Comment by overreg | Hacker News Reader

Comment by overreg | Hacker News Reader

"Organizations such as the Joint FAO/WHO Meeting on Pesticide Residues and the European Commission, Canadian Pest Management Regulatory Agency, and the German Federal Institute for Risk Assessment[30] have concluded that there is no evidence that glyphosate poses a carcinogenic or genotoxic risk to humans. The final assessment of the Australian Pesticides and Veterinary Medicines Authority in 2017 was that "glyphosate does not pose a carcinogenic risk to humans".[31] The EPA has evaluated the carcinogenic potential of glyphosate multiple times since 1986. In 1986, glyphosate was initially classified as Group C: "Possible Human Carcinogen", but later recommended as Group D: "Not Classifiable as to Human Carcinogenicity" due to lack of statistical significance in previously examined rat tumor studies. In 1991, it was classified as Group E: "Evidence of Non-Carcinogenicity for Humans", and in 2015 and 2017, "Not Likely to be Carcinogenic to Humans".[32][33]"

https://en.wikipedia.org/wiki/Roundup_(herbicide)

That's right- the IARC is the odd one out here and their results are based mainly on discredited experiments on rats that are known to be prone to getting cancer (meaning they aren't a good model for humans in this case).

Absence of evidence != Evidence of absence. This mistake is especially pernicious when facing the choice of repeated trials, and something inherent to this topic since constantly eating food that at some point was subject to this chemical is by definition a repeated trial.

interesting, I wonder what the modes of operation are for shuffling across classifications and what specific evidence is required.

Yes, absence of evidence is evidence of absence, under the right evidence-gathering circumstances.

Would you say that perhaps there are pigs which can fly, because absence of the evidence of the existence of flying pigs isn't evidence of their absence?

> under the right evidence-gathering circumstances.

1.) Would you say that perhaps the Parachute is not working?

"Conclusions: Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention."

https://www.bmj.com/content/363/bmj.k5094

2.) Would you say that perhaps the Mask is not working?

"Yes, masks reduce the risk of spreading COVID, despite a review saying they don’t" ( February 6 )

https://theconversation.com/yes-masks-reduce-the-risk-of-spr...

People used to think there were no black swans until they found them.

Re. flying pigs, we have total and complete observation of pigs for thousands of years, as well as a physical and biological understanding of why they can’t fly.

If you have that, then it’s pretty safe to draw conclusions.

If we randomly sample, say, 10,000 swans and find all of them to be white, then we can state that a certain percentage of swans are white, with a confidence interval around it. That percentage won't be 100% and the interval won't be +/- zero. There are multiple techniques for this:

https://en.wikipedia.org/wiki/Binomial_proportion_confidence...

Here is an online calculator:

https://www.statskingdom.com/proportion-confidence-interval-...

If we plug in 10,000 white swans out of 10,000 observations, and a confidence of 0.99 (we want to be 99% sure that the probability we calculate is within the range we calculate) the Clopper-Pearson exact result gives us a range [0.9995. 1]. Based on a observing a properly randomized, unbiased sample of 10,000 swans and finding them all to be white, we can be 99% confident that the probability of a swan being white could be as low as 99.95%, or as high as 100% (all swans are white).

If we want to be 99.99% certain of our range, it drops down to [0.999, 1]: 99.9% to 100% of swans are white, with a confidence of 99.99%.

There are lots of substances that can cause cancer, including ones that occur in nature, including in foods. The relevant question is whether the substance under consideration causes cancer above the noise floor, not in some mathematically pure sense like "No molecule of the substance could ever interact with something in a cell in order to trigger cancerous behavior."

E.g. roughly speaking, if you give megadoses of the stuff to a large number of rats and they don't have any more tumors than a control group, that's might be good evidence of absence, especially if repeated with large numbers of rats by different researchers in different countries and organizations.

Personally, I would take it a step further. Even if there is a non-zero statistical chance that it causes cancer, I think there has to be some room to ask whether the benefits outweigh the costs. To some, low food prices in a world of food shortages may very well merit some non-zero chance of cancer. Grown-up societies make these kinds of trade-offs all the time. A speed limit of 10 miles an hour would result in fewer dead than 55 mph. As a society, we are willing to sacrifice some non-zero number of people given the increase in time and convenience associated with the higher speed limit. This is, to most people, an acceptable trade-off. On the other hand, you have the hand-wringers arguing "even one life" is too many, and then driving home at 55 mph.

Also, every nonzero statistical chance has to be compared to the noise floor. Say that something is found to be capable of causing cancer, but at the environmental exposure levels, the risk is lower than from having one beer every three months.

check: glyphosate gut-brain axis

https://scholar.google.com/scholar?q=glyphosate+gut-brain+ax...

The important caveat here is in laboratory mice, which isn't to dismiss ongoing work but to temper strong claims a bit.

but enough to refute this type of claim:

"... glyphosate has been considered to be generally safe to animal health .."

Does it? You can harm those deeply inbreed and sickly lab mice with almost anything, and these types of results often don't generalize to animals outside of the lab setting. The few I skimmed don't indicate dose, generalize out form some tentative stuff from past studies, and some are making wild claims about things like autism which seem to be out of line with meta-analysis[1] of the links between dysbiotic bacteria with respect to ASD. And this analysis points to the effects only being on rat pups[2] where it was administered in drinking water. And digging a little further it seems that the evidence on actual levels in food being dangerous to humans or other mammals is lacking[3] so I don't think it refutes the claim at all.

[1] https://link.springer.com/article/10.1007/s10803-021-05002-y

[2] https://link.springer.com/article/10.1186/s12940-018-0394-x

[3] https://www.sciencedirect.com/science/article/abs/pii/S00139...

"Gut microbiota and neurological effects of glyphosate" ( 2019, NeuroToxicology )

"Abstract There are currently various concerns regarding certain environmental toxins and the possible impact they can have on developmental diseases. Glyphosate (Gly) is the most utilised herbicide in agriculture, although its widespread use is generating controversy in the scientific world because of its probable carcinogenic effect on human cells. Gly performs as an inhibitor of 5-enolpyruvylshikimate-3-phospate synthase (EPSP synthase), not only in plants, but also in bacteria. An inhibiting effect on EPSP synthase from intestinal microbiota has been reported, affecting mainly beneficial bacteria. To the contrary, Clostridium spp. and Salmonella strains are shown to be resistant to Gly. Consequently, researchers have suggested that Gly can cause dysbiosis, a phenomenon which is characterised by an imbalance between beneficial and pathogenic microorganisms. The overgrowth of bacteria such as clostridia generates high levels of noxious metabolites in the brain, which can contribute to the development of neurological deviations. This work reviews the impact of Gly-induced intestinal dysbiosis on the central nervous system, focusing on emotional, neurological and neurodegenerative disorders. A wide variety of factors were investigated in relation to brain-related changes, including highlighting genetic abnormalities, pregnancy-associated problems, diet, infections, vaccines and heavy metals. However, more studies are required to determine the implication of the most internationally used herbicide, Gly, in behavioural disorders."

read more: https://www.sciencedirect.com/science/article/abs/pii/S01618...

Reply on news.ycombinator.com