It's very common when it comes to health and fitness to read things while nodding, despite actually having relatively little understanding of what they are or how/why they affect the body.
Take hormones for instance. Sure, we know that hormones control our emotions and to an extent our body composition. But do we really know how that happens or why it happens?
This is most apparent when you head to one of a number of different bodybuilding forums or subreddits. There you'll see people arguing that they shouldn't eat X before X time because it stimulates X hormone. But if you were to probe a little deeper you'd possibly discover that they don't really realise what any of those things mean…
Read on then and we'll look at what hormones actually are, as well as what the most important ones do.
What Is a Hormone?
A hormone is a 'regulatory biochemical' produced by the glands and taken via the blood to different organs to regulate its physiology and behaviour. In that regard then you can think of it as an instruction that tells the organ to behave in a particular way and thus regulate a number of important biological functions.
These biological functions include:
While the hormones are created in the glands, many of them are regulated by the brain. Hormones can also act as neurotransmitters (meaning they tell neurons how to behave) – for instance melatonin is both a hormone and a neurotransmitter.
Different hormones are made in different ways. Protein hormones and catecholamines are types of hormones that are water soluble (dissolve in water) and thus can be easily carried around the circulatory system. Other hormones though such as steroid and thyroid hormones are 'lipid' soluble (fatty acids and their derivatives that are insoluble in water, but soluble in organic 'solvents' – including oils and waxes). Steroid and thyroid hormones must bond to 'plasma glycoproteins' which transport them.
In order to affect the target organs, hormones must bond to the target tissue via 'receptor proteins'. These are proteins that are designed to attract and capture those specific hormones and will only respond to the correct hormones. This is similar to the way that neurotransmitters must be received by specific receptors in order to be effective.
Some Important Hormones and Their Functions
Oestrogen is well known as the 'female sex hormone' and is almost like the 'opposite' of testosterone. It is found in greater quantities and contributes to the development of female 'secondary sex characteristics' (just as testosterone does the same for men). These include the breasts, a widened pelvis, decreased body fat in the buttocks etc. For bodybuilders out there though (and Alpha males) that doesn't mean you want to completely rid yourself of oestrogen as it's also protective against osteoporosis, heart disease, colon cancer, memory loss and more. It improves sleep, mental focus, emotional well-being, senses and pain tolerance.
Testosterone meanwhile is the 'male sex hormone' and similarly is responsible for the secondary male traits – such as facial hair, lower voice, etc. Testosterone is also responsible for increasing muscle mass (which is why men have more muscle than women) and for decreasing fat (raising blood glucose levels). In men, testosterone is produced predominantly in the testes.
Cortisol is often known as the 'stress hormone' and is responsible for our response to stressors. It itself is controlled by another hormone called corticotropin-releasing hormone (CRH). It also increases blood sugar and suppresses the immune system. This is why prolonged stress can be bad for us. Cortisol will decrease levels of other hormones such as testosterone.
DHEA is dehydroepiandrosterone and is a steroid hormone produced by the adrenal cortex. It is a precursor to oestrogens.
Pregnenolone is the precursor to all steroid hormones. It is made from cholesterol – this is why it's very important to make sure you are getting cholesterol in your diet (the good cholesterol that is – called LDL cholesterol).
Progesterone is a female hormone like oestrogen. This one works alongside oestrogen and prepares the womb for pregnancy.
The main thyroid hormones include THS, T3 and T4. TSH is Thyroid Stimulating Hormone, a hormone produced in the pituitary gland, and is responsible for stimulating the thyroid gland to produce T3 and T4. T4 is produced in more abundance (80% more), but T3 is more active (300%). T4 is a storage hormone and often gets converted into T3 in the liver (through the removal of an iodine molecule by an enzyme). From here T3 then enters the cells in order to maintain the metabolic process leading to more available energy for the body and preventing weight gain.
Insulin is a peptide hormone that is produced in the pancreas. Its job is to handle carbohydrate and fat metabolism in the body which it does by encouraging fat tissues and muscles to absorb glucose from the blood. Insulin also inhibits the release of glucagon, which prevents fat being burned as a source of energy.
Glucagon is a peptide hormone that is produced by the alpha cells of the pancreas. Its job is to raise the levels of glucose in the blood (the opposite of insulin). It does this by getting the liver to convert stored glycogen into glucose which is then in turn released into the blood.
Growth hormone is a peptide hormone that stimulates cell growth, reproduction and regeneration. It is a 'mitogen' meaning it only affects only certain cells. GH is also a stress hormone meaning it will raise blood glucose and free fatty acids. It also stimulates the production of IGF-1.
It is an 'anabolic agent' meaning it stimulates muscle growth while burning fat. It is produced, stored and secreted by the pituitary gland.
IGF-1 is another anabolic hormone consisting of 70 amino acids in a single chain. It is primarily produced in the liver and is stimulated by growth hormone. It can be reduced through poor nutrition and a range of conditions. IGF-1 works by binding to the IGF-1 receptors which stimulates cell growth and proliferation and which can prevent cell death. IGF-1 also mediates the effects of growth hormone.
Melatonin is a hormone as well as a neurotransmitter which is responsible for regulating the internal body clock and the sleep-wake cycle.
So there you have it, that's a big selection of the important hormones flowing through your body right now and a bit more understanding of what each of those does. The main takeaway message though should be that the balance of hormones is incredibly intricate and delicate and not something to be trifled with. Get enough sleep (this is when many of our hormones are produced), make sure to eat the right balance of micronutrients and macronutrients, exercise and get sunshine. Otherwise, leave your body to do its miraculous job!