Amazon indigenous group’s lifestyle may hold a key to slowing down aging
Tsimane people are unique for their healthy brains that age more slowly
University of Southern California, May 27, 2021
A team of international researchers has found that the Tsimane indigenous people of the Bolivian Amazon experience less brain atrophy than their American and European peers. The decrease in their brain volumes with age is 70% slower than in Western populations. Accelerated brain volume loss can be a sign of dementia.
The study was published May 26, 2021 in the Journal of Gerontology, Series A: Biological Sciences and Medical Sciences.
Although people in industrialized nations have access to modern medical care, they are more sedentary and eat a diet high in saturated fats. In contrast, the Tsimane have little or no access to health care but are extremely physically active and consume a high-fiber diet that includes vegetables, fish and lean meat.
“The Tsimane have provided us with an amazing natural experiment on the potentially detrimental effects of modern lifestyles on our health,” said study author Andrei Irimia, an assistant professor of gerontology, neuroscience and biomedical engineering at the USC Leonard Davis School of Gerontology and the USC Viterbi School of Engineering. “These findings suggest that brain atrophy may be slowed substantially by the same lifestyle factors associated with very low risk of heart disease.”
The researchers enrolled 746 Tsimane adults, ages 40 to 94, in their study. To acquire brain scans, they provided transportation for the participants from their remote villages to Trinidad, Bolivia, the closest town with CT scanning equipment. That journey could last as long as two full days with travel by river and road.
The team used the scans to calculate brain volumes and then examined their association with age for Tsimane. Next, they compared these results to those in three industrialized populations in the U.S. and Europe.
The scientists found that the difference in brain volumes between middle age and old age is 70% smaller in Tsimane than in Western populations. This suggests that the Tsimane’s brains likely experience far less brain atrophy than Westerners as they age; atrophy is correlated with risk of cognitive impairment, functional decline and dementia.
The researchers note that the Tsimane have high levels of inflammation, which is typically associated with brain atrophy in Westerners. But their study suggests that high inflammation does not have a pronounced effect upon Tsimane brains.
According to the study authors, the Tsimane’s low cardiovascular risks may outweigh their infection-driven inflammatory risk, raising new questions about the causes of dementia. One possible reason is that, in Westerners, inflammation is associated with obesity and metabolic causes whereas, in the Tsimane, it is driven by respiratory, gastrointestinal, and parasitic infections. Infectious diseases are the most prominent cause of death among the Tsimane.
“Our sedentary lifestyle and diet rich in sugars and fats may be accelerating the loss of brain tissue with age and making us more vulnerable to diseases such as Alzheimer’s,” said study author Hillard Kaplan, a professor of health economics and anthropology at Chapman University who has studied the Tsimane for nearly two decades. “The Tsimane can serve as a baseline for healthy brain aging.”
Healthier hearts and — new research shows — healthier brains
The indigenous Tsimane people captured scientists’ — and the world’s — attention when an earlier study found them to have extraordinarily healthy hearts in older age. That prior study, published by the Lancet in 2017, showed that Tsimane have the lowest prevalence of coronary atherosclerosis of any population known to science and that they have few cardiovascular disease risk factors. The very low rate of heart disease among the roughly 16,000 Tsimane is very likely related to their pre-industrial subsistence lifestyle of hunting, gathering, fishing, and farming.
“This study demonstrates that the Tsimane stand out not only in terms of heart health, but brain health as well,” Kaplan said. “The findings suggest ample opportunities for interventions to improve brain health, even in populations with high levels of inflammation.”
Tai chi about equal to conventional exercise for reducing belly fat in middle aged and older adults
University of Hong Kong, May 31, 2021
A randomized controlled trial found that tai chi is about as effective as conventional exercise for reducing waist circumference in middle-aged and older adults with central obesity. Central obesity, or weight carried around the midsection, is a major manifestation of metabolic syndrome and a common health problem in this cohort. The findings are published in Annals of Internal Medicine.
Tai chi is a form of mind-body exercise often described as “meditation in motion.” It is practiced in many Asian communities and is becoming increasingly popular in Western countries, with more than 2 million people practicing it in the United States. While it is known to be a suitable activity for older people including those who are not active, there previously has been little evidence on tai chi’s health benefits.
Researchers from the University of Hong Kong randomly assigned more than 500 adults over 50 with central obesity to a regimen of tai chi, conventional exercise, or no exercise over 3 months. Participants in the tai chi and exercise groups met for instructor-led workouts for 1 hour 3 times a week for 12 weeks. The tai chi program consisted of the Yang style of tai chi, the most common style adopted in the literature, and the conventional exercise program consisted of brisk walking and strength training activities. Waist circumference and other indicators of metabolic health were measured at baseline, 12 weeks, and 38 weeks. The researchers found that both the tai chi intervention and conventional exercise intervention group had reductions in waist circumference, relative to control. The reduction in waist circumference had a favorable impact on HDL cholesterol, or so-called good cholesterol, but did not translate into detectable differences in fasting glucose or blood pressure.
According to the study authors, their findings are good news for middle-aged and older adults who have central obesity but may be averse to conventional exercise due to preference or limited mobility.
Prenatal exposure to paracetamol associated with ADHD and autism symptoms in childhood
Study of more than 70,000 European children bolsters the findings of previous research
Barcelona Institute for Global Health (Spain), May 31, 2021
An epidemiological study of more than 70,000 children in six European cohorts has linked symptoms of attention-deficit/
In total, the researchers analysed 73,881 children for whom data were available on prenatal or postnatal exposure to paracetamol, at least one symptom of ASC or ADHD, and main covariates. Depending on the cohort, 14% to 56% of the mothers reported taking paracetamol while pregnant.
The study found that children exposed to paracetamol before birth were 19% more likely to develop ASC symptoms and 21% more likely to develop ADHD symptoms than children who were not exposed.
“Our findings are consistent with previous research,” explained ISGlobal researcher Sílvia Alemany, lead author of the study. “We also found that prenatal exposure to paracetamol affects boys and girls in a similar way, as we observed practically no differences.”
“Our results address some of the weaknesses of previous meta-analyses,” commented Jordi Sunyer, researcher at ISGlobal and last author of the study. “Considering all the evidence on the use of paracetamol and neurological development, we agree with previous recommendations indicating that while paracetamol should not be suppressed in pregnant women or children, it should be used only when necessary.”
At some point during pregnancy, an estimated 46%-56% of pregnant women in developed countries use paracetamol, which is considered the safest analgesic/antipyretic for pregnant women and children. However, mounting evidence has linked prenatal paracetamol exposure to poorer cognitive performance, more behavioural problems, and ASC and ADHD symptoms.
Those previous studies have been criticised for their heterogeneity. In the new study, therefore, “an effort was made to harmonise the assessment of ADHD and ASC symptoms and the definition of paracetamol exposure,” explained Alemany. “The sample is large,” she added, “and it includes cohorts from multiple European countries: the United Kingdom, Denmark, the Netherlands, Italy, Greece and Spain. We also used the same criteria for all of the cohorts, thereby reducing the heterogeneity of criteria that has hampered previous studies.”
The study also analysed postnatal exposure to paracetamol and found no association between paracetamol use during childhood and ASC symptoms. Nevertheless, the research team concluded that further studies are needed, given the heterogeneity of postnatal paracetamol exposure among the various cohorts, which ranged from 6% to 92.8%.
The six cohorts included the study were as follows:
1. Avon Longitudinal Study of Parents and Children (ALSPAC)2. Danish National Birth Cohort (DNBC)
3. Gene and Environment: Prospective Study on Infancy in Italy (GASPII)
4. Generation R Study
5. INMA (including four subcohorts)
6. Mother-Child Cohort in Crete (RHEA)
Waking just one hour earlier cuts depression risk by double digits
University of Colorado, May 28, 2021
Waking up just one hour earlier could reduce a person’s risk of major depression by 23%, suggests a sweeping new genetic study published May 26 in the journal JAMA Psychiatry.
The study of 840,000 people, by researchers at University of Colorado Boulder and the Broad Institute of MIT and Harvard, represents some of the strongest evidence yet that chronotype–a person’s propensity to sleep at a certain time –influences depression risk.
It’s also among the first studies to quantify just how much, or little, change is required to influence mental health.
As people emerge, post-pandemic, from working and attending school remotely– a trend that has led many to shift to a later sleep schedule–the findings could have important implications.
“We have known for some time that there is a relationship between sleep timing and mood, but a question we often hear from clinicians is: How much earlier do we need to shift people to see a benefit?” said senior author Celine Vetter, assistant professor of integrative physiology at CU Boulder. “We found that even one-hour earlier sleep timing is associated with significantly lower risk of depression.”
Previous observational studies have shown that night owls are as much as twice as likely to suffer from depression as early risers, regardless of how long they sleep. But because mood disorders themselves can disrupt sleep patterns, researchers have had a hard time deciphering what causes what.
Other studies have had small sample sizes, relied on questionnaires from a single time point, or didn’t account for environmental factors which can influence both sleep timing and mood, potentially confounding results.
In 2018, Vetter published a large, long term study of 32,000 nurses showing that “early risers” were up to 27% less likely to develop depression over the course of four years, but that begged the question: What does it mean to be an early riser?
To get a clearer sense of whether shifting sleep time earlier is truly protective, and how much shift is required, lead author Iyas Daghlas, M.D., turned to data from the DNA testing company 23 and Me and the biomedical database UK Biobank. Daghlas then used a method called “Mendelian randomization” that leverages genetic associations to help decipher cause and effect.
“Our genetics are set at birth so some of the biases that affect other kinds of epidemiological research tend not to affect genetic studies,” said Daghlas, who graduated in May from Harvard Medical School.
More than 340 common genetic variants, including variants in the so-called “clock gene” PER2, are known to influence a person’s chronotype, and genetics collectively explains 12-42% of our sleep timing preference.
The researchers assessed deidentified genetic data on these variants from up to 850,000 individuals, including data from 85,000 who had worn wearable sleep trackers for 7 days and 250,000 who had filled out sleep-preference questionnaires. This gave them a more granular picture, down to the hour, of how variants in genes influence when we sleep and wake up.
In the largest of these samples, about a third of surveyed subjects self-identified as morning larks, 9% were night owls and the rest were in the middle. Overall, the average sleep mid-point was 3 a.m., meaning they went to bed at 11 p.m. and got up at 6 a.m.
With this information in hand, the researchers turned to a different sample which included genetic information along with anonymized medical and prescription records and surveys about diagnoses of major depressive disorder.
Using novel statistical techniques, they asked: Do those with genetic variants which predispose them to be early risers also have lower risk of depression?
The answer is a firm yes.
Each one-hour earlier sleep midpoint (halfway between bedtime and wake time) corresponded with a 23% lower risk of major depressive disorder.
This suggests that if someone who normally goes to bed at 1 a.m. goes to bed at midnight instead and sleeps the same duration, they could cut their risk by 23%; if they go to bed at 11 p.m., they could cut it by about 40%.
It’s unclear from the study whether those who are already early risers could benefit from getting up even earlier. But for those in the intermediate range or evening range, shifting to an earlier bedtime would likely be helpful.
What could explain this effect?
Some research suggests that getting greater light exposure during the day, which early-risers tend to get, results in a cascade of hormonal impacts that can influence mood.
Others note that having a biological clock, or circadian rhythm, that trends differently than most peoples’ can in itself be depressing.
“We live in a society that is designed for morning people, and evening people often feel as if they are in a constant state of misalignment with that societal clock,” said Daghlas.
He stresses that a large randomized clinical trial is necessary to determine definitively whether going to bed early can reduce depression. “But this study definitely shifts the weight of evidence toward supporting a causal effect of sleep timing on depression.”
For those wanting to shift themselves to an earlier sleep schedule, Vetter offers this advice:
“Keep your days bright and your nights dark,” she says. “Have your morning coffee on the porch. Walk or ride your bike to work if you can, and dim those electronics in the evening.”
Olive oil nutrient may help prevent brain cancer
University of Edinburgh, June 2, 2021
A compound found in olive oil may help to prevent cancer developing in the brain, a study shows.
The oily substance – one of a group of nutrients known as fatty acids – stimulates the production of a cell molecule whose function is to prevent cancer-causing proteins from forming.
The study team says it is too soon to say whether dietary consumption of olive oil may help prevent brain cancer.
Their findings, however, point towards possible therapies based on the oil to prevent brain cancer from occurring.
Scientists from the University analysed the effect of oleic acid on a cell molecule, known as miR-7, which is active in the brain and is known to suppress the formation of tumours.
They found that oleic acid prevents a cell protein, known as MSI2, from stopping production of miR-7.
In this way, the olive oil component supports the production of miR-7, which helps prevent tumours from forming.
Researchers made their discoveries in tests on human cell extracts and in living cells in the lab.
The study, published in the Journal of Molecular Biology, was funded by the Medical Research Council and the Wellcome Trust.
“While we cannot yet say that olive oil in the diet helps prevent brain cancer, our findings do suggest that oleic acid can support the production of tumour-suppressing molecules in cells grown in the lab. Further studies could help determine the role that olive oil might have in brain health,” says Dr Gracjan Michlewski.
Study: Boosting selenium intake can help reduce osteoporosis risk
Central South University (China), May 29, 2021
Researchers from China have found that increased selenium intake may reduce a person’s risk for osteoporosis. In their report, experts from Central South University in Changsha recruited over 6,200 participants and measured the bone mineral density in the middle phalanges of the second to fourth fingers of their non-dominant hand. The team then assessed the participants’ dietary patterns, particularly their selenium intake, through a validated semi-quantitative food frequency questionnaire which the subjects answered twice within three weeks.
After analyzing the participants’ bone mineral density using a compact radiographic absorptiometry system, the team discovered that 9.6 percent of the subjects have osteoporosis. The majority of the cases were reported among women, with 19.7 percent having been diagnosed with the disease. Among men, only 2.3 percent were diagnosed with osteoporosis.
The researchers also compared the dietary data of those diagnosed with osteoporosis to those who were not. They found that there are significant differences between the participants in terms of age, gender, smoking and drinking habits, BMI, blood pressure levels, physical activity levels, nutrient supplementation, dietary calcium intake, dietary fiber intake and dietary energy intake. The factors above were measured as they are considered to be vital for the development and prevention of osteoporosis.
But most of all, the team observed a significant difference between the subjects with osteoporosis and those who don’t have the disease in terms of dietary selenium intake. The researchers found that those who have osteoporosis also have lower levels of dietary selenium consumption.
A person can increase his selenium intake by eating Brazil nuts, fish, shellfish, beef, turkey, chicken, fortified cereals, whole-wheat bread, beans, lentils and eggs. The recommended dietary allowance for selenium is 55 micrograms per day for adult men and women above 19 years old. For pregnant and lactating women, the recommended intake is between 60 to 70 micrograms per day.
However, in the study, which involved Chinese citizens, the participants’ selenium intake averaged only 43.5 micrograms per day. This is comparable to the average daily selenium intake of Europeans, which is 40 micrograms per day. The low selenium intake of both populations could be due to the low-selenium content of the soil in both areas.
Selenium and thyroid hormones
Selenium primarily functions in the body as an essential component of selenoproteins, composed of various enzymes and proteins that help protect the cells from damage and infections. Selenoproteins are also needed in producing DNA and in the metabolism of thyroid hormones. The thyroid glands have the highest concentration of selenium in the body.
In connection to thyroid hormones, the researchers postulated that low selenium levels might have increased the level of thyroid hormones in the blood, which may have caused an accelerated bone loss and osteoporosis in the subjects with low dietary selenium intake. Thyroid problems have indirect correlations with osteoporosis and are considered as secondary causes. This means that elevated thyroid hormone levels don’t directly cause osteoporosis, but they can influence how the body maintains a healthy mineral bone density.
In addition, hyperthyroidism, a thyroid disorder characterized by too much production of a thyroid hormone thyroxine, is considered as having a close link to the development of osteoporosis. This is because elevated levels of thyroxine accelerate the process of bone degradation, which is conducted by the osteoclasts. Osteoclasts are the cells that dissolvethe bones, initiating new bone production, which is conducted by another cell — the osteoblasts. Excessive thyroxine levels make the osteoclasts work faster than the osteoblasts, causing the bones to be fragile or brittle.
However, the researchers in the study did not confirm a causal relationship between dietary selenium intake and osteoporosis, but future studies are underway to provide support to their findings.
Juvenile selenium deficiency impairs cognition and energy homeostasis
University of Hawaii, May 26, 2021
According to news originating from Honolulu, Hawaii, by NewsRx correspondents, research stated, “Selenium (Se) is an essential micronutrient of critical importance to mammalian life.”
The news reporters obtained a quote from the research from University of Hawaii: “Its biological effects are primarily mediated via co-translational incorporation into selenoproteins, as the unique amino acid, selenocysteine. These proteins play fundamental roles in redox signaling and includes the glutathione peroxidases and thioredoxin reductases. Environmental distribution of Se varies considerably worldwide, with concomitant effects on Se status in humans and animals. Dietary Se intake within a narrow range optimizes the activity of Se-dependent antioxidant enzymes, whereas both Se-deficiency and Se-excess can adversely impact health. Se-deficiency affects a significant proportion of the world’s population, with hypothyroidism, cardiomyopathy, reduced immunity, and impaired cognition being common symptoms. Although relatively less prevalent, Se-excess can also have detrimental consequences and has been implicated in promoting both metabolic and neurodegenerative disease in humans.”
According to the news editors, the research concluded: “Herein, we sought to comprehensively assess the developmental effects of both Se-deficiency and Se-excess on a battery of neurobehavioral and metabolic tests in mice. Se-deficiency elicited deficits in cognition, altered sensorimotor gating, and increased adiposity, while Se-excess was surprisingly beneficial.”