Unlocking the Secrets of Hormone Health and Vitality

Analysis by Dr. Joseph Mercola

Story at-a-glance

  • I recently interviewed U.K. clinician Keith Littlewood about endocrine health, revealing important details that may help you boost your well-being and vitality
  • Littlewood, who splits his time between consulting with patients and completing a Ph.D. in endocrine research, bases his work on that of scientists like Ray Peat and has extensive clinical experience
  • Littlewood believes estrogen dominance and estrogen excess are among the primary causes of thyroid disruption
  • Littlewood recommends targeting your diet first to address your thyroid health, including getting enough protein, calories and healthy carbohydrates, and making sure you can utilize those carbohydrates
  • Fixing thyroid problems involves a comprehensive approach that addresses what you’re eating — avoiding low-carb and low-calorie diets — your stress levels and your exposure to environmental pollutants, like endocrine-disrupting chemicals, along with exercise, such as walking

Editor's Note: This article is a reprint. It was originally published June 16, 2024.

Endocrinology is a branch of medicine that focuses on the study of hormones and the glands and tissues that produce them. It addresses the intricate balance of hormones that regulate many of your body's essential functions, and how to keep them in the proper equilibrium. I recently interviewed U.K. clinician Keith Littlewood on this topic, revealing important details that may help you boost your well-being and vitality.

Littlewood, who splits his time between consulting with patients and completing a Ph.D. in endocrine research, bases much of his work on Ray Peat and has extensive clinical experience on how to improve energy, metabolism, digestion, sleep, fertility and other key foundations of optimal health.

The Importance of Understanding Thyroid Physiology

One of Littlewood's areas of focus is looking at how endocrine disruptors affect thyroid physiology at the molecular level and the super molecular level. Of the many hormones in your body, thyroid hormones are perhaps the most important, as they regulate your metabolism and are required for nearly every physiological process in your body. When your thyroid levels are unbalanced, it can spell serious trouble.

An imbalance can lead to significant health issues, including fibromyalgia, irritable bowel syndrome, eczema, gum disease and autoimmune disorders, just to name a few. This is because your thyroid impacts various parts of your body, making the symptoms of dysfunction diverse. Your hypothalamus secretes thyrotropin-releasing hormone (TRH) that triggers your pituitary gland to release thyroid stimulating hormone (TSH) that then causes your thyroid to release T4.

Nearly 90% of your thyroid hormone is released in an inactive form of T4. Your liver then converts T4 to T3 with the help of an enzyme. Thyroid problems may exist, however, even when standard thyroid function tests show normal results. Littlewood says:

"TSH can be just a completely redundant test for multiple reasons … even abundance of T4 can be problematic and stimulate certain pathways. And that's really why … T3 should be being looked at as opposed to TSH because stressed people have generally suppressed TSH values.

Chronic dieters can have suppressed TSH values. There are hormone-disrupting chemicals in the environment that can suppress how thyroid function is being modulated.

And I think that makes it even more complex when a clinician would just look at TSH and T4 and go, 'Well, your blood tests are completely normal, let's move on to something else or it's in your head.' This is a common theme that I've seen well over a decade now with clients who've had their blood tests and just because they looked at these two markers, they're euthyroid [normal thyroid function] rather than potentially hypothyroid.

… just looking at TSH and T4 on its own, it can be very muddy water to look into. That's why the relatively crude test of temperature and pulse can be pretty useful. But again, you want other markers as well. You want cholesterol, you might want to look at prolactin, other hormone levels, you might want to look at lactate, all of these other markers that could be useful in getting you to understand what thyroid is actually doing."

While people with subclinical hypothyroidism will often have normal lab work, if your body temperature and pulse rate are off, that's a tipoff that your thyroid is not functioning properly. Also, even if your TSH is low (which is what you want), it could be suppressed by cortisol and adrenaline. Checking your temperature and pulse after eating is one way to double-check that.

A cholesterol test can also be helpful. High cholesterol (mid- to high-200s) is often a sign that your thyroid is not converting cholesterol to steroid hormones. Conversely, low cholesterol can be a sign of infection.

The Primary Causes of Thyroid Disruption

While there are dozens of factors that may disrupt thyroid function, Littlewood believes estrogen dominance and estrogen excess are among the primary causes.

"I think if we look to the major kind of cohort who tend to suffer the most, it's women … estrogen will suppress thyroid function and when there's an estrogen dominance and estrogen excess, it will suppress how much thyroid hormone is being produced," he says. "This kind of state will need supplementing with thyroid hormone because thyroid hormone will help increase estrogen metabolism."

However, other factors, including diet and environmental pollution, also need to be addressed. "The diet becomes intricately involved with trying to resolve this. You can't just throw thyroid hormones and expect that you're going to, A, lose weight and B, resolve all those issues because if you don't have enough energy in the tank, then you're not going to be able to function at that point as well," Littlewood says.

He mentions Brassica vegetables, such as cabbage, Brussels sprouts, broccoli and cauliflower, which contain thiocyanates that may suppress thyroid function in large quantities, as one example. However, he adds that environmental pollutants can also be damaging, particularly if you have a genetic predisposition for thyroid problems or your diet isn't ideal. These factors can come together creating the "perfect storm" for disease:

"If you've got poor inheritable traits … your nutrition's not in good order … you're under lots of stress and you're exposing yourself to certain endocrine disruptors … [via] food choices, certain pesticides, very polluted environments in the city, perhaps even wireless exposure … All of these things can create a perfect storm. So, it becomes almost like a clinical ecology exercise to start with.

What can you remove from your environment that might be damaging you? And that could be a thousand different things for a thousand different people. So that's where it becomes quite useful to do your due diligence about what somebody needs. It's a needs analysis to get people to where they want to be. There's no point in just saying, 'Hey, his thyroid hormone, everything's going to work out right,' because it never happens like that."

Get Your Diet Right First

Many lifestyle factors can contribute to low thyroid function, including stress, inadequate light exposure and exposures to endocrine-disrupting chemicals. In terms of diet, high polyunsaturated fat (PUFA) intake, including linoleic acid, is a major culprit, as PUFAs interfere with your cell's ability to use active thyroid hormone.

With so many factors potentially affecting your endocrine health, where should you begin to get it all sorted out? Littlewood recommends targeting your diet first:

"One of the most common themes that I've found — and my practice is probably about 70% females overall — it's getting enough protein in, it's getting enough calories in, it's getting enough carbohydrates in and making sure that you can utilize those carbohydrates quite well … what you should be able to do is utilize carbohydrates as a fuel, everybody should be able to do it."

Low-carb diets can wreak havoc with your thyroid. For healthy thyroid function, you need to make sure T4 can be efficiently converted into T3.

To encourage the conversion of T4 to T3, eat a diet of whole, unprocessed or minimally processed foods and make sure you include enough protein and healthy, easily digested carbs that won't cause intestinal irritation or endotoxin production, such as whole fruit. Littlewood explains that he often sees issues among his patients who have followed low-carb diets:

"This is something that I've seen with lots of females coming in who've gone keto, they've gone carnivore and they're experiencing more disturbed menstrual cycles, increased hair loss. You can see that they're progesterone deficient. You see that estrogen taking a hold, and this is where it becomes problematic and you start to see the sleep, the digestion, the mood, energy, all of these things that tend to go out of whack.

So, I would say that the diet is the base for everybody to get that right. A lot of people are unsure of some of the chemicals that are around, and they tend to become more aware of that as the process goes on.

So, I do think it's getting the diet right first of all. I think it's becoming aware of the things that could potentially disrupt thyroid, decrease progesterone, increase estrogen, and then you could start to look at that straight away. But it's certainly something, I often work for at least a month or two, getting the diet right before you even consider entertaining them to think about thyroid hormone."

Fixing your gut health is also important. "Digestion goes hand in hand with thyroid. It goes hand in hand with regulating thyroid, absorbing thyroid from the gut as well, and also how to regulate insulin as well. And if you can't digest your nutrients, you are always going to have a problem with supporting the thyroid," Littlewood says.

The Estrogen Connection

Many people believe that they are low in estrogen due to bloodwork, when they actually have high levels in their organs. This is because serum estrogen levels are not representative of estrogen that's stored in tissues. Estrogen can be low in plasma, but high in tissues.1

Estrogen inhibits the conversion of T4 to T3, and is one of the major contributors to cancer in my view, but many clinicians assume serum levels are equivalent to tissue levels — and they're not. So, many people get false low results when their estrogen levels are actually high.

"The highest amount of T3 is found intracellularly. It's not in serum. So, if you apply that rationale to estradiol, for example, and maybe the other weaker estrogens like estrone and estriol, they are going to be in the tissues. Now, bear in mind, if you have any amount of adipose tissue, you are generating estrogen by default, and the amount of aromatase that's being produced will convert testosterone and other hormones also to estrogen," Littlewood explains.

A better option for gauging estrogen levels in fat and tissues is a prolactin blood test. Estrogen promotes the production of prolactin, which is a hormone produced by the pituitary gland:

"Prolactin can be very, very useful. I think keeping prolactin round about 10 milligrams per deciliter is the general idea. I think the average reference range is anywhere from 20 up to a couple of hundred … when you start to see prolactin that high, you start to infer that there're going to be some problems probably related to high estrogen.

Sometimes you can actually look at someone and tell whether they're estrogen dominant. You can certainly see it in guys drinking a lot of beer, a lot of phytoestrogens. You will tend to see a combination of weight gain that is promoted by high phytoestrogen exposure.

And in females, you can see that too. There are certainly estrogen-like traits with increased adiposity, certainly hormone dysregulation, which can go from dysregulated cycles to heavy clotting to dysmenorrhea, amenorrhea.

It can go both ways. And there are, again, the mixing or muddying of the water tends to be conflated by the increased estradiol will suppress thyroid hormone, will suppress progesterone … I think keeping prolactin as low as possible is great. And … progesterone will do that. It is predominantly a female hormone, but men do need it as well."

A Comprehensive Approach Works Best

Littlewood emphasizes that fixing your thyroid problems isn't as simple as taking thyroid hormones. You need to use a comprehensive approach that addresses what you're eating — avoiding low-carb and low-calorie diets — your stress levels and your exposure to environmental pollutants, like endocrine-disrupting chemicals.

"You can throw light deficiency with that as well, inadequate vitamin D," Littlewood says. "All of these things contribute to it." Often, it's the most fundamental, simple changes that make the biggest difference in your health. To that end, Littlewood also recommends regular exercise and movement, especially walking, to address endocrine issues and take your health to the next level:

"Very simple strategies can lead to some amazing results, and some of these things just get wrapped up in medical diagnosis, overtreatment, overdiagnosis, and I think this is still a huge problem. And like the ideas that we talked about, what are some of the things that Ray [Peat said that] have stuck with me? It's understanding that you don't need to go through this kind of overdiagnosis and overcomplication.

… exercise, I think, is key … I don't think he [Peat] placed exercise as high up there as he might've done. But again, he talked about living a life that had a lot of contentment to it and doing things that were useful and interesting, rather than spending a life of overexercising and breathless exercise, which would lead to this hyperthyroid state anyway.

… the right amount of exercise, it's not too much, certainly not too little, and that's, again, something you tend to see — people who've been exercising five, six days a week push themselves into a hole. So yeah, adequate strength training, mobility training, moderate amount of cardiovascular exercise through regular walking I think is where most people need to be."

If you want to learn more about Littlewood, you can find him via his websites, balancedbodymind.com and keithlittlewood.co.uk.

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