Placeholder Image

Subtitles section Play video

  • Anorexia nervosa is a common and dangerous illness

  • that affects millions of people.

  • For a long time, it's been thought of primarily as a psychiatric disorder,

  • but new research published this week in the journal Nature Genetics

  • suggests there's an important physiological aspect as well.

  • This research links the disorder to genetics and metabolism,

  • and it might change the way we understand the origins of the illness

  • as well as potential treatments.

  • Anorexia nervosa is an eating disorder.

  • Affected people may be dangerously underweight,

  • with a restricted intake of food,

  • and often also have a distorted body image.

  • The end result is that the body is starved of sufficient nutrients,

  • which can lead to various medical complications and even death.

  • In fact, according to the U.S. National Institute of Mental Health,

  • anorexia is the most deadly mental disorder.

  • Even with treatment, many patients struggle to fully overcome anorexia.

  • The authors of this new research suggest that current treatments

  • might be too focused on psychology,

  • and fail to consider the physiology involved in the disorder.

  • This study pulled together genetic data on almost

  • 17,000 cases of anorexia nervosa among people of European ancestry.

  • When they compared that dataset with a control group,

  • they found 8 genetic variants significantly associated with anorexia.

  • Interestingly, some of these genetic traits are also known

  • to be related to levels of physical activity, as well as to metabolism,

  • the processes inside the body that convert sustenance into energy.

  • People suffering from anorexia have been known to show signs

  • of abnormal metabolism, but this has often been thought of

  • as a side effect of being starved of nutrients.

  • However, the researchers say this genetic link means

  • that an unusual metabolism might actually be partly responsible for causing the disorder.

  • The researchers say we should think of anorexia nervosa

  • as arising from a combination of both psychological and physiological factors.

  • They say their analysis potentially expands the list of risk factors

  • for the disorder -- that is, characteristics that increase

  • a person's likelihood of developing it.

  • And that in turn opens up a whole new avenue for medical professionals

  • looking to develop treatments for this deadly disease.

  • And anorexia isn't the only illness that's more complicated than it seems.

  • Another new study this week, published in

  • the Journal of the American Medical Association,

  • found a similar duality with dementia -- but the other way around.

  • Dementia is defined as a decline in mental ability

  • that's severe enough to interfere with a person's daily life.

  • It can take many forms, but the most common is Alzheimer's disease,

  • which affects more than five million people in the US alone.

  • And Alzheimer's is known to be linked to genes.

  • There are well-known genetic risk factors that are

  • associated with a patient's likelihood of developing Alzheimer's.

  • But this new study found that dementia can also be

  • influenced by how healthy a person's lifestyle is.

  • Like the first study, this one looked at a wide sample of genetic data,

  • this time from nearly 200,000 people in the UK,

  • including more than 1700 recorded cases of dementia.

  • The researchers assembled a genetic risk score for each person,

  • but also a lifestyle health score based on each person's self-reported diet,

  • level of physical activity, and frequency of smoking or drinking alcohol.

  • They found that, even among people with a high genetic risk,

  • the incidence of dementia was significantly lower in people with a

  • healthier lifestyle versus people living less healthy.

  • The difference was small but noteworthy.

  • Of the study participants with high genetic risk of dementia,

  • the disease developed in 1.78% of those with unhealthy habits,

  • but only 1.13% of those with a healthier lifestyle.

  • In absolute terms, this would mean that if people at high genetic risk

  • improved their lifestyle, one case of dementia could be prevented

  • for each 121 at-risk individuals every decade.

  • So this is certainly not a cure, but it does seem that dementia,

  • like anorexia nervosa, is related to a combination of factors, both genetic and behavioral.

  • Which is exciting because as we learn more,

  • we might discover ways for people to offset their built-in risk

  • of dementia by adjusting their behavior and lifestyle.

  • But there's definitely still more to be learned.

  • Both of these studies looked at specific populations of people,

  • mainly those of European ancestry.

  • And it will no doubt take more study in more diverse populations

  • to tease out exact interrelationships between the various factors involved in these diseases.

  • But the takeaway here is that illness is complicated -

  • especially the ones we haven't figured out how to treat yet.

  • Genetics can be very helpful in understanding where diseases arise,

  • but your genes are not your destiny.

  • Diseases often have complex and interrelated causes,

  • and the more we come to understand that complexity,

  • the better chance we have in the fight against them.

  • Thanks for watching this episode of SciShow News.

  • If you're interested in helping us bring great videos to the world every day,

  • from news to quick questions to deep dives, you can support us on Patreon.

  • Check it out - patreon.com/scishow - that's the whole reason we can do this.

  • Thanks everybody.

Anorexia nervosa is a common and dangerous illness

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B1 US anorexia dementia genetic disorder lifestyle risk

Anorexia Isn't Just a Psychiatric Disorder

  • 791 14
    Jerry Liu posted on 2019/09/20
Video vocabulary