The Relationship Between Thyroid Health and Kidney Health

The kidneys are vital organs that play an important role in filtering our blood.  Since thyroid hormone affects every cell and tissue in the body, it shouldn’t be a surprise that having hypothyroidism or hyperthyroidism can have an impact on kidney health.  In this blog post I’m not only going to discuss the relationship between the thyroid gland and the kidneys, but I’m also going to give you some information that will help you to determine if your kidneys are working properly.  As a result, this blog post won’t only be beneficial for those with thyroid and autoimmune thyroid conditions, but will be valuable to anyone with kidneys (which hopefully describes YOU!).

I’d like to start out by discussing some of the basics of kidney function.  First of all, each kidney consists of filtering units called nephrons, and each nephron includes a filter called the glomerulus, along with a tubule.  These structures are part of the renal cortex, which is the outer part of the kidney.  The glomerulus filters your blood, and the tubule helps to remove toxins, reabsorbs ions, water, and nutrients, which in turn helps to maintain blood pH and electrolyte balance.  There is also something called a collecting duct, which reabsorbs solutes and water, which in turn forms urine.

Let’s go ahead and list some of the functions of the kidney in bullet-point format:

• Acid-base balance
• Maintaining fluid balance
• Regulation of electrolytes
• Removal of waste materials from food, medications, and toxic substances
• Regulation of blood pressure
• Production of certain hormones (i.e. erythropoietin) that help to produce red blood cells
• Activation of vitamin D

Health Conditions Involving The Kidneys

There are many health conditions associated with the kidneys, and I’m going to list a few of them below:

• Chronic kidney disease
• Kidney stones
• Glomerulonephritis
• Acute nephritis
• Polycystic kidney disease
• Urinary tract infections
• Acidosis
• Uremia
• Nephrotic syndrome

What Is Chronic Kidney Disease?

I’m not going to discuss all of these conditions I listed above, but I do want to discuss chronic kidney disease (CKD).  CKD is a common condition that refers to a long-term loss of kidney function.  It is identified by the presence of an abnormality of kidney structure or function (or both) for at least 3 months (1).  Some of the common risk factors for developing CKD include a family history, smoking, high blood pressure, diabetes, and obesity.  I’ll talk about the relationship between thyroid hormone imbalances and CKD shortly.

How is Chronic Kidney Disease Diagnosed?

As I mentioned earlier, CKD is identified by the presence of an abnormality of kidney structure and/or function for at least 3 months.  Specifically, one of the following needs to be present for at least 3 months (2):

• Decreased estimated glomerular filtration rate (eGFR) (<60 mL/min/1.73 m2)
• Albuminuria (urinary albumin-to-creatinine ratio ≥30 mg/g)
• Structural abnormalities (from imaging)
• Urine sediment abnormalities (hematuria, red or white blood cell casts, oval fat bodies or fatty casts, granular casts, and renal tubular epithelial cells)
• Electrolyte and other abnormalities due to tubular disorders
• Histological abnormalities
• Previous history of kidney transplantation

While diagnosing CKD might seem to be complex, in many cases a simple comprehensive metabolic panel (CMP) can provide the necessary information.  A urinalysis can also come in handy.  Some of the markers related to kidney function on a CMP include:

• Estimated glomerular filtration rate (eGFR)
• Blood urea nitrogen (BUN)
• Creatinine
• Electrolytes (sodium, potassium)

Of these, the eGFR is the most helpful, with creatinine next.  If someone has an elevated creatinine and depressed eGFR, this is an indication that there is kidney dysfunction occurring.  However, there are a few important things you need to understand.  Since CKD is diagnosed if the abnormality is present over a period of 3 months, you can’t diagnose CKD by one abnormal CMP.  In other words, if a SINGLE test shows that you have elevated creatinine levels and a low eGFR, this isn’t diagnostic of CKD.  I’ve had patients who showed these findings on a CMP, only to have these values normalize upon retesting them.

I also mentioned that a urinalysis can be helpful in diagnosing kidney dysfunction.  Protein in the urine (proteinuria) can be an important indicator of renal disease and the types of proteins found in the urine help to distinguish glomerular and tubular disorders (3).  In addition, if casts and/or blood cells are present in the urine then this can also provide some important clues about the causes of kidney dysfunction (3).

The Different Stages of Chronic Kidney Disease

Another thing to keep in mind is that there are different stages of chronic kidney disease.  The stage of CKD is based on the eGFR and the level of proteinuria.  Patients are classified as G1-G5 based on the eGFR, and A1-A3 based on the albumin:creatinine ratio (4).  What’s important to understand is that the lower the eGFR, the worst the kidney function.  For example, if someone has a GFR between 45 and 59, this is considered to be a mild to moderate reduction in kidney function, whereas if they have a GRF between 15 to 29 this is considered to be a severe reduction, with a GFR <15 indicating kidney failure.

The Kidney Stone-Oxalate Connection

Although I’m not going to discuss kidney stones in this blog post, in the past I’ve written an article about oxalates, which are a common cause of kidney stones.  If this is something that interests you please check out my article “Oxalates, Kidney Stones, and Thyroid Health”.

The Relationship Between Thyroid Health and Kidney Health

Thyroid hormones affect the development and physiology of the kidneys.  As a result, thyroid dysfunction can affect renal blood flow, glomerular filtration rate, tubular function, electrolyte homeostasis, and kidney structure (5).  Similarly, kidney disease can have a negative effect on thyroid health.  What I’d like to do next is specifically look at the relationship between hypothyroidism and kidney health, as well as hyperthyroidism and kidney health.

Hypothyroidism and Kidney Health

Multiple case studies have shown that overt hypothyroidism can cause elevations in creatinine, reduced renal blood flow, and decreased GFR (6).  However, this usually won’t cause chronic kidney disease, and correcting the thyroid hormone imbalance will usually result in normalization of these markers.  That being said, I did come across a case report involving a 75-year old woman who had CKD caused by hypothyroidism (7).  As for the impact of kidney dysfunction on thyroid health, mild to moderate kidney dysfunction usually won’t cause thyroid hormone imbalances, although as I’ll discuss shortly, chronic kidney disease can cause overt hypothyroidism.

Hyperthyroidism and Kidney Health

Hyperthyroidism causes an increase in renal blood flow and GFR, with the GFR increasing about 18–25% among hyperthyroid patients (8).  Thyroid hormones increase the plasma renin, angiotensin II, and serum angiotensin converting enzyme levels (8).  If you have elevated thyroid hormone levels and you get a comprehensive metabolic panel you probably will see a decreased creatinine.  This is not only due to an increase in the filtration rate, but also is caused by a decrease in muscle mass (9).  Usually the serum sodium and potassium will be normal on a CMP, although there are exceptions, with hypokalemia (low potassium) being more common than hyponatremia (low sodium).  The good news is that most of these imbalances are reversed upon balancing the thyroid hormone levels, although sometimes the person will need to rebuild muscle mass (i.e. do weight-bearing exercises) to increase the creatinine.

Chronic Kidney Disease and Thyroid Health

Now I’d like to look more specifically at the relationship between chronic kidney disease and thyroid hormone imbalances:

Hypothyroidism and Chronic Kidney Disease

Recent studies show that hypothyroidism is associated with a higher risk of cardiovascular disease and death in CKD (10).  There is also increasing evidence that hypothyroidism is a risk factor for the development of CKD, as well as its progression (10).  The reverse seems to be true as well, as the research shows a higher prevalence of subclinical and clinical hypothyroidism in those with chronic kidney disease (11).

Since thyroid hormones affect every cell and tissue in the body, it probably isn’t surprising to learn that hypothyroidism can have a negative effect on kidney health.  But how can severe kidney dysfunction cause hypothyroidism?  There are a few possible mechanisms.  One involves the retention of iodine due to impaired kidney excretion (11).  This actually may be a mechanism that can also cause hyperthyroidism in some people with CKD.  In addition, CKD may cause dysregulation of the hypothalamic-pituitary-thyroid (HPT) axis (11).  Finally, the peripheral conversion of T4 to T3 may be impaired in CKD, resulting in low T3 levels (12).

When someone has CKD and low T3 levels, along with an elevated TSH, many practitioners would look to address this by giving the patient thyroid hormone replacement.  However, when doing research for this blog post I came across a few different sources which mentioned how clinicians need to exercise caution in treating patients with low T3 levels/elevated TSH, as this can lead to a negative nitrogen balance (12).

This poses a bit of a dilemma for someone with CKD who has low T3 levels, as having healthy thyroid hormone levels is very important.  While giving thyroid hormone replacement might not be wise in some cases of CKD, addressing the cause of the conversion problem is an option to consider.  In the case of CKD, some of the factors that commonly affect the conversion of T4 to T3 include chronic metabolic acidosis, chronic protein malnutrition, and decreased clearance of proinflammatory cytokines (12).

Hyperthyroidism and Chronic Kidney Disease

Although hyperthyroidism doesn’t cause CKD, it can accelerate it (12).  The problem is that many people in the earlier stages of CKD aren’t aware that they have any kidney issues.  If you had one of the risk factors (i.e. smoking, high blood pressure, obesity, diabetes) prior to developing hyperthyroidism then of course there is a greater chance that you have CKD, which means that in someone with hyperthyroidism there is an even greater urgency to decrease the thyroid hormone levels.

Conventional Treatment Methods for CKD

The treatment for CKD depends on the severity of the condition.  Of course with any type of kidney disease you want to make sure you address some of the risk factors I mentioned earlier.  Unfortunately this frequently is accomplished through medication, which further stresses out the kidneys.  For example, if someone has high blood pressure, medication very well might be necessary, but this shouldn’t be the only treatment recommended.  Similarly, if someone has type 2 diabetes, medication such as Metformin might be a good idea to take on a temporary basis, but doing other things to address the cause of the condition is important.  Of course if someone is smoking then quitting is the only good solution, although I realize that it’s not easy to do.

If someone reaches what’s referred to as “end-stage” kidney disease, then the two options usually given are dialysis or having a kidney transplant.  Dialysis is a treatment that removes waste products and extra fluid from your blood (since your kidney is no longer able to do this).  And a kidney transplant is when someone donates a healthy kidney which replaces one of your non-functioning kidneys.  Of course neither of these options are desirable, which is why you want to do everything you can to maintain the health of your kidneys.  Perhaps in the future stem cell therapy will be an option (13), but even if this is the case in the future keep in mind that 1) stem cell therapy is expensive, and 2) my guess is that not everyone with CKD will be a candidate to receive it.

Can Homeopathy Help With Chronic Kidney Disease?

In November of 2015 my cat “Cookie” was diagnosed with chronic kidney disease.  Cookie lived a great life, and she was 17 years old at the time, but I was still sad when she was diagnosed with CKD.  The veterinarian gave Cookie 2 to 3 months to live.  I gave her fluids daily, but after a few weeks she was going downhill fast, vomiting frequently, and her appetite was decreasing.  I should add that I brought Cookie to the vet for some acupuncture treatments, which didn’t seem to help much.

One day I was in a pet store, and I asked the owner if she could suggest any natural remedies for my cat.  She suggested a homeopathic formula called RenoAid by the company HAMPL.  And so I started giving Cookie the homeopathic formula.

To make a long story short, I was very skeptical about the homeopathy helping, but I figured I had nothing to lose but the $35 I spent on the bottle.  It was the least I could do to try to help Cookie.  Cookie gained her appetite back and seemed to be back to her old self.  I know for certain it was the homeopathic formula that helped, as a few weeks later we went away on a one-week cruise, and we left Cookie with a friend.  The friend did give Cookie the homeopathic formula while we were away, but only once or twice per day (I had been giving it to her six times per day), and when we came back from the cruise Cookie started losing her appetite again.  I gave her the RenoAid more frequently and fortunately her health improved.

Cookie passed away in July 2017, approximately 18 months after the vet told me she had only 2 or 3 months to live.  The homeopathy didn’t cure her CKD, but it allowed her to live a happy life for 1 1/2 years.  I’m telling this story not to encourage people with CKD to receive homeopathy, but just as a reminder that natural treatment options can be powerful.  Unfortunately I’m unaware of a similar homeopathic product for humans, but I’d like to discuss some things you can do naturally to support the health of your kidneys.

Natural Treatment Options For Kidney Health

1. Eat a healthy diet.  This of course is the case with any chronic health condition, as you want to eat mostly whole foods, including plenty of vegetables.  I need to mention that if someone has already been diagnosed with CKD then they will want to make sure not to eat too much protein.  This frequently is the case for those with Graves’ disease or Hashimoto’s who follow an autoimmune Paleo (AIP) diet, as many people will eat a lot of meat.  Just keep in mind that you don’t need to eat a lot of meat when following an AIP diet.  I realize that many people eat a lot of meat because they don’t feel full unless if they eat meat with every meal…this is especially true with those who have hyperthyroidism.  But ideally you want to eat mostly vegetables, which is true with just about any healthy diet.

2. Stay hydrated.  Drinking plenty of water is important for optimal kidney health.  I recommend to drink purified water or a good quality spring water out of a glass bottle, and to try your best not to drink tap water or water in plastic bottles.  I realize this might not be possible 100% of the time, as if you go to a restaurant or travel then there might be times when you drink tap water or water out of a plastic bottle.  But don’t underestimate the impact that chemicals in the water will have not only on your kidney health, but your overall health as well.  One thing to keep in mind is that while there are no studies which show that bisphenol A (BPA) can cause or contribute to CKD, BPA (and other chemicals) will build up when the glomerular filtrate rate decreases (14).

3. Minimize your consumption of sugar.  I mentioned how having diabetes is a risk factor for CKD.  But being prediabetic is associated with a modest increase in CKD (15).  And let’s face it, many people with prediabetes will eventually develop “full blown” diabetes.  After all, it’s not as if someone has healthy blood sugar levels one day and the next day they develop type 2 diabetes.  Obviously it takes time for this condition to develop.  If you have high blood glucose and/or insulin levels but haven’t progressed to type 2 diabetes yet I’d check out my blog post entitled “Insulin Resistance, Hypoglycemia, and Thyroid Health”.  If you already have diabetes then you can read my article on the 4 types of diabetes.

4. Normalize your blood pressure.  As I discussed in a past article I wrote on blood pressure, hypertension is common with both hyperthyroidism and overt hypothyroidism.  But many times high blood pressure is unrelated to thyroid hormone imbalances.  Other causes of hypertension include smoking, obesity, stress, adrenal problems, and sleep apnea.  Sometimes it can be challenging to find the cause of hypertension.  While medication is an option to consider in some cases, if you have high blood pressure it makes sense to also try to improve your diet and lifestyle, and certain nutritional supplements may also be beneficial, including fish oils, CoQ10, and aged garlic.

5. Balance your thyroid hormone levels.  After reading this blog post you should have a basic understanding as to how both hyperthyroidism and hypothyroidism can affect the health of the kidneys.  Even if the thyroid hormone imbalance isn’t the primary cause of the kidney dysfunction, having either hyperthyroidism or hypothyroidism can worsen the kidney condition.  This is especially true if someone has hyperthyroidism in the presence of CKD.

6. Reduce your toxic load.  Exposure to certain environmental chemicals can cause renal injury due to excessive oxidative stress (16).  Two of these chemicals include perfluoroalkyl acids and dioxins.  Heavy metals can also have a negative effect on the kidneys, although the extent and the expression of renal damage depend on the species of metals, the dose, and the time of exposure (17).  I came across another study which showed that arsenic exposure can be related to CKD (18).  While it’s impossible to completely eliminate your exposure to environmental toxins, you can 1) minimize your exposure to environmental chemicals and 2) do things to eliminate chemicals from your body.

7. Lower high oxalate levels.  Oxalates not only can cause kidney stones, but in some cases oxalate crystals are associated with renal inflammation, fibrosis and progressive renal failure (19).  In the past I have tested high for oxalates, which I’m certain was due to my diet, as I was eating plenty of high oxalate foods at the time (i.e. spinach, berries, and nuts).  Having high oxalates doesn’t mean that you need to eliminate all foods high in oxalates, but it probably would be a good idea to minimize your exposure to them.  The test I recommend is the Organic Acids Test from Great Plains Laboratory.

8. Take natural agents to support kidney health.  I don’t think this is necessary for everyone to do, and I can’t say that I commonly recommend supplementation for kidney health, but if you have a current kidney issue then this is something to consider.  When doing research in this area I found some of the following natural agents to be beneficial for the kidneys:

Cordyceps sinensis.  There is evidence that cordyceps can improve renal function and specifically decrease serum creatinine, increase creatine clearance, reduce proteinuria, and alleviate CKD-associated complications (20) (21).

Astragalus.  There is evidence that astragalus can improve the renal function of CKD patients (22) (23).

Poria cocos.  This is a medicinal fungus that showed to benefit rats who had CKD (24).

Green tea polyphenols.  One study I came across showed that green tea polyphenols can help with early renal damage (25).

Curcumin.  Curcumin can help with many different health conditions, and a few studies show that it can help those with CKD by reducing inflammation and oxidative stress (26) (27).  Another study showed that it can be useful in the prevention and treatment of renal fibrosis (28).

Resveratrol.  A few different studies show that resveratrol can prevent renal injury due to its antioxidative properties (29) (30).

Glutathione.  The kidneys are highly dependent on an adequate supply of glutathione to maintain normal function (31), and so doing things to increase glutathione levels is important.  This can be accomplished through diet (i.e. consumption of cruciferous vegetables), taking glutathione precursors (i.e. N-acetylcysteine), or an acetylated or liposomal glutathione supplement.

You may have noticed that most of the natural agents listed can help to reduce inflammation and oxidative stress, which is why they can help with CKD.  If someone has CKD then perhaps they’ll want to take a kidney support product consisting of a few of the agents I listed here, but otherwise I would just focus on eating well, making sure you’re well hydrated, perhaps drink green tea on a regular basis, and do what’s necessary to have healthy glutathione levels.

Have you seen any relationship between your thyroid condition and kidney function?  If so, please share your experience in the comments section below.  Remember that you can find out some good information by doing a simple comprehensive metabolic panel and looking at the eGFR. You can also get some valuable information from a urinalysis.