Medical Bulletin 27/November/2023

Here are the top medical news of the day:

Not all are fine, some people get headaches from drinking red wine?

In a new study, scientists at the University of California, Davis, examined "red wine headache" why this happens -- even to people who don't get headaches when drinking small amounts of other alcoholic beverages.

A red wine may pair nicely with the upcoming Thanksgiving meal. But for some people, drinking red wine even in small amounts causes a headache. Typically, a "red wine headache" can occur within 30 minutes to three hours after drinking as little as a small glass of wine.

Researchers report that a flavanol found naturally in red wines can interfere with the proper metabolism of alcohol and can lead to a headache. The study was published in the journal Scientific Reports.

This flavanol is called quercetin and it is naturally present in all kinds of fruits and vegetables, including grapes.It's considered a healthy antioxidant and is even available in supplement form. But when metabolized with alcohol, it can be problematic.

"When it gets in your bloodstream, your body converts it to a different form called quercetin glucuronide," said wine chemist and corresponding author Andrew Waterhouse, professor emeritus with the UC Davis Department of Viticulture and Enology. "In that form, it blocks the metabolism of alcohol."

Scientists will next compare red wines that contain a lot of quercetin with those that have very little to test their theory about red wine headaches on people. It's unclear why some people seem more susceptible to them than others.

Researchers don't know if the enzymes of people who suffer from red wine headaches are more easily inhibited by quercetin or if this population is just more easily affected by the buildup of the toxin acetaldehyde.

Reference: Apramita Devi, Morris Levin, Andrew L. Waterhouse. Inhibition of ALDH2 by quercetin glucuronide suggests a new hypothesis to explain red wine headaches. Scientific Reports, 2023; 13 (1) DOI: 10.1038/s41598-023-46203-y.

Intermittent fasting is safe and effective for those with Type 2 diabetes

Time-restricted eating, also known as intermittent fasting is practiced in many parts of the world both culturally and with spiritual beliefs. This fasting can help people with Type 2 diabetes lose weight and control their blood sugar levels, according to a new study published in JAMA Network Open from researchers at the University of Illinois Chicago.

Study reports Participants who ate only during an eight-hour window between noon and 8 p.m. each day actually lost more weight over six months than participants who were instructed to reduce their calorie intake by 25%. Both groups had similar reductions in long-term blood sugar levels, as measured by a test of hemoglobin A1C, which shows blood sugar levels over the past three months.

The researchers believe this is partly because patients with diabetes are generally told to cut back on calories by their doctors as a first line of defense, so many of these participants likely had already tried -- and struggled with -- that form of dieting.

And while the participants in the time-restricted eating group were not instructed to reduce their calorie intake, they ended up doing so by eating within a fixed window.

"Our study shows that time-restricted eating might be an effective alternative to traditional dieting for people who can't do the traditional diet or are burned out on it," said Varady, a professor of kinesiology and nutrition.

Reference: Vasiliki Pavlou, Sofia Cienfuegos, Shuhao Lin, Mark Ezpeleta, Kathleen Ready, Sarah Corapi, Jackie Wu, Jason Lopez, Kelsey Gabel, Lisa Tussing-Humphreys, Vanessa M. Oddo, Shaina J. Alexandria, Julienne Sanchez, Terry Unterman, Lisa S. Chow, Alaina P. Vidmar, Krista A. Varady. Effect of Time-Restricted Eating on Weight Loss in Adults With Type 2 Diabetes. JAMA Network Open, 2023; 6 (10): e2339337 DOI: 10.1001/jamanetworkopen.2023.39337.

Traumatic memories can alter the brain connections

Associative learning, which includes classical conditioning, is one of the simplest types of learning and has been studied intensively over the past century.

Researchers found that fear conditioning led to learning-specific changes in neuronal-network activity in the dorsal part of the medial prefrontal cortex of mice. This study in Nature Communications demonstrates the use of combined methods for detailed visualization of the dynamics of neural networks, and describes techniques that could be used to uncover additional information about the neurological changes associated with learning and memory.

The research team used longitudinal two-photon imaging and various computational neuroscience techniques to determine how neural activity changes in the mouse prefrontal cortex after learning in a fear-conditioning paradigm. Prefrontal neurons behave in a highly complex manner, and each neuron responds to various sensory and motor events.

Importantly, the researchers uncovered direct evidence that associative memory formation was accompanied by a novel associative connection between originally distinct networks, i.e., the conditioned stimulus (CS, e.g., tone) network and the unconditioned stimulus (US, e.g., fearful experience) network.

"We successfully detected a neural population that encodes fear memory," says Agetsuma. "Our analyses showed us that fear conditioning induced the formation of a fear-memory neural network with 'hub' neurons that functionally connected the memory neurons."

Reference: Masakazu Agetsuma, Issei Sato, Yasuhiro R. Tanaka, Luis Carrillo-Reid, Atsushi Kasai, Atsushi Noritake, Yoshiyuki Arai, Miki Yoshitomo, Takashi Inagaki, Hiroshi Yukawa, Hitoshi Hashimoto, Junichi Nabekura, Takeharu Nagai. Activity-dependent organization of prefrontal hub-networks for associative learning and signal transformation. Nature Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-41547-5