Blog

By Dr.Ted Zava of ZRT Laboratory. Have you ever wondered where dietary iodine comes from? Most people are familiar with iodized salt and shellfish containing high levels of iodine, but few realize a vast assortment of food and drinks contain this essential nutrient.  What Food Products Contain the Highest Levels of Iodine? It may come as a surprise that most dietary iodine comes from dairy products such as milk, cheese and yogurt. Iodine is used to prevent bacteria growth in cattle feed and it can also be used as a sanitizer when milking cows. Because cows typically graze in fields...

Low testosterone in older men, often referred to as “male menopause” or even “andropause” is fairly well known — and testosterone replacement therapy in this age group has not been without its share of controversy, particularly with respect to heart health. Proper testing and dosing are all-important, as well as understanding a man’s physiology and all the factors that affect testosterone levels. For example, when giving testosterone transdermally it is critical to use testing methods such as dried blood spot or saliva to properly assess absorption of testosterone into the body, avoiding the problem of overdosing to achieve “normal” serum levels. But while...

Men and testosterone therapy have been a hot topic in the news recently. Stories are filled with cautions about the use of testosterone therapy in men causing heart attacks and leading many doctors to question testosterone supplementation. A closer look at the study may provide more insight. The study released is referenced at the end of this post. (1) This study looked at 55,593 men who started testosterone therapy. Some were over the age of 65 and a smaller number were under 65. There are two important subgroups - those with cardiovascular disease and those without. The study also looked...

BY Dr. Allison Smith ZRT Laboratory SHBG, or Sex Hormone Binding Globulin, controls testosterone effect in both men and women by modulating changes in sex steroid levels. When SHBG goes up, free testosterone goes down. I like to think of SHBG as a sponge that soaks up androgens and to some degree estrogens as well. Since it binds so specifically and tightly to testosterone, it makes up part of the equation that equals androgen excess or androgen deficiency. Knowing how to manipulate SHBG can be a useful tool in a number of scenarios. Role: Bind to and carry testosterone (and less strongly...

By Dr Allison Smith, ZRT Laboratory The testicles of a man in his 20s are known to contribute about 5-10mg of testosterone per 24-hour day and levels of total testosterone in the venous blood with that amount are observed to yield roughly 300-1200 ng/dL in the morning at the diurnal peak. Testosterone, whether endogenous or given exogenously, negatively feeds back on the hypothalamus, limiting GnRH and thus LH and FSH from the pituitary. A man taking supraphysiological doses of testosterone can expect to have very low or undetectable levels of LH and FSH in the serum. What happens when the...