Thiamine, also known as vitamin B1, is a water-soluble essential vitamin that is required for glucose production. While its role in glucose metabolism is largely understood, there isn’t a lot of research on the relationship between thiamine and thyroid health. But this doesn’t mean that a thiamine deficiency can’t be a factor in some people with thyroid and autoimmune thyroid conditions, which of course I’ll discuss in this article.
People are not commonly deficient in thiamine in Western diets. Moreover, many foods nowadays are fortified with thiamine, so a deficiency is even less probable, though several factors can predispose one to a thiamine deficiency. A lack of sufficient thiamine can be present in some people with thyroid and autoimmune thyroid conditions. This is especially true if fatigue is still a big factor after patients start a thyroid treatment regime, although there of course can be numerous other factors responsible for the fatigue. Underlying causes of thiamine deficiency remain unclear, but there is some evidence that the answer lies in enzymatic and intracellular signaling dysfunction.
Signs and Symptoms of a Thiamine Deficiency
Some of the common signs and symptoms of a thiamine deficiency include the following:
- Poor appetite
- Weight loss
- Muscle weakness
- Short-term memory loss
- Cardiovascular damage
You may notice poor appetite and weight loss as later signs and symptoms. They could be a result of a reduced ability to metabolize carbohydrates, the primary energy source of the body. Fatigue is also linked to issues of carbohydrate metabolism in cases of thiamine deficiency. Studies have shown that mitochondrial dysfunction occurs with low thiamine levels, which ultimately produce the poor improper carbohydrate metabolism and fatigue (1).
Neurological symptoms such as confusion, memory loss, and irritability can be linked to insufficient glucose metabolism and the lack of bioavailable glucose for neuronal cell function. Wernicke’s encephalopathy is a progressive neurological disorder that occurs after sustained thiamine deficiency. It is typically characterized by an altered mental state, oculomotor dysfunction, and an ataxic gait (2). Wernicke’s encephalopathy is not frequently diagnosed, and it can be fatal if left untreated. Additionally, Wernicke’s encephalopathy may not always be present in cases of thiamine deficiency. For this reason, attention to blood test results are crucial if physicians suspect an issue.
Another neurological condition that can result from a thiamine deficiency is Korsakoff’s syndrome. Korsakoff’s syndrome is characterized by an acute onset of memory loss (usually anterograde amnesia), inability to comprehend or use language, motor disorders, and an inability to process sensory information. Korsakoff’s syndrome may or may not accompany Wernicke’s encephalopathy. Occasionally, the two present together in what is known as Wernicke-Korsakoff syndrome.
Sometimes cardiovascular symptoms are present with neurological ones in patients with a thiamine deficiency. Cardiovascular conditions patients may acquire include congestive heart failure, edema, and cardiomegaly (an enlarged heart) (2). Still, the combination of cardiovascular and neurological symptoms is very rare.
Predisposing Factors to Thiamine Deficiency
A general risk factor for developing a thiamine deficiency is malnutrition. Other factors, however, directly or indirectly produce a similar effect where the excretion and inability to store thiamine leads to its deficiency. Certain predisposing factors are attributed to a thiamine deficiency. A thiamine deficiency comes about through different physiological pathways depending on the predisposing factors that are at play.
1. Alcoholism. This is perhaps the factor most closely associated with a thiamine deficiency. Not only do patients suffering from alcoholism usually have poor diets, but overconsumption of alcohol also leads to poor thiamine absorption in the gastrointestinal tract. Alcoholism has also been shown to reduce thiamine storage and prevent the phosphorylation of thiamine, a necessary step for its functionality (3).
2. Gastrointestinal Surgery: Surgeries affecting the GI tract can alter the way nutrients are absorbed. One case study demonstrated how after undergoing a sleeve gastric bypass procedure, a morbidly obese patient developed Wernicke’s encephalopathy, the usual complication associated with a thiamine deficiency. This patient in particular did not have any symptoms of Wernicke’s encephalopathy until four months postoperatively. When thiamine was administered as a treatment, the patient’s condition fully improved (4).
3. Gastric and Colon Cancer: Tumors occurring in the GI tract may use excessive amounts of thiamine for their growth. Certain anticancer medications may also interfere with thiamine function. A study showed how a 56-year-old female patient was successfully treated with thiamine after developing Wernicke’s encephalopathy while receiving treatment for colon cancer (5).
4. Hyperemesis Gravidarum: This is a complication associated with pregnancy, usually in the first trimester, that may be characterized by excessive vomiting, dehydration, and weight loss. On presentation to the emergency room, one female patient who was 22 weeks pregnant had poor neuromotor functioning and reported excessive vomiting throughout the pregnancy. Her MRI confirmed she had signs of Wernicke’s encephalopathy and she was promptly treated with thiamine, showing an improvement in her neurological symptoms (6).
5. Anorexia Nervosa: Anorexia nervosa is another disorder that can lead to progressive malnutrition…and thus cause a thiamine deficiency, along with other nutrient deficiencies. Patients often have habits of severe diet restrictions, negative body images, and may also have histories of bulimia nervosa (7).
6. Renal Dialysis: Patients undergoing renal dialysis who are also poorly nourished may be flushing excessive amounts of thiamine through dialysate, which is a fluid used in dialysis. In fact, the most common cause behind encephalopathy in renal dialysis patients is a thiamine deficiency. Recognizing thiamine deficiency in patients on dialysis treatment may be difficult. Uremia, or increased levels of urea in the blood, may mimic the same symptoms of a thiamine deficiency (8).
7. Magnesium Deficiency: Patients who have a magnesium deficiency are more likely to have a thiamine deficiency. Magnesium is a cofactor in the production of thiamine pyrophosphate (TPP), a molecule that is important in catalyzing several biochemical reactions.
8. Diabetes: Patients who have both type 1 and type 2 diabetes have a tendency to have low plasma thiamine levels, according to a study. Renal clearance was shown to be increased 24 times in type 1 diabetics and 16 times in type 2 diabetics (9). A greater number of thiamine transporter proteins on red blood cells were noted; the authors believed this was the underlying reason for the increased renal clearance of thiamine.
Food Sources of Thiamine
Legumes and beans are excellent sources of thiamine. A half cup of cooked black beans contain 27 percent of the recommended daily intake of thiamine (10). However, legumes are excluded from both a standard Paleo and an autoimmune Paleo diet. Many fish are also high in thiamine. Trout and tuna have some of the highest sources, while beef and pork also contain higher amounts. Although tuna is high in thiamine, it is also high in mercury, and so I would recommend not consuming this type of fish on a frequent basis. Eggs are also a good source of thiamine.
As for foods which are good sources of thiamine but are excluded from a standard and autoimmune Paleo diet, these include dairy, white rice, and cereals. Cereals and white rice are often fortified with additional thiamine, which explains why they usually rank high in foods with the largest recommended daily intake of thiamine. But of course I would recommend to focus on eating whole, healthy foods. And there are times when supplementing with thiamine is necessary, which I’m about to discuss.
Patients with a variety of conditions often supplement with additional thiamine. It is common for patients who are pregnant, patients with AIDS, alcoholism, ulcerative colitis, kidney disease, type 2 diabetes, and even Alzheimer’s to supplement with this nutrient. Three main stand-alone supplements of thiamine exist. They are:
Thiamine hydrochloride (HCL). This is the hydrochloride salt form of thiamine. While it is the closest form of pure thiamine among other thiamine supplements, it may be less readily absorbed compared to other forms. However, numerous studies have demonstrated that supplementing with high doses of thiamine HCL (i.e. 200 mg/day) can correct a thiamine deficiency.
Benfotiamine. This is actually a derivative of the thiamine molecule, but it is bioavailable as thiamine after ingestion. The molecule is hydrophobic and its structure gives rise to its unique high absorption rates, even higher than regular thiamine precursors that ultimately get converted into free thiamine (11). Increases in thiamine levels are typically detected within an hour of ingestion.
Sulbutiamine. This is a synthetic molecule that consists of two thiamine molecules bound by a sulfur group. It is prescribed often for asthenia (weakness), and is better absorbed by brain cells given it is far more lipophilic than free thiamine. Several studies have shown that sulbutiamine is effective at reducing fatigue symptoms for a variety of conditions including chronic postinfectious fatigue (CPIF) (12).
Should YOU Supplement With Thiamine?
Most of my patients don’t take a separate thiamine supplement. However, if you have hypothyroidism or Hashimoto’s and are experiencing moderate to severe fatigue, even after taking thyroid hormone medication, then it might be worth supplementing with high doses of thiamine on a short term basis.
As for how you can determine if you have a thiamine deficiency, whole blood testing is the most common method used, as this measures the biologically active form of thiamine, which is known as thiamine diphosphate. Another option is something called the erythrocyte (red blood cell) transketolase test. Transketolase is an enzyme that requires two cofactors, thiamine and magnesium. When someone has a thiamine deficiency this value is usually reduced. However, this marker isn’t commonly available at many labs.
Yet another option is to use a specialty lab such as SpectraCell. This lab measures thiamine, along with other nutrients and micronutrients, within an individual’s white blood cells. The downside is that this is an expensive test, and there isn’t research I’m aware of that shows this is an accurate method of testing for nutrients. I will say that there are some well known and respected healthcare professionals who recommend micronutrient testing to their patients, but I would like to see more research before I start routinely recommending this type of testing to my patients.
How Does Thiamine Relate To Thyroid Health?
The exact link between thiamine and thyroid health still remains unclear. Some studies have suggested that thyroid autoimmunity may actually contribute to a thiamine deficiency. The reason may be behind dysfunction in enzymes and issues with intracellular transport. The persistent fatigue that commonly accompanies Hashimoto’s, for example, even after thyroid treatment, may very well be linked to a thiamine deficiency in some cases.
In one study, three patients who had Hashimoto’s were treated by the administration of thyroid medication and thiamine. Patients either received oral thiamine supplementation (600 mg/day) or parenteral supplementation (100 mg/mL every four days). Fatigue was measured using the Fatigue Severity Scale over a period of three months. The results showed that treatment led to decreased fatigue, and some patients even reported that it was entirely gone. Patients reported feeling better within a few hours or days of their thiamine supplementation. The data implied that ongoing fatigue in Hashimoto’s (even after treatment with thyroid medication) may be a result of thiamine deficiencies instead of thyroid hormone dysfunction (13).
Of course there can be many other causes of fatigue, and so I’m not suggesting that if taking thyroid hormone medication doesn’t help to reduce fatigue that a thiamine deficiency is the only cause. I did mention earlier that supplementing with higher doses of thiamine for a short period of time might help. However, there of course can be many other factors which can lead to fatigue. For more information you can check out an article I wrote entitled “7 Ways To Increase Your Energy Levels”.
In addition, thiamine deficiencies were also present in a study (14) by the same authors who studied fatigue in inflammatory bowel disease (IBD) (i.e. Crohn’s Disease and ulcerative colitis). Patients with IBD in the study improved their fatigue after supplementing with high doses of thiamine. While this might suggest a connection between IBD and a thiamine deficiency, it’s also possible that other gut conditions can cause a thiamine deficiency due to malabsorption. Examples include small intestinal bacterial overgrowth (SIBO) and Celiac disease.
In summary, thiamine is an essential vitamin required for regular carbohydrate metabolism. Patients who experience continuous fatigue, even after taking thyroid hormone medication should consider testing for a thiamine deficiency, or supplementing with high doses of thiamine for a short period of time to see if the fatigue improves. If left untreated, severe thiamine deficiencies can lead to fatal encephalopathies, memory loss, and cardiovascular issues. Supplementation with thiamine is key when having a moderate to severe thiamine deficiency, along with treatment of any predisposing factors that may be contributing to the thiamine deficiency in the first place.
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