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Ketogenic Diet. Here’s What You Need To Know If You Have Hypothyroidism

Maybe you’re watching this video and you have hypothyroidism, Graves, or Hashimotos and you’re thinking maybe I should try the ketogenic diet, but you just don’t know if it safe or what consequences it might have on your Thyroid or your immune system. In this video series, I want to go over why I’m not a fan of the Ketogenic, Carnivore, low-carb diet when you have thyroid disease or Hashimotos. I will also review how these diets influence thyroid function and what thyroid labs you need to pay special attention to if you decide that you do want to try a ketogenic diet.

Keto and Low Carb Diets for Hypothyroidism

What Is Hypothyroidism?

Hypothyroidism, also known as an underactive thyroid, is a relatively common endocrine disorder that affects millions of individuals worldwide. It occurs when the thyroid gland, situated at the base of the neck, does not produce enough thyroid hormones. These hormones, primarily thyroxine (T4) and triiodothyronine (T3) play a crucial role in regulating metabolism, growth, and development throughout the body. When the thyroid gland doesn’t function properly, it can lead to a range of symptoms and health issues.

Several factors can contribute to the development of hypothyroidism. The most common cause is autoimmune thyroiditis, also known as Hashimoto’s thyroiditis. In this condition, the body’s immune system mistakenly attacks and damages the thyroid gland. Other causes include thyroid surgery, radiation therapy, certain medications, iodine deficiency, Iodine excess, Iron deficiency, and genetic disorders. Women, particularly those over the age of 60, are more prone to developing hypothyroidism, although it can affect individuals of any age or gender.

What Is A Ketogenic Diet?

The Ketogenic diet usually calls for eating very low carbs, typical you are at or below 50 grams (5-10% of your total caloric intake), Fat accounts for 55-60% of your total caloric intake diet, and protein is 30-35% your total caloric intake. While you don’t need to memorize those numbers, a ketogenic diet is essentially a low-carb, High fat, High protein, Low fiber, Low Starch diet.

Foods you can eat on the keto diet include fish and seafood, meat and poultry, non-starchy vegetables like bell peppers, broccoli, and zucchini, avocados, berries, nuts and seeds, eggs, high-fat dairy products, olive oil and other oils, and high-cocoa chocolate. Foods to avoid on a ketogenic diet include grains, sugary foods, high-carb fruits, transfats, alcohol, and starchy vegetables. Seems harmless but the high fat, high protein, low carb, and low fiber macronutrient profile is where the problem is not in the elimination or reduction of transfats, sugar, alcohol, and starchy foods. The problem is not what you are eating, it’s the ratios of what you are eating as well as many of the good carbohydrates and sources of Short Chain Fatty Acids that are reduced or restricted when following a ketogenic diet.

Ketogenic Diets and Thyroid disease

Is a Ketogenic Diet or Carnivore Diet Recommended For Thyroid Disease?

Ketogenic diets are becoming increasingly popular for everything from weight loss to autoimmunity. Most men and women start to investigate a ketogenic diet for weight loss and so you can see why so many patients with thyroid disease (hypothyroidism/Hashimotos) start to wonder about a ketogenic diet.

Numerous studies and patient experiences demonstrate that Ketogenic diets can help lose weight and that they can be very effective at accomplishing that goal. We know that weight loss has multiple benefits, But does that translate into a Ketogenic diet and Carnivore diets being right for everyone who struggles with weight gain? Should people who have thyroid disease or Hashimotos start a Keto diet? What effect does a high-fat, low-carb diet have on thyroid function? What impact does a ketogenic or Carnivore diet have on the gut microbiome? What effect does it have on the liver and bile acid production, How does the Ketogenic and Carnivore diet affect T3 levels and reverse T3 levels? what effect does it have on cortisol levels? how does it affect the estrobolome? How does it affect Bile acid production, Why do people who start a ketogenic and carnivore diet experience all kinds of food sensitivities when they transition out of a ketogenic/Carnivore diet?

These are just a few questions we need to better understand before we start recommending every patient with hypothyroidism and Hashimotos to jump on the Keto and Carnivore bandwagon.

Many well-known Functional Medicine celebrities are huge advocates for Ketogenic diets- they have built their entire practice and web presence around the promotion of ketogenic diets. But we need to look at all of this more objectively and ask the hard questions and compare it to the testing we run on our patients.

In this video/article series, I will go through Why I’m not a proponent of low-carb, High fat, High Protein diets like Keto and Carnivore for people with Hypothyroidism and Hashimotos.

What The Ketogenic Experts Are Not Telling You About Ketogenic Diets and Your Thyroid

In recent years, research has uncovered a fascinating link between gut bacteria and thyroid function, shedding light on how the microbiome within our digestive system can impact the health and balance of our thyroid gland. This connection holds particular relevance for individuals experiencing thyroid issues such as low T3 levels and impaired T4-T3 conversion- Both of these are very common Patterns of Thyroid dysfunction seen in functional medicine practices.

The gut microbiota, a diverse community of microorganisms inhabiting the digestive tract, plays a crucial role in maintaining overall health and metabolic balance. Emerging studies have highlighted the significant impact of gut bacteria on thyroid function, emphasizing their role in modulating hormone levels, metabolism, and immune responses.(*) This can be incredibly important for those patients who have hypothyroidism due to Hashimoto’s.

Reduce T3 Levels

Low Carb, High Protein, and High-Fat diets can affect T3 levels and if more ketogenic experts ran a comprehensive thyroid profile on their patients, they might start to see what I see. Low-carb diets, especially very low-carb or ketogenic diets, result in Low T3 levels. Why is this important? T3 is the active form of thyroid hormone and plays a crucial role in regulating metabolism, energy production, and overall physiological functions.

Low T3 levels are the real culprit for your hypothyroid symptoms and low-carb diets where we are restricting carbohydrates can lead to lower T3 levels. So what a ketogenic diet can do is take a sluggish malfunctioning thyroid and make it more sluggish and malfunctioning. (*)

Suppress TSH Levels

Low Carb, High Protein, and High-Fat diets suppress TSH levels. Thyroid-stimulating hormone (TSH) is produced by the pituitary gland to signal the thyroid gland to release thyroid hormones. Patients with hypothyroidism usually have elevated TSH levels but in some cases ie Hashimotos, we often see low TSH levels. Why is this important?

A Ketogenic diet (low carb, high fat, high protein) often increases cortisol levels. Elevated Cortisol levels will not only suppress TSH levels it will also impact T4-T3 conversion. Elevated Cortisol levels also have negative consequences on hormones and gut health.

Consider these side effects of High cortisol on gut function:

Thyroid Conversion

Low Carb, High Protein, High-Fat diets like Keto and Carnivore can also affect Thyroid Conversion. The conversion of thyroxine (T4) to triiodothyronine (T3) is a critical step in thyroid hormone metabolism. Low-carb diets, particularly those lacking sufficient calories or nutrients, can impair this T4-T3 conversion process in peripheral tissues, leading to altered thyroid hormone levels. Ketogenic diet and thyroid disease

Thyroid hormones are crucial for optimizing digestion and motility. Thyroid issues are one of the root causes of Small Intestinal Bacterial Overgrowth (SIBO). Because low levels of thyroid hormones will slow down every aspect of gut function, it will predispose you to bacterial over-growth.(*),(*) Thyroid hormone activation is highly dependent on carb intake. Failing to meet proper carb intake will lead to lower thyroid hormones.(*)

Your Gut Microbiome on Keto:Low Carb

2. How Keto Affect Your Gut Microbiome and Digestion

Gut health including digestion and the microbiome, immune health, and thyroid health are all inextricably interconnected. The gut microbiome is crucial in regulating mucosal immunity and protecting us against gut pathogens. This should be incredibly important to those with Hashimotos and other kinds of autoimmune diseases. Alterations in the microbiome caused by low-carb, high-fat, high-protein diets can have negative consequences on the microbiome as well as on the immune system, potentially compromising the integrity of the gut barrier and immune responses.

As I explained in many videos, most of the thyroid hormone (T4) the thyroid gland makes is not ready to be used by the body. It must be activated, and the places it gets activated, are in your liver, and the Gut by bacteria through a process called sulfation and glucuronidation(*).

The active form of thyroid hormone is T3. Gut bacteria Influence Your Thyroid Function in many ways and if you are someone who already has problems with converting T4 into T3, then a diet low in carbs, high in fat, and high in protein could further worsen gut microbial integrity.

Commensal gut microbes can convert inactive T4 into T3 sulfate, which can then be recovered as active T3 by an enzyme called intestinal sulfatase (*).

Research shows that:

  • Carbohydrates are important for deiodination, and they directly impact the levels of T3 in your body (*).
  • Carbohydrates in your diet directly impact how much of T4 gets converted to T3, the functional form of thyroid hormone (*).
  • Carbohydrates have been shown to have a direct impact on reducing stress hormones and stress levels.(*)

When diets are too low in carbohydrates, or too restrictive from a nutrient perspective, this will be perceived by the body as a stressor. The effect of stress on thyroid health is well-recognized and well-documented. (*)

Low-carb, high-protein, high-fat diets like the ketogenic (keto) diet and carnivore diet can have significant impacts on digestion and the gut microbiome in several ways. Here are some additional ways in which low-carb, high-protein, high-fat diets, and low-FIBER diets can affect digestion and the microbiome.

High Fat:High Protein:Low Carb Diets Affect on Microbiome

1. Gut Dysbiosis

Low-carb diets, particularly those that restrict carbohydrates from plant-based sources like fruits, vegetables, and whole grains, can alter the composition of the gut microbiome.(*) The reduction of dietary fibers, starches, and prebiotics in these diets often leads to a decrease in beneficial bacteria that thrive on fiber. Reducing dietary fibers also leads to a reduction in microbial diversity favoring the overgrowth of pathogenic disease-causing. (*) (check out this article on ways to improve your microbial diversity)

2. Reduction in Short-Chain Fatty Acid Production

The gut microbiota ferments dietary fibers to produce short-chain fatty acids (SCFAs) like butyrate, acetate, and propionate, which are essential for gut health and immune function. Low-carb diets may limit the availability of fermentable fibers, leading to reduced SCFA production. SCFAs help nourish the gut lining, support beneficial bacteria, and regulate inflammation in the gut. The SCFAs thicken the mucosal layer, which sits on top of the gut lining and serves as a shield between the delicate gut lining and gut bacteria/toxins. This mucosal layer also serves as a habitat and food source for our gut bacteria like akkermansia mucinphila.

When your mucous layer is thin, bacteria and toxins will come into contact with the epithelial lining and elicit an inflammatory immune response. This inflammation can lead to more permeability AKA leaky gut.

3. Altered pH and Bile Acid Secretion-

High-protein and high-fat diets can alter PH of the gastrointestinal tract and increase the production of secretion of bile acids.(*) Bile acids are produced in the liver from cholesterol and play a crucial role in the digestion and absorption of fats and fat-soluble vitamins. They are secreted into the intestine, where they aid in emulsifying dietary fats and facilitating their absorption.

Bile acids are important for fat digestion and nutrient absorption. Changes in pH levels due to low dietary carbohydrate consumption, or diets high in protein and fat diets can alter bile acid production.  Ultimately this impacts the growth of specific gut bacteria and influences the microbiome.  A high-fat diet can have a significant impact on the production and metabolism of bile acids in the body, including the formation of secondary bile acids.

When dietary fat intake is increased, especially in the context of a high-fat diet like the ketogenic diet, several changes can occur in the bile acid pool, leading to alterations in the composition and metabolism of bile acids.

High-fat diets can stimulate the synthesis and secretion of primary bile acids, such as cholic acid and deoxycholic acid, by the liver.  But here’s the thing, the more primary bile acids we have in the pool, the greater the likelihood that these primary bile acids could be later transformed by gut microbiota into Secondary Bile Acids. Secondary bile acids are very damaging to the gut mucosal lining(*),(*) and not something we want to encourage. Secondary bile acids not only cause diarrhea but numerous scientific reports describing BAs, especially secondary BAs, as strong carcinogens or promoters of colon cancers(*

Potential Health Implications: Secondary bile acids have been implicated in various physiological processes, including lipid metabolism, glucose homeostasis, colorectal cancer, and inflammation.(*) They can also interact with host cell receptors and influence pathways related to metabolism and inflammation. Imbalances in bile acid production, including an altered ratio of primary to secondary bile acids, have been associated with metabolic disorders and inflammatory conditions. (*)

Another consequence of disrupted bile acid metabolism thanks to low-carb diet plans, includes conditions such as non-alcoholic fatty liver disease (NAFLD), inflammatory bowel disease (IBD), and metabolic syndrome. The balance of bile acids, including secondary bile acids, is essential for maintaining gut health and metabolic homeostasis.

4. Constipation and Digestive Discomfort

Some individuals following low-carb, high-protein, high-fat diets may experience constipation or digestive discomfort due to reduced fiber intake and changes in bowel transit time. Fiber-rich foods help promote regularity and support healthy digestion by adding bulk to the stool and aiding in bowel movements.


Here’s What They Don’t Tell You About Ketogenic Diets and Your Thyroid

Why Low Carb Diet  Stresses Thyroid Function

When we restrict carbohydrate consumption, our body must find alternative ways to sustain blood sugar levels. To accomplish this, the body heavily relies on stress hormones like cortisol and adrenaline.

Cortisol plays a role in stimulating gluconeogenesis. Gluconeogenesis is the production of glucose. This is a process that occurs in the liver, where proteins and fats are converted into carbohydrates. Adrenaline also plays its part in the production of glucose.  Glucose is energy for cellular function.

Interestingly, carbohydrates have been shown to have a direct impact on reducing stress hormones and stress levels. Therefore, when you follow a low-carbohydrate diet like the ketogenic carnivore diet, your cortisol levels go up.

This is important because as cortisol levels go up, thyroid conversion of T4-T3 decreases and Reverse T3 levels go up. Both of these responses can further stunt thyroid function. Studies show that carbohydrate lowers stress hormones like cortisol and adrenaline. (*) This is a good thing as high cortisol is not only bad for the thyroid, it turns out that it’s also bad for your gut microbiome.

Research also suggests that individuals with hypothyroidism and Hashimotos tend to have higher levels of stress hormones to begin with. It is important to avoid making dietary changes that could further elevate these hormones, as can occur when combining the ketogenic diet and hypothyroidism.(*)

Understanding the potential impact of dietary choices on stress hormones is crucial, particularly considering the unique factors associated with hypothyroidism. Let’s delve into the reasons behind this connection in the following discussion.

Here’s What You Should Remember About Ketogenic Diets and Thyroid Disease

While the ketogenic diet can be effective for weight loss and lowering blood sugar, it’s not the only way to lose weight or get your blood sugar under control. Not only is a ketogenic diet not sustainable long term, but it can have disastrous effects on your thyroid and gut health. I reviewed several ways that a low-carb, high-protein, high-fat diet like a ketogenic diet, can put you at risk for gut and thyroid problems. Remember, carbohydrates are directly involved in activating thyroid hormones and when they are restricted your body perceives this as a stressor.

I also want you to remember that Ketogenic and Carnivore diets can increase cortisol levels, which once again reduces T3 levels and increases Reverse T3 levels. When it comes to stress and cortisol, remember that high cortisol impacts every aspect of digestion as does low thyroid function. If you plan to follow a high-fat, high-protein, low-carb, low-fiber diet like the Keto/Carnivore diet, be sure you work with a certified Functional Medical Practitioner who is knowledgeable about these connections and can monitor your gut health and thyroid hormone levels throughout the process.

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