Why Would My Sex Hormone Binding Globulin Be High?
Why would my sex hormone-binding globulin be high? Maybe you are asking this question about your sex hormone-binding globulin being elevated and what you can do about it? Both males and females can have this elevation leading to various hormone imbalance symptoms. Regardless of gender, I will discuss some of the driving forces behind sex hormone binding globulin secretion and production in your body.
If this is something that interests you keep reading, we are going to get into the details.
What Is Sex Hormone Binding Globulin?
First I wanted to explain briefly what sex hormone binding globulin (SHBG) is. This is a protein produced in the liver and there are different signals from the body that will make you produce more or less of this hormone. Its main function is to carry other hormones throughout your body so that they don't immediately bind to receptors in the local tissues it was secreted from . This allows the hormones to be more evenly distributed throughout your body. Mainly the sex hormone binding globulin binds things like estrogens and testosterone.
There are various types of estrogen that it binds to. There is E1, E2, E3 and there are different metabolites of those as well. All are carried by SHBG. The same thing is true for testosterone. There is dihydrotestosterone and other metabolites of testosterone that the sex hormone binding globulin binds and distributes.
Estrogens Cause SHBG to Be High
The thing that is most notable and commonly referenced as raising SHBG is estrogen. We know it does this for several reasons. Females have more sex hormone binding globulin than males. We also know that birth control can be used to to raise sex hormone binding globulin. For instance, in women with PCOS, they will sometimes be given birth control and that will raise their SHBG. This is not an absolute solutions for them but it can help. We also know women on birth control often have a lower free testosterone. That being caused by the same phenomenon.
For both males and females you have total testosterone which includes the amount that is bound to SHBG and unbound or free. Only a small part of your total testosterone is free and available or bioavailable. A bigger chunk of that is being bound up by the sex hormone binding globulin. So when you have an issue with low testosterone symptoms part of the issue can be you have even a smaller fraction that is free or bioavailable.
Estrogen comes in a lot of different forms and abnormalities can arise in males when they have more fat mass than muscle mass. The fat cells, or adipocytes, actually make some estrogen through aromatization. Aromatization is simply and enzyme reaction that turns testosterone into estrogen. This is the only place males get estrogen and it is a natural process for this to occur. When there is more fat cells these enzymes basically take a higher amount of the testosterone and turn it into estrogen. As a result, that estrogen gets circulated back up to the liver causing the liver to make more of this SHBG.
There is also the issue with xenoestrogens or environmental estrogens. These are things like plastics and other man made compounds that have a similar biochemical structure to estrogen. Because of the similar structure they can stimulate estrogen receptors in a similar way that the actual estrogens do. I did not look at any actual research but this is common sited as another form of estrogen. For now we will say it can theoretical stimulate the receptors in the liver to produce more SHBG.
Things like soy products or soy isoflavones are also weak estrogen known as phytoestrogens. It has very week estrogen effects. Contrary to popular believe it can actually help with some of the high estrogen effects. It does this by blocking the stronger estrogen from binding to the estrogen receptors. If someone has low estrogen, these could also bind to the estrogen sites in the liver and cause increase in SHBG. For the most part, the things with soy and estrogen can be overblown. However, if you have a high SHBG and consuming a lot of soy, it may be something to look at closely.
Viruses Cause SHBG to Be High?
Another thing that can raise sex hormone-binding globulin is viral hepatitis. This is pretty well documented and clear-cut. Other forms of hepatitis like NASH (non steatohepatitis) are not as clear cut. Some studies have found an increase where others have not. It is a little bit hard to tease out the effect of hepatitis (inflammation in the liver) and the effect of insulin. Insulin resistance is common with NASH. We know that insulin will drive down SHBG. What is not clear is if it is the inflammation in the liver that raises the SHBG. We do know that viral hepatitis causes increases in sex hormone binding globulin. So is it the virus itself or the inflammation in the liver. If it is the virus, there maybe other instances from other viruses and infections that can also raise sex hormone binding globulin. I do not have any research to support this theory however.
There are some other things to consider like medications. There is a medication used to treat psoriasis that is known to raise SHBG. The medication targets an immune chemical messenger called TNF alpha. The medication lowers TNF alpha which is a marker of inflammation marker. So it lowers inflammation through that mechanism. This medication actually raises SHBG. That doesn't mean everything that lowers inflammation will raise SHBG however. Taken together with the viral information this suggest that there is some effects of different immune chemicals on SHBG. You can read more about the causes of high SHBG and the link between SHBG and inflammation at the link above.
Dietary and Hormone Causes of Elevated SHBG
Putting yourself in caloric restriction and reduced protein (often vegan and vegetarian) diets will raise your sex hormone binding globulin. This may be more of an indirect route because of the effect on insulin. We know that insulin is a stimulus to lower your sex hormone binding globulin. Insulin goes up in response to things like eating a diet high in carbohydrates and protein. So if you are eating less of these, insulin goes down and SHBG goes up. There is also insulin like growth factor which is more of a growth hormone signal. Lower amounts of this will also raise sex hormone binding globulin. So if you are someone that is doing a lot of fasting or trying to lose weight and restricting calories, this may be why you have elevated sex hormone binding globulin.
Something else to pay attention to is the timing of testing and what you are doing around the test as this may also influence your numbers. For instance, if you are doing a 12 hr fasting test you may have a much higher SHBG because you will have lower insulin at this time. To get a true sense you might want to test for SHBG in both fasted and non-fasted state.
Thyroid hormone like thyroxine or t4 is also known to raise sex hormone binding globulin. So if you are on thyroid medication, this would be something to look at depending on how important it is to get your sex hormone binding globulin down. Some doctors are more aggressive and dose thyroid hormone high. Your thyroid medication dose may be something to consider depending on how you are dosing it.
The other thing to mention is that low free testosterone is a common reason this comes up to begin with. Most people that are looking at how to decrease their sex hormone binding globulin are males with low free testosterone. Wether you are male or female testosterone and other hormones are not just bound by sex hormone binding globulin. There are other hormones binding proteins that bind up hormones like albumin So if you have a low free testosterone and a normal total testosterone part of your issue may be related to albumin as well as sexual binding globulin.
This should answer the question, why would my sex hormone binding globulin be high and give you some ideas on what you can do about it. If you have questions about anything in this article, ask it in the comment below. If you want a customized plan, on how to lower your sex hormone binding globulin and hormonal imbalance, click on the link be low to get started.