Fiber bad, increases SHBG?

[twistedneck]

Dang, I like to eat fiber cerial every morning too.

Diet and Sex Hormone-Binding Globulin
C. Longcope, H. A. Feldman, J. B. McKinlay and A. B. Araujo
University of Massachusetts Medical School (C.L.), Worcester, Massachusetts 01655; and New England Research Institutes (H.A.F., J.B.M., A.B.A.), Watertown, Massachusetts 02172

Address all correspondence and requests for reprints to: Dr. C. Longcope, University of Massachusetts Medical School, Worcester, Massachusetts 01655.

The serum concentration of sex hormone-binding globulin (SHBG) is inversely related to weight and in animal studies is inversely related to protein intake. As SHBG can affect the biological activity of testosterone and estradiol, we wished to determine the role of protein intake on SHBG levels in men. Using data from the Massachusetts Male Aging Study we examined cross-sectional relationships between dietary components and SHBG levels in 1552 men (aged 40–70 yr) for whom these factors were known.

Analyzed by multiple regression, controlling for testosterone and estradiol levels, age (P < 0.001) and fiber intake (P = 0.02) were positively correlated to SHBG concentration, whereas body mass index (P < 0.001) and protein intake (P < 0.03) were negatively correlated to SHBG concentration. The intakes of calories, fat (animal or vegetable), and carbohydrate were not related to SHBG concentration. We conclude that age and body mass index are major determinants of SHBG concentrations in older men, and fiber and protein intake are also significant contributors to SHBG levels, but total caloric intake and the intake of carbohydrate or fat are not significant. Thus, diets low in protein in elderly men may lead to elevated SHBG levels and decreased testosterone bioactivity. The decrease in bioavailable testosterone can then result in declines in sexual function and muscle and red cell mass, and contribute to the loss of bone density

 

[Mr.X]

"The serum concentration of sex hormone-binding globulin (SHBG) is inversely related to weight and in animal studies"

Animal studies are hard to correlate to humans...

Mr.X

 

[Stryc-9]

Not only that, but the study indicates that the correlation between fiber and SHBG is negative. That means fiber is something you DO want in your diet. So go ahead and eat your fiber.

The positive correlation in this study is between SHBG and protein - with the conclusion being that low protein leads to a decrease in bioavailable testosterone levles (which bodybuilders have known all along!).

 

[twistedneck]

Hey Stryc-9, check this from the study

age (P < 0.001) and fiber intake (P = 0.02) were positively correlated to SHBG concentration

Age and fiber goes up, SHBG goes up.

whereas body mass index (P < 0.001) and protein intake (P < 0.03) were negatively correlated to SHBG concentration.

Gaining weight and eating a lot of protein reduce SHBG. why the fuck do they have to say 'negatively correlated'..

you with me on this?

 

[paul2110]

Fibre

Definitely a good idea to eat plenty of fibre. Helps to avoid constipation when taking in large amounts of protein.

Where do you guys dig up these lab reports from?

 

[twistedneck]

Pub med is a good place to start

http://www.ncbi.nlm.nih.gov/PubMed

 

[Deleted member 33117]

Since when has fat intake not been related to SHBG levels? There are a dozen studies showing taht eating saturated fat lowers shbg levels more than other fats, and eating a meal with 20% of less of its calories from fat starts elevating shbg levels within 2 hours of consuption.

 

[twistedneck]

BodybyFnaplix, I read this entire study and they discuss the issue of other studies that show a correlation with fat inatake and SHBG. The response they provide is based on this study being extremely large and encompassing a variety of life styles (over 1000 men). when the adjusted for all the factors only the above four mentioned were strongly correlated with SHBG. Interestingly, high total T levels are normally associated with high SHBG.. hmm.