Medical Bulletin 16/ May/ 2024

In a recent study featured in the Nutrition journal, investigators from Northumbria University, UK, delved into the correlation between adherence to a ketogenic diet and the various aspects of mental health—including calmness, contentment, alertness, and emotional well-being—among the overall healthy population.

The ketogenic diet, characterized by its high fat and low carbohydrate content, induces a metabolic shift from glycolysis to fatty acid oxidation, offering alternative energy sources for both the body and brain. While historically employed to manage epilepsy and investigated in various neurodegenerative and neurodevelopmental disorders, its implications for the general population remain less explored.

The ketogenic diet also offers potential benefits for mood regulation and stress reduction. This dietary approach prompts a metabolic shift in the body, favouring the production of ketone bodies, which have been associated with enhanced cognitive function and mood stabilisation. Additionally, by reducing carbohydrate intake and increasing fat consumption, the ketogenic diet may help decrease inflammation, a common factor in mood disorders like depression and anxiety. Through these mechanisms, the ketogenic diet holds promise as a strategy to improve mood and alleviate stress levels.

The study involved two cohorts, adhering to ethical standards. Cohort 1 (Feb-Oct 2021) completed the Perceived Stress Scale and Bond-Lader visual analog scales online. Cohort 2 (Jan-Jul 2022) used the Depression Anxiety Stress Scale and a loneliness scale. Both cohorts shared demographic, socioeconomic, and dietary data via an online platform, including a short-form food frequency questionnaire. The analysis compared psychological and dietary metrics between ketogenic and non-ketogenic diet groups.

Cohort 1 showed age and BMI differences between ketogenic and non-ketogenic groups, with higher blood pressure among ketogenic participants. Dietary patterns indicated more adherence to ketogenic guidelines. Cohort 2 displayed similar age differences but no significant BMI variation.

Both cohorts revealed better mood and lower stress levels among ketogenic participants, with Cohort 2 also reporting reduced depression, anxiety, stress, and loneliness. Longer adherence to the ketogenic diet correlated with psychological benefits in both cohorts, while the immediate metabolic state showed no significant impact on outcomes.

The findings concluded that a ketogenic diet could boost psychological well-being. Participants on the diet reported notably higher levels of calmness, contentedness, and alertness, along with reduced stress, depression, and anxiety. While improvements in loneliness were not statistically significant after adjusting for demographics, longer adherence to the diet correlated with greater benefits.

Reference: Sarah Garner, Evan Davies, Emma Barkus, Ann-Katrin Kraeuter; Ketogenic diet has a positive association with mental and emotional well-being in the general population; Nutrition; 2024; https://doi.org/10.1016/j.nut.2024.112420.

The blood-retinal barrier safeguards our vision by blocking microbial pathogens from reaching the retina and causing inflammation that could lead to vision loss. However, researchers at the University of Missouri School of Medicine found that the COVID-19 virus can penetrate this barrier, posing potential long-term consequences for eye health.

The study was published in the journal PLoS Pathogens.

The global COVID-19 pandemic caused by SARS-CoV-2 affected millions worldwide, leading to significant morbidity and mortality. Apart from respiratory symptoms, the virus also demonstrated a tendency to affect ocular tissues, resulting in various complications such as conjunctivitis, dry eye, redness, tearing, itching, ocular pain, retinal haemorrhage, optic nerve edema, neuropathies, cerebral vein thrombosis, and glaucoma.

SARS-CoV-2, the virus responsible for COVID-19, can spread through mucosal surfaces like the nose, mouth, and eyes when exposed to infectious aerosols. The eye, being an immune-privileged organ, is susceptible to viral replication, making it a potential site for the virus to persist.

Studies have shown that SARS-CoV-2 can infect various cells in the eye, including photoreceptor and ganglion cells, conjunctival epithelial cells, scleral and limbal cells. Additionally, preclinical research has demonstrated that SARS-CoV-2 can invade the eyes via neuronal pathways after exposure through the nasal route.

In the study, researchers utilized a humanized ACE2 mice model and discovered that SARS-CoV-2, the virus responsible for COVID-19, has the capability to infect the interior of the eyes, even if it doesn't initially enter the body through the eye's surface. Instead, their findings revealed that when the virus enters the body through inhalation, it not only targets organs like the lungs but also manages to reach highly protected organs such as the eyes. This occurs through the blood-retinal barrier, where the virus infects the cells lining this protective barrier, allowing it to penetrate and potentially cause harm to the eyes.

“Earlier, researchers were primarily focused on the ocular surface exposure of the virus. However, our findings reveal that SARS-CoV-2 not only reaches the eye during systemic infection but induces a hyperinflammatory response in the retina and causes cell death in the blood-retinal barrier. The longer viral remnants remain in the eye, the risk of damage to the retina and visual function increases,” said Pawan Kumar Singh, PhD, an assistant professor of ophthalmology.

“While viruses and bacteria have been found to breach the blood-retinal-barrier in immunocompromised people, this research is the first to suggest that the virus that causes COVID-19 could breach the barrier even in otherwise healthy individuals, leading to an infection that manifests inside the eye itself. Immunocompromised patients or those with hypertension or diabetes may experience worse outcomes if they remain undiagnosed for COVID-19 associated ocular symptoms.”

Reference: Monu Monu; Faraz Ahmad; Rachel M. Olson; Vaishnavi Balendira, Pawan Kumar Singh; SARS-CoV-2 infects cells lining the blood-retinal barrier and induces a hyperinflammatory immune response in the retina via systemic exposure; PLoS Pathogens; https://doi.org/10.1371/journal.ppat.1012156

Australian doctor Professor Richard Scolyer, who underwent a groundbreaking treatment for glioblastoma (GBM) one year ago, continues to remain free of cancer.

Despite being diagnosed with an aggressive subtype of glioblastoma, which typically results in survival of less than a year for most patients, Professor Scolyer recently shared that his latest MRI scan revealed no recurrence of the tumour.

Glioblastoma is a type of brain cancer that develops from glial cells, which are supportive cells in the brain. It is the most aggressive and malignant form of glioma, accounting for about 60-70% of all gliomas. Glioblastomas can occur in any part of the brain but are most common in the cerebral hemispheres of the brain. These tumours are highly infiltrative, meaning they invade and spread into nearby brain tissue, making complete surgical removal difficult.

Alongside his colleague, renowned medical oncologist Professor Georgia Long, Prof Scolyer was named Australian of the Year for his research on melanoma, which is now informing his own experimental therapy.

Over the past decade the pair’s research on immunotherapy, which uses the body’s immune system to attack cancer cells, has dramatically improved outcomes for advanced melanoma patients globally. Half are now essentially cured, up from less than 10%.

Prof Long and her team discovered that immunotherapy works better when a combination of drugs are used, and when they are administered before any surgery to remove a tumour.

Last year, Prof Scolyer became the first brain cancer patient to ever have combination, pre-surgery immunotherapy. He is also the first to be administered a vaccine personalised to his tumour's characteristics, which boosts the cancer-detecting powers of the drugs.

“Dr Scolyer’s story is exciting because it draws attention to how game-changing it would be for so many condemned patients if this novel approach to treatment of his glioblastoma did result in a cure,” said Professor Garth Cruickshank, Chair of our Scientific and Medical Advisory Board.

“People vary in their response to treatments. Indeed, very few people with GBM – perhaps 2-5% – may live up to five years, but most succumb earlier particularly if they are older, and their tumours are larger. In many cases we can say that age, extent of tumour (stage) and surgery, and other individual factors will all modify how the tumour behaves. Thus, a person with a small glioblastoma who has had good surgery and chemo and radiotherapy and is young (under 60) will have a good chance of surviving 18 months. One would need to see such a person surviving well at two years or more to start to consider whether this heralds a breakthrough. This new treatment is novel and interesting and applied in the kind of innovative way that we need to see researchers trying, so we all hope that this is offers the key to a better future for brain tumour sufferers.”

Reference: GBM Cells; Brain Tumour Research Centre of Excellence, Queen Mary University of London, UK.