Medical Bulletin 25/ June/ 2024

In a recent review published in Nutrition Research Reviews, researchers compared the effects of energy-restricted (ER) dietary patterns with nuts or without on body composition, weight, and glycemic management.

Nutritionists often recommend energy-restricted (ER) diets for achieving weight loss, improving body composition, and managing blood sugar levels. However, one of the challenges with ER diets is maintaining high diet quality while ensuring the intake of essential nutrients.

Nuts, known for being nutrient-dense, can play a crucial role in meeting these dietary requirements. They are rich in essential fatty acids (EFAs), which can improve glycemic management by reducing pro-inflammatory cytokines and insulin resistance. Their low carbohydrate and high unsaturated fat, fibre, B vitamins, magnesium, and protein content help increase fat oxidation, slow gastric emptying, and lower postprandial glucose levels. Additionally, nuts enhance satiety, preserve muscle mass, and mitigate the reduction in resting energy expenditure typically associated with weight loss.

The impact of nut consumption on glycemic indices—measures of blood sugar levels—varies across different studies. This inconsistency exists in both healthy individuals and those with conditions such as metabolic syndrome, dyslipidemia, or prediabetes. Some research suggests that nuts can positively influence blood sugar control, while other studies do not show significant effects.

For the study, researchers investigated the effects of incorporating nuts into a calorie-restricted diet on body measurements and glycemic control in overweight or obese individuals. They analysed randomized controlled trials (RCTs) to compare the impact of energy-restricted diets with or without nuts on body mass, composition, and blood sugar management.

The RCTs included overweight individuals with or without comorbidities who were undergoing weight loss treatments. The studies measured blood glucose levels using various methods, including venous blood draws, finger pricking, flash glucose monitors, and continuous glucose monitoring (CGM).

The results showed that a nut-enriched energy-restricted (ER) diet led to a weight reduction of -22.6 to -19.5 kg, or approximately -0.1 to -0.2 kg per week. The additional benefit of incorporating nuts into the ER diet varied between -1.4 to 0.4 kg. Significant variations between trials included the timing of nut supplementation, the types of nuts consumed, and the methods used for anthropometric measurements.

The research found limited evidence to support the advantages of nuts for body composition or glycemic management. While advantages in weight reduction and glycemia were variable when adding nuts to energy-restricted diets, there were no adverse effects. All trials found that an energy-restricted diet improved body mass with variable effects on glucose and insulin.

Reference: Mead LC, Hill AM, Carter S, and Coates AM. Effects of energy-restricted diets with or without nuts on weight, body composition, and glycaemic control in adults: a scoping review. Nutrition Research Reviews. Published online 2024:1–17. doi:10.1017/S0954422424000106

Having more positive experiences in life is associated with lower odds of developing brain disorders like Alzheimer's disease, slower cognitive decline with age, and even a longer life.

A study from Columbia researchers, published in the journal Proceedings of the National Academy of Sciences, suggested that the brain’s mitochondria may play a fundamental part.

Mitochondria supply energy to the brain, and the study showed that the molecular machinery used by mitochondria to transform energy is boosted in older adults who experienced less psychological stress during their lives compared with individuals who had more negative experiences.

In the study, researchers used data from two extensive studies involving nearly 450 older adults. Over two decades, these studies gathered detailed psychosocial information from the participants. After the participants passed away, their brains were donated for further analysis, providing data on the condition of their brain cells.

Researchers developed indices to convert participants’ reports of positive and negative psychosocial factors into a single overall psychosocial experience score. Additionally, each participant was scored on seven domains representing distinct genetic networks active in mitochondria.

The results showed that one mitochondrial domain, which assessed the organelle’s energy transformation machinery, was linked to psychosocial scores. Researchers further analysed mitochondria in specific brain cell types and discovered that the associations between mitochondria and psychosocial factors were driven not by neurons, but by glial cells.

The finding suggests that glial cells may play more significant roles than their traditionally assumed "supportive" functions.

“Greater well-being was linked to greater abundance of proteins in mitochondria needed to transform energy, whereas negative mood was linked to lower protein content. This may be why chronic psychological stress and negative experiences are bad for the brain, because they damage or impair mitochondrial energy transformation in the dorsolateral prefrontal cortex, the part of the brain responsible for high-level cognitive tasks. We think that the mitochondria in the brain are like antennae, picking up molecular and hormonal signals and transmitting information to the cell nucleus, changing the life course of each cell. If mitochondria can change cell behaviour, they can change the biology of the brain, the mind, and the whole person,” said the authors.

Reference: Èlia Vila, Raquel Pinacho, Roger Prades, Teresa Tarragó, Elena Castro, Eva Munarriz-Cuezva, J. Javier Meana, Ania Eugui-Anta, Mònica Roldan, América Vera-Montecinos, Belén Ramos, Inhibition of Prolyl Oligopeptidase Restores Prohibitin 2 Levels in Psychosis Models: Relationship to Cognitive Deficits in Schizophrenia, International Journal of Molecular Sciences, 24, 7, (6016), (2023)/ https://doi.org/10.3390/ijms24076016

According to new research presented at the American Diabetes Association’s 2024 Scientific Sessions and published in the Journal of the American College of Cardiology (JACC), Semaglutide, a medication initially developed for type 2 diabetes and obesity, significantly improves symptoms in men and women with a common type of heart failure that has had few therapeutic options. Women experienced greater weight loss and the same symptom benefits compared with men.

Obesity-related heart failure with preserved ejection fraction (HFpEF) is the most common type of HFpEF, and it is becoming a bigger problem worldwide, causing more illness and death.

Research shows that excess belly fat leads to changes in the body that contribute to both the development and worsening of heart failure, especially in women. People with obesity-related HFpEF have more severe heart failure symptoms, poorer functional status, a lower quality of life, and worse clinical outcomes compared to those without obesity. Therefore, there is an urgent need to develop effective and safe treatments specifically designed for obesity-related heart failure.

For the study, researchers analysed the effects of semaglutide 2.4 mg, given once weekly, compared to a placebo on various outcomes in the Semaglutide Treatment Effect in People with Obesity and HFpEF program. They evaluated 1,145 participants over 52 weeks, including 570 women.

The results revealed that:

1. Women lost 9.6% of their body weight on average with semaglutide, compared with 7.2% in men, marking a significant difference.

2. Both sexes saw notable improvements in HF symptoms, physical limitations, and exercise function.

3. At the start of the study, women had higher left ventricular ejection fractions, worse symptoms and physical limitations, and higher inflammation levels compared to men. Despite having higher BMIs, women had similar rates of hypertension and diuretic use and less atrial fibrillation compared to men.

“Understanding the sex differences in obesity-related HFpEF is of great importance. Obesity and visceral adiposity are key drivers of HFpEF development and progression, and this may be even more amplified in women, who represent the majority of people with the disease and bear a heavier burden of symptoms and physical limitations due to HFpEF. Our study sheds light on these differences and the consistent benefits of semaglutide for women and men,” said Mikhail Kosiborod, senior author of the study.

Reference: Subodh Verma, Mikhail N. Kosiborod, et al.; Efficacy of Semaglutide by Sex in Obesity-Related Heart Failure With Preserved Ejection Fraction: STEP-HFpEF Trials; Journal of the American College of Cardiology; 2024; https://doi.org/10.1016/j.jacc.2024.06.001.