The Naked Scientists

The Naked Scientists Forum

Author Topic: Why does cancer make us lose weight?  (Read 4107 times)

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Why does cancer make us lose weight?
« on: 08/10/2007 21:30:25 »
After having seen Comet & my ex-girlfriend lose a lot of weight as a result of cancer, I started wondering why that happens.

Any offers?


 

Offline elegantlywasted

  • Hero Member
  • *****
  • Posts: 573
    • View Profile
    • Deviant Art
Why does cancer make us lose weight?
« Reply #1 on: 08/10/2007 21:31:34 »
Chemo makes one nauseous, perhaps a lack of intake in calories?
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Why does cancer make us lose weight?
« Reply #2 on: 08/10/2007 21:37:08 »
Comet was eating as much as ever but still lost a lot of weight.
 

another_someone

  • Guest
Why does cancer make us lose weight?
« Reply #3 on: 08/10/2007 21:52:02 »
Chemo makes one nauseous, perhaps a lack of intake in calories?

My understanding is that weight loss happens even without chemo (i.e. prior to diagnosis - weight loss often being one of the factors leading to diagnosis).

Many diseases cause weight change, and of those, some cause weight loss and others weight gain.  Both TB and HIV are diseases known to cause weight loss.

I would imagine that since most cancers depend on uncontrolled growth, and thus having the body speed up its metabolism in order to support the fast growing tumour would seem logical.
 

Offline chris

  • Neilep Level Member
  • ******
  • Posts: 5339
  • Thanked: 65 times
  • The Naked Scientist
    • View Profile
    • The Naked Scientists
Why does cancer make us lose weight?
« Reply #4 on: 08/10/2007 21:54:00 »
Weight loss associated with malignancy (of both solid organs and the bone marrow) is known as "cancer cachexia" and is very often one of the presenting symptoms of the disease. Patients usually report a loss of appetite (and hence food intake) over a number of months. The same phenomenon is also seen in a number of inflammatory and infectious diseases, such as TB, leading doctors to conclude that the production of immune-system signalling hormones, called cytokines, could be responsible.

It may also well be a consequence of cancer called a paraneoplastic effect. These are usually chemical manifestations of the disease unrelated to the physical presence of the primary tumour. Cancers, with their deranged DNA and gene regulation, have access to the body's full genetic repertoire of hormones and growth factors, which can be produced in an uncontrolled manner. These hormones can affect other sensitive end-organs, with subsequent physiological consequences.

A good example of this is calcium. Tumours, particularly small cell lung cancers, can produce a hormone called PTHrp - a protein with parathyroid hormone like effects (the rp stands for related peptide). PTH is usually produced by the parathyroid glands (in the neck) in response to low blood calcium. The hormone triggers the loss of calcium from bone to increase the level in circulation in the bloodstream. The inappropriate production of the this hormone in a cancer patient can trigger hypercalcaemia (high blood calcium), kidney stones, kidney failure and hyperacidity in the stomach. All of these can contribute to appetite loss, and the associated bone resorption can also place patients at risk of fractures.

So many cancers can have chemical as well are purely physical effects, which is part of the way that they disable the body when they become advanced.

Chris
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Why does cancer make us lose weight?
« Reply #5 on: 08/10/2007 22:06:08 »
Thanks, Chris.

I'm aware that some diseases cause loss of appetite; but, as I said, Comet had been eating normally yet still lost a lot of weight. His stool has looked normal, and the quantity has been normal, so I assume his food had been digested OK.

Is there some way that the cancer can stop the nutrients being absorbed in the normal way?
 

Offline GBSB

  • Full Member
  • ***
  • Posts: 99
    • View Profile
    • Biomechanics and Health
Why does cancer make us lose weight?
« Reply #6 on: 09/10/2007 01:12:22 »
On my web site I trying to explain underlining mechanism of weight gain and weight loss and as well I explain how certain types of negative health condition cause weight loss.
There I explain that weight gain and weight loss by animals including the bears are misunderstand.

In short; between food intakes and weight gain is one factor that determines will body gain weight or not.
And as well I explain that between food restriction and weight loss is one factor that determines will body lose the weight or will lose the life.
 
Food is together with physical activity (exercise) are factors that enable sustain of the life and quality of life but for weight gain/weight loss it need to be understand something that is beyond obvious.
I am trying on my web page to explain that present understanding about cause of obesity and present understanding about building (and distribution) of the fat mass on the body is based on huge misconception.

One misconception is Counting Calories as way to understand, explain and to control weight of the body.
Please see link: http://www.biomechanicsandhealth.com/calories.htm
 
Another misconception is biological “Energy Balance”
Please see link: http://www.biomechanicsandhealth.com/energybalance.htm

In article “Food, Water, Air and Biomechanics” I’m trying to explain the biomechanical factor in weight gain/weight loss.
Also in this article I am trying to explain that Weight Loss Surgeries are medical practice based on misunderstanding.
 Please see link: http://www.biomechanicsandhealth.com/foodwaterandair.htm

On my (not impressive) web page is just one small part of my work and I hope you will find interesting.
 

Luka Tunjic
http://www1.biomechanicsandhealth.com/
 

The Naked Scientists Forum

Why does cancer make us lose weight?
« Reply #6 on: 09/10/2007 01:12:22 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums