Study finds average consumption of salt safe for heart health

New research shows that for the vast majority of individuals, sodium consumption does not increase health risks except for those who eat more than five grams a day, the equivalent of 2.5 teaspoons of salt.

Fewer than five per cent of individuals in developed countries exceed that level.

The large, international study also shows that even for those individuals there is good news. Any health risk of sodium intake is virtually eliminated if people improve their diet quality by adding fruits, vegetables, dairy foods, potatoes, and other potassium rich foods.

The research, published today in The Lancet, is by scientists of the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences, along with their research colleagues from 21 countries.

The study followed 94,000 people, aged 35 to 70, for an average of eight years in communities from18 countries around the world and found there an associated risk of cardiovascular disease and strokes only where the average intake is greater than five grams of sodium a day.

China is the only country in their study where 80 per cent of communities have a sodium intake of more than five grams a day. In the other countries, the majority of the communities had an average sodium consumption of 3 to 5 grams a day (equivalent to 1.5 to 2.5 teaspoons of salt).

"The World Health Organization recommends consumption of less than two grams of sodium -- that's one teaspoon of salt -- a day as a preventative measure against cardiovascular disease, but there is little evidence in terms of improved health outcomes that individuals ever achieve at such a low level," said Andrew Mente, first author of the study and a PHRI researcher.

He added that the American Heart Association recommends even less -- 1.5 grams of sodium a day for individuals at risk of heart disease.

"Only in the communities with the most sodium intake -- those over five grams a day of sodium -- which is mainly in China, did we find a direct link between sodium intake and major cardiovascular events like heart attack and stroke.

"In communities that consumed less than five grams of sodium a day, the opposite was the case. Sodium consumption was inversely associated with myocardial infarction or heart attacks and total mortality, and no increase in stroke."

Mente added: "We found all major cardiovascular problems, including death, decreased in communities and countries where there is an increased consumption of potassium which is found in foods such as fruits, vegetables, dairy foods, potatoes and nuts and beans."

The information for the research article came from the ongoing, international Prospective Urban Rural Epidemiology (PURE) study run by the PHRI. Mente is also an associate professor of the Department of Health Research Methods, Evidence and Impact at McMaster University.
Most previous studies relating sodium intake to heart disease and stroke were based on individual-level information, said Martin O'Donnell, co-author of the report, a PHRI researcher and an associate clinical professor of medicine at McMaster.
"Public health strategies should be based on best evidence. Our findings demonstrate that community-level interventions to reduce sodium intake should target communities with high sodium consumption, and should be embedded within approaches to improve overall dietary quality.
"There is no convincing evidence that people with moderate or average sodium intake need to reduce their sodium intake for prevention of heart disease and stroke," said O'Donnell.

Over-the-counter drugs, dietary supplements can lead to inaccurate test results

Over-the-counter (OTC) drugs and dietary supplements are widely used and popular, with US households spending an average of almost USD 350 annually on OTC products. In 2006 an average of EUR 67.50 was spent per person on OTC products in Germany.

The use of various OTC drugs and dietary supplements is highly prevalent in Europe and patients are often not willing to disclose this information to laboratory staff and the ordering physician as a survey published in Clinical Chemistry and Laboratory Medicine, published by De Gruyter in association with the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM), shows.

The study reports on the results of a survey of patients in 18 European countries which shows that those taking OTC products and dietary supplements are not aware of the potential effects on laboratory test results they may have. In addition, patients do not believe that they need to disclose this use to medical and/or laboratory staff.

The study shows that dietary supplements and OTC drugs are more frequently used by middle-aged patients - especially women - with the most common being multivitamins, multiminerals, cranberry and aspirin. All of these compounds, if consumed shortly before blood sampling, may cause changes in lab test results, thus leading to interpretation difficulties and possibly incorrect diagnoses.

Type of underwear is linked to men's semen quality

Men who wear boxer shorts have higher sperm concentrations than men who wear tighter fitting underwear, according to new research published today (Wednesday) in Human Reproduction [1], one of the world's leading reproductive medicine journals.

The researchers also found that boxer shorts-wearing men had lower levels of follicle-stimulating hormone (FSH), compared to men who most frequently wore briefs, "bikinis" (very brief briefs), "jockeys" (underwear that finishes just above the knee) or other tight-fitting underwear. FSH stimulates sperm production and the researchers say that these findings suggest that it kicks into gear when it needs to compensate for testicular damage from increasing scrotal temperatures and decreasing sperm counts and concentration.

The study differs from previous research on this topic because it includes a larger number of men (656) than previous studies, and because it is the first to go beyond the traditional, narrow focus on semen quality and include information on a variety of indicators of testicular function, such as reproductive hormones and sperm DNA damage. These can help in understanding how choices of underwear affect the key regulator of sexual development and reproduction, the hypothalamic-pituitary-gonadal axis.

The researchers, led by Dr Lidia Mínguez-Alarcón, a research scientist at Harvard T.H. Chan School of Public Health (Boston, USA), recruited the male partners of couples who were seeking infertility treatment at the Massachusetts General Hospital between 2000 and 2017. The men were aged between 18 and 56, had an average body mass index (BMI) of 26, and had not had vasectomies. Each of them provided a semen sample and blood sample on the same day, and they answered a questionnaire that asked about the style of underwear they wore most frequently in the preceding three months.
Among the 656 men, 53% (345) reported that they usually wore boxer shorts. They tended to be younger, slimmer and more likely to take hot baths or Jacuzzis than the men who wore other, more tightly fitting underwear.
Men who primarily wore boxer shorts had a statistically significant 25% higher sperm concentration, 17% higher total sperm count, 33% more swimming sperm in a single ejaculate and 14% lower FSH levels than men who did not usually wear boxers, after adjusting for factors that might affect the results, such as BMI, physical activity, hot baths and Jacuzzis, smoking and the year the sample was taken [2]. In addition, more sperm were correctly shaped, although this result was not statistically significant.
The greatest difference in sperm concentration was found between men wearing boxer shorts most frequently and men wearing jockeys or briefs.
There were no significant differences in other reproductive hormones or damage to the DNA of the sperm. When the researchers adjusted their results to take account of reproductive hormones, apart from FSH, they found the adverse effect of tighter underwear on sperm quality remained. However, when they adjusted for FSH levels, the effect was no longer significant. This suggested to them that it was the damage to sperm concentrations and total sperm count associated with wearing tighter underwear that could be responsible for the changes in FSH levels.
Dr Mínguez-Alarcón said: "An important strength of this study is that we were able to investigate the potential relationship between the type of underwear worn and indicators of testicular function such as reproductive hormone levels and DNA damage, which were missing in all previous studies on the topic. Because of this, we were able to find a potential compensatory mechanism whereby decreased sperm production relating to the type of underwear signals to the hypothalamus to increase secretion of gonadotropin, a hormone that acts on the testes and that is reflected by the increased levels of FSH, to try to increase sperm production. This hypothesis requires confirmation by further research."
The researchers point out that it may not be possible to generalise the findings of their study to all men as the study focused on men attending a fertility centre. However, the men in this study tended to have good semen quality when compared to the World Health Organization's reference standards. It is also not possible to prove from these findings that the type of underwear causes the difference in semen quality and FSH levels, only that that there is an association between them. Other factors that might affect scrotal heat, such as type of trousers (e.g. skinny jeans) and underwear fabric, could also affect the results.
Dr Mínguez-Alarcón concluded: "Since men can modify the type of underwear they choose to wear, these results may be useful to improve men's testicular function."

Exercise linked to improved mental health, but more may not always be better

A study of 1.2 million people in the USA has found that people who exercise report having 1.5 fewer days of poor mental health a month, compared to people who do not exercise. The study found that team sports, cycling, aerobics and going to the gym are associated with the biggest reductions, according to the largest observational study of its kind published in The Lancet Psychiatry journal.
More exercise was not always better, and the study found that exercising for 45 minutes three to five times a week was associated with the biggest benefits.

The study included all types of physical activity, ranging from childcare, housework, lawn-mowing and fishing to cycling, going to the gym, running and skiing.

Exercise reduces the risk of cardiovascular disease, stroke, diabetes, and mortality from all causes, but its association with mental health remains unclear.

Previous research into the effect of exercise on mental health has conflicting results. While some evidence suggests that exercise may improve mental health, the relationship could go both ways - for example inactivity could be a symptom of and contributor to poor mental health, and being active could be a sign of or contribute to resilience. The authors note that their study cannot confirm cause and effect.

"Depression is the leading cause of disability worldwide, and there is an urgent need to find ways to improve mental health through population health campaigns," says Dr Adam Chekroud, Assistant Professor of Psychiatry at Yale University, and Chief Scientist at Spring Health, USA. "Exercise is associated with a lower mental health burden across people no matter their age, race, gender, household income and education level. Excitingly, the specifics of the regime, like the type, duration, and frequency, played an important role in this association. We are now using this to try and personalise exercise recommendations, and match people with a specific exercise regime that helps improve their mental health." [1]

In the study, the authors used data from 1.2 million adults across all 50 US states who completed the Behavioural Risk Factor Surveillance System survey in 2011, 2013, and 2015. This included demographic data, as well as information about their physical health, mental health, and health behaviours. The study did not take mental health disorders into account, other than depression.
Participants were asked to estimate how many days in the past 30 days they would rate their mental health as 'not good' based on stress, depression and emotional problems. They were also asked how often they took part in exercise in the past 30 days outside of their regular job, as well as how many times a week or month they did this exercise and for how long.

All results were adjusted for age, race, gender, marital status, income, education level, employment status, BMI, self-reported physical health and previous diagnosis of depression.

On average, participants experienced 3.4 days of poor mental health each month.

Compared to people who reported doing no exercise, people who exercised reported 1.5 fewer days of poor mental health each month - a reduction of 43.2% (2.0 days for people who exercised vs 3.4 days for people who did not exercise).

The reduction in number of poor mental health days was larger for people who had previously been diagnosed with depression, where exercise was associated with 3.75 fewer days of poor mental health compared with people who did not exercise - equivalent to a 34.5% reduction (7.1 days for people who exercised vs 10.9 days for people who did not exercise).

Overall, there were 75 types of exercise recorded and these were grouped into eight categories - aerobic and gym exercise, cycling, household, team sports, recreational activity [2], running and jogging, walking, and winter or water sports.

All types of exercise were associated with improved mental health, but the strongest associations for all participants were seen for team sports, cycling, aerobic and gym exercise (reduction in poor mental health days of 22.3%, 21.6%, and 20.1%, respectively).

Even completing household chores was associated with an improvement (reduction in poor mental health days of around 10%, or around half a day less each month).

The association between exercise and improved mental health (a 43.2% reduction in poor mental health) was larger than many modifiable social or demographic factors. For example, people with a college education had a 17.8% reduction in poor mental health days compared with people with no education, people with normal BMI had a 4% reduction compared with people who were obese, and people earning more than US$50,000 had a 17% reduction compared with people earning less than US$15,000.

How often and for how long people completed exercise was also an important factor. People who exercised between three and five times a week had better mental health than people who exercised less or more each week (associated with around 2.3 fewer days of poor mental health compared with people who exercised twice a month).

Exercising for 30-60 minutes was associated with the biggest reduction in poor mental health days (associated with around 2.1 fewer days of poor mental health compared with people who did not exercise). Small reductions were still seen for people who exercised more than 90 minutes a day, but exercising for more than three hours a day was associated with worse mental health than not exercising at all. The authors note that people doing extreme amounts of exercise might have obsessive characteristics which could place them at greater risk of poor mental health.
"Previously, people have believed that the more exercise you do, the better your mental health, but our study suggests that this is not the case. Doing exercise more than 23 times a month, or exercising for longer than 90 minute sessions is associated with worse mental health," continues Dr Chekroud. [1]

"Our finding that team sports are associated with the lowest mental health burden may indicate that social activities promote resilience and reduce depression by reducing social withdrawal and isolation, giving social sports an edge over other kinds." [1]

The study used people's self-reported assessment of their mental health and exercise levels so could be subject to bias. It also only asked participants about their main form of exercise so could underestimate the amount of exercise they do if they do more than one type.

Writing in a linked Comment, Dr Gary Cooney, Gartnavel Royal Hospital, UK, says: "There is gathering interest and momentum around research into exercise as a treatment for mental health disorders. The appeal is multifaceted: patients, particularly those reluctant to pursue medication or psychological approaches, are drawn to the self efficacy of exercise, the ability to attain a degree of agency in their own process of recovery. Mental health professionals, for their part, recognise the urgent need to address the comparatively poor physical health outcomes in the psychiatric patient population. With very high rates of physical comorbidity, and marked reductions in life expectancy, an intervention that might improve both mental and physical health is of particular clinical interest."

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Large study finds link between 3 degenerative eye diseases, Alzheimer's

Alzheimer's disease is difficult to diagnose as well as treat, but researchers now have a promising new screening tool using the window to the brain: the eye.

A study of 3,877 randomly selected patients found a significant link between three degenerative eye diseases - age-related macular degeneration, diabetic retinopathy and glaucoma - and Alzheimer' disease.

The results offer physicians a new way to detect those at higher risk of this disorder, which causes memory loss and other symptoms of cognitive decline. .

The researchers, from the University of Washington School of Medicine, the Kaiser Permanente Washington Health Institute and the UW School of Nursing, reported their findings Aug. 8 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.

"We don't mean people with these eye conditions will get Alzheimer's disease," said lead researcher Dr. Cecilia Lee, assistant professor of ophthalmology at the UW School of Medicine. "The main message from this study is that ophthalmologists should be more aware of the risks of developing dementia for people with these eye conditions and primary care doctors seeing patients with these eye conditions might be more careful on checking on possible dementia or memory loss."

The participants in the study were age 65 and older and did not have Alzheimer's disease at the time of enrollment. They were part of the Adult Changes in Thought database started in 1994 by Dr. Eric Larson, who is at Kaiser Permanente Washington Health Research Institute. Over the five-year study, 792 cases of Alzheimer's disease were diagnosed by a committee of dementia experts. Patients with age-related macular degeneration, diabetic retinopathy, or glaucoma were at 40 % to 50% greater risk of developing Alzheimer's disease compared to similar people without these eye conditions. Cataract diagnosis was not an Alzheimer's disease risk factor.
"What we found was not subtle," said Dr. Paul Crane, professor of medicine, Division of General Internal Medicine, at the UW School of Medicine. "This study solidifies that there are mechanistic things we can learn from the brain by looking at the eye."
More than 46 million older adults are affected by dementia worldwide and 131.5 million cases are expected by 2050, the researchers said. Alzheimer' disease is the most common dementia,and discovering risk factors may lead to early detection and preventive measures, they said in their paper.
Lee said anything happening in the eye may relate to what's happening in the brain, an extension of the central nervous system. The possible connections need more study. She said a better understanding of neurodegeneration in the eye and the brain could bring more success in diagnosing Alzheimer's early and developing better treatments.
The researchers said several factors suggest the effects they uncovered were specific to ophthalmic conditions and not merely age-related phenomenon.
Larson said for years Alzheimer's researchers were focused on amyloid buildup in brain tissue, but that hasn't brought much benefit to patients.
"This paper is pointing to a new area of opportunity," he said.

Learning to ask older adults better questions about their memory

 Healthcare providers and researchers rely on screening questions to detect patients who may be at risk for developing Alzheimer's disease and other aging-related problems, but how these questions are worded may be confusing or trigger emotional responses. According to Penn State researchers, this may result in patients who answer the same questions differently, and for different reasons.
In a study with older Pennsylvania adults, researchers asked participants a variety of common screening questions and then followed up to learn more about how each participant felt about those questions.

For example, when asked "Have you had problems with your memory recently?" one patient may interpret "recently" as within the same week while another may interpret it as within the month. Or, a third may be frightened by trouble with their memory and brush off the question altogether.
Nikki Hill, assistant professor of nursing at Penn State, said the results will help clinicians and researchers ask better questions and better interpret patient responses.

"If someone has concerns about their memory, that could be important for a lot of different reasons," Hill said. "It could mean they have a problem that may continue to get worse, or maybe it's impacting them emotionally, or maybe they just need more information. So we're trying to learn the best questions to ask to really get at what our patients are experiencing and how best to respond."
According to previous research, older adults who report memory problems but score in the normal range on cognitive tests are up to twice as likely to develop Alzheimer's later.

Jacqueline Mogle, assistant professor at Penn State, said creating good questions is important not only for screening patients early for the disease, but also so researchers can ask good questions when studying these populations.
"When we ask people questions, we assume that they see the questions the same way we do," Mogle said. "However, that clearly isn't the case. What we might see as a straightforward question -- like 'Do you have problems with your memory?' -- may mean something very different for older adults. Right now it isn't clear how they are deciding to answer the question."
The researchers recruited 49 older adults in central Pennsylvania who did not have dementia to participate in the study. Each participant was asked a variety of questions commonly used to screen for Alzheimer's disease. After the participant answered, the researchers asked them follow-up questions about how and why they answered the way they did to help identify possible problems with the screening questions.
After analyzing the data, the researchers found 13 different types of problems in the screening questions. The two most common problems were vagueness -- "There are multiple ways to interpret the question" -- and an assumption that their behavior or experience is always the same. For example, they sometimes may have trouble remembering the day of the week but not always.
The researchers also found that some questions tended to provoke an emotional response. For example, one question asked the participant to "rate" themselves or their memory compared to others, which some participants associated with dips in confidence and feeling poorly about themselves.
Hill said that learning to ask better questions about a person's memory could help improve clinicians' understanding of their patients' unique experiences.
"For older adults, problems with memory and thinking is something that's experienced very differently from person to person," Hill said. "However, in the research to date, we don't tend to reflect how complicated of an experience that is. If we really want to understand how people are experiencing early symptoms and what is influencing their reporting of symptoms, we need to get at more of that individual experience, and our questions that we currently use aren't capturing it."
Hill added that it would be helpful for future studies to examine the best ways to reword and standardize screening questions to help reduce cognitive biases.
"Now that we've identified the types of problems that people report, we can take those questions, refine them, and test them out again in a larger, more representative group of older adults," Hill said. "Then we ask the new, refined questions and see if they perform better."

You're only as old as you think and do

Could increasing your physical activity or feeling more in control of your life be the secret to staying young? Employing these simple strategies may help older adults feel younger and that, in turn, could help improve their cognitive abilities, longevity and overall quality of life, according to research presented at the annual convention of the American Psychological Association.

"Research suggests that a younger subjective age, or when people feel younger than their chronological age, is associated with a variety of positive outcomes in older individuals, including better memory performance, health and longevity," said presenter Jennifer Bellingtier, PhD, of Friedrich Schiller University. "Our research suggests that subjective age changes on a daily basis and older adults feel significantly younger on days when they have a greater sense of control."

Bellingtier and co-author Shevaun Neupert, PhD, of North Carolina State University, enlisted 116 older adults (ages 60 to 90) and 106 younger adults (ages 18 to 36) and had them complete surveys each day for nine days. Participants were asked to respond to a series of statements on the level of control they felt they had each day (e.g., "In the past 24 hours, I had quite a bit of influence on the degree to which I could be involved in activities,") and were asked how old they felt that day.

The researchers found significant day-to-day variability in subjective age in both groups over the course of the study. They also found a significant association between perceived level of control each day and subjective age in the older adult group but not the younger group.

"Shaping the daily environment in ways that allow older adults to exercise more control could be a helpful strategy for maintaining a youthful spirit and overall well-being," said Bellingtier.
"For example, some interventions could be formal, such as a regular meeting with a therapist to discuss ways to take control in situations where individuals can directly influence events, and how to respond to situations that they cannot control. Smartphone apps could be developed to deliver daily messages with suggestions for ways to enhance control that day and improve a person's overall feeling of control," said Bellingtier. An intervention could also be something as simple as giving nursing home residents the opportunity to make more choices in their daily lives so that they can exercise more control.
In addition to amping up perceived control, another strategy for maintaining a younger subjective age and enjoying the benefits that go with it may be as simple as increasing physical activity, according another study presented in the same session.
"Our results suggest that promoting a more active lifestyle may result in a more youthful subjective age," said Matthew Hughes, PhD, University of North Carolina, Greensboro, who presented the study.
Hughes and his colleagues recruited 59 adults in the Boston area between the ages of 35 and 69 who were not engaged in routine physical activity. All participants were given a FitBit fitness tracker and researchers monitored their daily step counts for five weeks. Individuals with greater increases in their step counts at the end of the study reported lower subjective ages, the researchers found.
While promising, the results are still preliminary, cautioned Hughes.
"As this was part of a pilot study, our sample size was small," he said. "While the results suggest that walking may contribute to feeling younger, further research with a larger sample in a more controlled setting is needed to confirm."