Changes Of Thyroid Hormonal Status In Patients Receiving Ketogenic Diet

[DuggaDugga]

Changes of thyroid hormonal status in patients receiving ketogenic diet due to intractable epilepsy. - PubMed - NCBI

BACKGROUND:
Ketogenic diet (KD), which is high in fat and low in carbohydrates, mimics the metabolic state of starvation and is used therapeutically for pharmacoresistant epilepsy. It is known that generation of triiodothyronine (T3) from thyroxine (T4) decreases during fasting periods. The aim of this study was to evaluate the thyroid function of children receiving KD for at least 1 year due to drug-resistant epilepsy.

METHODS:
A total of 120 patients [63 males, 52.5%; mean age 7.3±4.3 years, median interquartile range (IQR): 7.0 (4-10 years)] treated with KD for at least 1 year were enrolled. Seizure control, side effects, and compliance with the diet were recorded, and free T3, free T4, and thyroid-stimulating hormone (TSH) levels were measured at baseline and at post-treatment months 1, 3, 6, and 12. The Mann-Whitney U-test, repeated measures analysis of variance (ANOVA) with post-hoc Bonferroni correction, and logistic regression analysis were used for data analysis.

RESULTS:
Hypothyroidism was diagnosed and L-thyroxine medication was initiated for eight, seven and five patients (20 patients in total, 16.7%) at 1, 3, and 6 months of KD therapy, respectively. Logistic regression analysis showed that baseline TSH elevation [odds ratio (OR): 26.91, 95% confidence interval (CI) 6.48-111.76, p<0.001] and female gender (OR: 3.69, 95% CI 1.05-12.97, p=0.042) were independent risk factors for development of hypothyroidism during KD treatment in epileptic children.

CONCLUSIONS:
KD causes thyroid malfunction and L-thyroxine treatment may be required. This is the first report documenting the effect of KD treatment on thyroid function. Thyroid function should be monitored regularly in epileptic patients treated with KD.

Haven't been able to locate the full study unfortunately. Would be interested in seeing the full methods and results.
What amazes me is that their conclusion is not to stop prescribing ketogenic diets (KD), which clearly inhibit the metabolic rate, but instead that they should be prescribed along with thyroxine.
Nevermind that the KD is clearly detrimental to the patient, they're suggesting L-thyroxine (Levothyroxine - Wikipedia), which is T4, The liver limits conversion of T4 to T3 when glycogen stores are depleted, which is exactly what a KD induces.

Out of curiosity, I poked around pubmed to see if any similar studies were conducted.

Effect of low-carbohydrate diets high in either fat or protein on thyroid function, plasma insulin, glucose, and triglycerides in healthy young adu... - PubMed - NCBI

A low-carbohydrate diet, frequently used for treatment of reactive hypoglycemia, hypertriglyceridemia, and obesity may affect thyroid function. We studied the effects of replacing the deleted carbohydrate with either fat or protein in seven healthy young adults. Subjects were randomly assigned to receive seven days of each of two isocaloric liquid-formula, low-carbohydrate diets consecutively. One diet was high in polyunsaturated fat (HF), with 10%, 55%, and 35% of total calories derived from protein, fat, and carbohydrate, respectively. The other was high in protein (HP) with 35%, 30%, and 35% of total calories derived from protein, fat, and carbohydrate. Fasting blood samples were obtained at baseline and on day 8 of each diet. A meal tolerance test representative of each diet was given on day 7. The triiodothyronine (T3) declined more (P less than .05) following the HF diet than the HP diet (baseline 198 micrograms/dl, HP 138, HF 113). Thyroxine (T4) and reverse T3 (rT3) did not change significantly. Thyroid-stimulating hormone (TSH) declined equally after both diets. The insulin level was significantly higher 30 minutes after the HP meal (148 microU/ml) than after the HF meal (90 microU/ml). The two-hour glucose level for the HP meal was less, 85 mg/dl, than after the HF meal (103 mg/dl). Serum triglycerides decreased more after the HF diet (HF 52 mg/dl, HP 67 mg/dl). Apparent benefits of replacing carbohydrate with polyunsaturated fat rather than protein are less insulin response and less postpeak decrease in blood glucose and lower triglycerides. The significance of the lower T3 level is unknown.

Granted this study is from the 80's, it absolutely blows my mind that their (desirable, "apparent benefits") dependent variable is decreased insulin signaling.

 

[brigadierbarty]

Full article

Library Genesis: Scientfic Articles

 

[rei]

What amazes me is that their conclusion is not to stop prescribing ketogenic diets (KD), which clearly inhibit the metabolic rate, but instead that they should be prescribed along with thyroxine.

Ketogenic diet is effective for controlling seizures, so stopping the diet is not an option. What is amazing is that they did not compare saturated fat to unsaturated considering what is known about the differences.

 

[Encai]

Granted this study is from the 80's, it absolutely blows my mind that their (desirable, "apparent benefits") dependent variable is decreased insulin signaling.

Yep, it's amazing that a 15% drop of triglyerides is shown as desirable, but a 40% decrease in T3 is not known to mean anything...