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- Jun 13, 2012
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A Danish study conducted in 2007 found that the levels of testosterone and sex-hormone binding-globulin (SHBG) have been drastically decreased in men since the 1920’s [1]. The researchers found that men born in the 1920’s had higher levels of both testosterone and SHBG than men born in the 1960’s. This is highly relevant because low levels of testosterone and SHBG are strongly associated with metabolic-syndrome [2-4]. The authors state in the Danish study: "we speculate that the secular decline in testosterone serum levels could be secondary to the decline in SHBG levels". Which is consistent with other studies showing SHBG and testosterone have positive associations with one another [5-7].
The researches hypothesize the cause of this phenomenon: "large changes in lifestyle as well as the environment occurred in Denmark during the 20th century with a general significant increase in standard of life along with an increased industrialization" and: "it could be speculated that the observed secular decline in serum SHBG levels could be linked to increased incidence of obesity/metabolic syndrome in the later cohorts".
A 2007 conducted in America has found the same trend. They found that overall, testosterone levels in American men were about 20% higher in 1987 than in 2007, indicating a 1% loss of testosterone in males, per year, regardless of age [8]. The researchers hypothesize that: “Such a secular trend in T might be attributable to parallel population-level changes in the distribution of health and lifestyle factors, independent of age” and “We therefore hypothesize that the observed age-matched decline in serum testosterone is due to some undocumented historical or contemporary influence, health-related or environmental”.
A similar trend has been found with sperm-concentration. Sperm-counts have been steadily decreasing since the early part of the 1900’s [9-12].
So what are some factors that are causing low testosterone and low SHBG? My guess would be on high levels of estrogen, which suppress luteinizing-hormone (LH) secretion; a hormone responsible for testosterone-production and follicle-stimulating-hormone (FSH), which is a hormone responsible for sperm-production. Estrogen suppresses testosterone, which then leads to adverse metabolic effects. Studies using aromatase-inhibitors in men show that testosterone levels are drastically increased, along with LH and FSH, while estrogen concentrations decrease by about 50% [13-17]. Aromatase is the enzyme located in adipocytes (fat-cells), which converts androgens (like testosterone) into estrogens (like estradiol).
The western-diet (a diet high in animal-foods, processed-foods, fats and sugar) has been blamed for causing excess estrogen and low SHBG for a multitude of reasons [18-19].
The first reason being that the western-diet promotes obesity… since obese persons have excess aromatase-enzymes located in their adipose-tissue, hyper-conversion of androgens into estrogens is observed in obesity [6]. The high-fat/low-fiber component of the western-diet is a key promotor of excessive levels of estrogen. Dietary-fat seems to promote estrogen while dietary-fiber seems to lower estrogen [20-25].
The second reason seems to be the estrogen itself, located within dairy-products [26-27] and meat [28-29]. A Japanese study conducted in 2010 looked directly at hormone levels in men before and after drinking a pint of milk [30]. Milk consumption increased estrogen in men by about 29%, followed by a 18% decrease in testosterone, a 25% decrease in LH and a 7% decrease in FSH.
The third reason is that the western-diet lowers SHBG [18], which then increases the metabolic-clearance-rate (MCR) of testosterone [6].
The forth reason is dioxin/xenoestrogen exposure. Dioxins are industrial chemicals and environmental pollutants that are considered endocrine-disruptors or “gender-benders”. Dioxins are known for their estrogenic-effects and are antagonistic towards androgens. These xenoestrogens are fat-soluble and are highly attracted to fatty-tissues. For this reason, the main source of dioxins exposure in humans is consumption of animal-fat [31]. Fish seems to be the greatest contributor to dioxin exposure than any other food source, followed by, milk, beef, cheese, eggs, pork and poultry.
It is interesting to note how diet affects androgen and SHBG levels. A classic study by Longcope et al. [32] showed that SHBG was inversely associated with: body-weight, BMI, visceral-fat, excess calories, dietary-protein, dietary-fat (especially animal-fat) and alcohol. SHBG was positively associated with testosterone, age, carbohydrate and dietary-fiber. After multiple-regression analysis, foods high in dietary-protein (think meat, eggs and dairy-products) strongly decreased SHBG, while foods high in dietary-fiber (think vegetables, whole-grains and legumes) strongly increased SHBG. This finding by Longcope et al. explains why SHBG and testosterone has decreased in western-cultures since the beginning of the 1900’s. The evolution of the American diet, since the beginning of the 1900’s, now shows that Americans eat much more meat, cheese, ice-cream and total-fat and much less whole-grains since 1909 [33].The results of this finding by Longcope prove that in order to increase SHBG, we must consume less calories, less fat, less protein, less alcohol, we must lose excess body-fat (exercise) and eat more fiber (vegetables) and carbohydrates (whole-grains and legumes).
Another classic study by Rosner et al. found that men eating a diet rich in whole-grains had 23% and 33% higher concentrations of testosterone and SHBG compared to men eating a diet rich in meat [34]. And a study done on British men showed that vegan-men had about 15% higher SHBG and testosterone levels compared to men eating the standard western-diet [35].
The Danish researchers (in regards to the plummeting androgen levels in men) warn: "it is alarming that changes of this magnitude can be detected over such a relatively short time, evolutionarily speaking".
[1] J Clin Endocrinol Metab. 2007 Dec;92(12):4696-705. Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys. Andersson AM, Jensen TK, Juul A.
[2] Diabetes Care. 2004 May;27(5):1036-41. Testosterone and sex hormone-binding globulin predict the metabolic syndrome and diabetes in middle-aged men. Laaksonen DE, Niskanen L, Punnonen K.
[3] Aging Male. 2012 Mar;15(1):1-6. Testosterone and sex hormone-binding globulin have significant association with metabolic syndrome in Taiwanese men. Liao CH, Huang CY, Li HY.
[4] J Clin Endocrinol Metab. 2005 May;90(5):2618-23. Endogenous sex hormones and metabolic syndrome in aging men. Muller M, Grobbee DE, den Tonkelaar I.
[5] J Clin Endocrinol Metab. 2005 Jan;90(1):157-62. Associations of sex-hormone-binding globulin (SHBG) with non-SHBG-bound levels of testosterone and estradiol in independently living men. de Ronde W, van der Schouw YT, Muller M.
[6] Cancer Res. 1982 Aug;42(8 Suppl):3281s-3285s. Obesity, androgens, estrogens, and cancer risk. Kirschner MA, Schneider G, Ertel NH.
[7] Ann Med. 1996 Feb;28(1):13-5. Decreased androgen levels and obesity in men. Vermeulen A.
[8] J Clin Endocrinol Metab. 2007 Jan;92(1):196-202. A population-level decline in serum testosterone levels in American men. Travison TG, Araujo AB, O'Donnell AB.
[9] BMJ. 1992 Sep 12;305(6854):609-13. Evidence for decreasing quality of semen during past 50 years. Carlsen E, Giwercman A, Keiding N.
[10] Ugeskr Laeger. 1993 Aug 16;155(33):2530-5. Decline in semen quality from 1930 to 1991. Carlsen E, Giwercman AJ, Keiding N.
[11] N Engl J Med. 1995 Feb 2;332(5):281-5. Decline in semen quality among fertile men in Paris during the past 20 years. Auger J, Kunstmann JM, Czyglik F.
[12] Environ Health Perspect. 1997 Nov;105(11):1228-32. Have sperm densities declined? A reanalysis of global trend data. Swan SH, Elkin EP, Fenster L.
[13] J Clin Endocrinol Metab. 2004 Mar;89(3):1174-80. Effects of aromatase inhibition in elderly men with low or borderline-low serum testosterone levels. Leder BZ, Rohrer JL, Rubin SD.
[14] J Clin Endocrinol Metab. 2000 Jul;85(7):2370-7. Estrogen suppression in males: metabolic effects. Mauras N, O'Brien KO, Klein KO.
[15] Nat Clin Pract Endocrinol Metab. 2008 Jul;4(7):415-9. Treatment of male infertility secondary to morbid obesity. Roth MY, Amory JK, Page ST.
[16] Fertil Steril. 2011 Feb;95(2):809-11. The effect of aromatase inhibitor letrozole on body mass index, serum hormones, and sperm parameters in infertile men. Saylam B, Efesoy O, Cayan S.
[17] Eur J Endocrinol. 2008 May;158(5):741-7. Letrozole once a week normalizes serum testosterone in obesity-related male hypogonadism. Loves S, Ruinemans-Koerts J, de Boer H.
[18] Scand J Clin Lab Invest Suppl. 1990;201:3-23. Western diet and Western diseases: some hormonal and biochemical mechanisms and associations. Adlercreutz H.
[19] Am J Med. 1985 Mar;78(3):363-6. Hyperestrogenemia, diet, and disorders of Western societies. Phillips GB.
[20] Cancer. 1995 Dec 15;76(12):2491-6. Effects of a very low fat, high fiber diet on serum hormones and menstrual function. Implications for breast cancer prevention. Bagga D, Ashley JM, Geffrey SP.
[21] Rev Infect Dis. 1984 Mar-Apr;6 Suppl 1:S85-90. Estrogens, breast cancer, and intestinal flora. Gorbach SL.
[22] Prev Med. 1987 Jul;16(4):525-31. Diet and the excretion and enterohepatic cycling of estrogens. Gorbach SL, Goldin BR.
[23] N Engl J Med. 1982 Dec 16;307(25):1542-7. Estrogen excretion patterns and plasma levels in vegetarian and omnivorous women. Goldin BR, Adlercreutz H, Gorbach SL.[24] Am J Med. 1985 Jan;78(1):23-7. Effects of a high-complex-carbohydrate, low-fat, low-cholesterol diet on levels of serum lipids and estradiol. Rosenthal MB, Barnard RJ, Rose DP.
[25] Nutrition. 1991 Mar-Apr;7(2):137-9; discussion 139-40. Reduction of serum estradiol in postmenopausal women given free access to low-fat high-carbohydrate diet. Heber D, Ashley JM, Leaf DA.
[26] J Dairy Sci. 2010 Jun;93(6):2533-40. Estrone and 17beta-estradiol concentrations in pasteurized-homogenized milk and commercial dairy products. Pape-Zambito DA, Roberts RF, Kensinger RS.
[27] J Dairy Sci. 2012 Apr;95(4):1699-708. Comparison of estrone and 17β-estradiol levels in commercial goat and cow milk. Farlow DW, Xu X, Veenstra TD.
[28] Med Hypotheses. 2005;65(6):1028-37. The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers. Ganmaa D, Sato A.
[29] Handb Exp Pharmacol. 2010;(195):355-67. Hormonal growth promoting agents in food producing animals. Stephany RW.
[30] Pediatr Int. 2010 Feb;52(1):33-8. Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows. Maruyama K, Oshima T, Ohyama K.
[31] http://www.epa.gov/pbt/pubs/dioxins.htm
[32] J Clin Endocrinol Metab. 2000 Jan;85(1):293-6. Diet and sex hormone-binding globulin. Longcope C, Feldman HA, McKinlay JB.
[33] Am J Clin Nutr. 2010 May;91(5):1530S-1536S. Trends in food availability, 1909-2007. Barnard ND.
[34] Life Sci. 1987 May 4;40(18):1761-8. Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Anderson KE, Rosner W, Khan MS.
[35] Br J Cancer. 2000 Jul;83(1):95-7. Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men. Allen NE, Appleby PN, Davey GK.
.
The researches hypothesize the cause of this phenomenon: "large changes in lifestyle as well as the environment occurred in Denmark during the 20th century with a general significant increase in standard of life along with an increased industrialization" and: "it could be speculated that the observed secular decline in serum SHBG levels could be linked to increased incidence of obesity/metabolic syndrome in the later cohorts".
A 2007 conducted in America has found the same trend. They found that overall, testosterone levels in American men were about 20% higher in 1987 than in 2007, indicating a 1% loss of testosterone in males, per year, regardless of age [8]. The researchers hypothesize that: “Such a secular trend in T might be attributable to parallel population-level changes in the distribution of health and lifestyle factors, independent of age” and “We therefore hypothesize that the observed age-matched decline in serum testosterone is due to some undocumented historical or contemporary influence, health-related or environmental”.
A similar trend has been found with sperm-concentration. Sperm-counts have been steadily decreasing since the early part of the 1900’s [9-12].
So what are some factors that are causing low testosterone and low SHBG? My guess would be on high levels of estrogen, which suppress luteinizing-hormone (LH) secretion; a hormone responsible for testosterone-production and follicle-stimulating-hormone (FSH), which is a hormone responsible for sperm-production. Estrogen suppresses testosterone, which then leads to adverse metabolic effects. Studies using aromatase-inhibitors in men show that testosterone levels are drastically increased, along with LH and FSH, while estrogen concentrations decrease by about 50% [13-17]. Aromatase is the enzyme located in adipocytes (fat-cells), which converts androgens (like testosterone) into estrogens (like estradiol).
The western-diet (a diet high in animal-foods, processed-foods, fats and sugar) has been blamed for causing excess estrogen and low SHBG for a multitude of reasons [18-19].
The first reason being that the western-diet promotes obesity… since obese persons have excess aromatase-enzymes located in their adipose-tissue, hyper-conversion of androgens into estrogens is observed in obesity [6]. The high-fat/low-fiber component of the western-diet is a key promotor of excessive levels of estrogen. Dietary-fat seems to promote estrogen while dietary-fiber seems to lower estrogen [20-25].
The second reason seems to be the estrogen itself, located within dairy-products [26-27] and meat [28-29]. A Japanese study conducted in 2010 looked directly at hormone levels in men before and after drinking a pint of milk [30]. Milk consumption increased estrogen in men by about 29%, followed by a 18% decrease in testosterone, a 25% decrease in LH and a 7% decrease in FSH.
The third reason is that the western-diet lowers SHBG [18], which then increases the metabolic-clearance-rate (MCR) of testosterone [6].
The forth reason is dioxin/xenoestrogen exposure. Dioxins are industrial chemicals and environmental pollutants that are considered endocrine-disruptors or “gender-benders”. Dioxins are known for their estrogenic-effects and are antagonistic towards androgens. These xenoestrogens are fat-soluble and are highly attracted to fatty-tissues. For this reason, the main source of dioxins exposure in humans is consumption of animal-fat [31]. Fish seems to be the greatest contributor to dioxin exposure than any other food source, followed by, milk, beef, cheese, eggs, pork and poultry.
It is interesting to note how diet affects androgen and SHBG levels. A classic study by Longcope et al. [32] showed that SHBG was inversely associated with: body-weight, BMI, visceral-fat, excess calories, dietary-protein, dietary-fat (especially animal-fat) and alcohol. SHBG was positively associated with testosterone, age, carbohydrate and dietary-fiber. After multiple-regression analysis, foods high in dietary-protein (think meat, eggs and dairy-products) strongly decreased SHBG, while foods high in dietary-fiber (think vegetables, whole-grains and legumes) strongly increased SHBG. This finding by Longcope et al. explains why SHBG and testosterone has decreased in western-cultures since the beginning of the 1900’s. The evolution of the American diet, since the beginning of the 1900’s, now shows that Americans eat much more meat, cheese, ice-cream and total-fat and much less whole-grains since 1909 [33].The results of this finding by Longcope prove that in order to increase SHBG, we must consume less calories, less fat, less protein, less alcohol, we must lose excess body-fat (exercise) and eat more fiber (vegetables) and carbohydrates (whole-grains and legumes).
Another classic study by Rosner et al. found that men eating a diet rich in whole-grains had 23% and 33% higher concentrations of testosterone and SHBG compared to men eating a diet rich in meat [34]. And a study done on British men showed that vegan-men had about 15% higher SHBG and testosterone levels compared to men eating the standard western-diet [35].
The Danish researchers (in regards to the plummeting androgen levels in men) warn: "it is alarming that changes of this magnitude can be detected over such a relatively short time, evolutionarily speaking".
[1] J Clin Endocrinol Metab. 2007 Dec;92(12):4696-705. Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys. Andersson AM, Jensen TK, Juul A.
[2] Diabetes Care. 2004 May;27(5):1036-41. Testosterone and sex hormone-binding globulin predict the metabolic syndrome and diabetes in middle-aged men. Laaksonen DE, Niskanen L, Punnonen K.
[3] Aging Male. 2012 Mar;15(1):1-6. Testosterone and sex hormone-binding globulin have significant association with metabolic syndrome in Taiwanese men. Liao CH, Huang CY, Li HY.
[4] J Clin Endocrinol Metab. 2005 May;90(5):2618-23. Endogenous sex hormones and metabolic syndrome in aging men. Muller M, Grobbee DE, den Tonkelaar I.
[5] J Clin Endocrinol Metab. 2005 Jan;90(1):157-62. Associations of sex-hormone-binding globulin (SHBG) with non-SHBG-bound levels of testosterone and estradiol in independently living men. de Ronde W, van der Schouw YT, Muller M.
[6] Cancer Res. 1982 Aug;42(8 Suppl):3281s-3285s. Obesity, androgens, estrogens, and cancer risk. Kirschner MA, Schneider G, Ertel NH.
[7] Ann Med. 1996 Feb;28(1):13-5. Decreased androgen levels and obesity in men. Vermeulen A.
[8] J Clin Endocrinol Metab. 2007 Jan;92(1):196-202. A population-level decline in serum testosterone levels in American men. Travison TG, Araujo AB, O'Donnell AB.
[9] BMJ. 1992 Sep 12;305(6854):609-13. Evidence for decreasing quality of semen during past 50 years. Carlsen E, Giwercman A, Keiding N.
[10] Ugeskr Laeger. 1993 Aug 16;155(33):2530-5. Decline in semen quality from 1930 to 1991. Carlsen E, Giwercman AJ, Keiding N.
[11] N Engl J Med. 1995 Feb 2;332(5):281-5. Decline in semen quality among fertile men in Paris during the past 20 years. Auger J, Kunstmann JM, Czyglik F.
[12] Environ Health Perspect. 1997 Nov;105(11):1228-32. Have sperm densities declined? A reanalysis of global trend data. Swan SH, Elkin EP, Fenster L.
[13] J Clin Endocrinol Metab. 2004 Mar;89(3):1174-80. Effects of aromatase inhibition in elderly men with low or borderline-low serum testosterone levels. Leder BZ, Rohrer JL, Rubin SD.
[14] J Clin Endocrinol Metab. 2000 Jul;85(7):2370-7. Estrogen suppression in males: metabolic effects. Mauras N, O'Brien KO, Klein KO.
[15] Nat Clin Pract Endocrinol Metab. 2008 Jul;4(7):415-9. Treatment of male infertility secondary to morbid obesity. Roth MY, Amory JK, Page ST.
[16] Fertil Steril. 2011 Feb;95(2):809-11. The effect of aromatase inhibitor letrozole on body mass index, serum hormones, and sperm parameters in infertile men. Saylam B, Efesoy O, Cayan S.
[17] Eur J Endocrinol. 2008 May;158(5):741-7. Letrozole once a week normalizes serum testosterone in obesity-related male hypogonadism. Loves S, Ruinemans-Koerts J, de Boer H.
[18] Scand J Clin Lab Invest Suppl. 1990;201:3-23. Western diet and Western diseases: some hormonal and biochemical mechanisms and associations. Adlercreutz H.
[19] Am J Med. 1985 Mar;78(3):363-6. Hyperestrogenemia, diet, and disorders of Western societies. Phillips GB.
[20] Cancer. 1995 Dec 15;76(12):2491-6. Effects of a very low fat, high fiber diet on serum hormones and menstrual function. Implications for breast cancer prevention. Bagga D, Ashley JM, Geffrey SP.
[21] Rev Infect Dis. 1984 Mar-Apr;6 Suppl 1:S85-90. Estrogens, breast cancer, and intestinal flora. Gorbach SL.
[22] Prev Med. 1987 Jul;16(4):525-31. Diet and the excretion and enterohepatic cycling of estrogens. Gorbach SL, Goldin BR.
[23] N Engl J Med. 1982 Dec 16;307(25):1542-7. Estrogen excretion patterns and plasma levels in vegetarian and omnivorous women. Goldin BR, Adlercreutz H, Gorbach SL.[24] Am J Med. 1985 Jan;78(1):23-7. Effects of a high-complex-carbohydrate, low-fat, low-cholesterol diet on levels of serum lipids and estradiol. Rosenthal MB, Barnard RJ, Rose DP.
[25] Nutrition. 1991 Mar-Apr;7(2):137-9; discussion 139-40. Reduction of serum estradiol in postmenopausal women given free access to low-fat high-carbohydrate diet. Heber D, Ashley JM, Leaf DA.
[26] J Dairy Sci. 2010 Jun;93(6):2533-40. Estrone and 17beta-estradiol concentrations in pasteurized-homogenized milk and commercial dairy products. Pape-Zambito DA, Roberts RF, Kensinger RS.
[27] J Dairy Sci. 2012 Apr;95(4):1699-708. Comparison of estrone and 17β-estradiol levels in commercial goat and cow milk. Farlow DW, Xu X, Veenstra TD.
[28] Med Hypotheses. 2005;65(6):1028-37. The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers. Ganmaa D, Sato A.
[29] Handb Exp Pharmacol. 2010;(195):355-67. Hormonal growth promoting agents in food producing animals. Stephany RW.
[30] Pediatr Int. 2010 Feb;52(1):33-8. Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows. Maruyama K, Oshima T, Ohyama K.
[31] http://www.epa.gov/pbt/pubs/dioxins.htm
[32] J Clin Endocrinol Metab. 2000 Jan;85(1):293-6. Diet and sex hormone-binding globulin. Longcope C, Feldman HA, McKinlay JB.
[33] Am J Clin Nutr. 2010 May;91(5):1530S-1536S. Trends in food availability, 1909-2007. Barnard ND.
[34] Life Sci. 1987 May 4;40(18):1761-8. Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Anderson KE, Rosner W, Khan MS.
[35] Br J Cancer. 2000 Jul;83(1):95-7. Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men. Allen NE, Appleby PN, Davey GK.
.
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