Fetbobbas Forum

“…remember that prolonged dieting (Atkins, low-fat, low-calorie, or a combination) tends to shut down thyroid function. This is usually not a problem with the thyroid gland (therefore blood tests are likely to be normal) but with the liver, which fails to convert T4 into the more active thyroid principle, T3. The diagnosis is made on clinical ground with the presence of fatigue, sluggishness, dry skin, coarse or falling hair, an elevation in cholesterol, or a low body temperature. I ask my patients to take four temperature readings daily before the three meals and near bedtime. If the average of all these temperatures, taken for at least three days, is below 97.8 degrees F (36.5 C), that is usually low enough to point to this form of thyroid problem; lower readings than that are even more convincing. It may be appropriate for those of you who fit these criteria to be prescribed thyroid by your doctor, and if so, a natural form of the hormone, which contains T3, is far superior to the most popular form of prescription thyroid, synthetic T4.” -Dr. Robert Atkins

In a recent interview, Dr. Peat explained that the thyroid can be affected "locally" by the glycogen content of the liver. In the presence of low glycogen, the liver decreases conversion of thyroxine (T4) to the more metabolically active thyroid hormone, triiodothyronine (T3). Because more than 2/3 of active thyroid hormone is converted in the liver, this is significant.

Thyroid hormone is protective against anti-hair hormones, so supporting it by whatever means necessary is a top priority.

As for fatty acids disturbing thyroid signaling, Chris Masterjohn explained this brilliantly on a recent podcast I did with him and Chris Kresser:

"Free fatty acids interfere with thyroid signaling and as we know in the blogosphere recently, interfering with thyroid signaling can affect blood lipids."

I interrupted Chris to ask specifically what kinds of fatty acids interrupted thyroid signaling:

"There's good preliminary evidence that any unsaturated free fatty acids are quite good at inhibiting thyroid function. Not just PUFA but oleic acid is pretty good at it too. You can't do anything to suppress oleic acid because your body can produce it itself. PUFAs play a role, but you have a lot more oleic acid in the body. Basically, any release of free fatty acids will inhibit thyroid signaling. The best evidence for this is at the level of thyroid binding to the nuclear receptor and then binding to DNA. It seems that the concentrations of free fatty acids can get high enough in the nucleus of the cell to inhibit signaling there and that will not be reflected in free T3 levels in the blood or anything like that. It would be very difficult to detect it clinically."