By Ross Macdonald
This is the first of two articles on the androgenic hormone testosterone produced by both men and women. It is important in muscle mass, bone density, red blood cells, obesity, and ED (erectile dysfunction). Low levels are linked to an increased risk of cardiovascular disease (CVD), metabolic syndrome and prostate cancer. These will be addressed in this series.
Testosterone is measured at two levels—bonded and free—the latter being the active form. Bonded testosterone makes up about 90% of the total and is bonded to bones and muscle. Free testosterone flows in the blood and is important for many health aspects.
Metabolic Syndrome is a combination: waist size (obesity), high blood pressure, high cholesterol, and high blood sugar. It leads to diabetes, heart disease, and the inability to process fats and sugars. Men with low testosterone have an increasing prevalence of diabetes, hypertension, stress, and visceral belly fat. With total testosterone levels at the optimum level, (550ng/dl) or above, the chance for this syndrome decreases
The important consideration is hormone balance. As men grow older they are more at risk for increases in an enzyme called aromatase. Obesity can cause estrogen levels to rise because one of the main causes, belly fat, produces aromatase which coverts testosterone into estrogen. When testosterone and estrogen are in youthful balance there are many protective effects. Research has shown there is an increase in mortality when estrogen levels are either too low or too high.
Measuring FREE testosterone is the most accurate way of assessing levels in men. The balance should be 15-20ng/dl free with estrogen less than 30ng/dl. An in balance between these two hormones leads to diet—resistant belly fat which is due to either too much estrogen or too little testosterone. In men this fat increases estrogen resulting in memory loss, lack of motivation, depression, and low libido. Belly fat can also be linked to stress, which releases hormones like cortisol, which signals the body to maintain its fat and weight and also to low DHEA (the precursor to these hormones).
Low testosterone, which may be linked to stress, can also lead to belly fat in both men and women. This type of fat resists diet, is very difficult to remove, and can increase estrogen levels. This jump in estrogen levels helps to develop platelet aggregation, coagulation and inflammation in arteries which may cause a heart attack.
High HDL levels (good cholesterol) protect against heart attacks by helping to remove plaque from arteries. Testosterone enables HDL to remove this built up cholesterol from arterial walls and cycles it back to the liver for disposal. This is known as Reserve Cholesterol Transport (RCT). Adequate levels of testosterone are required for optimal support of this process; low levels may cause a drop in HDL increasing the chance of CVD.
A major research study revealed that free testosterone levels below 17pg/dl resulted in a 3.3-fold greater risk of developing arterial disease. In perspective aging men with levels below 17pg/dl often have HDL levels below 40-50 mg/dl. Chronic heart failure (CHF) is characterized by exercise intolerance, shortness of breath, and muscle wasting. Low testosterone is one of the main culprits. Testosterone increases anabolic function, improves arterial dilation and is a known anti inflammatory agent.
The Journal of the American Medical Association published a study measuring estradiol (the active form of estrogen) in men with chronic heart failure (CHF). The end results were: men with the lowest level were 217% more likely to die and men in the highest level were 133% more likely to die sooner from all sources than men with a balanced estradiol—testosterone level.
A 2004 report on strokes from the American Heart Association followed 195 men for 8 years. The results showed that men with low testosterone had a 3.57 greater risk for the processes leading to a stroke than the control group who had adequate levels.