Latest News & Research: 6 August 2019
This week: Why Nanna and Grandpa need to lift • Meal timing strategies appear to lower appetite, improve fat burning • Nuts may benefit male sexual function
Why Nanna and Grandpa need to lift
For many older adults, resistance training may not be part of their daily routine, but a new position statement suggests it is vital to improving their health and longevity.
‘When you poll people on if they want to live to 100 years old, few will respond with a ‘yes’’ said Maren Fragala, PhD, director of scientific affairs at Quest Diagnostics and lead author of the position statement.
‘The reason mainly being that many people associate advanced age with physical and cognitive decline, loss of independence and poor quality of life’ added Mark Peterson, PhD, M.S., FACSM, an associate professor of physical medicine and rehabilitation at Michigan Medicine and one of the senior authors of the statement.
The position statement, published in the Journal of Strength and Conditioning Research, and supported by the National Strength and Conditioning Association, highlights the benefits of strength and resistance training in older adults for healthier ageing.
Fragala explains that while ageing does take a toll on the body, the statement provides evidence-based recommendations for successful resistance training, or exercise focused on building muscle endurance, programs for older adults.
‘Ageing, even in the absence of chronic disease, is associated with a variety of biological changes that can contribute to decreases in skeletal muscle mass, strength and function’ Fragala said; ‘Such losses decrease physiologic resilience and increase vulnerability to catastrophic events.’
She added; ‘The exciting part about this position statement is that it provides evidence-based recommendations for resistance training in older adults to promote health and functional benefits, while preventing and minimizing fears.’
The position statement provides 11 practical applications divided into four main components: program design variables, physiological adaptations, functional benefits, and considerations for frailty, sarcopenia and other chronic conditions.
The applications include suggestions on training types and amounts of repetitions and intensities, patient groups that will need adaptations in training models, and how training programs can be adapted for older adults with disabilities or those residing in assisted living and skilled nursing facilities.
‘Current research has demonstrated that resistance training is a powerful care model to combat loss of muscle strength and mass in the ageing population’ said Peterson, a member of the University of Michigan Institute for Healthcare Policy & Innovation and Michigan Center on the Demography of Aging.
‘We demonstrate in this position statement just how much resistance training can positively affect physical functioning, mobility, independence, chronic disease management, psychological wellbeing, quality of life and healthy life expectancy. We also provide recommendations for how to optimize resistance training programs to ensure safety and effectiveness.’
Fragala added that the benefits of participating in resistance training as an older adult outweigh the risks.
‘The coauthors of this paper and the hundreds of other prolific researchers whose work we synthesized in this position statement have found that in most cases, the vast benefits of resistance training largely outweigh the risks when training is properly implemented’ Fragala says.
The authors had the support of the National Strength and Conditioning Association for the statement.
‘Too few of older Americans participate in resistance training, largely because of fear, confusion and a lack of consensus to guide implementation’ Peterson said; ‘By having this consensus statement supported by the National Strength and Conditioning Association, we hope it will have a positive impact on empowering healthier ageing.’
Source: Michigan Medicine
Meal timing strategies appear to lower appetite, improve fat burning
Researchers have discovered that meal timing strategies such as intermittent fasting or eating earlier in the daytime appear to help people lose weight by lowering appetite rather than burning more calories, according to a report published online today in the journal Obesity, the flagship journal of The Obesity Society. The study is the first to show how meal timing affects 24-hour energy metabolism when food intake and meal frequency are matched.
‘Coordinating meals with circadian rhythms, or your body's internal clock, may be a powerful strategy for reducing appetite and improving metabolic health’ said Eric Ravussin, PhD, one of the study's authors and associate executive director for clinical science at Louisiana State University's Pennington Biomedical Research Center in Baton Rouge.
‘We suspect that a majority of people may find meal timing strategies helpful for losing weight or to maintain their weight since these strategies naturally appear to curb appetite, which may help people eat less’ said Courtney M. Peterson, PhD, lead author of the study and an assistant professor in the Department of Nutrition Sciences at the University of Alabama at Birmingham.
Peterson and her colleagues also report that meal timing strategies may help people burn more fat on average during a 24-hour period. Early Time-Restricted Feeding (eTRF) -- a form of daily intermittent fasting where dinner is eaten in the afternoon -- helped to improve people's ability to switch between burning carbohydrates for energy to burning fat for energy, an aspect of metabolism known as metabolic flexibility. The study's authors said, however, that the results on fat-burning are preliminary. ‘Whether these strategies help people lose body fat need to be tested and confirmed in a much longer study’ said Peterson.
For the study, researchers enrolled 11 adult men and women who had excess weight. Participants were recruited between November 2014 and August 2016. Adults, in general good health, aged 20-to-45-years old were eligible to participate if they had a body mass index between 25 and 35 kg/m2 (inclusive), body weight between 68 and 100 kg, a regular bedtime between 9:30 p.m. and 12 a.m., and for women, a regular menstrual cycle.
Participants tried two different meal timing strategies in random order: a control schedule where participants ate three meals during a 12-hour period with breakfast at 8:00 a.m. and dinner at 8:00 p.m. and an eTRF schedule where participants ate three meals over a six-hour period with breakfast at 8:00 a.m. and dinner at 2:00 p.m. The same amounts and types of foods were consumed on both schedules. Fasting periods for the control schedule included 12 hours per day, while the eTRF schedule involved fasting for 18 hours per day.
Study participants followed the different schedules for four days in a row. On the fourth day, researchers measured the metabolism of participants by placing them in a respiratory chamber -- a room-like device -- where researchers measured how many calories, carbohydrates, fat and protein were burned. Researchers also measured the appetite levels of participants every three hours while they were awake, as well as hunger hormones in the morning and evening.
Although eTRF did not significantly affect how many calories participants burned, the researchers found that eTRF did lower levels of the hunger hormone ghrelin and improved some aspects of appetite. It also increased fat-burning over the 24-hour day.
‘By testing eTRF, we were able to kill two birds with one stone’ said Peterson, adding that the researchers were able to gain some insight into daily intermittent fasting (time restricted-feeding), as well as meal timing strategies that involve eating earlier in the daytime to be in sync with circadian rhythms. The researchers believe that these two broader classes of meal timing strategies may have similar benefits to eTRF.
Hollie Raynor, PhD, RD, LDN, who was not associated with the research, said ‘this study helps provide more information about how patterns of eating, and not just what you eat, may be important for achieving a healthy weight.’ Raynor is a professor and interim dean of research in the Department of Nutrition, College of Education, Health, and Human Sciences at The University of Tennessee, Knoxville.
Peterson and colleagues said prior research was conflicted on whether meal timing strategies help with weight loss by helping people burn more calories or by lowering appetite. Studies in rodents suggest such strategies burn more calories, but data from human studies were conflicting -- some studies suggested meal timing strategies increase calories burned, but other reports showed no difference. The study's authors said, however, that previous studies did not directly measure how many calories people burned or were imperfect in other ways.
Source: The Obesity Society
Nuts may benefit male sexual function
Men participating in a clinical trial who added two handfuls of nuts a day to their regular diet reported improvements in sexual function.
The 14-week trial compared a group of men who added a daily dose of 60g of almonds, hazelnuts, and walnuts to a Western-style diet with an equivalent group of men who ate the same diet but without nuts.
The investigators, from research centres in Spain, believe that this is the first study to show that eating nuts can benefit sexual function. It should be noted that the study, the findings of which were published in the journal Nutrients, was partly financed by a grant from the International Nut and Dried Fruit Council.
A 2018 analysis of the trial data had already reported that daily consumption of these nuts appeared to improve sperm quality. The recent analysis uses the same trial data but focuses on the effect of nut consumption on sexual and erectile function. The findings suggest that adding nuts to a Western style diet can improve orgasm quality and sexual desire.
The researchers used two sources of data to assess changes in erectile function: participant responses to questionnaires and biomarkers in blood samples.
The data for the new study came from 83 healthy males aged between 18 and 35 years. All of the men were following a Western-style diet, which, in contrast to the Mediterranean diet, is low in fruits and vegetables and high in animal fats.
The researchers randomly assigned 43 of the men to the nut-enriched group and the remaining 40 to the control group. Both groups continued with their Western-style diet. However, those in the nut-enriched group also consumed two handfuls daily of mixed nuts while the control group members did not supplement their diet with nuts.
The participants filled in a standard questionnaire about erectile and sexual function at both the start and the end of the 14-week trial. They also gave blood and sperm samples at these times. In the samples, the researchers measured the levels of nitric oxide and the molecule E-selectin as ‘surrogated markers of erectile endothelial function.’
Compared with those in the control group, the participants who added nuts to their diet showed significant increases in two measures of erectile and sexual function: orgasmic function and sexual desire.
However, between the two groups, there were no significant differences in how much the scores on erectile function, intercourse satisfaction, and overall satisfaction had changed by the end of the study.
In addition, the before and after levels of the two markers of erectile endothelial function — NO and E-selectin — did not significantly differ between the two groups.
The authors concluded that ‘Including nuts in a regular diet significantly improved auto-reported orgasmic function and sexual desire’ and called for further, large-scale studies to confirm their findings and discover the mechanisms that explain why eating nuts might benefit sexual function.
Source: Medical News Today