Sugar has a greater effect on your bodybuilding or fitness goals than you may have first realized. Eating too much fructose and glucose can turn off the gene that regulates the levels of active testosterone and estrogen in the body. When this regulatory mechanism is disabled, many health problems can arise.
This was shown in a new study in mice and human cell cultures in the Journal of Clinical Investigation. This discovery reinforces the advice of those in the health and fitness world to eat complex carbohydrates and avoid sugar. Table sugar is made of glucose and fructose, while fructose is also commonly used in sweetened beverages, syrups, and low-fat food products. Estimates suggest North Americans consume 33 kilograms of refined sugar and an additional 20 kilograms of high fructose corn syrup per person, per year.
Glucose and fructose are metabolized in the liver. When there’s too much sugar in the diet, the liver converts it to lipid (fat). Using live mice and human liver cell cultures, the scientists discovered that the increased production of lipid shut down a gene called SHBG (sex hormone binding globulin), reducing the amount of SHBG protein in the blood. SHBG protein plays a key role in controlling the amount of testosterone and estrogen that’s available throughout the body. If there’s less SHBG protein, then more testosterone and estrogen will be released throughout the body, which is associated with an increased risk of acne, infertility, polycystic ovaries, and uterine cancer in overweight women. Abnormal amounts of SHBG also disturb the delicate balance between estrogen and testosterone, which is associated with the development of cardiovascular disease, especially in women.
It was discovered that low levels of SHBG in a person’s blood means the liver’s metabolic state is not functioning properly. The cause is an inappropriate diet, or that something is inherently wrong with the liver. This is shown to be the case long before there are any disease symptoms.
With this new understanding, SHBG can now be used as a biomarker for monitoring liver function well before symptoms arise. It can also be used for determining the effectiveness of dietary interventions and drugs aimed at improving the liver’s metabolic state.”
Physicians have traditionally measured SHBG in the blood to determine a patient’s amount of free testosterone, which is key information for diagnosing hormonal disorders. In addition, SHBG levels are used to indicate an individual’s risk for developing type 2 diabetes and cardiovascular disease.
The discovery dispels the earlier assumption that too much insulin reduces SHBG, a view which arose from the observation that overweight, pre-diabetic individuals have high levels of insulin and low levels of SHBG. This new study proves that insulin is not to blame and that it’s actually the liver’s metabolism of sugar that counts.