Researchers in Germany have conducted a randomized placebo-controlled study of vitamin D3 supplementation in overweight people who took part in a structured weight loss program for 12 months. They found that daily vitamin D3 at a dose of 3,333 IU did not affect weight loss. However, small but significant decreases in levels of triglycerides and the cytokine TNF-alpha occurred in the blood of people who received vitamin D3. Also, a small (+5%) but statistically significant increase in levels of bad cholesterol (LDL-C) occurred among vitamin D3 recipients. Unexpectedly, a small but statistically significant increase in testosterone levels was detected in men who received vitamin D3. Two hundred HIV-negative overweight and otherwise healthy people were recruited for the weight loss study. As part of the program, participants were educated about nutrition and healthy eating habits and received weekly counselling via telephone with a nutritionist for the first six months of the study. Half of the participants received vitamin D3 at a dose of 3,333 IU/day for 12 consecutive months, while the other half received placebo.
Among a subset of 54 men—31 received vitamin D and 23 received placebo—extensive laboratory assessments of testosterone were performed. This report focuses on the 54 men. The average age of the men was 48 years and half of them smoked tobacco. Vitamin D levels prior to randomization were suggestive of deficiency, about 30 nmol/litre. The men lost an average of 6 kg over the course of a year. The men who received vitamin D had their levels rise to 86 nmol/litre. Before we can present further results on testosterone, some background information is necessary. In adult males, most testosterone (95%) is made by the testicles—between 3 mg and 10 mg each day. The adrenal glands produce the remaining amount of this hormone. In the blood, most testosterone is bound to two proteins: In theory, only testosterone that has broken loose or becomes free from those previously mentioned proteins is available for use by tissues. This unbound testosterone is called “free testosterone” in laboratory tests.
Analysis of blood tests sometimes report testosterone assessments as follows: total testosterone – this includes testosterone bound to blood proteins and free testosterone free testosterone – this can be directly measured or calculated using total testosterone levels, SHBG and albumin concentration and equations bioavailable testosterone – this refers to free testosterone plus testosterone loosely bound to albumin Different laboratories have different reference ranges for testosterone, and levels of this hormone tend to fall with age. Note that testosterone levels often fall in cases of chronic infections such as HIV and inflammatory conditions such as cancer, severe kidney and lung disease. Also, some drugs and substances can decrease testosterone levels, including the following: chronic, excessive use of alcohol Results—Testosterone and vitamin D In different assessments, participants who received vitamin D had relatively small but statistically significant increases in testosterone compared to placebo.
For instance, total testosterone levels rose by 3 nmol/litre to 13.4 nmol/litre after 12 months. A similar trend occurred with bioavailable testosterone and free testosterone. Why did an increase occur? There are several pieces of evidence to suggest that vitamin D may have played a role in the increased testosterone levels detected in this study. Such evidence is important to consider because the primary purpose of the study was to assess weight loss and not to assess changes in testosterone. Moreover, the numbers of men in the substudy were relatively small. Here is some evidence that may support the vitamin D findings of this study: In experiments on mice, those that do not have receptors for vitamin D suffer from less-than-normal levels of testosterone. The testicles have receptors for vitamin D, suggesting that this vitamin plays some role there. A previous cross-sectional study in people found a link between vitamin D levels in the blood and testosterone levels in the blood.
Taken together, these previous bits of research along with the present German study suggest that vitamin D may modestly alter testosterone levels in males. Because of the previously mentioned issues, the present study’s results cannot be taken as definitive, only suggestive. Also, because researchers did not assess factors influenced by testosterone, such as sex drive, mood or muscle strength, the clinical significance of these changes in testosterone levels is not clear. Still, the findings from the present study are intriguing and require confirmation in a large randomized clinical trial. Zanatta L, Zamoner A, Zanatta AP, et al. Nongenomic and genomic effects of 1α,25(OH)(2) vitamin D(3) in rat testis. [Epub ahead of print] Foresta C, Strapazzon G, De Toni L, et al. Bone mineral density and testicular failure: evidence for a role of vitamin D 25-hydroxylase in human testis. Journal of Clinical Endocrinology and Metabolism. Zittermann A, Frisch S, Berthold HK, et al. Vitamin D supplementation enhances the beneficial effects of weight loss on cardiovascular disease risk markers.
American Journal of Clinical Nutrition. Pilz S, Frisch S, Koertke H, et al. Effect of vitamin D supplementation on testosterone levels in men. Hormone and Metabolic Research. Sex drive is a hot topic these days, and I can’t help but notice blogs surface around Valentine’s Day showing how certain foods, nutrients, and lifestyle factors can boost libido and keep you stimulated in bed. Many of these articles neglect the underlying hormones that control sex drive. While losing your sex drive or struggling with issues like erectile dysfunction can become complex issues, hormonal imbalances play a significant role in these issues. Many things promote these imbalances in hormones, including a high-sugar, refined carbohydrate diet, caffeine, stress, dairy (if you are sensitive to it), hormones in the food supply in dairy products and meat, and estrogen-like toxins from pesticides, plastics, and pollution. Let’s briefly look at some of these hormones that influence sex drive, what knocks them out of balance, and then how to balance them.
Among its numerous problems, high insulin levels create sex hormone problems and can lead to infertility; hair growth where you don’t want it (your face if you’re a woman); hair loss where you do want it (your head); low testosterone, loss of chest, leg, and arm hair, and breast growth in men; Along with increasing belly fat, high insulin and insulin resistance create fatigue after meals, sugar cravings, blood sugar swings or hypoglycemia, high triglycerides, low HDL, high blood pressure, problems with blood clotting, and increased inflammation often accompanied by low sex drive. When insulin becomes out of whack, other hormones quickly follow, and your sex drive can take a massive crash. Let’s look at a few of those hormones. Testosterone is a wonderful brain-boosting hormone that improves mood, memory, motivation, overall cognitive function, and of course, sex drive. Testosterone isn’t just a guy’s hormone. Imbalanced levels of this hormone in women can reduce desire, increase body fat, lower muscle mass, and create a fuzzy memory.
Insulin resistance drives down testosterone levels, significantly impairing sex drive and sexual function. Low testosterone also leads to other problems, such as decreased muscle mass and more fat deposition in the belly, seen in all those big guts in men over forty years old. Leptin puts the brakes on your appetite. This hormone tells your brain to stop eating. Except when you eat a lot of sugar, processed foods, and flour, leptin doesn’t work anymore. Fat cells continue to produce this hormone, but your brain doesn’t “hear” its call and eventually becomes leptin resistant. I often see insulin resistance and leptin resistance go hand in hand with my patients. Most people don’t realize leptin also monitors sexual behavior. One study looked at three groups of men and found those with higher leptin levels – most likely due to leptin resistance – also had significantly higher body mass index (BMI) and lower levels of testosterone. Growth hormone (GH) is your “fountain of youth” hormone that you mostly produce during deep sleep.
Secreted by the pituitary gland, GH improves muscle mass, helps your body utilize fat, and helps maintain optimal libido. Reduced muscle mass, increased abdominal obesity, and diabesity as well as lower libido are hallmark symptoms of GH deficiencies. Researchers find a direct link between GH, insulin levels, and sexual function. Studies show insulin reduces your body’s ability to make GH, altering testosterone levels and reducing libido. When you are introduced to a stressful situation, your body releases a hormone called cortisol. Cortisol is responsible for setting off all the physiological responses associated with stress. Studies have shown that when cortisol is released into the bloodstream you become less sensitive to leptin, the hormone that tells your brain you are full. When this happens, you tend to eat more and crave more sugar. Prolonged, unremitting stress may lead to insulin resistance, diminished sex drive, and infertility. You’ve likely experienced the effects of cortisol during a stressful situation.
Sex is probably the last thing on your mind during those situations. Simply put, chronic stress crashes your sex hormones and quickly knocks you out of the mood. 4 Surprising Culprits that Kill Your Sex Drive You know that cheap, high-calorie, nutrient-poor processed foods (or “food-like substances”) are a sure-fire way to diminish your sex drive. Yet you might not suspect the following culprits could also contribute: 5 Ways to Optimize Sex Drive The good news is when you control your blood sugar and normalize insulin levels, other hormones quickly follow that lead. Numerous factors can contribute to low sex drive and erectile dysfunction. Blood work can reveal abnormal testosterone levels (in men) or estrogen dominance (in women) and other hormonal imbalances that can put you out of the mood. For most people, I’ve found these five strategies can help increase sex drive. What one strategy would you add here to keep you “in the mood”? Share yours below or on my Facebook fan page.