RE: Sleep Deprivation Does Not Treat Depression
Cancer is the result of a fixed set of physiological conditions that arise primarily from inadequate diet that cause excess glycation of telomerase, and obesity which causes excess cell multiplication (more fat = more tissue = more cell multiplication = more risk of cancer) so cancer I'd address primarily with diet. Of course certain activities, such as drinking and smoking also cause cancer because they bring toxins into your system (ethanol = destroys mitochondria, smoking = a bunch of shit). Diet can also affect mood, but that's somewhat besides the point.
Depression can also be addressed with cognitive behavioral therapy in severe cases so I agree, exercise is not the only possible solution, but if you exercise regularly the likelihood that you will develop depression is much lower.
The SSRI's etc. are super useless in my experience. They don't work for many patients and need to be cycled if they work, so in short not a solution.
Exercise on the other hand is an actual solution because it has several beneficial effects on multiple brain systems that are involved in the development of depression (e.g.: the hypothalamus, which does not atrophy when you exercise regularly, in fact, it appears as if exercise facilitates neurogenisis in the hypothalamus).
Hey @granunic0rn, please cite your sources! I'm glad that you're discussing some points on the molecular and systems level, but these are some serious claims made without any background cited.
Like, access google scholar, type in: effects of glycation on genome expression. Read abstracts of results, form opinion or find the next best review that discusses the issue at length to form an adequate opinion on the consensus of the field.
In Biology they all pretty much agree that glycation and adiposity is bad for health because it destroys the genome. They have numerous reasons for that believe (it's a theory, but it has plenty of evidence: I refer to the DNA = broken you'll get cancer theory).
I personally read a summary by Amen (2016), but that one is privately published so IDK if you want to give me a 10 minute mail so that I can send the PDF to you.
Alternatively, if you really really really want to know I'll provide you with a list of references that Amen used in his paper.
It's mostly rodent, mammal and bird studies though. Obviously cannot lock humans into cages and feed them diets that are suspected to cause cancer or vice verse study effect of diets that prevent cancer (human lifespan is a serious limitation for those, rodents are much better because you can have a few generations in a decade and publish results). However, the AMEN paper mostly addresses diet and the physiological mechanisms that destroy the body when you are on a 'bad' diet.
Nonetheless, you can extrapolate some of the research findings to bio-physiological processes and then speculate that they would also affect the psyche in a detrimental way. Speculate because there is currently no consensus in neuroscience.
There is consensus on certain things, like facilitation of neurogenisis in the hypothalamus of rats that are exercised with some evidence supporting this claim in humans (e.g.: elderly patients in a nursing home after 12 week light exercise program), but of course you cannot claim that this can HEAL a disorder.
It can merely reverse some of the physiological deterioration that occurs in old age and with the (somewhat) limited restoration of the system there is a possibility of the reversal of symptoms (more or less).
I recently wrote a paper on the topic of exercise and self-regulation. Exercise seems to improve self-regulation because it improves blood flow which increases blood flow to the PFC which is the decision making center. The PFC is furthest away from the heart and thus more likely 'just because of the distance' to be cut off from blood flow compared to say the brain stem which is actually connected to the two main arteries going into the brain which basically means its never starved for blood. On the other hand the PFC is only connected to one artery and thus could be more easily starved from blood if the heart muscle is not able to move sufficient volume of blood to the brain. Exercise makes this less likely because exercise grows the heart muscle and improves blood circulation (sheer volume increases per pump, larger heart muscle pumps more blood per beat, larger heart muscle can pump at higher frequency if necessary, etc.)
You can start by reading the paper from Reynard, Gervitz, Berlow et. al (2011) in Psychophysiological Biofeedback. The article is called Heart Rate Variability as a Marker of Self-Regulation.
The article itself summarizes a lot of the finding, BUT it obviously links to a long list of articles who explain the biological, physiological and psychological background at length. Please don't ask me to link all the articles I have on that topic individually and research it for yourself a little. The articles cited in this article are a good start, but there are much better biological papers I have to admit.
My offer for the Amen article and its content list still stand. I'll have to find the email with his article but I know I still have it. However, it's like 2 AM here already and I think I won't look that up tonight. So get back to me tomorrow and I'll see what I can find for you.
If you are interested in diet effect mood there are really interesting studies with parasites, like the mildew mushroom. It can produce human hormones like estrogen or melatonin. So the parasite can induce sleep or sleep disorders. It also likes to make hormones that increase hunger so you keep feeding it before it moves to the next target.
Of course, in this case this would be an effect of diet in conjunction with a parasite, but diet in general can have effect on mood too.
We can argue about the magnitude of the effect on the human psyche, nonetheless the positive or negative effects of diet on the physiological function of the human body are undeniable.
The better the foundation, the better your likelihood to stay healthy (physically and mentally). You are what you eat is a maxim that holds true, however, I won't claim that you'll get depression just because you eat a certain type of food. No one can proof that beyond a doubt. We can just show that consumption of certain macro (or micro-nutrients) correlates with certain symptoms of certain disorders.
Good luck actually finding the causal relations. That's a different beast to slay.