A tiny bit about hormones

Posted: 04/11/2012 in English, Paleo Diet, Science and stuff
Tags: , , , , , , , , ,

Hey Everyone,

This time we are going through some hormones in a nutshell. What they are good for, what they do, etc. I use the book of Robb Wolf – The Paleo Solution (web) It is a really good book and I can recommend it. If you have the time and want to read more about the paleo lifestyle read the following too: Loren Cordain – The Paleo Diet, Loren Cordain – The Paleo Diet for Athletes.

I hope you find this article easy to go through, very clear and understandable. Let’s get ready for rumble. 🙂

Cortisol

(this is gonna be longer than the others)

Cortisol raises blood sugar levels, which can cause fat gain. Although many people don’t know this, cortisol release from stress and a lack of sleep factors prominently in body fat gain, leading to that pesky spare tire around the midsection. Cortisol shouldn’t be feared, because it is a crucial anti-inflamatory—we just don’t want too much of it.

Geek-Speak

Cortisol is often referred to as a “stress hormone,” given that it is released in response to stress and anxiety. Cortisol increases blood pressure and activity of the immune system. It will trigger the breakdown of muscle mass by converting protein (amino acids) into glucose via gluconeogenesis. Cortisol decreases insulin sensitivity, lowers the rate of bone formation, and causes a loss of collagen in the skin and other connective tissues. The following increase cortisol levels: intense or prolonged physical activity, caffeine, sleep deprivation, stress, subcutaneous fat tissue, and certain contraceptives.

A bit more detailed part.

Without being the least bit cynical, I could boil life down to food, sleep, and sex. On the food side of the equation, we have all that goes into getting it (brains to plan, brawn to procure and defend). Once we have that food, we eat it and either burn it or store it. This is all related to our short and long term energy management, body-fatness, fertility, etc. Insulin and glucagon are there to help regulate our storage and utilization of energy.

However, Cortisol is also a player in this game, as it also has effects on energy storage and a host of other functions:

1. Regulating the immune response. Too much of an immune response can lead to autoimmunity or significant problems from “collateral damage” caused by an overactive immune system. Many diseases are not fatal in and of themselves (like the H1N1 flu), but they sometimes become fatal because of an overreaction by the immune system. Cortisol “puts the breaks” on the immune system and is very important in both our susceptibility to disease and how we respond to illness.

2. How much sodium we have in our blood. More cortisol means more sodium and thus more blood volume. Typically, this will lead to higher blood pressure, with the associated stress on the heart, vasculature, and kidneys.

3. Regulates connective tissue strength. Too much cortisol can weaken connective tissue in our skin and elsewhere. Cortisol can and does make you wrinkle faster.

4. Perhaps most important to our discussion here, cortisol releases glucose and fatty acids from the liver and blunts insulin sensitivity.

Most people are familiar with the idea that cortisol is a “stress” hormone, but this is misleading and more a function of our modern lives than cortisol really being a “stress” hormone. Cortisol is in fact critical to life, and a lack of cortisol will mean significant health problems, including death! This is again a story of shooting for the right amount of a hormone, and if you have been paying attention thus far, we are talking about levels that we might find in our Paleolithic ancestors.

A normal day for our Paleolithic ancestors would start by awakening with relatively high cortisol levels. This is not the Monday morning commute blues: Paleo Edition. This is nature’s way of making sure we are alert, energized, and ready to go! Cortisol causes the release of glucose and fatty acids from the liver. That’s energy our Paleolithic ancestors needed to move camp, hunt, gather, and generally get the day going. Now, this scenario was normal and, in fact, nonstressful. Keep in mind there are normal operating parameters for all our hormones and it is quite normal for Cortisol to be elevated in the morning.

Normal cortisol profile. High in the AM, low in the PM.

Cortisol works in synchrony with insulin and glucagon to regulate our energy levels. When we need more energy (early in the day or fleeing from a predator) Cortisol is relatively high. In the evening, when we are winding down and going to bed, Cortisol should drop. Now, what if our Paleolithic ancestors were ambushed by a rival camp or they stumbled upon a particularly large and cranky carnivore that wanted to see just who was at the top the food chain that day? Did those situations happen and were they stressful? Yes, they happened, and yes, they were stressful. But the stresses of Paleolithic consequence sorted themselves out quickly. For good or ill. They tended not to drag on and they did not happen every day.

Our modern life may not involve the risk of being eaten by a bear (generally), but it does come with a host of its own stressors. Some quite immediate and tangible, others more mental. But in general, our stressors in modern times are chronic, as opposed to the acute stresses for which we are so well equipped. Possibly losing a job in a bad economy, getting mugged while on the train, a near miss while driving, thinking about the kids’ college education . . . lack of sleep. These are modern issues that register as a stress, and in a cumulative fashion, they can crush us. Beat That Dead Horse White Boy!

The critical concept here is acute vs. chronic stress.

We are genetically wired for dealing with acute (brief/infrequent) stress. This stress was answered with some kind of physical activity (fight or flight) that made use of that glucose and fat released from the liver. Then things returned to a relatively “mellow” norm. We are not well suited to the stresses of modern life. These stresses affect people in different ways and to different degrees, but they are most assuredly “there,” and they are cumulative. When you are subjected to stress, particularly chronic stress, your body releases cortisol much more frequently than it should. This gets ugly when cortisol is not only high in the morning, but all day long, even at bedtime.

The consequences can be dire, as the more stressed we get, the worse our ability to deal with stress becomes. It is a nasty snowball effect that is called a “feed forward” mechanism in biology. Abnormally elevated cortisol begins to disturb sleep, which makes us more prone to daily stress, which raises cortisol. The consequences of this downward spiral include suppressed immune function, chronically elevated blood sugar levels, decreased insulin sensitivity, impaired ability to form long-term memory, and decreased sex drive and libido. Yes folks, cortisol is a big deal.

You Know… Everything Is Like Related. And Stuff.

Chronic stress can and does raise cortisol levels. Stress can come from a variety of places and is somewhat subjective, but one of the first things to be affected by stress and increased cortisol is sleep. Once your sleep gets buggered, the wheels  fall off the wagon. Keep in mind this works both ways. An otherwise manageable stress level can be made nearly fatal by sleep disturbances. Staying up too late, or simply neglecting sleep quality and duration, can seriously undermine your ability to deal with otherwise manageable levels of stress.

Insulin

Insulin is critical in regulating blood sugar, body fat, and aging. To live long, look good, and keep our marbles, we would do well to keep our insulin on the low side by controlling carbs and certain lifestyle factors.

Geek-Speak

Insulin acts as a nutrient-storage hormone that maintains blood glucose levels. In simple terms, insulin puts nutrients into our cells. What we will find, however, is that insulin plays a key role in a staggering number of critical processes completely unrelated to blood sugar management.

Insulin is relevant not only in glucose storage, but also in fat and protein (amino acid) storage. Insulin is released from the beta cells of the pancreas primarily in response to increasing blood levels of glucose and amino acids and plays a significant role in micronutrient storage and conversions. Insulin’s primary role as a nutrient sensor (when you ingest food, insulin tells those nutrients where to be stored) greatly influences genetic expression surrounding aging by up or down regulating maintenance and repair at the cellular level. If you are interested in aging, your level of body fat, when or if you will lose your marbles, and whether or not your “reproductive machinery” works, you will want to keep an eye on insulin.

Glucagon

Glucagon helps normalize blood sugar and energy levels between meals by releasing energy from the liver and allowing us to better access our body fat for energy.

Geek-Speak

Glucagon is the counter-hormone to insulin and prompts the release of glucose from the liver, as well as free fatty acids from fat stores, by a process called lipolysis. Glucagon secretion is stimulated by decreased blood glucose levels (hunger), increased blood amino acid levels, and the hormone cholecystokinin (CCK). High levels of insulin, free fatty acids, ketone bodies, or urea in the bloodstream will inhibit glucagon release. Insulin and glucagon play complementary roles of helping us to manage energy levels by storing and releasing nutrients at the right time. Insulin facilitates the passage of nutrients into cells, while glucagon tends to release stored nutrients to be used for energy.

Leptin

Leptin tells our body how much fuel we have in storage, and when we are “full.” If we lose the ability to sense leptin, appetite control is lost.

Geek-Speak

Leptin regulates both appetite and metabolism. Leptin enters the central nervous system where it acts on receptors in the brain that control energy intake and expenditure. Leptin is produced by white adipose tissue (fat cells), as well as the cells lining the wall of the stomach. The leptin produced by the cells in the stomach is responsible for controlling appetite. When Leptin is working correctly, it’s very effective at telling us we are “full” after eating a meal. As we will see, when leptin signaling (how a hormone “talks to a receptor”) breaks, it is the beginning of problems ranging from cancer to accelerated aging to neurological degeneration.

Ghrelin

Ghrelin tells us we are hungry or low on energy. We would like this to be an accurate message, but it is important to note that stress and lack of sleep can alter ghrelin levels and unfavorably increase our sense of hunger.

Geek-Speak

Ghrelin is a hormone that stimulates hunger, increases food intake, and increases fat mass. It is produced by cells in the lining of the stomach, as well as epsilon cells of the pancreas. Ghrelin is also produced in the hypothalamic arcuate nucleus, where it stimulates the secretion of growth hormone. Inadequate sleep is associated with high levels of ghrelin. A little down the road, you will discover just how important sleep is to maintaining a lean, healthy body. Since sleep deprivation increases ghrelin, and since ghrelin increases appetite, this is one of the reasons why sleep disturbance leads to increased food intake.

Adiponectin

Adiponectin is another of several satiety hormones. Not only does it tell us when we’ve had enough food, but it also protects our arteries from oxidative damage.

Geek-Speak

Adiponectin is a protein hormone that is secreted by adipose tissue and has the following effects: decreases gluconeogenesis (the conversion of protein into glucose), increases glucose uptake, and protects from endothelial dysfunction (a common feature of atherosclerosis). Although released by adipose tissue, levels of adiponectin in the bloodstream of adults is inversely correlated with percentage of body fat (folks with low body fat have high adiponectin). Adiponectin is an independent risk factor for metabolic syndrome and plays a role in the suppression of the metabolic derangements that may result in type 2 diabetes, obesity, atherosclerosis, and nonalcoholic fatty liver disease.

Peptide YY

Peptide YY (a.k.a. PYY) is yet another hormone trying to tell us when to stop eating. Protein and fat release a lot of PYY and are thus very satisfying. Carbohydrate, by contrast, releases relatively little PYY, which is why your breakfast of bran muffins and juice leave you ravenous in a few hours.

Geek-Speak

PYY is a gut hormone that reduces hunger while simultaneously improving central nervous system sensitivity to leptin. PYY is released by neuroendocrine cells in the ileum and colon in response to feeding. Protein causes greater PYY secretion than fat, which causes greater PYY secretion than carbohydrate. PYY plays a synergistic role with leptin in helping us feel satisfied after a meal.

Insulin-like Growth Factor-1

Insulin-like Growth Factor-1 (IGF-1) is another hormone we want “just the right amount” of. It aids in physical recovery, but poor diet can abnormally raise IGF levels, which in turn increases both our likelihood for cancer and our rate of aging.

Geek-Speak

IGF-1 is critical to the growth of children and has an anabolic effect in adults. IGF-1 activates the insulin receptor but generates a response that is only 10 percent of that observed for insulin. Low IGF-1 promotes cell maintenance and stress resistance. IGF-1 levels are highest during pubescent growth spurts. Exercise, stress, and nutrition can affect IGF-1 levels. Increased levels of IGF-1 stimulates both growth and aging. Now that you have met the players in this digestion/endocrinology orchestra, you likely understand a little about the chemistry of our food and “who” the primary hormones are that we must consider in digestion, health, and disease. Gold star for you. This is a nice start, but we have some more work to do. Next, we need to consider what actually happens to both our food and our hormones during various conditions like fasting and overeating. With this knowledge we will be in a position to understand Type 2 diabetes, various types of cancer, Alzheimer’s, Parkinson’s, infertility, cardiovascular disease, and osteoporosis.

Growth hormone

Growth hormone (HGH) is critical for maintaining lean body mass, burning fat, and even fixing DNA damage. Its secretion is dramatically improved by brief intense exercise, low carbohydrate intake, punctuated eating (intermittent fasting), and restful sleep. HGH levels tend to decrease with age, but by emulating the exercise, food, and lifestyle of our HG ancestors, we can dramatically improve our production of the youth hormone.

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