December 2016 – Vol. 10, Issue 12

In This Issue…

  • High levels of calcium in blood linked to higher risk of diabetes
  • Vitamin C may reduce anxiety
  • Dosage study in athletes suggests 2200 IU per day of vitamin D is proper amount for repletion
  • This nutrient is crucial in the regulation of intestinal permeability
  • Can vitamin B12 alleviate ringing in the ears?


CLINICAL UPDATE – High levels of calcium in blood linked to higher risk of diabetes
          Serum levels of calcium were measured in 12,800 people who did not have diabetes and then followed for almost nine years.  In that time, over 1500 of the original participants developed diabetes.  People who had the highest levels of calcium in their blood had an increased risk of diabetes, although this relationship was only statistically significant in black participants.
          Although the mechanism is not fully understood, the presence of calcium in blood (versus in cells or bone, for example) suggests a metabolic abnormality.  This study provides further evidence that functional deficiency of certain micronutrients do not necessarily correlate to serum levels and in fact, relying on serum levels to assess micronutrient deficiency may actually be misleading.
          (American Journal of Clinical Nutrition, October 2016)
           LINK to ABSTRACT
Serum calcium and incident type 2 diabetes: the Atherosclerosis Risk in Communities (ARIC) study.



CLINICAL UPDATE – Vitamin C may reduce anxiety
          In some recently published animal studies, vitamin C status was shown to significantly impact the susceptibility to either anxiety or depressive behavior in mice.  In the first study, mice were either given vitamin C fortified water or were completely deprived of vitamin C and then were subjected to an anxiety-inducing exercise (a forced swim test).  The anxiety response in vitamin C depleted mice was worse than in those given vitamin C, especially in the females, leading researchers to conclude that vitamin C status “is critical for determining vulnerability to anxiety.”
          In a similar but unrelated experiment, mice were once again subjected to a stress test (specifically called the tail suspension test) and given either vitamin C or fluoxetine (an antidepressant often sold under the trade name Prozac).  The researchers observed changes in brain physiology that produce significant antidepressant effects, similar to fluoxetine, when the mice were given vitamin C, thus confirming “antidepressant-like effects of ascorbic acid.”
          (Nutrition Research, December 2016)
          (Journal of Nutritional Biochemistry, December 2016)
          LINK to ABSTRACT
Vitamin C impacts anxiety-like behavior and stress-induced anorexia relative to social environment in SMP30/GNL knockout mice.
          LINK to ABSTRACT Subchronic administration of ascorbic acid elicits antidepressant-like effect and modulates cell survival signaling pathways in mice.



CLINICAL UPDATE – Dosage study in athletes suggests 2200 IU per day of vitamin D is proper amount for repletion
          In this study, vitamin D levels were measured on 102 highly trained athletes who were randomly assigned to take either  400 IU, 1100 IU or 2200 IU of vitamin D per day orally for one year.  Vitamin D levels under 50 nmol/l was considered deficient while vitamin D levels between 50-75 nmol/l was considered insufficient.  (Above 75 nmol/l was considered sufficient).  After one year of supplementation, 80% of the athletes taking 2200 IU per day had adequate vitamin D status.  Not surprisingly, the athletes taking 2200 IU/day of vitamin D achieved higher levels than the athletes taking only 1100 IU or 400 IU daily, suggesting that 2200 IU of vitamin D per day is a more appropriate dose for repleting vitamin D status in this group.
          (European Journal of Clinical Nutrition, September 2016)
          LINK to ABSTRACT
The impact of 1-year vitamin D supplementation on vitamin D status in athletes: a dose-response study.


 CLINICAL UPDATE – This nutrient is crucial in the regulation of intestinal permeability
          The most abundant amino acid in plasma is glutamine, which plays a key role in maintaining the integrity of the intestinal tract. This review paper highlights the importance of glutamine in preventing intestinal permeability disorders like “leaky gut syndrome,” and elucidates its functional role in maintaining intestinal barrier function.  According to this review, depletion of this amino acid increases intestinal permeability.
          (Current Opinion in Clinical Nutrition and Metabolic Care, January 2017)
          LINK to ABSTRACT
Glutamine and the regulation of intestinal permeability: from bench to bedside.


CLINICAL UPDATE – Can vitamin B12 alleviate ringing in the ears?
          In this randomized, double-blind trial, 40 patients with tinnitus (chronic ringing in the ears) were divided into two groups of 20:  Group A received intramuscular injections of vitamin B12 weekly for six weeks and Group B received placebo (saline) injections.  For the patients in Group A that were vitamin B12 deficient, a significant improvement in tinnitus occurred after the B12 therapy.  The authors suggest a link between vitamin B12, which plays a role in proper nerve function, and tinnitus, which they suggest is linked to disturbed cochlear (ear) neural activity.
          (Noise & Health, April 2016)
          LINK to ABSTRACT
Therapeutic role of Vitamin B12 in patients of chronic tinnitus: A pilot study.