been reported in multiple studies, but there is limited long-term data of its effects in women and little understanding about why the diet may reduce risk of death.

The Mediterranean diet is a plant-based diverse diet that is rich in plants (nuts, seeds, fruits, vegetables, whole grains, legumes). The main fat is olive oil (usually extra virgin), and the diet additionally includes moderate intake of fish, poultry, dairy, eggs, and alcohol, and rare consumption of meats, sweets, and processed foods.

The study looked at the long-term benefits of following a Mediterranean diet in women, as part of the Women’s Health Study. Researchers examined around 40 biomarkers to understand how this diet improves health.

The biggest health benefits came from improvements in metabolism and inflammation. Other significant factors included changes in triglyceride levels, body fat, and insulin resistance. Smaller contributions came from changes in branched-chain amino acids, HDL and LDL cholesterol, blood sugar levels, and blood pressure.

“Our research provides significant public health insight: even modest changes in established risk factors for metabolic diseases—particularly those linked to small molecule metabolites, inflammation, triglyceride-rich lipoproteins, obesity, and insulin resistance—can yield substantial long-term benefits from following a Mediterranean diet. This finding underscores the potential of encouraging healthier dietary habits to reduce the overall risk of mortality,” said lead author Shafqat Ahmad.

“For women who want to live longer, our study says watch your diet! The good news is that following a Mediterranean dietary pattern could result in about one quarter reduction in risk of death over more than 25 years with benefit for both cancer and cardiovascular mortality, the top causes of death in women (and men). The health benefits of the Mediterranean diet are recognized by medical professionals, and our study offers insights into why the diet may be so beneficial,” said senior author Samia Mora.

Reference: Ahmad S, Moorthy MV, Lee I, et al. Mediterranean Diet Adherence and Risk of All-Cause Mortality in Women. JAMA Netw Open. 2024;7(5):e2414322. doi:10.1001/jamanetworkopen.2024.14322

Researchers at the Del Monte Institute for Neuroscience at the University of Rochester have identified mechanisms in the brain’s hippocampal network that are rescued by ketones. These findings build on previous research showing that ketones can alleviate neurological and cognitive affects.

The results are published in the journal PNAS Nexus.

As we age, our brain naturally becomes more resistant to insulin, a hormone crucial for energy regulation and cellular communication. Insulin resistance in the brain disrupts the communication between neurons, leading to a cascade of negative effects. This breakdown in neuronal communication manifests in various ways, including changes in mood, such as increased anxiety or depression, and cognitive decline, where memory, attention, and problem-solving skills deteriorate. Over time, these issues can progress to more severe conditions like neurodegeneration, contributing to diseases such as Alzheimer’s and Parkinson’s.

"Once neuronal function is lost, there is no recovering the connection, so we need to identify when the function first becomes impaired," said Nathan A. Smith, the principal investigator of this research. "This study accomplishes that by bringing us closer to understanding how to rescue the function of impaired neurons and prevent or delay devastating diseases like Alzheimer's."

Using mice model, researchers studied the hippocampus, a brain region important for learning and memory. They discovered that acute insulin resistance harms several key brain functions, such as synaptic activity, axonal conduction, network synchronization, synaptic plasticity, and action potential properties, all crucial for neuron communication.

To address this, they gave the mice D-βHb (D-beta-hydroxybutyrate), a type of ketone produced when the body burns fat instead of glucose for energy. They found that D-βHb (D-beta-hydroxybutyrate) improved the previously damaged synaptic activity, increased axon conduction, resynchronized neurons, and enhanced synaptic plasticity.

“This research has implications for developing ketone-based therapies targeting specific neuronal dysfunctions in conditions involving insulin resistance/hypoglycemia like diabetes or Alzheimer's disease,” said Smith.

Reference: Bartosz Kula, Botond Antal, Corey Weistuch, Florian Gackière, Alexander Barre, Victor Velado, Jeffrey M Hubbard, Maria Kukley, Lilianne R Mujica-Parodi, Nathan A Smith, D-ꞵ-hydroxybutyrate stabilizes hippocampal CA3-CA1 circuit during acute insulin resistance, PNAS Nexus, Volume 3, Issue 5, May 2024, https://doi.org/10.1093/pnasnexus/pgae196