I have now had three blood tests and met with two endo drs, so I understand the importance of SHBG levels as they relate to free T.
What we know is, One of the most common ways for low testosterone to develop is when the level of SHBG (sex hormone binding globulin) is high. SHBG “floats” in the bloodstream and combines with free testosterone.
This makes the testosterone “bound” or not free. When it’s bound, it cannot affect a man’s libido.
Here is a research article that shows a relationship between a meat diet and a vegetarian diet. The articles a little old, so I’ll look for others as well.
yourhealthbase.com/database/a98k.htm
WORCESTER, MASSACHUSETTS. Both total and bioavailable testosterone levels decline as men age and the decrease is often accompanied by a decline in sexual function, loss of bone density and muscle mass, and an increase in cholesterol level. The decline in bioavailable testosterone is partially due to an age-related increase in sex hormone-binding globulin (SHBG) which removes the free testosterone from circulation.
Multiple regression analysis of the collected data showed that a high intake of protein corresponded to a lower level of SHBG and thus by inference, a higher level of free testosterone.
A high fiber intake, on the other hand, was clearly correlated with a high SHBG level. Other research has shown that vegetarians tend to have higher SHBG levels than do non-vegetarians.
The data analysis also found that advanced age and a high serum testosterone level were associated with higher SHBG levels whereas a greater body mass index and waist/hip ratio both correlated with a lower SHBG level. No correlation was found with total calorie intake or intakes of fats and carbohydrates. The researchers conclude that elderly men can increase their bioavailable testosterone levels by increasing their protein intake.
The scary thing is that SHBG is produced in the liver. Thereby bringing up the question does this then force our livers to work harder and possibly bring up an entirely different subject.
I have ironically over the last couple of years been lowering my meat intake thinking I wanted to be more healthy and eat less meat. I truly doubt this is this culprit for my problems, but it might have been the catalyst to push me over the top and lower my Free T to extremely low levels. A week ago I just started going back eating more chicken and turkey.
“Decreased serum testosterone levels stimulate the production of SHBG by the liver”