Obese people may show some shrinkage in their brain tissue as early as middle age, a large new study confirms.

The study, based on brain scans of thousands of adults in the United Kingdom, found that those with higher body fat levels tended to show differences in brain structure compared to thinner people.

Those differences included a lower volume of gray matter.

Gray matter contains most of the brain’s nerve cells, while another type of brain tissue — white matter — contains the fibers that connect different parts of the brain.

The new findings, published April 23 in the journal Radiology, add to evidence linking obesity to certain brain structure differences. Earlier this year, another study — pulling from the same data source — found that middle-aged adults with abdominal obesity tended to have less gray matter volume than their normal-weight counterparts.

What does it all mean? Past research has linked obesity to a heightened risk of dementia in old age. Meanwhile, studies have tied gray matter shrinkage to dementia risk, as well.

So it’s possible the current findings help connect the dots, researchers said.

But they were quick to point out the study’s limitations: It did not assess people’s memory or other mental skills, and it’s not clear what the differences in brain structure mean.

It’s not even clear that extra body fat is the reason for the brain differences, said lead researcher Dr. Ilona Dekkers, of Leiden University Medical Center in the Netherlands.

One possibility, she said, is that “non-optimal” brain structure comes before the excessive weight gain. The lower tissue volume was seen, in part, in the brain’s “reward” circuitry and areas related to movement.

Dekkers said it’s also possible that the brain differences result from other things that go along with obesity — such as poor diet or lack of exercise.

On the other hand, she said, excess body fat may directly affect the brain.

“Recent studies are showing that being obese has a substantial impact on our hormonal and immune systems, which has been shown to lead to inflammatory reactions that also affect brain tissue,” Dekkers said.

Dr. Harold Bays, a U.S. endocrinologist who was not involved in the study, made similar points.

“Is it possible that unhealthy nutrition and physical inactivity could be partly responsible, and it’s not just the body fat itself?” he said. “Yes.”

There’s a key culprit in the battle against sitting. Time spent watching TV and videos has remained consistently high in the United States over the past 15 years, but time sitting at a computer has increased dramatically, new research finds.

Leisure-time computer use increased between 4.8% and 38% for various age groups between 2001 and 2016, said Yin Cao, senior author of the new study and an assistant professor of surgery at Washington University School of Medicine in St. Louis.
Overall, up to 43% of the US population used a computer for two or more hours a day and up to 25% used a computer for three or more hours each day in 2016.
The result of these increases: Teens spent about 8.2 hours a day sitting while adults sat for 6.4 hours a day.

Both groups saw a one-hour increase over the decade ending in 2016, Cao said.
Cao believes that her research, published Tuesday in JAMA, will help Americans better understand our sedentary habits — and change them.

Sitting trends over the past 15 years

“Research evidence has been growing on the association between sedentary behavior — primarily TV watching — and a variety of diseases, including obesity, cardiovascular disease, cancer, Type 2 diabetes and overall mortality,” Cao said.

For the first time, the US Department of Health and Human Services mentioned in last year’s edition of its physical activity guidelines “that people would benefit from both increasing moderate to vigorous activity and also reducing time spent sitting,” she said.

She wondered: How much do Americans sit, and how has the trend changed over the past 15 years? To answer these questions, Cao and her co-authors used data from the National Health and Nutrition Examination Survey on 51,896 people — 10,359 children, 9,639 teens and 31,898 adults — from 2001 through 2016.
Overall, up to 65% of the population reported watching TV for at least two hours each day, the study found. “This is quite high and has been overall stable over the past 15 years,” Cao said. Computer time, though, has been increasing over that same period.

Just 43% of children reported using a computer for one hour per day or more in 2001; that rate increased to 56% in 2016, the study indicates. The estimated prevalence for teens increased from 53% to 57%, and for adults it went from 29% to 50% between 2003 and 2016. Only adults and teens reported their total sitting time.
“Hopefully, this paper will be helpful in terms of setting the national achievable goal of reducing sitting, given that we already know prolonged sitting is bad for many health outcomes,” Cao said.

Every little bit helps

Peter Katzmarzyk, a professor at Louisiana State University’s Pennington Biomedical Research Center and a member and fellow of the American College of Sports Medicine, said the study’s value is in showing trends over time.
Katzmarzyk, who was not involved in the research, noted that the paper also highlights some important differences across demographic groups that could result in health disparities. “For example, levels of sitting were higher in males, in African Americans and also in adolescents and adults with overweight or obesity,” he said.

Although everyone needs to focus on increasing activity and reducing sitting, “it is even more important to limit the time spent sitting in people who are not meeting the physical activity guidelines, because they are at highest risk” for chronic diseases and premature mortality, he said.

A separate study published this week in the Journal of the American College of Cardiology found that moderate-to-vigorous physical activity offset the link between sitting time and increased risk of death from all causes and cardiovascular disease death risk. The study tracked nearly 150,000 people ages 45 and older.
Keith Diaz, an assistant professor of behavioral medicine in the Columbia University Department of Medicine, said that the message of the research published in JAMA may be familiar but that it is important.

“Largely, we’re becoming more sedentary as a nation, and one of the principal contributors to that rise in sedentary time is our computer usage,” said Diaz, who did not participate in the research.

“What I was really struck by was, 62% of children are watching TV for two or more hours per day,” he said. “And they’re using computers a lot, too.”

A parent, he added, “these behaviors really manifest early on, in childhood, and it’s probably something we have to start curtailing and targeting really early if we are going to break this vicious cycle of us becoming a more sedentary society.”
He said people who have read his research often ask him two questions: “What should I do when I take a break from my sitting time?” and “When I take that break, how long does that break have to be?”

His most recent study found that intensity matters but is not essential.

“So if you were to replace 30 minutes of sedentary time with 30 minutes of light activity — a casual stroll down the hall — you would lower your risk of early death by 17%,” he said. Replace 30 minutes of sitting with more vigorous activity, and you lower your risk by 35%.

He also found that “short bursts of activity, if you get enough of them across the day, will be enough to lower your risk from sitting all day.”
“To combat sitting doesn’t require you going to the gym and working out for hours at a time,” he said.

Getting off your office chair or the couch and taking a short break here or there is enough, he said: “It doesn’t have to be complicated. It doesn’t have to be hard. It doesn’t have to be long.”

Drinking your favourite cup of coffee has been linked to a slew of health benefits, such as a longer life span, and a decreased risk of conditions including depression, heart attacks and certain cancers.

But a new study suggests that there may be a downside to your morning brew: Researchers found that drinking two or more cups of coffee or tea may increase a person’s risk of lung cancer.

The findings were presented on March 31, here at the annual meeting of the American Association for Cancer Research.

Of note, the link was even true for nonsmokers. People who smoke cigarettes are also more likely to drink coffee and tea, it was difficult in previous studies to disentangle the effects of these drinks from those of smoking, in developing lung cancer, said lead study author Jingjing Zhu, a Ph.D. student at Vanderbilt University in Tennessee.

In the new study, an international group of researchers analyzed data from 17 different studies that included a total of 1.2 million participants in the U.S. and Asia. The studies noted whether participants drank coffee or tea or smoked cigarettes. About half were nonsmokers.

The participants were tracked for an average of 8.6 years. During that time, more than 20,500 participants developed lung cancer.

The researchers found that nonsmokers who drank two or more cups of coffee a day had a 41% higher risk of lung cancer than those who didn’t drink coffee. Similarly, nonsmokers who drank two or more cups of tea a day had a 37%  greater risk of lung cancer than non-tea drinkers. (Because data was taken from multiple studies, the exact definition of a cup varied.)

The study also found that a person’s risk didn’t change significantly between ages, races or the type of coffee people drank — both decaf and caffeinated coffee seemed to be associated with similar risks. In fact, decaf coffee was associated with a 15% higher risk than caffeinated coffee, Zhu said.

The study had several limitations. For example, although the participants were tracked for years after the studies started, data on smoking and coffee and tea intake was measured only one time, at the beginning of the studies. So if people changed their behaviours throughout the years, it could have skewed the results, Zhu said.

What’s more, if nonsmokers were exposed to second-hand smoke — which wasn’t accounted for but could also increase lung cancer risk — that could have also skewed the results, she said.

Dr Julie Fisher, an oncologist at the Levine Cancer Institute in North Carolina who was not part of the study, said that the findings were “interesting” and “compelling,” but noted that because it’s an association finding, she “certainly would not draw conclusions based on this.”

However, though there’s still much more research needed, Fisher told Live Science that she agreed that “maybe there’s something in the coffee brewing process” that’s driving the link.

Other coffee findings presented at the meeting were more comforting: Drinking coffee wasn’t associated with an increased risk of glioma or colorectal cancer in men and women; nor was it associated with bladder cancer or renal cell carcinoma in male smokers. Coffee was found to be associated with a lower risk of breast cancer in post-menopausal women and tea with a lower risk of glioma in women. In both men and women, decaf coffee was found to be associated with a lower risk of colorectal cancer.

Hypoproteic diets are most often discussed for patients with chronic kidney disease (CKD) who do not receive dialysis.

A very low-protein diet supplemented with ketoanalogues of essential amino acids(keto-diet) proved effective in ameliorating metabolic disturbances of advanced CKD and delaying the initiation of dialysis without deleterious effects on nutritional status.

Several recent studies report that the keto-diet could also slow down the rate of decline in renal function, with better outcomes after the initiation of dialysis. Results of a single-centre randomized controlled trial addressing the rate of CKD progression revealed a 57% slower decline in renal function with the keto-diet compared with a conventional low-protein diet (LPD). The keto-diet allowed the safe management of selected patients with stage 4-5 CKD, delaying dialysis for almost 1 year, with a major impact on patient quality of life and health expenditures. Therefore, the keto-diet could be a link in the integrated care model. Careful selection of patients, nutritional monitoring, and dietary counselling are required.

Low protein diets (LPDs) are milestones in chronic kidney disease (CKD). Concerns over compliance and safety limit their use. The aim of this study was to test the feasibility and main results of a multiple-choice approach to LPDs adapted to patient preferences.

Methods

From December 2007 to January 2013, all CKD patients (stages 4/5; progressive stage 3) without contraindications (malnutrition, short life expectancy), were offered two main LPDs (proteins 0.6 g/kg daily): Vegan supplemented (LPD-KA) or with “aproteic” commercial food (LPD-ACF). LPDs followed a qualitative approach based on forbidden and allowed food; one to three free meals per week, and flexible control policy (1–3 mo). Start of dialysis, death, and combined outcome (death–dialysis) were analyzed by Kaplan-Meier curves and Cox model. Comparison with dialysis in patients with glomerular filtration rate (GRF) <15 mL/min, (corresponding to “early” dialysis start) employed standardized mortality rates, with respect to the Italian and the United States Dialysis Registry.

Results

One hundred eighty-five patients (222 patient-years) started at least a trial of LPD-KA, 122 (177 patients-years) LPD-ACF; only 3 patients with GFR <30 mL/min denied an LPD trial. Patients who chose LPD-KA were younger than those on LPD-ACF (63 versus 74 y), had less comorbidity (82% versus 93%), higher proteinuria (1.4 versus 0.7 g/d) and lower GFR (17 versus 23 mL/min) (P < 0.001). Median daily protein intake was 0.7 g/kg on both diets (Maroni-Mitch formula). The combined outcome (death or dialysis) was not influenced by the diet chosen (Cox analysis). The relative risk for death on the diet (patients with GFR <15 mL/min) was 0.5 with respect to the Italian Registry and 0.3 to the United States Dialysis Registry. The diets had comparable costs (1 y on dialysis: 50 patient-years on LPD).

Conclusions

The choice of diet is strictly linked to patient characteristics, thus supporting a multiple-choice offer. Once corrected for baseline data, both LPDs led to similar results, suggesting at least survival equivalence with dialysis, at a lesser cost.

Spring has sprung! The birds are singing, the sun is out and it’s time to put away your winter jackets for the season. Researchers have studied the impact of nature on human well-being for years, but recent studies have found a more direct correlation between human health, particularly related to stress, and the importance of people’s access to nature and managed landscapes.

Tensed or stressed out? Head to the cottage or local park. One study found that students sent into the forest for two nights had lower levels of cortisol — a hormone often used as a marker for stress — than those who spent that time in the city.

We know the natural environment is “restorative,” and one thing that a walk outside can restore is your waning attention. In one early study, researchers worked to deplete participants’ ability to focus. Then some took a walk in nature, some took a walk through the city, and the rest just relaxed. When they returned, the nature group scored the best on a proofreading task. Other studies have found similar results — even seeing a natural scene through a window can help.

People who live within a half mile of green space (such parks, public gardens, and greenways) were found to have a lower incidence of fifteen diseases by Dutch researchers — including depression, anxiety, heart disease, diabetes, asthma and migraines.

Get down and dirty! Soil is the new Prozac, according to Dr. Christopher Lowry, a neuroscientist at the University of Bristol in England. Mycobacterium vaccae in soil mirrors the effect on neurons that Prozac provides. The bacterium stimulates serotonin production, which explains why people who spend time gardening and have direct contact with soil feel more relaxed and happier.

Living landscapes help you heal faster. Multiple studies have discovered that plants in hospital recovery rooms or views of aesthetically-pleasing gardens help patients heal up to one day faster than those who are in more sterile or harsh environments.

All of these benefits reinforce the importance of maintaining our yards, parks and other community green spaces. Trees, shrubs, grass, and flowering plants are integral to human health. Not only do they provide a place for kids and pets to play, they directly contribute to our mental and physical well-being.