Blood Sugar Instability Is Making Your Hashimoto's Worse

By Anca Vereen, Integrative Dietitian

Here is a question I ask every single Hashimoto's client I work with: what does your blood sugar feel like throughout the day?

The answers are revealing. Many describe feeling shaky or irritable between meals. Some get headaches or brain fog in the late afternoon. Others find that they feel dramatically worse on days when they skip meals, eat high-carbohydrate foods, or have disrupted sleep. A significant number report cravings for sugar and refined carbohydrates that feel almost uncontrollable.

None of this is a willpower problem. All of it is a physiology problem. And it is directly relevant to how active their Hashimoto's is.

The Blood Sugar and Autoimmunity Connection

When blood glucose rises sharply, as it does after eating refined carbohydrates, sugar, or highly processed foods, insulin surges in response. This insulin surge drives blood sugar back down, often overshooting, which then triggers a catecholamine response (adrenaline and cortisol) to bring glucose levels back up.

This catecholamine surge does something critical in the context of Hashimoto's: it activates the immune system. Specifically, the sharp rise in blood glucose activates NF-kB, a key inflammatory signalling molecule, and elevates IL-17, one of the cytokines most associated with driving autoimmune activity. The result is a measurable increase in autoimmune reactivity with every blood sugar spike.

There is also a mechanism involving advanced glycation end products (AGEs). When glucose attaches to proteins in the body over time, it forms these damaging compounds. AGEs activate RAGE receptors, which trigger an inflammatory cascade that further stimulates autoimmune activity.

The implication is significant: every time you are caught in a blood sugar rollercoaster, you are fanning the flames of your autoimmune disease.

How Hashimoto's Creates Blood Sugar Dysregulation

Here is what makes this particularly challenging: Hashimoto's itself impairs blood sugar regulation, creating a vicious cycle.

Hypothyroidism reduces the rate at which cells take up glucose, slowing glucose transport across cell membranes. It impairs the gut's absorption of glucose. It decreases the cortisol and insulin responses to low blood sugar, making hypoglycaemia episodes harder for the body to self-correct. And it increases susceptibility to insulin resistance through multiple pathways.

Research confirms that autoimmune thyroid disease patients are prone to fat metabolism disorders, and thyroid hormone levels have a close correlation with blood lipid metabolism, insulin metabolism, and inflammatory factors.

So you have a situation where dysglycemia drives autoimmune activity, and Hashimoto's itself creates conditions for dysglycemia. Again, a self-perpetuating loop.

What Dysglycemia Looks Like in Practice

The clinical picture I see in Hashimoto's patients with significant dysglycemia tends to include one of a few patterns.

Some have hypoglycaemia-dominant patterns: energy crashes mid-morning or mid-afternoon, feeling irritable or shaky if meals are delayed, waking in the early hours of the morning (often 2 to 4am), feeling worse on lower-carbohydrate days.

Some have insulin resistance-dominant patterns: energy slumps after meals, difficulty losing weight particularly around the abdomen, fatigue after eating carbohydrates, elevated fasting blood glucose or HbA1c.

And many have a mixed pattern that alternates between both, which is particularly common in Hashimoto's given the way the condition dysregulates multiple metabolic pathways simultaneously.

There is also the question of other autoimmune overlap. Hashimoto's patients have higher rates of Type 1 diabetes (pancreatic autoimmunity) and Addison's disease (adrenal autoimmunity) than the general population. These are worth screening for if blood sugar dysregulation is particularly severe or resistant to dietary intervention.



What I Recommend for Blood Sugar Balance With Hashimoto's

The dietary changes here are genuinely some of the most impactful interventions available for autoimmune management, and they are entirely within your control.

Eating to stabilise blood glucose means prioritising protein, healthy fats, and fibre at every meal. Protein and fat slow glucose absorption and reduce the insulin spike from carbohydrates. Fibre slows digestion and buffers blood sugar rises. Starting the day with a protein-rich breakfast rather than toast, cereal, or fruit alone is often transformative.

Meal timing matters. Eating at regular intervals, roughly every 3 to 4 hours, prevents the blood sugar troughs that trigger catecholamine and immune activation. Going long periods without food, particularly skipping breakfast, sets up a blood sugar and stress hormone pattern that drives inflammation for the rest of the day.

Reducing refined carbohydrates and added sugars is foundational. This does not mean eliminating all carbohydrates. It means shifting away from foods that spike glucose rapidly, such as white bread, pastries, sugary drinks, and most processed foods, and towards complex carbohydrates combined with adequate protein and fat.

Magnesium is particularly valuable here. It supports insulin signalling, reduces cortisol reactivity, and is commonly depleted in people with both Hashimoto's and blood sugar dysregulation. I use it regularly in practice as part of the foundational nutritional support.

Berberine is worth mentioning for those with significant insulin resistance patterns. Research supports its ability to improve insulin sensitivity through mechanisms similar to metformin, without the medication's side effects. As always, individualised guidance from a practitioner is important.

Consistent, moderate movement is one of the most effective blood sugar interventions available. Even a 15 to 20 minute walk after meals meaningfully reduces post-meal glucose spikes. Resistance training improves insulin sensitivity over time. The key is avoiding excessive high-intensity exercise, which can raise cortisol and worsen the immune-inflammatory picture in people with active autoimmunity.

Anca Vereen is an integrative dietitian specialising in autoimmune and hormonal health. Visit ancavereen.com for personalised support.