If I wrote down these 2 elements on a MindMap: Thyroid dysfunction and Adiposity, how would you connect them? Would you reflexively draw an arrow from the former to the latter to flag that the thyroid underpins the weight management issues? My arrow would be the other way around.
According to every scrap of data, the likelihood that someone’s subclinical or even frank hypothyroidism is the source of the excess weight is quite low, while the probability that their excess adiposity has had profound effects on both the anatomy of the gland and the physiology of the HPT is much higher.
And the change in the direction of this relationship – adiposity as the cause not the consequence – changes everything, from what we tell our patients, to what effective management, and success, in terms of follow-up TFT patterns, actually looks like. It’s far from semantics. Because while we may not encounter any cassava excesses in our practice, an established goitrogen with a long history, we do see unhealthy adiposity often and it is the ‘newest’ goitrogen on the block, so to speak.
The definition of a goitrogen is something that interferes with thyroid hormonogenesis and thyroid function in any way.
Abdominal adiposity, that is excessive for that individual, (I don’t believe this can be simply determined by BMI alone but requires us to apply a more sophisticated lens & metric) interferes in many many ways.
Aligned with this recognition is the seismic shift in understanding that we’ve undergone regarding ‘who or what’ is the boss of the thyroid. Hypothalamus & pituitary, I hear you say? Nope. These guys are just the middle managers – and the real bosses are a board of directors that includes adipose tissue. Stop and think about this – makes sense, right? The HPT is attributed with being the major endocrine axis that determines how much ‘energy’ we have to spend – so of course it’s taking direct messaging and direction from the adipocytes! Add to this, that excess energy consumption drives up TSH, a trophic agent for the gland – a stimulator of proliferation without differentiation and with no guarantee of an adequate supply of the greater requirements for micronutrients required to ‘grow a bigger gland’ without architectural or functional disturbance. These are just the 1st two stages of goitrogenic effect resulting from over-nutrition, that I refer to as The Over-Feed and The Under-Resourced Thyroid…
But what can follow are 2 more stages: ‘The Disturbed’ and finally, ‘The Diseased’ thyroid – which include pathophysiological processes such as adipocyte infiltration of the actual gland (akin to the liver infiltration in NAFLD) seronegative thyroiditis, as well as epigenetic changes impairing DNA correction etc etc all a consequence of weight gain…not the cause.
Thyroid dysfunction –> weight gain or Weight gain –> thyroid dysfunction…Time to rethink this relationship?
Fat is a Goitrogen
According to every scrap of research, the likelihood that someone’s subclinical or even frank hypothyroidism is the source of their excess weight is quite low, while the probability that their excess weight has had profound effects on both the anatomy of the gland and the physiology of the HPT is much higher. So rather than a reflexive assumption that someone who presents with weight gain or ongoing unhealthy weight should have their thyroid checked to see if that is the cause – the TFTs absolutely should be performed but instead to understand one of the key consequences of this excess adiposity. In this recording we highlight the 4 stages of impact, moving from: the ‘Overfed’ to the ‘Under-Resourced’, the ‘Disturbed’ and finally the ‘Diseased Thyroid’. The reversal of this relationship – adiposity as the cause not the consequence of thyroid dysfunction – changes everything, from what we tell our patients, to what effective management, and success, in terms of follow-up TFT patterns, actually looks like. We need to be alert and responsive to the most common and contemporary thyroid disruptor in our patients: fat is a goitrogen.
If you are an Update in Under 30 Subscriber, you will find it waiting for you in your online account. You can become an Update in Under 30 Subscriber to access this episode and the entire library of Update in Under 30 audio’s and resources here.