Changes of thyroid hormonal status in patients receiving ketogenic diet due to intractable epilepsy

We have had a number of references to ketogenic diets recently - so this paper, though it is about a specific use of such a diet, might well have relevance.

J Pediatr Endocrinol Metab. 2017 Jan 11. pii: /j/jpem.ahead-of-print/jpem-2016-0281/jpem-2016-0281.xml. doi: 10.1515/jpem-2016-0281. [Epub ahead of print]

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

Kose E, Guzel O, Demir K, Arslan N.

Abstract

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.

PMID: 28076316

DOI: 10.1515/jpem-2016-0281

ncbi.nlm.nih.gov/pubmed/280...

3 Replies

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  • That's interesting, thank you for posting.

  • Very interesting.

    Am I reading this correctly: all subjects had been on a ketogenic diet for at least a year *prior* to the study beginning? Perhaps it's just badly worded.

    It is, I believe, known that there is a relationship between epilepsy and thyroid function to begin with. Likewise certain epileptic drugs have been shown to cause hypothyroidism. These children were all medicated. Not having read the full paper I wonder whether these two factors have been controlled for?

    The researchers suggest that having a high tsh to begin with ( and being female - and the subjects are pre-pubescent children so this is VERY interesting) are independent risk factors. This looks like a Turkish study...I wonder what TSH range is used to diagnose hypothyroidism? If it is akin to the UK, the patients with 'a high TSH' may have been hypothyroid to begin with. The diet may not have caused thyroid malfunction but worsened an existing condition?

    The fact that these children were suffering from drug-resistant epilepsy - and still medicated - to begin with is also interesting. Leads one to question the nature of the diagnosis.

    Thanks Helvella.

  • Thankyou for posting. I was advised to do a version of a keto diet. I'm not convinced it is what I need so I was interested to read this article. Obviously as the poster below points out, there are limitations to the study, however it's good to hear a variety of opinions. It was my belief that a keto diet isn't that healthy for the thyroid, when I tried low carb before I certainly struggled. Recently I have increased protein intake (without consciously cutting carbs) however and I certainly have a lot more stable energy during the day.

    Chloe

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