Tag: overweight

Categories : Diet and Nutrition Metabolic DisordersTags :

Body Clock Disruption on High-fat Diet Leads to Obesity

On By ModernMedia
Photo by Ilya Mashkov on Unsplash

According to a new study, when rats are fed a high fat diet, this disturbs the body clock in their brain that normally controls satiety, leading to over-eating and obesity. 

This new research, published in the Journal of Physiology, may be a cornerstone for future clinical studies that could restore the proper functioning of the body clock in the brain, to avoid overeating.

It was believed that the body clock resided only in the hypothalamus, but research over the years has clarified that some control of our body’s daily rhythms (hormone levels, appetite etc) lies in several other parts of the brain and body, including a group of neurons in the evolutionary ancient brainstem, called the dorsal vagal complex (DVC).

Specifically, the DVC has been shown to moderate food intake by inducing satiety. In obesity, research has shown that daily rhythms in food intake and the release of hormones related to eating, are blunted or eliminated. It is unclear if the malfunctioning of brain centres controlling appetite is a cause or the result of obesity.

This new study found that rats on a high-fat diet, before they started to gain weight, showed changes in the DVC’s daily neuronal rhythms and its response to appetite hormones. Thus, the researchers proposed that DVC disruption causes obesity.

Two groups of rats were used: those fed a well-balanced control diet (10% kcal from fat) and a high-fat diet (70% kcal from fat). To mimic the impact of unhealthy diet on humans, the researchers introduced the new diet to adolescent rats and monitored their food intake over 24h for four weeks.

Using multi-electrode arrays, the researchers measured DVC changes over 24h, simultaneously monitoring around a hundred DVC neurons from each brainstem slice. With this, circadian changes of neuronal activity could be assessed as well as neuronal responses to metabolically-relevant hormones in each of the diet groups.

Rats being nocturnal animals is a limitation of the study. The DVC activity peaked at the end of day, the rest phase for rodents, but an active phase for humans. Thus, it remains to be established if the phase of the brainstem clock is set to day and night, or whether it depends on patterns of rest and activity. These findings however could lead to understanding how to reset the body clock and tackle obesity.

First author Dr Lukasz Chrobok said:

“I’m really excited about this research because of the possibilities it opens up to tackle the growing health issue of obesity. We still do not know what are the time cues which are able to reset or synchronise the brainstem clock. Hopefully, the restoration of daily rhythms in this satiety centre before or after the onset of obesity may provide new therapeutic opportunities.”

Source: The Physiological Society

Categories : Cardiovascular DiseaseTags :

Weight Loss Not Prioritised in Heart Patient Care

On By ModernMedia
Image source: Neonbrand on Unsplash

Weight loss is given insufficient priority in the management of heart patients despite the benefits, according to a new study of over 10 000 European patients.

In overweight and obese patients with coronary heart disease, weight loss is strongly recommended to reduce the risk of another heart event by improving blood pressure and lipids levels and reducing diabetes risk. This study investigated the management of patients who were overweight or obese at the time of hospitalisation for a first or recurrent heart event such as heart attack. The researchers examined lifestyle advice received, actions taken, and the relationship between weight changes and health status.

The researchers pooled data from the EUROASPIRE IV (2012 to 2013) and EUROASPIRE V (2016 to 2017) studies, which included 10 507 patients with coronary heart disease. Patients were visited 6 to 24 months after hospitalisation for their heart event (the average gap was 16 months). The visit consisted of an interview, questionnaires and a clinical examination including weight, height and blood tests.

The study found that less than 20% had a healthy body mass index (BMI) at the time of hospitalisation for a heart event. Some 16 months later, 86% of patients who were obese during hospitalisation were still obese while 14% of overweight patients had become obese. Young women were particularly affected, with nearly half of those under 55 years being obese. Yet more than a third of obese patients reported they had not received advice on physical activity or nutrition and nearly one in five said they had not been informed that they were overweight. Half of all patients reported not receiving such advice.

Weight management proved effective, with overweight or obese patients who lost 5% or more of their body weight having significantly lower levels of hypertension, dyslipidaemia, and previously unrecognised diabetes compared to those who gained 5% or more of their body weight. However, quitting smoking was observed to result in a 1.8kg average weight gain compared to an 0.4kg average weight gain in persistent smokers.

Study author Professor Catriona Jennings of the National University of Ireland – Galway said cardiac rehabilitation programmes, which typically emphasise exercise, should give equal priority to dietary management. She said: “Weight loss is best achieved by adopting healthy eating patterns and increasing levels of physical activity and exercise. Whilst actively trying to lose weight at the same time as trying to quit smoking is not advised, adopting a cardio-protective diet and becoming more physically active has the potential to mitigate the effects of smoking cessation on weight gain in patients trying to quit. Their aim is to maintain their weight and to avoid gaining even more weight following their quit.”

“Uptake and access to cardiac rehabilitation programmes is poor with less than half of patients across Europe reporting that they completed a programme,” added Professor Jennings. “Such programmes would provide a good opportunity to support patients in addressing overweight and obesity, especially for female patients who were found to have the biggest problem with overweight and obesity in the study. Uptake and access could be improved with the use of digital technology, especially for women, who possibly are less likely to attend a programme because they have many other competing priorities, such as caring for others. There are good reasons for people to address their weight after a cardiac event – but it’s not easy and they do need help.”

The study was published in European Heart Journal – Quality of Care and Clinical Outcomes, a journal of the European Society of Cardiology (ESC).

Source: European Society of Cardiology (ESC)

Journal information: Harrison, S.L., et al. (2021) Cardiovascular risk factors, cardiovascular disease, and COVID-19: an umbrella review of systematic reviews. European Heart Journal – Quality of Care and Clinical Outcomes. doi.org/10.1093/ehjqcco/qcab029.

Categories : Mental HealthTags :

Excess Body Fat Associated with Dementia Risk

On By ModernMedia
Photo by Siora Photography on Unsplash
Photo by Siora Photography on Unsplash

Researchers at the University of South Australia are warning that high levels of body fat can add to the risk of dementia and stroke.

Having examined grey brain matter from about 28 000 people, the reseachers’ study demonstrated that increased body fat incrementally leads to increased atrophy of grey matter in the brain, resulting in greater risk of declining brain health. Obesity is a major and growing issue worldwide; World Health Organization data shows that more than 1.9 billion adults are overweight, with 650 million being obese. 

The lead researcher, Dr Anwar Mulugeta of UniSA, said the findings add to the growing number of issues known to be associated with being overweight or obese.

“Obesity is a genetically complex condition characterised by the excessive body fat,” Dr Mulugeta said. “Commonly linked to cardiovascular disease, type 2 diabetes, and chronic inflammation (a marker of dementia), obesity currently costs Australia’s economy about $8.6 billion dollars each year.

“While the disease burden of obesity has increased over the past five decades, the complex nature of the disease means that not all obese individuals are metabolically unhealthy, which makes it difficult to pinpoint who is at risk of associated diseases, and who is not.

“Certainly, being overweight generally increases your risk for cardiovascular disease, type 2 diabetes, and low-grade inflammation, but understanding the level of risk is important to better direct supports.

“In this study, we investigated the causal relationships of individuals within three metabolically different obesity types* ­– unfavourable, neutral and favourable – to establish whether specific weight groups were more at risk than others.”

These three obesity subtypes are:

  • ‘unfavourable’ – people who tend to have fat around their lower torso and abdominal area. These people have a higher risk of type 2 diabetes and heart diseases.
  • ‘favourable’ – people who have have wider hips but a lower risk of type 2 diabetes and heart diseases.
  • ‘neutral’ – people who have relatively low or very low risk of the cardiometabolic diseases.

Dr Mulugeta continued, “Generally, the three obesity subtypes have a characteristic of higher body mass index, yet, each type varies in terms of body fat and visceral fat distribution, with a different risk of cardiometabolic diseases.

“We found that people with higher levels of obesity especially those with metabolically unfavourable and neutral adiposity subtypes had much lower levels of grey brain matter, indicating that these people may have compromised brain function which needed further investigation.

“However, we did not find conclusive evidence to link a specific obesity subtype with dementia or stroke. Instead, our study suggests the possible role of inflammation and metabolic abnormalities and how they can contribute to obesity and grey matter volume reduction.”

The study analysed the genetic data of up to 336 000 individual records in the UK Biobank, along with self-reported information and linked hospital and death register records to connect dementia and stroke.

It found that, in middle to elderly age groups (37-73), grey brain matter decreased by 0.3 percent for every extra 1 kg/m2, which is equivalent of an extra 3 kg of weight for persons of average height (173 cm).

Senior investigator Professor Elina Hyppönen, Director of UniSA’s Australian Centre for Precision Health based at SAHMRI, said keeping to a healthy weight is important for general public health.

“It is increasingly appreciated that obesity is a complex condition, and that especially excess fat which is located around the internal organs have particularly harmful effects on health,” Prof Hyppönen said.

“Here, we used the individuals’ genetic and metabolic profiles to confirm different types of obesity. In practice, our findings very much support the need to look at the type of obesity when assessing the type of likely health impact.

“Even in a relatively normal weight individual, excess weight around the abdominal area may be a cause of concern.”

Source: University of South Australia