There is a pattern that I’ve noticed on every live-stream that I’ve appeared on talking about ketosis that someone always asks the question: “What about the thyroid?” That’s literally how it’s asked. . . someone I am unfamiliar with keys in the question, “What about the thyroid?”
The blunt sarcastic response in my head is usually, “Well, what about it?”
Buried within the vague periscope or twitter question above is the real question that is on the minds of thousands of people, “Does ketosis effect the thyroid . . . ?”
There’s loads of information about the thyroid on the internet. Much of it is garbage. Seriously. Ask Google about “thyroid,” and you’ll see thousands of articles, posts and comments on WebMD, Women’s Health, and Wikipedia all across the “interwebby.” Everyone, and I mean everyone, seems to have a “thyroid opinion.” Much of the “wikopinion” out there is here-say, conjecture and anecdotal. It doesn’t really give people any foundational understanding of what their thyroid is doing, or more importantly for that matter – what their thyroid isn’t doing.
Of late, the Paleo and Vegetarian thought leaders seem to decry nutritional ketosis because they claim that this dietary approach suppresses thyroid function. This wiki-theory (yes, it is just a theory) was extrapolated from a single study where the T4 level dropped in the first few weeks after ketosis was entered. But just because T4 drops, doesn’t mean the diet suppresses the thyroid. Using T4 as a screening test alone for assessment of thyroid function is 1987 thinking (1987 brought us the Kia Concord and the Subaru Justy just so you get the mental picture). T4 fluctuates with a number of binding proteins and following this number alone is really bad medicine. Taking thyroid advise from the Paleo people is like asking your Fed Ex driver about the correct lift on your 4×4 truck. Really?
Excessive insulin, the hormone produced when you eat sugar, starch and some proteins, actually stimulates thyroid peroxidase antibodies and can cause exacerbation of thyroiditis (causing over-production or under-production of thyroid hormone). Because 85% of the people I see in my office over-produce insulin (this is referred to as insulin-resistance), in response to starches, there is a significant flux in thyroid function due to this pre-diabetes state (insulin over-production) on high carbohydrate based diets.
Leptin, the hormone produced by fats cells when they are “full,” actually stimulates the conversion of T4 to T3. At least 40% of my obese, insulin-resistant patients are also leptin-resistant, meaning they over-produce leptin as well. This has a suppression effect on T4 (by converting it to T3) and is the usual cause of the T4 levels being lower when initially staring a ketogenic diet. It is also the reason that some people feel anxious or “activated” when changing to nutritional ketosis. Leptin-resistance is driven by a high level of fructose in the diet and the presence of high triglycerides, inhibiting the leptin signal from crossing the blood-brain barrier. As a person follows a ketogenic diet and lifestyle, leptin returns to normal over 3-6 months and T4 levels normalize. The Paleo and Vegetarian nay-sayers never mention that . . . do they? What they won’t tell you is that calorie restriction, which is a must for weight loss, on the DASH, Mediterranean, Paleo or Vegetarian diet causes suppression of testosterone, leucine, and thyroid function, causing worsening T4 suppression over time. Hmmm . . . put that in your low-fat green vegetarian taco, and smoke it.
Wait . . . I don’t advocate smoking so, ignore that.
The point is, a ketogenic lifestyle stabilizes thyroid function and improves auto-immune thyroiditis. I’ve seen it happen clinically for over 12 years. It, also, dramatically helps stabilize the other 30 hormones involved with the diseases of civilization including obesity, insulin resistance and diabetes.
Watch my live-stream recording below to find out more about the thyroid.