November 2013 - Vol. 7, Issue 11

In This Issue….                                                 

-   New study confirms the need for measuring testosterone levels in men
-   Conclusions challenged from review of vitamin D on bone health
-   Evidence mounts for link between vitamin D and multiple sclerosis
-   Glutamine repairs chemotherapy-induced damage to gut
-   Study sheds light on the mechanism behind vitamin B6’s role in fighting inflammation of the colon
-   Zinc suggested as part of type 2 diabetic treatment regimen
-   Low B1 causes blood vessel constriction

CLINICAL UPDATE – New study confirms the need for measuring testosterone levels in men

Over 8700 men with confirmed low levels of testosterone (<300ng/dL) were studied in this cohort, all of which received coronary angiography. Of the 8709 men, 14% received testosterone therapy, 86% did not. The rates of heart attack, stroke and death were 29% higher in the group receiving testosterone therapy. The study emphasizes the need to measure testosterone levels before androgen therapy is initiated, especially in lieu of the fact that testosterone prescriptions are on the rise, even in the absence of clinical hypogonadism.
(Journal of the American Medical Association, November 2013)
(JAMA Internal Medicine, August 2013)

LINK to ABSTRACT Association of testosterone therapy with mortality, myocardial infarction, and stroke in men with low testosterone levels.
LINK to ABSTRACT Trends in androgen prescribing in the United States, 2001 to 2011.

CLINICAL UPDATE – Conclusions challenged from review of vitamin D on bone health

A recent meta-analysis on the effect of vitamin D supplements on rates of osteoporosis concluded that “continuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate.” Yet the authors also state “six findings [studies] of significant benefit, two of significant detriment, and the rest were non-significant.” Critics are quick to point out that in almost half of the included studies (10 of 23), dosages were less than 800IU daily. Similarly, the argument that bone health cannot be evaluated in the context of only one vitamin, in this case vitamin D, has been raised, since supplementation of vitamin D does not address the synergistic concept of other nutrients – vitamin K, calcium, magnesium, for example – in the complete picture of bone health.
(Lancet, October 2013)

LINK to ABSTRACT Effects of vitamin D supplements on bone mineral density: a systematic review and meta-analysis.

CLINICAL UPDATE – Evidence mounts for link between vitamin D and multiple sclerosis

Vitamin D status was measured in 98 patients with multiple sclerosis and blood levels of vitamin D were much lower in the patients with MS compared to healthy controls. But researchers also found that the levels of vitamin D were correlated to the severity of multiple sclerosis. In a separate study of 200 MS patients, low levels of vitamin D were indicative of depressive symptoms in MS patients.
(International Journal of Preventative Medicine, May 2013)
(Journal of Research in Medical Sciences, March 2013)

LINK to ABSTRACT Vitamin d3 concentration correlates with the severity of multiple sclerosis.
LINK to ABSTRACT The relation between Vitamin D status with fatigue and depressive symptoms of multiple sclerosis.

CLINICAL UPDATE – Glutamine repairs chemotherapy-induced damage to gut

Two studies – in vitro and in vivo – evaluated the effect of the amino acid glutamine on intestinal permeability induced by the chemotherapeutic drug methotrexate. Both studies, performed by a French research team, demonstrated that glutamine “prevents methotrexate induced gut barrier disruption,” a common and unpleasant side effect of chemotherapy.
(Clinical Nutrition, October 2013)

LINK to ABSTRACT Glutamine and arginine improve permeability and tight junction protein expression in methotrexate-treated Caco-2 cells.
LINK to ABSTRACT Glutamine supplementation, but not combined glutamine and arginine supplementation, improves gut barrier function during chemotherapy-induced intestinal mucositis in rats.

CLINICAL UPDATE – Study sheds light on the mechanism behind vitamin B6’s role in fighting inflammation of the colon

Researchers investigated the link between vitamin B6 and inflammatory markers in the colon. They found that the active form of vitamin B6 (pyridoxal-5-phosphate) is a necessary cofactor in the enzyme that metabolizes an important lipid (called sphingosine-1-phosphate) that plays a key role in activating an inflammatory response. In their conclusion, the researchers suggest “vitamin B6 supplementation may offer an additional tool for the management of inflammatory bowel disease.”
(Journal of Nutritional Biochemistry, December 2013)

LINK to ABSTRACT Dietary vitamin B6 intake modulates colonic inflammation in the IL10(-/-) model of inflammatory bowel disease.

CLINICAL UPDATE – Zinc suggested as part of type 2 diabetic treatment regimen

In vitro and animal studies demonstrate that zinc mimics the action of insulin. Several other studies demonstrate its role in regulating inflammation, oxidative stress and insulin action, specifically in reducing fasting blood glucose and glycated haemoglobin (HbA1c), leading to the conclusion that “zinc supplementation may have beneficial effects on glycemic control.”
(Food and Nutrition Bulletin, June 2013)

LINK to ABSTRACT Zinc as a potential coadjuvant in therapy for type 2 diabetes.

CLINICAL UPDATE – Low B1 causes blood vessel constriction

In this experiment, a deficiency of vitamin B1 (thiamine) caused a significant decrease in nitric oxide production in blood vessels. This caused a reduced ability for blood vessels to experience acetylcholine-mediated relaxation and increased the contractile response of the aorta, which ultimately resulted in vascular dysfunction.
(Nutrition, Metabolism and Cardiovascular Disease, 2013)

LINK to ABSTRACT Thiamine deficiency leads to reduced nitric oxide production and vascular dysfunction in rats.