Medical Bulletin 25/ April/ 2024

The study, published in the journal Brain Stimulation, suggested that the treatment, known as transcranial direct current stimulation, holds promise as a non-invasive, drug-free option to treat depression and anxiety symptoms, which affect 1 in 4 older adults.

“Depression and anxiety can affect mental health, cognitive function, and independence in older individuals. While medication and therapy are frontline treatments, there's a need for accessible, non-invasive options for those unresponsive to medication or unable to access intensive clinic-based programs” said the study’s senior author Adam Woods, Ph.D., professor of clinical and health psychology at the UF College of Public Health.

In the study, nearly 400 older adults were randomly assigned to one of two groups: 12 weeks of tDCS paired with cognitive training designed to improve working memory and processing speed, or 12 weeks of cognitive training paired with a placebo version of tDCS. Researchers also collected data from cognitive, functional, and neuroimaging tests as well as self-report measures of psychological symptoms, including depression and anxiety.

After controlling for factors such as prescription drugs that may impact depression and anxiety symptoms, the researchers found that participants who received the tDCS treatment had significant improvements in mild depression and moderate to severe state anxiety, compared with the group that did not receive tDCS.

“Research shows that stimulating this brain area reduces psychological symptoms in diagnosed psychiatric disorders. Surprisingly, similar effects were observed in older adults without psychiatric histories. This therapeutic effect is crucial as even mild depression and anxiety in older adults can lead to adverse outcomes”

said Hanna Hausman, the study’s lead author.

Reference: Hanna K. Hausman, Gene E. Alexander, Ronald Cohen, Yunfeng Dai, Samuel Wu, Adam J. Woods; tDCS reduces depression and state anxiety symptoms in older adults from the augmenting cognitive training in older adults study (ACT); Journal: Brain Stimulation; https://doi.org/10.1016/j.brs.2024.02.021

A study published in the journal Frontiers in Nutrition and conducted at The Norwegian University of Science and Technology explored whether exercising increased the production of adiponectin concentrations in breast milk.

Breast milk contains adiponectin, a hormone impacting glucose and fat metabolism. It can influence infant metabolism by crossing the intestinal barrier. Adiponectin is primarily secreted by white adipose tissue. Its low levels are linked to insulin resistance and type 2 diabetes. Maternal lifestyle, including smoking, BMI, gestational diabetes, and diet, has been shown to affect the composition of breast milk. Aerobic exercise, either as moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT), may increase circulating levels of adiponectin.

The study involved exclusively breastfeeding participants with 6–12 week-old term infants undergoing three laboratory conditions:

Moderate-intensity continuous training (MICT)

High-intensity interval training (HIIT)

and No activity (REST)

Breast milk samples were collected before, immediately after, 1 hour after, and 4 hours after each condition, and adiponectin concentrations were measured. Researchers then compared adiponectin concentration changes post-MICT and HIIT.

The results showed that adiponectin concentrations increased 1 h after HIIT, from 4.6 μg/L to 5.6 μg/L. This change was 0.9 μg/L greater than the change between these two-time points in the REST condition. There were no other statistically significant changes in adiponectin concentrations.

“One of the reasons why the WHO recommends breastfeeding during the first six months of life is that breast-fed children are less likely to be overweight and obese than formula-fed children. However, new research shows that the composition of breast milk varies between mothers who have high and low body mass indexes, and that differences in breast milk composition can play a role in the transfer of obesity from mother to child” said Trine Moholdt, researcher, Norwegian University of Science and Technology.

Reference: Holmen, M., et al. (2023). High-intensity exercise increases breast milk adiponectin concentrations: a randomised cross-over study. Frontiers in Nutrition. doi.org/10.3389/fnut.2023.1275508.

A study led by USC found that a junk food-filled high-fat, sugary diet may disrupt brain memory ability for a long time in adolescents.

The study appears in the May issue of the journal Brain, Behavior, and Immunity.

Long-term junk food consumption affects key brain regions. The prefrontal cortex, responsible for decision-making and impulse control, shows reduced activity, leading to impaired decision-making and increased impulsivity. The hippocampus, crucial for learning and memory, is also negatively affected, impairing memory retention.

In the study, researchers tracked acetylcholine levels in rats on a fatty, sugary diet and a control group by analysing brain responses to memory tests. Post-mortem brain examinations were conducted to assess acetylcholine disruptions. The memory test involved rats exploring new objects in different locations, followed by reintroducing them to similar scenes with one new object added. Rats on the junk food diet struggled to remember previously seen objects and their locations, unlike the control group, which showed familiarity.

“Acetylcholine signalling is a mechanism to help them encode and remember those events, analogous to ‘episodic memory’ in humans that allows us to remember events from our past. That signal appears to not be happening in the animals that grew up eating the fatty, sugary diet” said lead author Anna Hayes.

Reference: Anna M.R. Hayes, Scott E. Kanoski, et al; Western diet consumption impairs memory function via dysregulated hippocampus acetylcholine signaling; Journal: Brain, Behavior, and Immunity; https://doi.org/10.1016/j.bbi.2024.03.015