DavidPerlmutterMD · 2021-10-04 · David Perlmutter (host), Steven Gundry
What Our Fatigue Reveals About Our Health - with Dr. Gundry | The Empowering Neurologist EP. 134
37 research-tied claims examined: 2 contradicted 1 overstated 2 context 24 supported 8 unverified
2 Contradicted by research
About 70% of ingested fructose is absorbed through the portal vein and metabolized by the liver into uric acid and triglycerides.
"But so fructose is such a toxin that about 70% of fructose is absorbed directly through the portal vein and goes to the liver for quote, "detoxification." And it's detoxified into two compounds: uric acid and triglycerides." (said at 0:33:52)
The claim that fructose is a toxin that is 'detoxified' by the liver into only uric acid and triglycerides is contradicted by human metabolic and tracer studies. Fructose is a standard dietary carbohydrate, not a toxin. While splanchnic tissues (the gut and liver) extract a large proportion of absorbed fructose via the portal vein, its primary metabolic fates are conversion into glucose (~50%), lactate (~15–25%), glycogen (~15%), and oxidation to carbon dioxide. De novo lipogenesis into fatty acids and triglycerides accounts for only a minor fraction (typically <1–5% of an ingested load under normal physiological conditions). Uric acid is generated transiently as a minor byproduct of AMP degradation following rapid phosphorylation by ketohexokinase, not as a primary end-product or detoxification pathway.
- contradicts: Metabolic effects of fructose and the worldwide increase in obesity. (Physiological reviews 2010) · cited 1250x in the literature
"Fructose has the same chemical formula as glucose (C(6)H(12)O(6)), but its metabolism differs markedly from that of glucose due to its almost complete hepatic extraction and rapid hepatic conversion into glucose, glycogen, lactate, and fat." (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: Does fructose consumption contribute to non-alcoholic fatty liver disease? (Clinics and research in hepatology and gastroenterology 2012) · cited 114x in the literature
"This hexose is essentially metabolized in splanchnic tissues, where it is converted into glucose, glycogen, lactate, and, to a minor extent, fatty acids." (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: Metabolism of sugars: A window to the regulation of glucose and lipid homeostasis by splan… (Clinical nutrition (Edinburgh, Scotland) 2021) · cited 66x in the literature
"The gut and liver are required to process fructose and galactose into glucose, lactate, and fatty acids." (abstract, background, passage verified)
pubmedfull study (doi)
Blue light exposure stimulates hunger and ghrelin release.
"And that blue light actually served a very, very good purpose evolutionarily, because during summer we would have much longer periods of blue light, we would have blue light into the late evening, and that would stimulate us to eat because that's when the food was available, and it awakens us and it makes us hungry. It turns on ghrelin." (said at 0:56:20)
Human experimental studies examining the acute effects of blue light on appetite hormones do not support the claim that blue light stimulates hunger or activates ghrelin release. In a controlled inpatient study assessing morning and evening blue-enriched light exposure (PMID: 27191727), blue light altered glucose metabolism and reduced sleepiness, but did not significantly increase ghrelin levels or subjective hunger. Furthermore, in sleep-restricted adults (PMID: 22988459), morning blue light exposure significantly increased levels of leptin (a satiety hormone) and did not stimulate ghrelin release.
- contradicts: Light modulates leptin and ghrelin in sleep-restricted adults. (International journal of endocrinology 2012) · cited 43x in the literature
"Compared to the 5-hour sleep/dim-light condition, the red, green, and blue morning light exposures significantly increased leptin concentrations (t(1,32) = 5.7; P < 0.0001, t(1,32) = 3.6; P = 0.001, and t(1,32) = 3.0; P = 0.005, resp.). Morning red light and green light exposures significantly decreased ghrelin concentrations (t(1,32) = 3.3; P < 0.003 and t(1,32) = 2.2; P = 0.04, resp.), but morning blue light exposures did not." (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: Morning and Evening Blue-Enriched Light Exposure Alters Metabolic Function in Normal Weigh… (PloS one 2016) · cited 98x in the literature
"Blue-enriched light exposure acutely alters glucose metabolism and sleepiness, however the mechanisms behind this relationship and its impacts on hunger and appetite regulation remain unclear." (abstract, conclusions, passage verified)
pubmedfull study (doi)
Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.