Once a week.
Subscribe to our weekly newsletter.
Vegetarian (and vegan) diet linked to higher stroke risk
Scientists still don't fully understand how abstaining from animal products affects the body.
- A new study tracked the health of more than 48,000 people over 18 years.
- The participants were divided into three groups – meat eaters, vegetarians (including vegans) and fish eaters.
- The results showed that, compared to meat eaters, vegetarians had a 20% increased chance of stroke, but also a 22% decreased chance of heart disease.
Vegetarian and vegan diets have become increasingly popular in recent decades, promising to reduce the risk of conditions like obesity, ischaemic heart disease, high blood pressure and certain types of cancer. Still, scientists still don't fully understand how abstaining from animal products affects the body. Now, new research sheds light on one potential risk of vegetarian and vegan diets: increased likelihood of stroke.
The study, published last week in the British Medical Journal, examined the risk factors associated with ischaemic heart disease and stroke, and it tracked the health of 48,188 men and women living in Oxford over 18 years. Each participant was grouped in one of three groups: vegetarian (including vegans), meat eater or fish eater. None of the participants had a history of ischaemic heart disease, stroke, or angina (or cardiovascular disease), and the researchers accounted for other risk factors including physical activity, education level, smoking habits and alcohol consumption.
The results showed that vegetarians were about 20 percent more likely to have had a stroke than meat eaters. However, vegetarians also had a 22 percent lower risk of heart disease, an effect the researchers suggested could be because vegetarians tend to have lower blood pressure, body mass index (BMI), cholesterol levels and incidence of diabetes.
What explains the higher risk of stroke among vegetarians? The study couldn't provide an exact biological explanation, but the researchers did reference several studies that show:
"...that individuals with a very low intake of animal products had an increased incidence and mortality from haemorrhagic and total stroke, and also a possibly higher risk of ischaemic stroke mortality, suggest that some factors associated with animal food consumption might be protective for stroke."
The researchers noted that vegetarians might suffer from a lack of several key nutrients.
"Vegetarians and vegans in the EPIC-Oxford cohort have lower circulating levels of several nutrients (eg, vitamin B12, vitamin D, essential amino acids, and long chain n-3 polyunsaturated fatty acids), and differences in some of these nutritional factors could contribute to the observed associations."
The results don't necessarily suggest you should change your diet. What's probably more important is to make sure that you're eating high-quality foods. For meat eaters, one easy way to improve your diet is to avoid processed foods, which a growing body of research shows can shorten lifespan and cause multiple diseases. Also, for both vegetarians and meat eaters, eating organic foods seems to be worth the slight increase in cost.
A 2018 study, for example, found that people who ate organic foods were 25 percent less likely to develop certain kinds of cancer than people who ate "conventional" diets. The New York Times reported:
"Those who ate the most organic fruits, vegetables, dairy products, meat and other foods had a particularly steep drop in the incidence of lymphomas, and a significant reduction in postmenopausal breast cancers."
The finding is remarkably similar to the Dunning-Kruger effect, which describes how incompetent people tend to overestimate their own competency.
- Recent studies asked participants to rate the attractiveness of themselves and other participants, who were strangers.
- The studies kept yielding the same finding: unattractive people overestimate their attractiveness, while attractive people underrate their looks.
- Why this happens is unclear, but it doesn't seem to be due to a general inability to judge attractiveness.
There's no shortage of disparities between attractive and unattractive people. Studies show that the best-looking among us tend to have an easier time making money, receiving help, avoiding punishment, and being perceived as competent. (Sure, research also suggests beautiful people have shorter relationships, but they also have more sexual partners, and more options for romantic relationships. So call it a wash.)
Now, new research reveals another disparity: Unattractive people seem less able to accurately judge their own attractiveness, and they tend to overestimate their looks. In contrast, beautiful people tend to rate themselves more accurately. If anything, they underestimate their attractiveness.
The research, published in the Scandinavian Journal of Psychology, involved six studies that asked participants to rate the attractiveness of themselves and other participants, who were strangers. The studies also asked participants to predict how others might rate them.
In the first study, lead author Tobias Greitemeyer found that the participants who were most likely to overestimate their attractiveness were among the least attractive people in the study, based on average ratings.
Ratings of subjective attractiveness as a function of the participant's objective attractiveness (Study 1)
"Overall, unattractive participants judged themselves to be of about average attractiveness and they showed very little awareness that strangers do not share this view. In contrast, attractive participants had more insights into how attractive they actually are. [...] It thus appears that unattractive people maintain illusory self‐perceptions of their attractiveness, whereas attractive people's self‐views are more grounded in reality."
Why do unattractive people overestimate their attractiveness? Could it be because they want to maintain a positive self-image, so they delude themselves? After all, previous research has shown that people tend to discredit or "forget" negative social feedback, which seems to help protect a sense of self-worth.
To find out, Greitemeyer conducted a study that aimed to put participants in a positive, non-defensive mindset before rating attractiveness. He did that by asking participants questions that affirmed parts of their personality that had nothing to do with physical appearance, such as: "Have you ever been generous and selfless to another person?" Yet, this didn't change how participants rated themselves, suggesting that unattractive people aren't overestimating their looks out of defensiveness.
The studies kept yielding the same finding: unattractive people overestimate their attractiveness. Does that bias sound familiar? If so, you might be thinking of the Dunning-Kruger effect, which describes how incompetent people tend to overestimate their own competency. Why? Because they lack the metacognitive skills needed to discern their own shortcomings.
Greitemeyer found that unattractive people were worse at differentiating between attractive and unattractive people. But the finding that unattractive people may have different beauty ideals (or, more plainly, weaker ability to judge attractiveness) did "not have an impact on how they perceive themselves."
In short, it remains a mystery exactly why unattractive people overestimate their looks. Greitemeyer concluded that, while most people are decent at judging the attractiveness of others, "it appears that those who are unattractive do not know that they are unattractive."
Unattractive people aren't completely unaware
The results of one study suggested that unattractive people aren't completely in the dark about their looks. In the study, unattractive people were shown a set of photos of highly attractive and unattractive people, and they were asked to select photos of people with comparable attractiveness. Most unattractive people chose to compare themselves with similarly unattractive people.
"The finding that unattractive participants selected unattractive stimulus persons with whom they would compare their attractiveness to suggests that they may have an inkling that they are less attractive than they want it to be," Greitemeyer wrote.
Every star we can see, including our sun, was born in one of these violent clouds.
This article was originally published on our sister site, Freethink.
An international team of astronomers has conducted the biggest survey of stellar nurseries to date, charting more than 100,000 star-birthing regions across our corner of the universe.
Stellar nurseries: Outer space is filled with clouds of dust and gas called nebulae. In some of these nebulae, gravity will pull the dust and gas into clumps that eventually get so big, they collapse on themselves — and a star is born.
These star-birthing nebulae are known as stellar nurseries.
The challenge: Stars are a key part of the universe — they lead to the formation of planets and produce the elements needed to create life as we know it. A better understanding of stars, then, means a better understanding of the universe — but there's still a lot we don't know about star formation.
This is partly because it's hard to see what's going on in stellar nurseries — the clouds of dust obscure optical telescopes' view — and also because there are just so many of them that it's hard to know what the average nursery is like.
The survey: The astronomers conducted their survey of stellar nurseries using the massive ALMA telescope array in Chile. Because ALMA is a radio telescope, it captures the radio waves emanating from celestial objects, rather than the light.
"The new thing ... is that we can use ALMA to take pictures of many galaxies, and these pictures are as sharp and detailed as those taken by optical telescopes," Jiayi Sun, an Ohio State University (OSU) researcher, said in a press release.
"This just hasn't been possible before."
Over the course of the five-year survey, the group was able to chart more than 100,000 stellar nurseries across more than 90 nearby galaxies, expanding the amount of available data on the celestial objects tenfold, according to OSU researcher Adam Leroy.
New insights: The survey is already yielding new insights into stellar nurseries, including the fact that they appear to be more diverse than previously thought.
"For a long time, conventional wisdom among astronomers was that all stellar nurseries looked more or less the same," Sun said. "But with this survey we can see that this is really not the case."
"While there are some similarities, the nature and appearance of these nurseries change within and among galaxies," he continued, "just like cities or trees may vary in important ways as you go from place to place across the world."
Astronomers have also learned from the survey that stellar nurseries aren't particularly efficient at producing stars and tend to live for only 10 to 30 million years, which isn't very long on a universal scale.
Looking ahead: Data from the survey is now publicly available, so expect to see other researchers using it to make their own observations about stellar nurseries in the future.
"We have an incredible dataset here that will continue to be useful," Leroy said. "This is really a new view of galaxies and we expect to be learning from it for years to come."
Tiny specks of space debris can move faster than bullets and cause way more damage. Cleaning it up is imperative.
- NASA estimates that more than 500,000 pieces of space trash larger than a marble are currently in orbit. Estimates exceed 128 million pieces when factoring in smaller pieces from collisions. At 17,500 MPH, even a paint chip can cause serious damage.
- To prevent this untrackable space debris from taking out satellites and putting astronauts in danger, scientists have been working on ways to retrieve large objects before they collide and create more problems.
- The team at Clearspace, in collaboration with the European Space Agency, is on a mission to capture one such object using an autonomous spacecraft with claw-like arms. It's an expensive and very tricky mission, but one that could have a major impact on the future of space exploration.
This is the first episode of Just Might Work, an original series by Freethink, focused on surprising solutions to our biggest problems.
Catch more Just Might Work episodes on their channel: https://www.freethink.com/shows/just-might-work