Bioidentical Hormones 101 
The Book, by Jeffrey Dach MD

Chapter 6. Hunt Study Shows Thyroid Prevents Heart Attacks

Hunting Dog Hunt Study Thyroid prevents Heart AttacksChapter 6. Hunt Study Shows Thyroid Prevents Heart Attacks

In 1976, an endocrinologist named Broda Barnes MD was the first to connect low thyroid function with heart disease with his book, Hypothyroidism, the Unsuspected Illness.  How did Broda Barnes discover the connection between low thyroid and heart disease?  Dr. Barnes took summer vacations in Graz, Austria every year to study the autopsy files.  The town of Graz had a high prevalence of thyroid disorders, and anyone in Graz who died over the past 100 years required an autopsy to determine cause of death, as mandated by the authorities.  The Graz autopsy data showed that low thyroid patients survived the usual childhood infectious diseases thanks to the invention of antibiotics, yet years later,  develop heart disease instead.  Barnes also found that thyroid treatment was protective in preventing heart attacks, based on his own clinical experience.  Likewise for diabetes, Dr. Barnes found that adding thyroid medication was beneficial at preventing the onset of vascular disease in diabetics.  Again, blood tests are usually normal.  New research like the Hunt Study confirms that Broda Barnes was right all along, creating a paradigm shift in thyroid treatment.

The Hunt Study - Thyroid Function and Mortality from Heart Disease

TSH is short for thyroid stimulating hormone, made by the pituitary gland.  TSH actually stimulates the thyroid gland to make more thyroid hormone, and can therefore be used as a barometer of thyroid function.  If thyroid function is low, the pituitary sends out more TSH to stimulate the thyroid to make more thyroid hormone.  Mainstream Medicine regards the TSH as the single most important test for determining thyroid function. High TSH means low thyroid function, and a Low TSH means normal or high thyroid function.

What Did The Hunt Study Find?

The Hunt Study from the April 2008 Archives of Internal Medicine examined mortality from coronary heart disease (CHD) and TSH level. (1-2)  The authors conclude, "The results indicate that relatively low but clinically normal thyroid function may increase the risk of fatal CHD."  (CHD=coronary heart disease).   The Hunt Study measured thyroid function with the TSH test in 17,000 women and 8,000 men with no known thyroid disease or heart disease.  All patients had "normal TSH" levels meaning the TSH values were in the lab reference range of 0.5 to 3.5.   The women were stratified into three groups, lower TSH, intermediate and upper TSH levels, and mortality from heart disease was recorded over an 8 year observation period.

70% Increase in Heart Disease Mortality for TSH in Upper Normal Range

The Hunt study found that group with the higher TSH had 70% increased mortality from heart disease compared to the lower TSH group.  Remember all these TSH vales were in the normal lab range.

Results of the Hunt Study below:


TSH range           

Risk of Death from Heart Disease

Group 1    

Group 2

Group 3





Baseline Risk

40%   Higher than Baseline

70%   Higher than Baseline



This Finding is Earthshaking!! 

This means that merely by taking natural thyroid pills to reduce TSH to the low end of "normal" (0.5), one can reduce death from cardiovascular disease by 70 percent.  This mortality benefit is mind boggling and far exceeds any drug intervention available. Another report from the Hunt Study published in 2007 showed that LDL cholesterol was linearly associated with TSH level. (2)

The Conclusion is Clear

The best way to normalize lipoprotein profile and reduce mortality from heart disease is to reduce TSH to the lower end of the normal range with thyroid medication.  A TSH in the upper end of the normal range is associated with increased cardiovascular mortality and elevations in LDL lipo-protein measurements.  A TSH at the lower end of the normal range is associated with protection from heart disease.

Important Point:

A low thyroid condition, and high TSH, dramatically increases risk for heart disease.  


Statin Drugs or Thyroid to Prevent Heart Disease in Women?

Another chapter of this book discusses the issue of statin drugs for women.  Decades of published statin drug studies show that statin drugs simply don't work for women, and don't reduce mortality from heart disease in women.  But on the other hand, the HUNT study shows that TSH levels in the lower normal range provide a 70% reduction in heart disease mortality for women.  This can be accomplished safely with inexpensive thyroid medication under a physician's supervision.  So for women concerned about preventing heart disease, this is good news.

Natural Thyroid is Better

Rather than Synthroid, we prefer to use natural thyroid which is a desiccated porcine thyroid gland from RLC Labs or Armour Thyroid.  The reason for this is that we have seen better clinical results with the natural thyroid preparations compared to Synthroid.

Natural Thyroid is Safer, but can Cause Adverse Effects of Palpitations

Although natural thyroid is safe, there is always the possibility of adverse effects from thyroid excess, defined as too much thyroid medication.  The first sign of thyroid excess is usually a rapid heart rate at rest or perhaps palpitations at rest.  We spend time with each patient discussing the adverse effects before starting patients on thyroid medication.  Usually, patients will notice the heart rate going up or the heart beat sounding louder than usual as the first sign that can be easily recognized.  Once recognized, the patient is instructed to stop the thyroid medication, and symptoms usually resolve within 6 hours (for natural thyroid).  It is perfectly safe to stop the thyroid medication at any time, as there will be no acute changes, merely a gradual reversion to the original state that existed before starting the thyroid pills.

Some patients are very sensitive to thyroid medication and will have thyroid excess symptoms such as rapid heart rate and palpitations from small amounts of thyroid medication.  These are usually the elderly with underlying heart disease and/or magnesium deficiency.  Thyroid medication should be avoided in these cases.  Measuring magnesium levels and magnesium supplementation is very important in patients contemplating thyroid in order to reduce the risk of cardiac excitability.

A small subset of patients initially starting thyroid will notice symptoms of thyroid excess with a rapid heart rate, and they will stop the medication for a day or two and restart at a lower dosage with no further problems.  This is more common in Hashimoto's patients whose own production of thyroid hormones may fluctuate from month to month.  Patients with magnesium deficiency or adrenal fatigue with low cortisol output on salivary testing will also tend to be more sensitive to small amounts of thyroid medication, so caution is advised in these groups as well.

Thyroid Excess Can Rarely Cause Atrial Fibrillation

Atrial fibrillation is a common type of cardiac arrhythmia which is more common in elderly males with underlying heart disease.  However, it can happen to anyone as a result of severe thyroid excess from  excessive thyroid medication.  However, atrial fibrillation and thyroid excess can be avoided by spending time with the patient discussing the symptoms of thyroid excess, and the importance of stopping the thyroid medication when symptoms are first noted.  Patients are instructed to monitor their heart rate and to stop the thyroid medication at the first sign of thyroid excess.


Excessive thyroid medication can cause rapid heart rate, palpitations and in severe excess, cardiac arrhythmia such as atrial fibrillation.  Magnesium deficiency can predispose to cardiac irritability.  Best to avoid thyroid excess by maintaining dosage in the proper range.

Mainstream Doctors Don't Have Time To Discuss Adverse Effects

One of the reasons the mainstream conventional docs will give only a minuscule amount of Synthroid to the low thyroid patient is that they simply don't have the time to discuss thyroid excess, which is more likely if the patient is not alerted to the symptoms to watch for.  In addition, mainstream medical docs don't recognize the syndromes of adrenal fatigue and magnesium deficiency, so they can run into problems with thyroid excess without understanding why, producing caution and tendency to under treat.

In patients with underlying heart disease who are prone to cardiac arrhythmias, thyroid excess can cause atrial fibrillation with characteristic EKG appearance.  Atrial fibrillation can be a problem, because if it becomes chronic and doesn't go away on its own, the cardiologist will try a maneuver called cardioversion, the application of an electrical shock to restart a normal cardiac rhythm, or blood thinners, all of which is not without risk.  So it is better to avoid atrial fibrillation altogether by simply stopping the thyroid pills whenever symptoms of rapid heart rate or palpitations are noted while at rest.  Exercise induced rapid heart rate, of course, doesn't count since that is normal cardiovascular response to exercise.

How To Design A Better Hunt Study

How would I design an even better Hunt Study? That's easy. Include another group of patients with TSH levels above and below the study group, namely, below 0.5, and above 3.5.  I would also include data on annual CAT coronary calcium scores.  I would predict that the lower TSH group (below 0.5) would have even less heart disease than the higher TSH group, and that coronary calcium score, indicating plaque burden, would go up as TSH went up.

Thanks and credit goes to William Davis MD and Jacob Teitelbaum MD.  Their articles on the Hunt study brought this to my attention.(3)(4)

For references see the web site

Articles With Related Interest:

Saving Tim Russert and George Carlin

Reversing Heart Disease with Calcium SCore

Hypothyroid Type Two

Cholesterol Drugs for women

References for Chapter 6.
Hunt Study Shows Thyroid Prevents Heart Attacks

(1)  Arch Intern Med. 2008;168(8):855-860. Thyrotropin Levels and Risk of Fatal Coronary Heart Disease,  The HUNT Study. Arch Intern Med. 2008;168(8):855-860.

(2)  European Journal of Endocrinology, Vol 156, Issue 2, 181-186, 2007 The association between TSH within the reference range and serum lipid concentrations in a population-based study. The HUNT Study . Bjørn O Åsvold1,2, Lars J Vatten1, Tom I L Nilsen1 and Trine Bjøro.

(3)  Jacob Teitelbaum, MD. Low Thyroid (Even if Tests are Normal) is a Major Cause of Heart Attacks,

(4)   William Davis MD, on the Hunt Study at the Heart Scan Blog.

(5) iochemically_hypothyroid_patients.pdf    International Hormone Society, lab references, clinically hypothyroid , lab euthyrroid

Author: Jeffrey Dach MD

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