Fructose Under Fire As Study Reveals It Is More Damaging To The Liver Than Glucose

Discussion in 'Articles & Scientific Studies' started by Mito, Oct 3, 2019.

  1. Mito

    Mito Member

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    “Fructose may be more damaging to your health than glucose according to a rigorous new animal study comparing the effect of both sweetening compounds on liver metabolism. The research presents some of the clearest causal evidence to date demonstrating how a high-fructose diet not only disrupts the liver’s ability to metabolize fat but also fundamentally damages its mitochondria.

    “This is one of a series of studies that we've been doing concerning what role high fructose in the diet plays in terms of insulin resistance and metabolic syndrome,” explains C. Ronald Kahn, lead author on the study. “Fructose makes the liver accumulate fat. It acts almost like adding more fat to the diet. This contrasts the effect of adding more glucose to the diet, which promotes the liver's ability to burn fat, and therefore actually makes for a healthier metabolism.”.........

    ........“The most important takeaway of this study is that high fructose in the diet is bad,” says Kahn. “It's not bad because it's more calories, but because it has effects on liver metabolism to make it worse at burning fat. As a result, adding fructose to the diet makes the liver store more fat, and this is bad for the liver and bad for whole body metabolism.”

    Fructose under fire as study reveals it is more damaging to the liver than glucose
     
  2. Kartoffel

    Kartoffel Member

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    Fructose is bad because it's bad. And that's why it's bad for the liver. Did I mention that fructose is bad?
     
  3. lampofred

    lampofred Member

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    There were 2 variables in this study. Regular fat versus high fat and glucose versus fructose. Fructose only caused a problem when accompanied with high fat, not with regular fat (I can't get access to the full article, but I'm betting the fat was high in PUFA). So why are they placing the blame on only fructose and not the fat?
     
  4. Hans

    Hans Member

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    High fructose with PUFA is very damaging. The diets were most likely pretty awful too and fructose requires more copper. A high fructose diet lowers copper and when copper levels drop, iron accumulates in the liver and causes a lot of oxidative stress which is potentiated by PUFA.
     
  5. GAF

    GAF Member

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    Is this study a stupid premise? Does anyone really eat a high FAT high fructose diet?
     
  6. Collden

    Collden Member

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    Cant see the details but it looks like another study where they just fed mice pure fructose which is completely irrelevant to reality since it is almost always consumed in balance with glucose.

    In contrast there are studies where mice are fed on very high sucrose diets for their whole lives without developing any hint of fatty liver.
     
  7. OP
    Mito

    Mito Member

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    “The researchers analyzed different known markers of fatty liver to determine the effects of each diet. For example, they looked at levels of acylcarnitines in the liver's cells. Acylcarnitines are produced when the liver burns fats. High levels of these are a bad sign, since it means there is a lot of fat in the liver being burned. Acylcarnitines were highest in the animals on the high-fat plus high fructose diet. They were lower in the high-fat plus glucose diet than in the plain high-fat diet, which reflected previous observational findings and indicated that glucose performed an assistive fat-burning action in these animals.”

    High-fructose and high-fat diet damages liver mitochondria: Increases fatty-liver disease risk and metabolic syndrome
     
  8. tankasnowgod

    tankasnowgod Member

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    Soooo, when Mildronate reduces Fatty Acid Oxidation, its a performance enhancing miracle drug, but when fructose reduces Fatty Acid Oxidation, even in the context of a High Fat Diet, it's harmful to the Liver?
     
  9. OP
    Mito

    Mito Member

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    “Dr. Kahn and colleagues plan believe that developing a drug which blocks fructose metabolism could prevent the negative actions of fructose and help prevent fatty liver disease and its adverse metabolic consequences, including impaired glucose tolerance and type 1 diabetes.”
     
  10. jb116

    jb116 Member

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    :darts:
     
  11. nwo2012

    nwo2012 Member

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    The first thing I thought of was that it is favorable for the body to not "burn fat".
    Scientism is a more dogmatic religion than Catholicism.
     
  12. Rafael Lao Wai

    Rafael Lao Wai Member

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    Lol exactly
     
  13. tankasnowgod

    tankasnowgod Member

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    KHAAAAAAAANNNNN!!!!!

     
  14. Dharma Student

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    Check the choline-methionine status of the animal subjects. It is easy to design a study to "prove" that fructose is harmful if you are biased or ignorant. All you need to do is make sure that the subjects are deficient in choline or other lipotropic factors.

    It was shown in 1949 that provision of adequate choline can completely prevent liver damage by high alcohol or sugar diets: Liver Damage Produced by Feeding Alcohol or Sugar and its Prevention by Choline

    Dietary fructose exacerbates hepatocellular injury when incorporated into a methionine-choline-deficient diet

    Only about 11% of U.S. population consumes even the IOM's "adequate intake" level of choline: Assessment of total choline intakes in the United States

    And the "adequate intake" level is probably too low by a substantial factor: Common nutrient supplementation may hold the answers to combating Alzheimer's disease

    If you really want fatty liver, include some PUFAs in the choline-deficient diet. "Mice fed a PUFA-rich MCD formula showed extensive hepatic lipid peroxidation, induction of proinflammatory genes, and histologic inflammation. When PUFAs were substituted with more saturated fats, lipid peroxidation, proinflammatory gene induction, and hepatic inflammation all declined significantly." Polyunsaturated fat in the methionine-choline-deficient diet influences hepatic inflammation but not hepatocellular injury. - PubMed - NCBI

    N
    ote the first paragraph in this latter study: "Dietary formulas that are completely devoid of methionine and choline (MCD) induce steatohepatitis in mice ( 14). MCD diets are often used to investigate the pathogenesis of fatty liver disease because they rapidly induce steatosis and necroinflammation and over longer periods cause hepatic fibrosis ( 2, 5)."

    So it is standard practice to put animals on Met and Choline deficient diets to investigate fatty liver disease. The disease is caused by the Met and Choline deficiency but they blame it on the presence of fructose. SMH
     
  15. OP
    Mito

    Mito Member

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    According to the study “This effect is specific to fructose. Indeed, equally high levels of glucose in the diet actually improve the fat-burning function of the liver. This explains why high dietary fructose has more negative health impacts than glucose does, even though they have the same caloric content.”

    Choline and PUFA could be factors in liver fat but then why did substituting glucose for fructose decrease liver fat? Presumably they used the same amount of dietary choline and PUFA for both the glucose/high fat diet and the fructose/high fat diet.
     
  16. Dharma Student

    Dharma Student Member

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    It just means that metabolism of fructose requires somewhat higher amounts of choline and methionine than metabolism of glucose because of its different metabolic pathway. Plus, healthy liver cells primarily utilize amino acids for fuel. The liver is supposed to export fat to other tissues, not burn fat.
    Each Organ Has a Unique Metabolic Profile - Biochemistry - NCBI Bookshelf "How does the liver meet its own energy needs? α-Ketoacids derived from the degradation of amino acids are the liver's own fuel. In fact, the main role of glycolysis in the liver is to form building blocks for biosyntheses. Furthermore, the liver cannot use acetoacetate as a fuel, because it has little of the transferase needed for acetoacetate's activation to acetyl CoA. Thus, the liver eschews the fuels that it exports to muscle and the brain."

    Thus, if liver cells are burning fat, this is generally pathological. Liver should be exporting fats, ketones, and glucose to other tissues. The authors of the study you are citing are saying that the liver was sick on both the glucose/high fat and the fructose/high fat diets. That's likely because they liver was either deficient or poisoned by other aspects of the diet provided.
     
  17. Dharma Student

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    Dietary fructose exacerbates hepatocellular injury when incorporated into a methionine-choline-deficient diet

    This study reported that degree of fatty liver was similar regardless of whether the Met- and choline-deficient animals were fed glucose or fructose, but the fructose diet produced more cell damage:

    "Mice fed MCD formulas developed similar degrees of hepatic steatosis whether they contained glucose or fructose. By contrast, mice fed MCD-fructose developed significantly more hepatocellular injury than mice fed MCD-glucose, judged by histology, apoptosis staining and serum alanine aminotransferase. Liver injury in MCD-fructose mice coincided with an exaggerated rise in the ratio of long-chain saturated to unsaturated fatty acids in the liver. Notably, hepatic inflammation was not enhanced in mice fed MCD-fructose, correlating instead with hepatic lipid peroxidation, which was equivalent in the two MCD groups.

    Discussion
    Fructose is more cytotoxic than glucose when used as the source of carbohydrate in MCD formulas."​

    But this is a bait and switch! The problem here is not fructose in the diet, its the deficiency of methionine and choline. From the same study:

    "Diets devoid of methionine and choline (methioninecholine deficient; MCD) cause hepatic steatosis and inflammation that mimics non-alcoholic steatohepatitis in human beings (13). MCD feeding induces steatosis because methionine and choline deprivation stimulates the hepatic uptake of fatty acids from the circulation (2) while at the same time preventing the physiological export of triglyceride from the liver in the form of VLDL particles (4, 5). Commonly used commercial MCD formulas not only lack methionine and choline, but also are enriched in sucrose and fat. These nutrients themselves stimulate hepatic lipid accumulation, and thus they have the potential to amplify the fatty liver disease induced by methionine and choline deprivation alone."​

    Realize that its presently professionally profitable to produce studies attacking fructose; you are likely to get your paper published and lauded if you produce more "evidence" that sugar is bad, which takes heat off of "heart-healthy polyunsaturated fats." IMO this paper you cited is just another confirming that there currently exists a popular bias against fructose in the research community. Fructose is the whipping boy. To me its hilarious given that humans are among the few species that have specific taste receptors for detecting fructose which are estimated to emerged in our lineage ~30 million years ago. They're all on a "fructose is bad" kick just like they were (and many still are) on a "saturated fats are bad" kick. As I said, its easy to produce the results you want by design. John Ioannidis mathematically proved that intra-discipline bias in assumptions, research design and interpretations is one of the main reasons most published research findings are unreliable: Why Most Published Research Findings Are False.
     
  18. jzeno

    jzeno Member

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    Average American. Explains obesity epidemic. HFCS + foods cooked with vegetable oils=Just about everyone in America.
     
  19. Dharma Student

    Dharma Student Member

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    That's true, and almost all are likely choline deficient as well. Not hard, since there's no micronutrients in HFCS or vegetable oils. Assessment of total choline intakes in the United States
     
  20. Dharma Student

    Dharma Student Member

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    That's true, and almost all are likely choline deficient as well, since there's no choline in refined sugars or vegetable oils which make up 30-50% of energy intake of SAD. Assessment of total choline intakes in the United States
     
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