October 2017 – Vol. 11, Issue 10

 In This Issue…

  • Low vitamin B6 may thwart a healthy immune response
  • Taking supplemental biotin may interfere with some common diagnostic hormone tests
  • Is HDL3 the new superhero of heart health?
  • Case report:  Vitamin B1 saves patient from severe lactic acidosis


CLINICAL UPDATE – Low vitamin B6 may thwart a healthy immune response
            Vitamin B6 plays a key role in a healthy immunity due to its role in regulating the inflammatory response.  To explore this link, a group of scientists measured several aspects of the immune response in mice that were given a vitamin B6 depleted diet.  They found that vitamin B6 deficiency reduced lymphocyte proliferation – the ability of lymphocytes (white blood cells) to respond adequately to immune stressors.   The capacity of the white blood cells (lymphocytes) to grow and multiply – something that directly correlates with healthy immunity – was compromised when cells were deficient in vitamin B6.  Further, the ability of those lymphocytes to differentiate, or be more adaptable to appropriate endogenous (cancer) or exogenous (pathogens) threats, was also compromised.  This study lends evidence to confirm that vitamin B6 deficiency can potentially reduce healthy cellular immunity.            (Journal of Immunological Research, 2017)
LINK to ABSTRACT Effects of Vitamin B6 Deficiency on the Composition and Functional Potential of T Cell Populations. 
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CLINICAL UPDATE – Taking supplemental biotin may interfere with some common diagnostic hormone tests
Biotin, also known as vitamin B7, is a common micronutrient found in over-the-counter supplements that has the unique distinction of irreversibly binding with a protein (avidin) found in raw egg whites. In fact, biotin has such an unusually strong affinity to the protein avidin that many diagnostic tests for hormones use antibodies that have an avidin molecule attached to it, so an analyte can be counted and quantified. The problem is that excess biotin in the blood due to supplementation may interfere with such diagnostic tests.
          In this study, 6 healthy adults were measured for 11 analytes – mostly thyroid hormones plus vitamin D, prostate specific antigen and the iron storage protein ferritin.  Then they took 10mg per day of biotin (a dose common in over-the-counter supplements for healthy adults) for seven days and the 11 analytes were measured again. Finally, a third measurement of the 11 analytes was made at day 14 after biotin supplements were stopped for a week.  
          Almost 40% of the assays that use biotin-bound antibodies demonstrated biotin-associated interference with some being falsely high and others being falsely low.  Conversely, none of the assays that use non-biotinylated antibodies showed interference.  The authors conclude that ingesting biotin for one week could potentially interfere with some clinical lab test results and should be noted by patients and practitioners when ordering and interpreting certain blood tests.
          (Journal of the American Medical Association, September  2017)
LINK to ABSTRACT Association of Biotin Ingestion With Performance of Hormone and Nonhormone Assays in Healthy Adults.


CLINICAL UPDATE – Is HDL3 the new superhero of heart health?
The role of high density lipoproteins in protecting against heart disease is well established but new research suggests that HDL3 is the real player in protecting arteries.   Two main types of HDL exist – small, dense, protein-rich HDL3 and large, light, lipid-rich HDL2.  Although small, dense lipoproteins are typically characterized as dangerous and atherogenic, this only applies for low density lipoproteins.  The opposite is true for high density lipoproteins, according to this research.
          Both HDL2 and HDL3 are beneficial lipoproteins, but it seems that HDL3 may be the real “workhorse” in preventing atherosclerosis.  It protects the cardiovascular system via two steps.  First, HDL3 transfers lipid peroxides, the molecules that wreak havoc on the arterial wall lining, from LDL to HDL.  Then, the protein portion of the HDL (the apolipoprotein A  molecule) changes the damaging peroxides into benign hydroxides at which point they can be safely delivered to the liver for excretion.
          (BBA Clinical, August 2017)
LINK to ABSTRACT Antioxidative activity of high-density lipoprotein (HDL): Mechanistic insights into potential clinical benefit.
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CLINICAL UPDATE – CASE REPORT: Vitamin B1 saves patient from severe acidosis
            In this case report, a 75-year-old female diabetic was admitted to the hospital due to a sudden onset of shock and severe lactic acidosis.  The patient had been taking buformin, which is a diabetic drug in the biguanide class (structurally similar to metformin) that is designed to help regulate blood sugar in diabetics.
           Interestingly, biguanides (buformin, metformin, etc) are contraindicated for patients with any condition that predisposes them to lactic acidosis (e.g. kidney or liver failure).  This is because biguanides promote the conversion of glucose to lactate to lower glucose levels in the bloodstream, and can thus increase the risk of lactic acidosis in susceptible individuals. 
            Upon arrival at the hospital, the patient was diagnosed with severe lactic acidosis, a buildup of the metabolic by product lactate in the blood.  Since blood pH must be maintained in a relatively narrow homeostatic range, any buildup of lactate can be dangerous as it can potentially make the blood too acidic.  Doctors administered sodium bicarbonate via blood infusion to buffer the acidosis in the blood but her excess lactate in the blood persisted for an entire day.  On the second day in the hospital, doctors suspected vitamin B1 deficiency in this patient since her lactic acidosis did not respond at all to conventional biguanide-associated lactic acidosis treatment. Seventeen hours after administration to the hospital, doctors gave intravenous high dose thiamine (vitamin B1) and the patient’s response was dramatic.  Her severe lactic acidosis was fully resolved in 24 hours, leading doctors to give a final diagnosis of vitamin B1 deficiency due to the toxic effects of buformin. 
            Interestingly, in this case, the patient’s serum concentration of vitamin B1 was only marginally lower than the normal range.   But since biguanides inhibit thiamine absorption as well as the protein that transports thiamine to cells, this patient likely had a functional deficiency of vitamin B1, which was promptly corrected with vitamin B1 administration.  In fact, the authors refer to thiamine as a “metabolic resuscitator” and suggest that when diabetic patients taking biguanides present with lactic acidosis, thiamine deficiency should be suspected in order to not delay recovery.
          (Internal Medicine, 2017)
LINK to ABSTRACT The Dramatic Recovery of a Patient with Biguanide-associated Severe Lactic Acidosis Following Thiamine Supplementation. 
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