News for hackers. Stuff that matters.
Re:Drugs that tamp down inflammation in the brain could slow... by lhl on Saturday December 07, 2019 @03:15AM (#21729117)
Alternatively, you can quite dramatically reduce inflammation in the brain via some simple lifestyle modifications (cutting out sugar, intermittent fasting):

Mattson, Mark P., Keelin Moehl, Nathaniel Ghena, Maggie Schmaedick, and Aiwu Cheng. “Intermittent Metabolic Switching, Neuroplasticity and Brain Health.” Nature Reviews. Neuroscience 19, no. 2 (February 2018): 63–80. https://doi.org/10.1038/nrn.2017.156.

Pinto, Alessandro, Alessio Bonucci, Elisa Maggi, Mariangela Corsi, and Rita Businaro. “Anti-Oxidant and Anti-Inflammatory Activity of Ketogenic Diet: New Perspectives for Neuroprotection in Alzheimer’s Disease.” Antioxidants 7, no. 5 (April 28, 2018). https://doi.org/10.3390/antiox7050063.

Gao, Yuanqing, Maximilian Bielohuby, Thomas Fleming, Gernot F. Grabner, Ewout Foppen, Wagner Bernhard, Mara Guzmán-Ruiz, et al. “Dietary Sugars, Not Lipids, Drive Hypothalamic Inflammation.” Molecular Metabolism 6, no. 8 (June 20, 2017): 897–908. https://doi.org/10.1016/j.molmet.2017.06.008.

White, Hayden, Karthik Venkatesh, and Bala Venkatesh. “Systematic Review of the Use of Ketones in the Management of Acute and Chronic Neurological Disorders.” Journal of Neurology and Neuroscience 08, no. 02 (2017). https://doi.org/10.21767/2171-6625.1000188.

Alirezaei, Mehrdad, Christopher C. Kemball, Claudia T. Flynn, Malcolm R. Wood, J. Lindsay Whitton, and William B. Kiosses. “Short-Term Fasting Induces Profound Neuronal Autophagy.” Autophagy 6, no. 6 (August 16, 2010): 702–10. https://doi.org/10.4161/auto.6.6.12376.

Mattson, Mark P. “Energy Intake, Meal Frequency, and Health: A Neurobiological Perspective.” Annual Review of Nutrition 25 (2005): 237–60. https://doi.org/10.1146/annurev.nutr.25.050304.092526.

This incidentally also reduces system-wide inflammation among other benefits as well:

Houtman, Judith, Kiara Freitag, Niclas Gimber, Jan Schmoranzer, Frank L. Heppner, and Marina Jendrach. “Beclin1‐driven Autophagy Modulates the Inflammatory Response of Microglia via NLRP3.” The EMBO Journal, January 7, 2019, e99430. https://doi.org/10.15252/embj.201899430.

Camell, Christina, Emily Goldberg, and Vishwa Deep Dixit. “Regulation of Nlrp3 Inflammasome by Dietary Metabolites.” Seminars in Immunology 27, no. 5 (September 2015): 334–42. https://doi.org/10.1016/j.smim.2015.10.004.

Yamanashi, Takehiko, Masaaki Iwata, Naho Kamiya, Kyohei Tsunetomi, Naofumi Kajitani, Nodoka Wada, Takahiro Iitsuka, et al. “Beta-Hydroxybutyrate, an Endogenic NLRP3 Inflammasome Inhibitor, Attenuates Stress-Induced Behavioral and Inflammatory Responses.” Scientific Reports 7, no. 1 (August 9, 2017): 7677. https://doi.org/10.1038/s41598-017-08055-1.

Youm, Yun-Hee, Kim Y. Nguyen, Ryan W. Grant, Emily L. Goldberg, Monica Bodogai, Dongin Kim, Dominic D’Agostino, et al. “Ketone Body β-Hydroxybutyrate Blocks the NLRP3 Inflammasome-Mediated Inflammatory Disease.” Nature Medicine 21, no. 3 (March 2015): 263–69. https://doi.org/10.1038/nm.3804.

Marín‐Aguilar, Fabiola, Ana V. Lechuga‐Vieco, Elísabet Alcocer‐Gómez, Beatriz Castejón‐Vega, Javier Lucas, Carlos Garrido, Alejandro Peralta‐Garcia, et al. “NLRP3 Inflammasome Suppression Improves Longevity and Prevents Cardiac Aging in Male Mice.” Aging Cell 0, no. 0 (n.d.): e13050. https://doi.org/10.1111/acel.13050.

Xiao, Yichen, Wenna Xu, and Wenru Su. “NLRP3 Inflammasome: A Likely Target for the Treatment of Allergic Diseases.” Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology 48, no. 9 (2018): 1080–91. https://doi.org/10.1111/cea.13190.

Bugyei-Twum, Antoinette, Armin Abadeh, Kerri Thai, Yanling Zhang, Melissa Mitchell, Golam Kabir, and Kim A. Connelly. “Suppression of NLRP3 Inflammasome Activation Ameliorates Chronic Kidney Disease-Induced Cardiac Fibrosis and Diastolic Dysfunction.” Scientific Reports 6 (December 21, 2016). https://doi.org/10.1038/srep39551.

Re:Drugs that tamp down inflammation in the brain could slow... by steelframe on Saturday December 07, 2019 @11:28AM (#21731069)
Eight of those studies have been published only in the past 3 years. Until I see a pattern of repeated results, I'm going to file these under "pop science." "Keto is the shizzle, let's get our pubz!" Let's see what happens as others work on repro over the next 10+ years.
Re:Drugs that tamp down inflammation in the brain could slow... by lhl on Saturday December 07, 2019 @01:17PM (#21731681)
The top papers I included are purposefully recent as they are recent reviews on an emerging area of research.

Having read a lot of papers this year, my conclusion btw is actually that recent papers are much better than older papers. One, newer papers allow you to spelunk through older papers in the citation chain (all peer reviewed work has substantive reference lists), and two, and state of understanding of basic human biology is miniscule and for emerging topics (like chronic inflammation, or human metabolism) our understanding has changed enormously due to recent discoveries (at a much improving rate).

As an FYI, the inflammasome wasn't even discovered until 2002 [1] so you can basically be guaranteed that any prior research is going to be missing some key context. This is repeated for many pathways and processes that we take for granted (and a lot of it has barely filtered out to clinical practice much less pop culture) and will this will be repeating itself for quite some time, since we're still discovering so many new things that turn our understanding of biology on its head (just a handful of examples off the top of my head: role of microbiota (the wild west!), vagus nerve communication, autophagy, epigenetics, circadian clocks, and yes, most of ketone metabolism, particularly BHB as a signaling molecule).

[1] https://en.wikipedia.org/wiki/Inflammasome#History

Re:Drugs that tamp down inflammation in the brain could slow... by whoanow on Saturday December 07, 2019 @01:12PM (#21731650)
TIL the benefits of eating less refined carbs and intermittent fasting is still up for debate to some folks.
Re:Drugs that tamp down inflammation in the brain could slow... by DataWorker on Saturday December 07, 2019 @02:26PM (#21732051)
Add salt, fat, coffee, wine, eggs, and about a dozen other things researchers can’t agree on. nutrition research is hella sketchy
Re:Drugs that tamp down inflammation in the brain could slow... by JMTQp8lwXL on Saturday December 07, 2019 @02:33PM (#21732098)
The only fat that is really problematic is trans fats, and those are pretty much banned most places now. Fats, from particularly protein sources, contain more bioavailable micronutrients than fruits and vegetables.
Re:Drugs that tamp down inflammation in the brain could slow... by johnr2 on Saturday December 07, 2019 @01:49PM (#21731863)
> cutting out sugar

I'll assume you mean refined sugar here. I'd expect the benefits of eating fresh fruit and sugar-containing vegetables to outweigh most of the harm done by their sugar content.

Re:Drugs that tamp down inflammation in the brain could slow... by JMTQp8lwXL on Saturday December 07, 2019 @02:29PM (#21732071)
By eating the whole fruit, you're consuming the fiber, which changes how your body metabolizes the sugar (more slowly), as opposed to say, drinking a glass of apple juice.

The sugar itself between fruits and refined sugars contained in processed foods isn't all that different. Apples contain fructose, glucose, and sucrose, but in different ratios compared to table sugar. The more important factor is the quantity of sugar you're consuming.

Re:Drugs that tamp down inflammation in the brain could slow... by gexla on Saturday December 07, 2019 @03:16PM (#21732323)
But we don't even need to eat sweet fruits. If you look at your plate size as a constraint, then fruit carries an opportunity cost. You're adding sweet fruit in place of something else which could add more nutritional value in that same space. If you do eat fruit, then eat something which isn't sweet (tomato for example.)
Re:Drugs that tamp down inflammation in the brain could slow... by lhl on Saturday December 07, 2019 @03:17PM (#21732334)
Very few vegetables (starchy tubers are the main exception) contain much sugars (and specifically fructose, which is uniquely bad for your liver), so I think it's worth separating out fruit vs vegetables, but yes, there's also a very different metabolic response to acellular sugars (the best review I've seen on the subject is actually a talk given by Gabor Erdosi: https://www.youtube.com/watch?v=8rcfvRGZsDs), but I'd also say that the harm is contextual. If you're metabolically flexible, or if you're actively replenishing muscle or liver glycogen, your body comp is where you want it, and your insulin sensitivity/glucose disposal is good, then yeah, sure, have some fruit if you want. If you're like the majority of American adults though, then it's probably not doing you any favors.

* 2013–2014 NHANES Data shows 70.2% of US adults are overweight or obese. [1] 37.7% being obese. Note, that this percentage is reported at 39.8% in 2015-2016 (using the same NHANES data). [2]

* The NIH estimates that "Between 30 and 40 percent of adults in the United States have NAFLD." [3]

* The CDC says: "An estimated 33.9% of U.S. adults ... had prediabetes in 2015" and "Nearly half (48.3%) of adults aged 65 years or older had prediabetes." (only 1/3 are "aware" of this). Another 9.4% of the population is estimated to be diabetic. [4] That means well over half of American adults are pre-diabetic or diabetic, and that number is only going up.

It's important to recognize that diabetes is only the endpoint and it is usually preceded with Metabolic Syndrome markers. Here's a recent analysis of 2009-2016 NHANES data: https://www.liebertpub.com/doi/10.1089/met.2018.0105

* 80.1% of Americans had at least one marker of MetS by ATP III criteria

* Using more restrictive (calculated in the study) cutoffs gave a result of 12.2% of American adults in "optimal metabolic health"

Sadly, what's notably missing from all of this is measurement of fasting insulin - almost no one gets this measured (and I've both had personal experience and tons of stories from friends where Doctor's will actively fight back when requesting to have your FI tested) - it's been know for decades that hyperinsulemia and insulin resistance (best calculated by HOMA or HOMA2, indices which require FG and FI to calculate) will precede hyperglycemia by years or decades (subclinical diabetes). The insulin assay costs $8 direct-to-consumer pricing in the US when added onto standard FG/A1c testing. (FI is also required to calculate your NAFLD LFS, the best index for diagnosing NAFLD.)

To me, what was sort of shocking/amazing to me after doing my own research is how negligently ignorant GPs/clinicians are about literally the most common disease that's killing their patients.

Based on what I've learned this year, I have some (pretty well-founded IMO) opinions now, but I'm actually not all that interested in these Nutrition Wars arguments (the quality of the research is very poor and population-level dietary policy has honestly been such a disaster, but almost impossible to turn around due to institutional momentum/regulatory capture) but so much of metabolic health is contextual and bio-individual. I'd rather people pick some good surrogate markers they can track sequentially and then make controlled lifestyle modifications and see what actually helps them. Everyone should just do more of what works for them, and do less of what doesn't and worry less about what "experts" say on the matter.

[1] https://www.niddk.nih.gov/health-information/health-statisti...

[2] https://www.cdc.gov/nchs/data/databriefs/db288.pdf

[3] https://www.niddk.nih.gov/health-information/liver-disease/n...

[4] https://www.cdc.gov/diabetes/data/statistics-report/prevalen...

Re:Drugs that tamp down inflammation in the brain could slow... by ScottFree on Saturday December 07, 2019 @10:35AM (#21730771)
Have any of these studies been reproduced?
Re:Drugs that tamp down inflammation in the brain could slow... by lhl on Saturday December 07, 2019 @01:22PM (#21731712)
The body of work, while still emergent, is fairly robust IMO if that's what you're asking. I've cherry picked just a few out of hundreds of papers in my personal archive related to this topic, but if you have an interest you can easily check Pubmed or Researchgate to both follow the citation chain and get a sense of which research teams are publishing and working on what aspects (sadly there's no tool to do that automatically, although it seems like that might be a cool thing to build).
Re:Drugs that tamp down inflammation in the brain could slow... by baked_ziti on Saturday December 07, 2019 @01:13PM (#21731656)
The keto diet is a low fiber high saturated fat intake diet. The effects of low fiber consumption and high intake of saturated fat are well established, and they certainly aren't inflammation reducers. Also, fasting is not without risks.
Re:Drugs that tamp down inflammation in the brain could slow... by JMTQp8lwXL on Saturday December 07, 2019 @02:35PM (#21732108)
Keto has a concept of "net carbs". The calculation is: All carbs, minus fiber, minus sugar alcohols (most sugar alcohols are not metabolized or bioavailable). Keto doesn't restrict the subtracted types of carbs.
Re:Drugs that tamp down inflammation in the brain could slow... by whoanow on Saturday December 07, 2019 @01:25PM (#21731732)
Keto is a low carb high fat diet. With keto you can have as much fibre as you like as long as it's not paired with carbs.
Re:Drugs that tamp down inflammation in the brain could slow... by Geee on Saturday December 07, 2019 @01:52PM (#21731876)
In general, carbs / sugar paired with fiber are healthy. Sugar without fiber is unhealthy. Fiber is always healthy.
Re:Drugs that tamp down inflammation in the brain could slow... by omilu on Sunday December 08, 2019 @01:19PM (#21737245)
>>>Fiber is always healthy

Fiber is indigestible, provides no nutritional value. It just passes through. The only thing its good for is being the scaffolding to make a nice turd.

Re:Drugs that tamp down inflammation in the brain could slow... by Geee on Sunday December 08, 2019 @03:42PM (#21738156)
No, fiber supports the microbiome in the gut, which is nowadays understood as being really important for overall health.

https://www.nytimes.com/2018/01/01/science/food-fiber-microb...

Re:Drugs that tamp down inflammation in the brain could slow... by baked_ziti on Saturday December 07, 2019 @01:36PM (#21731798)
> With keto you can have as much fibre as you like as long as it's not paired with carbs.

Plants, which are extremely high in carbs, are where fiber comes from.

High intake of saturated fat is associated with heart disease.

Re:Drugs that tamp down inflammation in the brain could slow... by whoanow on Saturday December 07, 2019 @02:41PM (#21732145)
There are a ton of low carb vegetables, you should google it.
Re:Drugs that tamp down inflammation in the brain could slow... by lhl on Saturday December 07, 2019 @04:04PM (#21732543)
As mentioned, plenty (maybe even most!) vegetables are not very high in digestible carbs - certainly not the ones that are high in fiber and nutrients (you can probably skip the potatoes unless you're on a mono-diet). But this is where I think you really need to reconsider where you're getting you're data from...

> High intake of saturated fat is associated with heart disease.

First off, associations, especially in nutritional epidemiology, is trash:

Ioannidis, John P. A. “The Challenge of Reforming Nutritional Epidemiologic Research.” JAMA, August 23, 2018. https://doi.org/10.1001/jama.2018.11025.

Archer, Edward, Carl J. Lavie, and James O. Hill. “The Failure to Measure Dietary Intake Engendered a Fictional Discourse on Diet-Disease Relations.” Frontiers in Nutrition 5 (November 13, 2018). https://doi.org/10.3389/fnut.2018.00105.

Archer, Edward, Michael L. Marlow, and Carl J. Lavie. “Controversy and Debate: Memory-Based Methods Paper 1: The Fatal Flaws of Food Frequency Questionnaires and Other Memory-Based Dietary Assessment Methods.” Journal of Clinical Epidemiology 104 (December 2018): 113–24. https://doi.org/10.1016/j.jclinepi.2018.08.003.

I don't think people realize just how bad the quality of data is in these sort of survey studies. IMO anything w/ an HR/OR of <2 should probably be outright ignored, if not taken with a big salt block before using as a hypothesis for an interventional trial.

But more interestingly, is how nutritional myths can sustain after it's been overturned. It turns out that on meta-analysis (n=347747), again keeping in mind how we should treat observational studies, the HR between eating the highest and lowest saturated fat consumption is... exactly 1.0.

Siri-Tarino, Patty W, Qi Sun, Frank B Hu, and Ronald M Krauss. “Meta-Analysis of Prospective Cohort Studies Evaluating the Association of Saturated Fat with Cardiovascular Disease.” The American Journal of Clinical Nutrition 91, no. 3 (March 1, 2010): 535–46. https://doi.org/10.3945/ajcn.2009.27725.

Lets see what some other teams say. This analysis uses the GRADE approach for evidence analysis:

"Saturated fats are not associated with all cause mortality, CVD, CHD, ischemic stroke, or type 2 diabetes, but the evidence is heterogeneous with methodological limitations."

Souza, Russell J. de, Andrew Mente, Adriana Maroleanu, Adrian I. Cozma, Vanessa Ha, Teruko Kishibe, Elizabeth Uleryk, et al. “Intake of Saturated and Trans Unsaturated Fatty Acids and Risk of All Cause Mortality, Cardiovascular Disease, and Type 2 Diabetes: Systematic Review and Meta-Analysis of Observational Studies.” BMJ 351 (August 12, 2015). https://doi.org/10.1136/bmj.h3978.

There have still been plenty of studies so lets focus on adequately controlled RCTs, the highest evidence we might have:

"When pooling results from only the adequately controlled trials there was no effect for major CHD events (RR = 1.06, CI = 0.86–1.31), total CHD events (RR = 1.02, CI = 0.84–1.23), CHD mortality (RR = 1.13, CI = 0.91–1.40) and total mortality (RR = 1.07, CI = 0.90–1.26). Whereas, the pooled results from all trials, including the inadequately controlled trials, suggested that replacing SFA with mostly n-6 PUFA would significantly reduce the risk of total CHD events (RR = 0.80, CI = 0.65–0.98, P = 0.03), but not major CHD events (RR = 0.87, CI = 0.70–1.07), CHD mortality (RR = 0.90, CI = 0.70–1.17) and total mortality (RR = 1.00, CI = 0.90–1.10).

Conclusion

Available evidence from adequately controlled randomised controlled trials suggest replacing SFA with mostly n-6 PUFA is unlikely to reduce CHD events, CHD mortality or total mortality. The suggestion of benefits reported in earlier meta-analyses is due to the inclusion of inadequately controlled trials. These findings have implications for current dietary recommendations."

Hamley, Steven. “The Effect of Replacing Saturated Fat with Mostly N-6 Polyunsaturated Fat on Coronary Heart Disease: A Meta-Analysis of Randomised Controlled Trials.” Nutrition Journal 16 (May 19, 2017). https://doi.org/10.1186/s12937-017-0254-5.

This isn't the only RCT meta-analysis confirming this. Here's one w/ n=62421 from another team:

"The current available evidence found no significant difference in all-cause mortality or CHD mortality, resulting from the dietary fat interventions. RCT evidence currently available does not support the current dietary fat guidelines. The evidence per se lacks generalisability for population-wide guidelines."

Harcombe, Zoë, Julien S. Baker, James J. DiNicolantonio, Fergal Grace, and Bruce Davies. “Evidence from Randomised Controlled Trials Does Not Support Current Dietary Fat Guidelines: A Systematic Review and Meta-Analysis.” Open Heart 3, no. 2 (August 1, 2016): e000409. https://doi.org/10.1136/openhrt-2016-000409.

So how did this come to be in the first place? Harcombe et al have done a ton of interesting research on this topic, which I'll include for those wanting to dive into the history of the topic (I'm personally a bit bored by the whole lipid heart stuff; turns out that MetS is a 10X greater risk factor, and also if you get a CAC scan every 5 years and keep a 0 score, you're CHD risk is basically nil) :

Harcombe, Zoë, Julien S. Baker, Stephen Mark Cooper, Bruce Davies, Nicholas Sculthorpe, James J. DiNicolantonio, and Fergal Grace. “Evidence from Randomised Controlled Trials Did Not Support the Introduction of Dietary Fat Guidelines in 1977 and 1983: A Systematic Review and Meta-Analysis.” Open Heart 2, no. 1 (January 1, 2015): e000196. https://doi.org/10.1136/openhrt-2014-000196.

Harcombe, Zoë, Julien S. Baker, and Bruce Davies. “Evidence from Prospective Cohort Studies Did Not Support the Introduction of Dietary Fat Guidelines in 1977 and 1983: A Systematic Review.” British Journal of Sports Medicine 51, no. 24 (December 2017): 1737–42. https://doi.org/10.1136/bjsports-2016-096409.

Harcombe, Zoë. “Dietary Fat Guidelines Have No Evidence Base: Where next for Public Health Nutritional Advice?” Br J Sports Med 51, no. 10 (May 1, 2017): 769–74. https://doi.org/10.1136/bjsports-2016-096734.

Harcombe, Zoe. “US Dietary Guidelines: Is Saturated Fat a Nutrient of Concern?” British Journal of Sports Medicine 53, no. 22 (November 1, 2019): 1393–96. https://doi.org/10.1136/bjsports-2018-099420.

Oh, just in case anyone wants to dive into the best risk factors I found (and I've done a lot of digging on risk factors) for avoiding heart disease:

Reverse prediabetes (HR: 0.44):

Vistisen, Dorte, Mika Kivimäki, Leigh Perreault, Adam Hulman, Daniel R. Witte, Eric J. Brunner, Adam Tabák, Marit E. Jørgensen, and Kristine Færch. “Reversion from Prediabetes to Normoglycaemia and Risk of Cardiovascular Disease and Mortality: The Whitehall II Cohort Study.” Diabetologia, May 23, 2019. https://doi.org/10.1007/s00125-019-4895-0.

Maintain a CAC=0 (HR: 0.41):

Blaha Michael J., Cainzos-Achirica Miguel, Greenland Philip, McEvoy John W., Blankstein Ron, Budoff Matthew J., Dardari Zeina, et al. “Role of Coronary Artery Calcium Score of Zero and Other Negative Risk Markers for Cardiovascular Disease.” Circulation 133, no. 9 (March 1, 2016): 849–58. https://doi.org/10.1161/CIRCULATIONAHA.115.018524.

And a few interesting final thoughts on etiology (and circling back to the original topic of inflammation):

Malhotra, Aseem, Rita F. Redberg, and Pascal Meier. “Saturated Fat Does Not Clog the Arteries: Coronary Heart Disease Is a Chronic Inflammatory Condition, the Risk of Which Can Be Effectively Reduced from Healthy Lifestyle Interventions.” Br J Sports Med 51, no. 15 (August 1, 2017): 1111–12. https://doi.org/10.1136/bjsports-2016-097285.

Tsoupras, Alexandros, Ronan Lordan, and Ioannis Zabetakis. “Inflammation, Not Cholesterol, Is a Cause of Chronic Disease.” Nutrients 10, no. 5 (May 12, 2018). https://doi.org/10.3390/nu10050604.

(Cholesterol is a whole different can of worms than saturated fat (I'll leave that as an exercise to the reader), but cholesterol is also a terrible marker. "Most major heart attacks occur in people with normal cholesterol": https://www.sciencedaily.com/releases/2017/04/170412105837.h...)

Re:Drugs that tamp down inflammation in the brain could slow... by baked_ziti on Sunday December 08, 2019 @02:31PM (#21737699)
> associations, especially in nutritional epidemiology, is trash: > I think you really need to reconsider where you're getting you're data from...

I'm going to go with established medical science on this one.

> Most medical, scientific, heart-health, governmental, and professional authorities agree that saturated fat is a significant risk factor for cardiovascular disease, including the World Health Organization,[1] the Food and Nutrition Board of the National Academy of Medicine,[2] the Academy of Nutrition and Dietetics,[3] the Dietitians of Canada,[3] the Association of UK Dietitians,[4] the American Heart Association,[5] the British Heart Foundation,[6] the Heart and Stroke Foundation of Canada,[7] the World Heart Federation,[8] the British National Health Service,[9] the United States Food and Drug Administration,[10] and the European Food Safety Authority.[11] All of these organizations recommend restricting consumption of saturated fats to reduce that risk.

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

Re:Drugs that tamp down inflammation in the brain could slow... by lhl on Sunday December 08, 2019 @06:36PM (#21739254)
Actually, I think it's an important distinction that your citation aren't on "established medical science", but rather nutritional guidelines, which are consensus statements at best (but since their first introduction in 1980 have as much political as scientific policy).

They have bent to scientific evidence, but very slowly. The 2015 US Dietary guideline revision quietly removed both dietary cholesterol and total fat consumption [1]:

"In the new DGAC report, one widely noticed revision was the dropping of dietary cholesterol as a “nutrient of concern.” This surprised the public, but is concordant with scientific evidence demonstrating no appreciable relationship between dietary cholesterol and serum cholesterol1 or clinical cardiovascular events in general populations.2 The DGAC should be commended for this evidence-based change.

A far less noticed, but more momentous, change was the new absence of any limitation on total fat consumption. The DGAC neither listed total fat as a nutrient of concern, nor proposed any limitation on its consumption. Rather, they concluded, “Reducing total fat (replacing total fat with overall carbohydrates) does not lower CVD risk Dietary advice should put the emphasis on optimizing types of dietary fat and not reducing total fat.”"

Even at their best, guidelines will trail what the scientific evidence shows by years. I don't see how what you've posted reflects "established medical science" at all, unless you have recent evidence that shows saturated fat intake as being harmful. Here's a recent direct critique on btw on why the WHO guidelines are wrong for saturated fat limits specifically:

Astrup, Arne, Hanne CS Bertram, Jean-Philippe Bonjour, Lisette CP de Groot, Marcia C. de Oliveira Otto, Emma L. Feeney, Manohar L. Garg, et al. “WHO Draft Guidelines on Dietary Saturated and Trans Fatty Acids: Time for a New Approach?” BMJ 366 (July 3, 2019): l4137. https://doi.org/10.1136/bmj.l4137.

For those wanting to learn more about how nutritional guidelines are made and their impact, this short history is a good introduction: https://www.nutritioncoalition.us/dietary-guidelines-for-ame...

And here are some more peer-reviewed critiques on how nutrition guidelines should be improved:

Bero, Lisa A., Susan L. Norris, and Mark A. Lawrence. “Making Nutrition Guidelines Fit for Purpose.” BMJ 365 (April 16, 2019). https://doi.org/10.1136/bmj.l1579.

Johnston, Bradley C., Pablo Alonso-Coello, Malgorzata M. Bala, Dena Zeraatkar, Montserrat Rabassa, Claudia Valli, Catherine Marshall, et al. “Methods for Trustworthy Nutritional Recommendations NutriRECS (Nutritional Recommendations and Accessible Evidence Summaries Composed of Systematic Reviews): A Protocol.” BMC Medical Research Methodology 18, no. 1 (December 5, 2018): 162. https://doi.org/10.1186/s12874-018-0621-8.

Magni, Paolo, Dennis M Bier, Sergio Pecorelli, Carlo Agostoni, Arne Astrup, Furio Brighenti, Robert Cook, et al. “Perspective: Improving Nutritional Guidelines for Sustainable Health Policies: Current Status and Perspectives.” Advances in Nutrition 8, no. 4 (July 6, 2017): 532–45. https://doi.org/10.3945/an.116.014738.

Fogelholm, Mikael. “Nutrition Recommendations and Science: Next Parallel Steps.” Journal of the Science of Food and Agriculture 96, no. 4 (March 15, 2016): 1059–63. https://doi.org/10.1002/jsfa.7479.

Teicholz, Nina. “The Scientific Report Guiding the US Dietary Guidelines: Is It Scientific?” BMJ 351 (September 23, 2015). https://doi.org/10.1136/bmj.h4962.

Archer, Edward, Gregory Pavela, and Carl J Lavie. “The Inadmissibility of ‘What We Eat In America’ (WWEIA) and NHANES Dietary Data in Nutrition & Obesity Research and the Scientific Formulation of National Dietary Guidelines.” Mayo Clinic Proceedings 90, no. 7 (July 2015): 911–26. https://doi.org/10.1016/j.mayocp.2015.04.009.

[1] Mozaffarian, Dariush, and David S. Ludwig. “The 2015 US Dietary Guidelines – Ending the 35% Limit on Total Dietary Fat.” JAMA 313, no. 24 (June 23, 2015): 2421–22. https://doi.org/10.1001/jama.2015.5941.