Rather than focus on things that are wrong (how this causes that, what might cause this, how do I fix that) think of a car.

Pretend that car has no fluids at all.

So, you learn what fluids it needs. Gas, ok, easy. Oil, yeah. Then there's transmission fluid, coolant, brake fluid, steering pump fluid, differential fluid, wiper fluid and some cars have suspension fluid and additional fluids to keep fluids dry.

So say some guy droves up in a 30 year old car, smoking like a coal miner.

Rather than figure out how under certain conditions something might happen to the transmission fluid that makes it shift from second to third weird sometimes uphill at night, you drain the fluid and put fresh in.

The point is rather than look at it from the not working side look what's supposed to be there.

In car terms, replace ALL the fluids. In terms of human nutrition you need all the things you need and in the right amounts and the law of biogenic unicity ("no two people have the same DNA/biochemistry) says this is going to vary, practice has shows it can be by a lot.

So if the body came with a manual like cars did, you'd probably see something like:

1) Primary energy pathway (APT Synthesis)
2) Immune Primary Antioxidant system
3) Ancillary reactions.

and so on. This is why we teach Kreb's cycle/The Citric Acid cycle (http://en.wikipedia.org/wiki/Citric_acid_cycle) in school with the "powerhouse of the cell" crap about the Mitochondria.

1) The bottom line here is we make most of the chemicals in this reaction except three, Niacin, Ascorbate and Citrate. Those we have to eat.

2) The antioxidant system (http://en.wikipedia.org/wiki/Antioxidant) is how the body uses a handful of chemicals to keep oxidation at bay, when there's more oxidation than your body's ability to defend against it, you die. In short, E recharges C, C recharges E, glutathione recharges C but needs Mg, Se and NAC (N-acetyl cysteine) for it's synthesis. (Be careful of that link, there's some misinformation there saying selenium doesn't help heart health when in fact Wikipedia's own Entry on a heart ailment known as Keshan Disease points out Selenium is the only cure and preventative: ("It had been linked to the coxsackie B virus. Current research suggests that the lack of selenium results in a more virulent strain of the coxsackievirus becoming the dominant viral species present in the population of virus" (http://en.wikipedia.org/wiki/Keshan_disease). Finland supplemented their soil nationwide because of this and got the gains in heart health they expected which is very well documented in both Academic circles and farmers making videos on youtube)

3) Ancillary reactions are: Selenium also in the right amount confers immunity to all viruses and B6 and zinc are required for the biochemical pathways of thought and memory, most people need more. (Lipinski 2015)

These explain in no small way what vitamins Hoffer himself took after 50 years of research in the fields he and Pauling invented. When the first vitamin was discovered in the 1930s, more followed quickly and food producers in the time bragged about how many vitamins they added. Now food producers cover up the fact they take them out. Millions have already died because of vitamins inadvertently removed from the food supply, infantile scurvy (1911), Pellagra (1866-1935), Beri Beri (1897-1929) and Rickets (1645-1945) are the first deficiency diseases we identified by WWII. These are not the only ones.

Both the Chinese medical and Pauling make the same claim: all disease state is a deficiency. When fully and properly fad and every part of the immune system is operating properly the human body can resist cancer and Ebola. Mexico and Morocco have 100 cancer deaths per 100,000 people, Denmark has 400. Most cluster between 250-350 and this is all diet the substance that reactivate human gene p53, deactivated in cancer patients is a substance made in response to mold by many plants but in largest concentration in tangerine skin. Nobody eats more of this that the Moroccans, expectantly in Tangiers that tangerines were named for, Mexico is second only by half a percent. No other country even comes close. Cancer stats can be found easily.

The point is if you have enough of the substances your body needs it'll work properly. Pay attention to the ones outlined above notice what Hoffer took and for a healthy person that's a good start for having optimal amounts of the substances required by the body to fend off disease. Most deficiency disease just go away over tie slowly with time although certain substances can be upregulated on occasion.

xRefs:
Lipinski 2015: Can Selenite be an Ultimate Inhibitor of Ebola andOther Viral Infections?
http://www.journalrepository.org/media/journals/BJMMR_12/2014/Dec/Lipinski632014BJMMR14858.pdf

Orthomolecular psychiatry: varying the concentrations of substances normally present in the human body may control mental disease
L Pauling - Science, 1968 - science.sciencemag.org
http://science.sciencemag.org/content/160/3825/265

Infantile Scurvy (1911)
http://jamanetwork.com/journals/jamapediatrics/article-abstract/1173426

Scott and Scuvy
http://idlewords.com/2010/03/scott_and_scurvy.htm

Abram Hoffer, Vitamins he took.
http://www.youtube.com/watch?v=PpQLkfDonNM

Selenium in Finland
http://www.youtube.com/watch?v=71rfSrIZy6M

High serum alpha‐tocopherol, albumin, selenium and cholesterol, and low mortality from coronary heart disease in northern Finland https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2796.1995.tb01139.x