While it is certainly true that “no gland is an island” — nothing is the body ever acts alone! — the thyroid gland is uniquely important. It is the master regulator of our metabolism. But what does that really mean for our health and vitality?
Metabolism is a big catch-all phrase, so let’s break it down by what the thyroid does in different functional areas.
The thyroid makes and stores calcitonin, a hormone that regulates calcium. An under-performing thyroid can prevent the long ends of your bones from forming correctly, so it can contribute to to poor bone and joint health.
The thyroid helps move food through your gastrointestinal system (this process is called peristalsis). It’s kind of like a subway system: when the thyroid is sluggish, the train doesn’t arrive on schedule (and maybe not at all!). If the amount of time it takes for your food to move through your gut is longer than it should be, you are much more likely to develop an unbalanced ratio of yeast and bacteria.
This promotes inflammation, poor nutrient absorption, an increased risk of leaky gut and food sensitivities. Constipation is a common consequence of an under-active thyroid. No matter what the cause, constipation is always a red flag!
Hypothyroidism is not as common in men as women, but it can occur. When it does, it can decrease sex drive and sperm count, and even cause impotence.
Liver & Gallbladder:
Your liver is like the mesh drain that keeps your plumbing from getting clogged. It’s the ultimate filter for your blood It traps toxins, cleans up excess hormones (often from endocrine disrupting chemicals), and breaks down byproducts from drugs, alcohol and other substances. The resulting sludge gets stored in the gallbladder for ultimate disposal. Your liver also plays a key role in hormone metabolism, especially for the thyroid.
So if thyroid isn’t working well, and/or your liver is over-taxed, everything slows way down and gets stagnant. Stagnation breeds toxicity and disease, so this is a critical piece of functional “plumbing” that you need to have in A-OK shape.
We never, ever stop growing! New cells, that is. One role of thyroid hormones is to help make a triggering substance called insulin-like growth factor (IGF-1) in the liver. When the rate of dying cells overtakes the growth of new cells, we are on the fast path to declining health.
Anyone who’s interested in maintaining lean body weight needs an adequate amount of lipase. This enzyme processes fat so it can be burned for energy. Low thyroid function makes it hard for cells to respond to lipase. So stored fat can’t be used, and we end up relying on starches and sugars for short-term, high-cost energy.
A nasty extra piece to this problem is that even the adrenal gland hormones (epinephrine and norepinephrine) lose their fat-burning ability when thyroid function is low.
Glucose & Insulin:
Glucose, like fat, is what the body uses to create energy. Your beautiful brain absolutely has to have glucose to function. An under-performing thyroid slows down glucose absorption. Your cells can’t use glucose efficiently, or dispose of the excess. This promotes fatigue, unstable mood, light-headedness, and — worst of all — degraded cognition and memory. Your adrenal glands try to compensate by pushing out more and more stress hormones, prompting the liver to release stored glucose into your bloodstream.
The ultimate effect is exhausted adrenal glands, a sluggish liver, and sub-optimal function in your hypothalamus and pituitary glands, the master controllers of the endocrine system.
Remember that lowered thyroid function drives a sluggish liver/gallbladder, so fat is not cleared from the bloodstream as it should be. We end up accumulating fat faster than it can be cleared. So if you see high triglycerides, high cholesterol and high LDL (the carrier protein that moves cholesterol from the liver to other sites in the body), it may well be a sign of poor thyroid function upstream.
This is NOT a statin deficiency; statins, like proton pump inhibitors, are a very short term patch for a problem that needs to be corrected.
Next, we’ll look at how other functions of this critical gland work. Then we’ll look at where it can get off track, and how we can bring it back up to operating speed — so that you can enjoy better health!
The thyroid gland is a bit like old late night television commercials: “But wait! There’s more!” The thyroid operates on a whole body level, and its proper functioning is essential for whole body health. Let’s look at some of the other ways it influences who and how we are… starting with your beautiful brain.
Elegant as our brains are, they are nonetheless completely dependent on what happens in the body as a whole. As you’ll remember from Part One, the thyroid’s effect on glucose metabolism is critical for the brain’s energy source. But the brain is also super-rich in thyroid hormone receptor sites. So if thyroid hormone production is low or out of balance, it’s no wonder that brain function suffers: brain “fog” and forgetfulness are common signs of thyroid and adrenal gland dysfunction.
One of the ways that the thyroid and brain are enmeshed is the interaction of brain chemistry — specifically serotonin and dopamine — with thyroid hormones. And the factors that degrade brain and thyroid health are the same culprits: poor blood sugar control, stress hormone overload, degraded gut function, an over-taxed liver, and so on.
Estrogen & Breast Cancer:
We don’t tend to think of the thyroid and the liver in conjunction with breast health. Mistake. Remember that an under-performing thyroid leads to a sluggish liver — and one of the liver’s many jobs is eliminating excess hormone from the body. It does this through a detoxification process (called conjugation) that converts fat-soluble substances to a water-soluble form for excretion.
If this doesn’t work efficiently, a form of estrogen called estradiol can proliferate. This can lead to conditions like breast cancer, uterine fibroids and ovarian cysts.
Temperature & Hot Flashes:
Generally associated with perimenopause, hot flashes and night sweats can also be caused by thyroid dysfunction. While the thyroid has the primary responsibility for maintaining body temperature, the ovaries and adrenal glands can also cause sudden shifts in body heat. You don’t want to write off temperature variations as being due to “the change” (as it used to be called) without looking at the body as an interdependent whole.
While there is definitely a time and place for bio-identical hormone replacement therapy (HRT), it’s really smart to make sure that’s what’s needed. And, by the way, no-one should have to suffer through perimenopause without adequate support for their adrenal glands!
Progesterone levels surge in the second part of the menstrual cycle, with a rise in body temperature associated with ovulation. This progesterone surge also turns up the dial on an enzyme called thyroid peroxidase (TPO). TPO is a catalyst for the production of the main thyroid hormones, T4 (an inactive, storage form) and T3 (an active hormone, which can be used by any cell). Low progesterone levels are associated with heavy menstrual bleeding and mood changes tied to the cycle. Lack of sufficient progesterone also depresses TPO activity, and that reduces T4 production. So the storage cupboard is pretty bare when it comes time to convert T4 to T3, the active, usable form your cells need.
There can be a number of reasons progesterone output is sub-optimal, so prescribing progesterone creams or intra-uterine delivery is not an ideal strategy for cycling women. With the endocrine system, you always want to look both upstream (is the pituitary gland working properly?), and downstream (is the liver working properly?). Another question to ask is, are the progesterone receptor sites on your cells getting enough exposure to circulating thyroid hormone? This matters, because the thyroid hormones “prime” the progesterone receptors. It’s like the receptors have blindfolds on, until the thyroid hormones remove them. You can have plenty of available progesterone, but if your cell receptor sites can’t “see” it, you’re not going to get what you need.
I’ve written extensively elsewhere about the need for adequate hydrochloric acid (HCL) in the stomach. This is critical for a happy, healthy digestive system — and the person who depends on it! Insufficient or weak HCL is actually the cause of many cases of acid reflux or GERD, and many other digestive woes. But guess what? Yep, the thyroid plays a role here, too. Inadequate thyroid function diminishes the production of gastrin, a vital component in the production of HCL. So I like to keep what sailors call “a weather eye” on the thyroid, even when we’re talking about digestion.
In a situation where a hypo-functioning thyroid is depressing HCL production, there won’t be enough potent stomach acid to break down protein to release B12. Inadequate amounts of B12 and folic acid (B9) can lead to what’s rightly called pernicious anemia. Folic acid is particularly important for women in their child-bearing years, because of its role in forming a baby’s neural tube. Lack of stomach acid also decreases our ability to absorb iron. Combined with low amounts of progesterone getting into the cells, causing heavy menstrual bleeding, poor iron absorption can be another driver of anemia.
One of the key markers for heart health is the amino acid homocysteine. When it gets too high, we are at greater risk of heart disease, as well as for neurodegenerative diseases and dementia. Sub-optimal thyroid function may impede the liver’s ability to manage the levels of this key amino acid.