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Hormones and Diet
Part One: Growth Hormone
By Gary F. Zeolla
Note: This article was revised and expanded and incorporated as a chapter in the book God-given Foods Eating Plan.
Hormones have a direct affect on a person's body composition (muscularity versus fatness), strength and energy levels, sex drive and performance, various aspects of the aging process, and one's health in general. And what you eat has a direct bearing on your hormone levels. This two-part article will look at this relationship between hormones and diet.
In this investigation, it will become apparent that many common dietary recommendations are wrong- headed when it comes to hormone optimization. So be prepared to have some of your preconceptions rattled.
Hormones to be Discussed
Human growth hormone (HGH or GH) and testosterone are the two primary anabolic hormones. This means that increased levels of these hormones will increase muscular size and strength. They are also lipolytic, meaning they mobilize body fat for use as fuel, leading to a reduction in body fat. Thyroid hormone (specifically, trilodothyronine, T3) would be another hormone with anabolic and lipolytic properties.
Cortisol is the primary "catabolic" hormone. Increased levels will have the opposite effect of anabolic hormones, namely decreased muscle size and strength. Cortisol is also lipogenic, meaning it directs the body to store body fat. And importantly, as cortisol levels rise, levels of growth hormone and testosterone levels drop, and vice-a-versa.
Insulin can be anabolic in that it helps to drive amino acids (protein) into muscle cells, thus improving the rate of muscle recovery and growth from exercise. But insulin can be lipogenic in that chronically high levels increase body fat.
Glucagon works in opposition to insulin. As glucagon rises, insulin drops, and vice-a-versa. And its actions are opposite that of insulin. It leads to muscle breakdown but also to the loss of body fat.
Insulin-like growth factor (IGF-1) is a hormone-like substance that has both anabolic and lipolytic effects.
There are many other hormones in the body. But these are the ones that are primary affected by diet. The first two will be the primary focus of this article, but the others will be touched on as well. This first part of this two-part article will focus on growth hormone. Part Two will focus on testosterone.
Growth Hormone Background and Terminology
Before getting to the discussion on GH and diet, some background on GH and a note on terminology will be helpful.
GH-stimulatory factor, also known as Growth Hormone Releasing Hormone (GHRH), is produced by the Hypothalamus and induces the Anterior Pituitary to release GH.
GH-inhibitory factor, also known as Somatostatin, is similarly produced by the Hypothalamus and acts upon the Anterior Pituitary to halt GH release.
GH levels are highest during our growth spurt at puberty and decline steadily from then on. Stated differently, we release about 20-times less GH at 80 than we did at 20!!
Surprisingly, the amount of GH produced by the body isn't greatly reduced as we grow older, just the amount that is released into the blood stream. It has been proposed that an age-related rise in somatostatin levels underlies the observed drop in GH with age past puberty. The pot-belly that characterizes most older males is often the result of reduced GH (Creatine Newsletter).
So the important point in regards to GH is not its production but how much is actually released into the blood stream. So throughout this article, discussion will be on GH release (or secretion) rather than on GH production.
Growth Hormone and Blood Sugar
The most important point in regards to growth hormone (GH) and diet is that "Growth hormone levels increase significantly when insulin levels are low" (Jamieson, p. 85). "More precisely, the cause of growth hormone inhibition is not high insulin levels but rather high blood sugar (which, because insulin is secreted to bring down blood sugar level, overlaps in time with high insulin levels)" (Faigin, p.201).
To explain further, "… glucose inhibits the secretion of growth hormone by acting on specific areas of the hypothalamus. Consequently, during the day, when food is consumed periodically, growth hormone secretion by the pituitary is suppressed, and insulin release by the pancreas is increased" (Dean).
But it should be noted that it is not just any food that causes a rise in blood sugar and the consequent insulin release, but primary carbohydrates. And some kinds of carbs cause a greater blood sugar increase than others. This issue is discussed in the article *The Glycemic Index.
I won't repeat all the details of that article here, but the important point is that low glycemic foods will not increase blood sugar as much as high glycemic foods. And eating a large amount of carbs at once will cause a greater increase in blood sugar levels than eating a small amount of carbs. Also, eating fat with carbs will blunt the rise in blood sugar.
What this means is, consuming a large amount of high glycemic carbs by themselves could completely halt growth hormone release. Or more generally, a high carbohydrate, low fat diet is absolutely devastating to growth hormone levels. This is one of the reasons why many people trying to lose weight on such a diet "plateau" after a period of time. Their inability to continue to lose weight is partly due to suppressed GH levels.
Moreover, a study comparing a group of boys consuming meals composed of high-glycemic index (GI) foods verses low GI foods found, "There were higher levels of the hormones insulin, noradrenaline, and cortisol after the high-GI meals" (Brand-Miller, p.230). So a rapid rise in blood sugar and insulin can lead to a rise in cortisol, with its attendant catabolic and lipogenic properties.
However, "… we need insulin to promote the benefits of growth hormone. Studies show that GH fails to cause growth in animals lacking a pancreas and it also fails if carbohydrates are restricted from the diet" (Jamieson, p.56). The reason for his could be that a strict low carb diet would lead to chronically low insulin levels, and insulin, as indicated above, is needed to drive amino acids into the muscle cells.
Moreover, IGF-1 is produced in the body through the combined actions of GH and insulin. And IGF-1 "… is at least as powerful an anabolic agent as either of its parents" (Faigin, p. 90). But a low carb diet would lead to a reduction in IGF-1 levels. So a low carb diet is not the answer either. In fact, this relationship of insulin, growth hormone, and IGF-1 is one reason why those following a low carb diet also often plateau after a period of time.
There is a relationship with thyroid hormone here as well. "Raising GH has a profound effect on normalizing thyroid function … " (Jamieson, p.100). However, "Studies also show that diets that continuously restrict carbohydrate (like the Atkin's diet, for instance) cause a reduction in T3, and that administering carbohydrate can restore T3 levels after they have declined" (Faigin, p.139). This reduction in T3 is another reason people will often plateau on low carb diets.
So an ideal GH enhancing diet would include some carbs, but not an excessive amount. And the focus would be on low glycemic carbs.
Growth Hormone and Protein
Next to be considered is the relationship of GH to protein intake. "GH is released after the consumption of protein. This might signify to the body that it is now an opportune moment to build" (Creatine Newsletter).
Moreover, "Hormonally, protein intake is positively correlated with growth hormone, IGF-1, and glucagons. These hormones, collectively, exert an anabolic and lipolytic effect" (Faigin, p.156).
This article is about diet, not supplements. But the following paragraph would apply to raising GH levels via diet as well as via supplements:
People are curious why others get better results for their HGH supplementation. When we looked into why, we discovered that growth hormone supplementation increases the need for protein and people who supply the additional protein did better with their HGH supplementation program" (HGH Magazine, "Whey Protein").
So there is a synchronicity going on here. Increased protein intake will increase GH levels, and increased GH levels will increase the need for protein. Moreover, frequent protein feedings will increase absorption of protein and produce frequent GH spikes.
So an ideal GH raising diet would include frequent feedings of high quality protein.
Growth Hormone, Potassium, Sodium, and Fiber
The next dietary nutrient to be looked at is potassium. "Medical science has known for some time that even modest potassium deficiency causes growth hormone and IGF-1 suppression" (HGH Magazine, "Potassium").
The reason for this is rather complicated but important to understand. It relates to cellular hydration.
Cellular hydration, however, is more complex than simply guzzling water. Fluid is constantly moving in and out of the cell across an electrical gradient bisected by the cell membrane. The key to obtaining the positive benefits of "cell volumization" is to maximize intracellular fluid. Drinking water will improve your overall hydration status, but it will not significantly alter the ratio of intracellular to extracellular fluid.
Water moves in and out of cells with electrolytes. The mineral sodium is the chief extracellular electrolyte, whereas the mineral potassium is the chief intracellular electrolyte. By increasing your potassium intake and reducing your sodium intake, you can shift water from the extracellular compartments of your body into the cells (HGH Magazine, "Potassium").
An increased intracellular hydration increases HGH release. And historically, human beings consumed far more potassium than sodium. So their intracellular hydration would have been high. But in recent decades, there has been a shift to a lower potassium to sodium ratio. Many even consume more sodium than potassium. And this leads to a drop in intracellular hydration and thus GH.
The reason for this change in the potassium to sodium ration is two fold. First, the best source by far for potassium is vegetables, and second fruit. But there has been a trend towards consuming less fruit and veggies than historically were eaten. And second, processed foods, fast foods, and restaurant foods are often high, sometimes very high in sodium. And the consumption of such foods has risen dramatically.
So to enhance your GH levels, the answer is obvious-eat more veggies and fruits and less processed, fast, and restaurant foods. So enhancing GH is yet one more reason to add to the long list of reasons to eat your veggies and fruit.
And adding to this is the following, "The American Physicians' Association has found that fibers in whole grains, some fruits, and vegetables keep sugars in the intestinal tract for longer periods. This makes your blood glucose level go up more slowly than if you ate a simple sugar" (HGH Magazine, "Fiber").
So fiber consumption would help to stabilize blood sugar, thus further enhancing GH release.
Bedtime Growth Hormone Release
There are two times when the release of growth hormone is the greatest. First, "… the largest burst of GH is released during the early hours of sleep-hence our eating habits are crucial to maximizing this nighttime secretion " (Jamieson, pp. 85,86). More specifically, "Growth hormone is especially dependent on sleep, because a major growth hormone surge occurs during the first episode of slow-wave sleep, approximately 30-70 minutes after falling asleep" (Faigin, p.200).
However, consumption of carbs at bedtime can blunt this crucial release of growth hormone. And the greater the amount of carbs and the higher the glycemic rating of the carbs, the greater will be the increase in blood sugar and the greater the suppression of GH. Thus, "… going to bed with a belly-full of carbs is hormonally unwise and may diminish, if not nullify, nocturnal growth hormone release" (Faigin, p.201).
It if for this reason that some will recommend not eating at all for at least two hours before bedtime. However, as indicated above, the consumption of protein will increase GH release. So an even better approach would be to limit carbohydrate consumption but to eat some protein at bedtime.
Exercise Induced GH Release
A second significant release of GH can occur in response to exercise. Any type of exercise will cause some increase in GH levels. But vigorous exercise will cause a greater release than exercise done at a low or moderate intensity.
Moreover, strength training will cause a greater release than aerobic exercise. For instance, riding an exercise bike at a high intensity will cause a 166% increase in GH, but weight training at a high intensity will cause a 400% increase.
All weight-training exercises are effective promoters of GH release, but those that involve the use of high-resistance and major muscle groups tend to be the most effective. Applying maximum effort to fewer repetitions of squats, leg presses, deadlifts, overhead presses, bench presses, standing curls, and leg curls will optimize your results (Jamieson, p.92).
I'm not sure how curls and leg curls got listed here, as they are isolation exercises (only work one muscle group). But the rest are quality compound movements (work more than one muscle group). And the powerlifts (squats, benches, and deadlifts) would be especially effective GH inducing exercises.
But how does all of this relate to diet? A common recommendation by fitness "experts" is to consume a carbohydrate-rich meal prior to a workout to provide fuel for that workout. And then it is recommended to consume carbs, especially high-glycemic carbs, post-workout to replenish glycogen stores. I have made these same recommendations and have followed these practices myself.
However, "a carbohydrate-rich, pre-workout meal squelches exercise-induced growth hormone secretion." And, "Another disadvantage of a pre-workout meal rich in carbohydrate pertains to its effect on brain chemistry…. By elevating serotonin, a neurotransmitter with sedative properties, a carbohydrate-rich meal can adversely affect motivation and energy levels. A protein based pre-workout meal has the opposite effect" (Faigin, pp. 240, 241). So protein would be much better to consume pre-workout than carbohydrate.
Post-workout, it is generally recommended to consume some kind of drink consisting of high glycemic carbs like dextrose or maltodextrin. But, "The insulin spike produced by these high-carbo concoctions will, literally within seconds of swallowing your first gulp, kick you out of the heightened fat-burning state you worked so hard during your workout to attain."
A high-glycemic carb drink will also blunt any growth hormone release that is occurring due to the exercise. It will also further increase cortisol levels, which would already be elevated from the exercise. But, "By contrast, a medium-sized protein or protein/ fat meal will not thwart post-workout exercise fat burning. Rather, it will perpetuate the fat-burning momentum generated by your workout" (Faigin, p.243).
Putting It All Together
Putting all of the above information together, the ideal growth hormone inducing diet would consist of a moderate amount of low glycemic carbs like whole grains, substantial quantities of protein, and copious amounts of vegetables, along with some fruit. It would also limit carb consumption pre- and post-workout and at bedtime.
Part Two of this article will focus on testosterone and look at how dietary fat fits into the picture.
Brand-Miller, Jennie, et. al. The New Glucose Revolution. Marlowe & Company: New York, 2003.
Creatine Newsletter. Issue 20. Growth Hormone De-Mystified.
Dean, Ward M.D. Neuroendocrine Theory of Aging Chapter 3; Part 1 Energy Homeostat Dysfunction.
Di Pasquale, Mauro. The Anabolic Solution for Powerlifters. N/A. 2002. For details on this book and nutrition program, see the Metabolic Diet Web site.
Faigin, Rob. Natural Hormonal Enhancement. Extique Publishing: Cedar Mountain, NC. 2000. For details on this book and nutrition program see the Extique Web site.
HGH Magazine. "Fiber helps manage HGH, Insulin, and Cholesterol." "Potassium and HGH - What your doctor does NOT tell you." "Whey Protein Supercharges HGH Supplements."
Jamieson, James and Dr. L.E. Dorman. Growth Hormone: Reversing Human Aging Naturally. Published by J. Jamieson: St. Louis, MO, 1997.
Schuler, Lou. The Testosterone Advantage Plan. Rodale: USA, 2002.
Thorton, Jim. "Maximum Testosterone." Men's Health. April, 2005, pp. 146-155,182.
Hormones and Diet: Part Two: Testosterone
Hormones and Diet: Part One: Growth Hormone Copyright © 2005 by Gary F. Zeolla.
Disclaimers: The material presented in this article is intended for educational purposes only. The author is not offering medical or legal advice. Accuracy of information is attempted but not guaranteed. Before undertaking any diet, exercise, or health improvement program, one should consult your doctor. The author is in no way responsible or liable for any bodily harm, physical, mental, or emotional, that results from following any of the advice in this article.
The above article first appeared in the free FitTips
for One and All email newsletter.
It was posted on this site September 1, 2005.
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