Nutrition and Cancer: Finding Evidence of Direct Benefits

[nomadreid]

Using the keywords "nutrition" and "cancer", the Internet spews out thousands of articles. Ignoring the supermarket-checkout-magazine type of article, the others tend to either (a) be debunking various myths or (b) advising to avoid carcinogenic substances or (c) recommending to have a healthy diet in general to avoid conditions (obesity, starving, circulation problems, etc.) that could weaken the immunological system. However, I do not find -- but perhaps I am not looking in the right place -- evidence of specific foods that have been shown to have a direct (instead of the indirect connection via "general health" such as keeping up the immune system) benefit for a human patient who already has cancer (especially lung cancer). Does this exist?

 

[CWatters]

Not sure about specific foods but there have been articles on nutrition and exercise and its effect on cancer survival..

https://journals.lww.com/journalppo...t_of_Nutrition_and_Exercise_on_Cancer.15.aspxThis one cites some studies into food groups like red meat, carbs or sugar and reccurance..
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3832963/#__ffn_sectitle

 

[Ygggdrasil]

I'm not sure how much evidence there would be on specific foods, though much research on cancer and metabolism is ongoing. Furthermore, cancer is not one single disease, so the answer may be quite different depending on the type (or even subtype) of cancer. Here are a few that come to mind:

1) Eating grapefruit can affect how the body takes up and metabolizes specific drugs, so people taking specific drugs should usually avoid eating grapefruit while taking these drugs: https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm292276.htm

2) Very new, preliminary research suggests that diet could boost the effectiveness of certain chemotherapy drugs. Essentially, certain anti-cancer drugs disrupt metabolic signaling processes throughout the body, such as insulin signaling, which can cause unwanted side effects that in some cases can require patients to be taken off treatment. In some cases, it may be possible to control these side-effects through control of diet (for example, using a low carbohydrate diet to prevent hyperglycemia that might occur from treatment with certain anti-cancer drugs). These benefits, however, have only been demonstrated in animal studies and await clinical trials in humans to verify their safety and efficacy. For more info see:
https://www.theguardian.com/science...ogist-to-study-effect-of-diet-on-cancer-drugs
https://www.nature.com/articles/s41586-018-0343-4

 

[nomadreid]

Thanks very much, Ygggdrasil and CWatters.
CWatters: unfortunately, the first of the two links you posted offers only a short abstract, with an option to pay for the full article. Sometimes abstracts are sufficiently informative, but this one begs to see the details behind it. You wouldn't have a link to a pre-print?

 

[Laroxe]

Really most nutritional advice seems to reflect a moral message rather than credible evidence a classic example would be the health benefits of the Mediterranean diet, its based on a diet, no one in the Med has every eaten and the benefits, well there aren't any. Most of the stuff you will see is based on prevention and even that has weak to none existent support. You seem to be looking for things that are often described as functional foods and there have been some interesting ideas, some more credible than others but they never seem to do what was expected.

Various antioxidants were really thought to offer hope but basically what was discovered is that we didn't understand what the body used them for our white cells uses reactive oxygen to kill abnormal cells, giving large doses of antioxidants can interfere with this function, they found that people taking supplements actually increased their risk of cancer. Its now thought that they also interfere with treatments like radiotherapy.

Apparently cancers generally are less efficient in their use of nutrients and require lots of glucose, so the idea was to adopt a a very low sugar diet to starve the cancer, it didn't. In fact the only ones left that still seem credible are diets rich in phytoestrogen like soya which could influence cancer of the prostate, but we have drugs that are far more efficient.

So I'm afraid there is nothing that has evidence of any direct effect and this must be a difficult time to be diagnosed with cancer as there are so many developments, people might feel they will miss out on some new treatment and lung cancers are notoriously difficult to treat.

 

[nomadreid]

Thanks, Laroxe, this was also my impression. The article
https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/antioxidants-fact-sheet
does a good job in indicating the negative results of research on antioxidants and a few other substances, and
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4933959/
is pretty good in saying that apparently the idea that cancer risk might be lowered by certain nutrients came historically from a false contrapositive from correlations between the extreme lack of certain nutrients and a higher rate of cancer --i.e., that some substances may be carcinogenic, but that this conclusion has not been borne out.

 

[Laroxe]

Just an update on my position. Along with the new biologic therapies, there has been an explosion in the information we have about cell metabolism and signalling molecules. Obviously cancer has been a focus of a great deal of attention and its become increasingly evident that caners are characterised by an increased rate of mutation and tumours often have a mix of cells with very different genetic makeup.

Cancers which have the ability to ignore many of the signalling molecules, avoid immune surveillance, spread through tissue, stimulate angiogenesis and preferentially use the bodies food resources sometimes seem to have developed superpowers. However all these abilities come at a cost and cancers also come with a range of weaknesses. It seems there are in fact a number of nutritional products that can impact on these processes. It seems that their effects are not at a level that would produce a significant clinical effect, but they can cause significant stress on cancer cells by interfering with their functioning.

Research seems to be concentrating on two main areas the first is in whether these products can increase the effectiveness of other therapies and there is an increasing body of evidence that they can. Several have been identified that act as radio-sensitizers, increasing the sensitivity to radiotherapy and knowing which pathways are effected by drugs can allow some food products to be used that increase their toxicity to cancer cells but not in normal cells. There is also some evidence that these approaches can stop or delay resistance developing. The second main area of work is in using the natural molecules as models for drug development, basically developing new molecules that have a more powerful effect.

So the answer becomes more of a maybe. The evidence is still largely from in vitro and animal studies, evidence in humans is starting to appear.
A few examples

https://www.ncbi.nlm.nih.gov/pubmed/29872613

https://www.ncbi.nlm.nih.gov/pubmed/28953264

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2758121/

 

[nomadreid]

Thanks for the update, Laroxe.
A couple of bits of historical trivia: the article on tumeric makes me think of Bharat B. Aggarwal, a biochemist who did a lot of research, later much of it found to be fraudulent, on curcumin and cancer; although his research has been largely discredited, I wonder idly how many of the research spin-offs still in circulation used, directly or indirectly, any of his dubious results.
Another article cited was from the journal "Nutrients" in 2017; the following year, the editor-in-chief and a bunch of others on the editorial board resigned saying that they were pressured into publishing mediocre papers, as may not be surprising for an open access journal.(https://www.sciencemag.org/news/201...fter-alleged-pressure-publish-mediocre-papers) Whether the article cited was one of them? Always hard to tell...
Nonetheless, the post appears to be a very nice summary of the state of current research, with the conclusion of a big "maybe" to my original question.