In part one of this three part series, I introduced peer-reviewed science that shows "at least 1 in 4 men over 30 have low testosterone."1-4 With regard to common symptoms, these men suffer with "reductions in motivation, initiative, self-confidence, concentration and memory, sleep quality, muscle bulk and strength, diminished physical or work performance, feeling sad or blue, depressed mood, mild anemia, and increased body fat and body mass index."5-6
Men with low serum total testosterone concentrations are at significantly greater risk for death from any cancer, cardiovascular disease or respiratory disease.7 Even more troubling is the greater incidence of cardiovascular events in men whose testosterone levels are much higher than what's commonly considered as "low." This is alarming because as a study published in the Journal of the American College of Cardiology demonstrated, it doesn't matter if a man's total testosterone is very low (below 340 ng/dL ) or moderately low (up to 549 ng/dL) – all men with levels below 549 ng/dL show an increased risk for suffering a cardiovascular event.8
Fascinating is the fact that science shows exactly why aging men are experiencing a loss of healthy testosterone as they age: chronic stress, resulting in hypercortisolemia. The mechanisms of action are several-fold. Acting through the classic glucocorticoid receptor, cortisol directly inhibits testosterone production in testicles by Leydig cells;9-11 and stimulates the activity of the aromatase complex;12-15 in turn, aromatase increases the conversion of circulating testosterone into estradiol while decreasing testosterone concentrations.12-15
T Levels in Practice: The Classic Male Patient
How do sagging testosterone levels affect chiropractic practice? Think of your typical overweight male patient who presents with central adiposity (a telltale sign of high aromatase expression) coupled with chronic back pain that just won't go away. Research published as recently as 2012 shows that "low testosterone" could be a causal factor for increased pain in this type of chronically stressed patient.
For example, one study evaluated 46 healthy men during resting and stressful conditions, measuring pain thresholds, pain and anxiety ratings, and testosterone and cortisol levels.16 In these men, stress significantly increased anxiety ratings and cortisol levels, and decreased testosterone levels.16 Increased stress / cortisol levels also increased pain ratings and decreased pain thresholds, while lower testosterone levels were positively correlated with increased pain.16
Results indicated that testosterone can decrease and cortisol can increase pain, suggesting that acute clinical pain may be relieved by controlling stress / cortisol and managing consequent stress-related low testosterone concentrations.16
The Connection Between Testosterone and Insulin
From a "whole body health" standpoint, add to this list an additional mechanism of action: Stress / cortisol also directly interferes with healthy insulin physiology. This is seen when healthy men exhibit fasting plasma glucose concentrations and degrees of insulin resistance that are directly correlated with fasting plasma cortisol concentrations (i.e., when cortisol goes up, insulin goes up, insulin resistance goes up, and insulin sensitivity correspondingly goes down).17-18
It turns out that fasting plasma glucose and insulin concentrations are directly correlated with fasting plasma cortisol concentrations,19-22 and the degree of insulin sensitivity is inversely correlated with fasting plasma cortisol concentrations (i.e., again, higher cortisol levels raise insulin levels and lower insulin sensitivity).19-22 So, in essence, hypercortisolemia plays a role as a "diabetic switch," setting the stage for dysglycemia, metabolic syndrome and diabetes in the future.
The subject of insulin and insulin sensitivity ties directly into testosterone, as "testosterone and insulin status are also directly correlated."23-31 Among adult men, the insulin secretion rate and fasting plasma insulin concentration are inversely proportional to serum testosterone concentrations (i.e., high insulin levels are associated with low testosterone and low insulin levels are associated with high testosterone),23 while whole-body insulin sensitivity is shown to be positively correlated with serum testosterone concentrations.23-24
In other words, in men who have challenges with high postprandial blood sugar levels, simple carbohydrates that evoke an insulin spike / increase will sabotage the production of healthy testosterone. While this is not likely to be an issue in young men, who can consume carbohydrates and their blood sugar / insulin recovers quickly, it is one of the most likely "troubleshooting" keys to help discover why an overweight male patient may have chronically low testosterone. In these men, avoiding simple carbohydrates may be a powerful key to boosting healthy testosterone – now and in the future.
Testosterone and Insulin Facts
- Testosterone and insulin status are directly correlated in non-exercising men.23-31
- The serum testosterone concentration and the fasting plasma insulin concentration are inversely proportional in non-exercising men.23-31
- Testosterone directly stimulates glucose uptake in muscle.32
- Increasing serum testosterone concentration increases insulin sensitivity in men.23-31
In the third and final installment of this article series, I will outline a three-step program that combines diet, exercise and supplementation, based on peer-reviewed science, to help boost testosterone in otherwise healthy male patients.
Editor's note: Read the conclusion of Dr. Smith's series in the March 1 issue of DC.
- Faloon W. "Startling Low Testosterone Blood Levels in Male Life Extension Members." Life Extension, June 2010.
- Vann M. "1 in 4 Men Over 30 Has Low Testosterone." ABC News, Sept. 13, 2007.
- Age distribution, United States. CensusScope: http://censusscope.org/us/chart_age.html.
- Araujo AB, Esche GR, Kupelian V, et al. Prevalence of symptomatic androgen deficiency in men. J Clin Endocrinol Metab, 2007 Nov;92(11):4241-7.
- Bhasin S, Cunningham GR, Hayes FJ, et al: Task Force, Endocrine Society. Testosterone therapy in men with androgen deficiency syndromes: An Endocrine Society clinical practice guideline. J Clin Endocrinol Metab, 2010;95:2536-2559.
- Yeap BB, Hyde Z, Norman PE, et al. Associations of total testosterone, sex hormone-binding globulin, calculated free testosterone, and luteinizing hormone with prevalence of abdominal aortic aneurysm in older men. J Clin Endocrinol Metab, 2010;95:1123-1130.
- Laughlin GA, Barrett-Connor E, Bergstrom J. Low serum testosterone and mortality in older men. J Clin Endocrinol Metab, 2008;93:68-75.
- Ohlsson C, Barrett-Connor E, Bhasin S, et al. High serum testosterone is associated with reduced risk of cardiovascular events in elderly men. The MrOS (Osteoporotic Fractures in Men) study in Sweden. J Am Coll Cardiol, 2011;58:1674-1681.
- Fenske M. Role of cortisol in the ACTH-induced suppression of testicular steroidogenesis in guinea pigs. J Endocrinol, 1997;154:407-414.
- Welsh TH Jr, Bambino TH, Hsueh AJ. Mechanism of glucocorticoid-induced suppression of testicular androgen biosynthesis in vitro. Biol Reprod, 1982;27:1138-1146.
- Hu GX, Lian QQ, Lin H, et al. Rapid mechanisms of glucocorticoid signaling in the Leydig cell. Steroids, 2008;73:1018- 1024.
- McTernan PG, Anderson LA, Anwar AJ, et al. Glucocorticoid regulation of p450 aromatase activity in human adipose tissue: gender and site differences. J Clin Endocrinol Metab, 2002;87:1327-1336.
- Schmidt M, Renner C, Löffler G. Progesterone inhibits glucocorticoid-dependent aromatase induction in human adipose fibroblasts. J Endocrinol, 1998;158:401-407.
- Simpson ER, Ackerman GE, Smith ME, Mendelson CR. Estrogen formation in stromal cells of adipose tissue of women: induction by glucocorticosteroids. Proc Natl Acad Sci, 1981;78:5690-5694.
- Wang W, Li J, Ge Y, et al. Cortisol induces aromatase expression in human placental syncytiotrophoblasts through the cAMP/Sp1 pathway. Endocrinology, 2012;153:2012-2022.
- Choi JC, Chung MI, Lee YD. Modulation of pain sensation by stress-related testosterone and cortisol. Anaesthesia, 2012 Oct;67(10):1146-51.
- Richards JC, Johnson TK, Kuzma JN, et al. Short-term sprint interval training increases insulin sensitivity in healthy adults but does not affect the thermogenic response to ß-adrenergic stimulation. J Physiol, 2010;588:2961-2972.
- Winnick JJ, Sherman WM, Habash DL, et al. Short-term aerobic exercise training in obese humans with type 2 diabetes mellitus improves whole-body insulin sensitivity through gains in peripheral, not hepatic insulin sensitivity. J Clin Endocrinol Metab, 2008;93:771-778.
- Phillips DI, Barker DJ, Fall CH, et al. Elevated plasma cortisol concentrations: A link between low birth weight and the insulin resistance syndrome? J Clin Endocrinol Metab, 1998;83:757-760.
- Smith GD, Ben-Shlomo Y, Beswick A, et al. Cortisol, testosterone, and coronary heart disease: prospective evidence from the Caerphilly study. Circulation, 2005;112:332-340.
- Nielsen MF, Caumo A, Chandramouli V, et al. Impaired basal glucose effectiveness but unaltered fasting glucose release and gluconeogenesis during short-term hypercortisolemia in healthy subjects. Am J Physiol Endocrinol Metab, 2004;286:E102-E110.
- Paddon-Jones D, Sheffield-Moore M, Creson DL, et al. Hypercortisolemia alters muscle protein anabolism following ingestion of essential amino acids. Am J Physiol Endocrinol Metab, 2003;284:E946-E953.
- Tsai EC, Matsumoto AM, Fujimoto WY, Boyko EJ. Association of bioavailable, free, and total testosterone with insulin resistance: Influence of sex hormone-binding globulin and body fat. Diabetes Care, 2004;27:861-868.
- Pitteloud N, Hardin M, Dwyer AA, et al. Increasing insulin resistance is associated with a decrease in Leydig cell testosterone secretion in men. J Clin Endocrinol Metab, 2005;90:2636-2641.
- Vikan T, Schirmer H, Njølstad I, Svartberg J. Low testosterone and sex hormone- binding globulin levels and high estradiol levels are independent predictors of type 2 diabetes in men. Eur J Endocrinol, 2010;162:747-754.
- Barrett-Connor E, Khaw KT. Endogenous sex hormones and cardiovascular disease in men. A prospective population-based study. Circulation, 1988;78:539- 545.
- Simon D, Charles MA, Nahoul K, et al. Association between plasma total testosterone andcardiovascular risk factors in healthy adult men: The Telecom Study. J Clin Endocrinol Metab, 1997;82:682-685.
- Wickman S, Saukkonen T, Dunkel L. The role of sex steroids in the regulation of insulin sensitivity and serum lipid concentrations during male puberty: a prospective study with a P450-aromatase inhibitor. Eur J Endocrinol, 2002;146:339-346.
- Kapoor D, Goodwin E, Channer KS, Jones TH. Testosterone replacement therapy improves insulin resistance, glycaemic control, visceral adiposity and hypercholesterolaemia in hypogonadal men with type 2 diabetes. Eur J Endocrinol, 2006;154:899-906.
- Rubinow KB, Snyder CN, Amory JK, et al. Acute testosterone deprivation reduces insulin sensitivity in men. Clin Endocrinol, 2012;76:281-288.
- Kupelian V, Hayes FJ, Link CL, et al. Inverse association of testosterone and the metabolic syndrome in men is consistent across race and ethnic groups. J Clin Endocrinol Metab, 2008;93:3403-3410.
- Salehzadeh F, Rune A, Osler M, Al-Khalili L. Testosterone or 17ß-estradiol exposure reveals sex-specific effects on glucose and lipid metabolism in human myotubes. J Endocrinol, 2011;210:219-229.
Dr. Kyl Smith, a 1993 graduate of Parker College of Chiropractic, is the director of education for Progressive Laboratories and author of the book The Testosterone Switch, which includes hundreds of references for diet, exercise and nutritional supplements that increase testosterone levels in men.