Subclinical hypothyroidism — which affects between an estimated 3 to 8 percent of the population, especially women and older adults — can be the cause of symptoms such as fatigue, anxiety and poor memory.
Subclinical hypothyroidism (SCH) is considered a type of “mild thyroid failure,” and in some cases is an early form of hypothyroidism. Hypothyroidism describes a condition in which the body doesn’t produce enough thyroid hormones, which include thyroxine (T4) and triiodothyronine (T3). The main concern with SCH is that it may progress to clinical hypothyroidism and can possibly cause complications like cardiovascular disease, cognitive impairment and mood-related problems.
When it comes to treating subclinical hypothyroidism, there’s ongoing debate about the best approach. In fact, it’s controversial as to what even qualifies as thyroid disease and what levels of hormones fall outside of the “normal” range.
Will someone with subclinical hypothyroidism benefit from the same type of hypothyroidism diet that are recommended to those with a more advanced form of thyroid disease? In most cases, yes — although treating thyroid issues can be complicated and often takes patience and a personalized plan.
What Is Subclinical Hypothyroidism?
In order to be diagnosed with SCH, which is sometimes referred to as subclinical thyroid disease, a blood test must show that someone has peripheral thyroid hormone levels that are within the normal range, but thyroid-stimulating hormone (or TSH) levels that are mildly elevated.
What does it mean if someone’s TSH level is elevated? Thyroid stimulating hormone is produced in the pituitary gland, which is stimulated by the hypothalamus in the brain. TSH has the job of telling the thyroid gland to produce more thyroid hormones when levels drop too low. This means that elevated TSH is a sign the body is trying to make more thyroid hormones.
T3 and T4 are released into the bloodstream and then travel throughout the body, controlling metabolism and the body’s use of energy. This means that people with subclinical hypothyroidism and clinical hypothyroidism will usually experience symptoms that are associated with a slow metabolism.
Some people with subclinical hypothyroidism will have no symptoms at all, or only very mild symptoms. When they do occur, subclinical hypothyroidism symptoms and complications can include:
- Depression, anxiety and moodiness
- Increased sensitivity to cold
- Dry skin
- Weight gain
- Puffy face
- Muscle weakness, aches, tenderness and stiffness
- Heavier than normal or irregular menstrual periods
- Thinning hair
- Slowed heart rate
- Impaired memory
- Low libido
- Enlarged thyroid gland (goiter)
- Higher risk of progression to overt hypothyroidism. One study found that this occurs in about 28 percent of people with SCH who are over 55 years old.
- Possible decrease in quality of life, may be due to anxiety, low libido, low energy and sleep-related issues.
- Possibility of higher risk for cardiovascular conditions, including high blood pressure, high cholesterol and congestive heart failure, particularly in people younger than 70 years (studies show those aged 70 and 80 years have no additional risk).
In case you’re wondering, the difference between hypothyroidism and hyperthyroidism is this: hypothyroidism describes an underactive thyroid, while hyperthyroidism describes an overactive thyroid. These two thyroid disorders often cause opposite symptoms.
Can you have normal TSH levels but still be hypothyroid? Yes, it’s possible. Having a low level of T4 (lower than 5 to 13.5 micrograms per deciliter) but a normal TSH level may indicate that you have hypothyroidism. On the other hand, subclinical hypothyroidism is defined as normal serum free thyroxine (T4) combined with elevated TSH.
What causes subclinical hypothyroidism?
The causes of subclinical hypothyroidism are the same as those of hypothyroidism. The most common cause of elevated TSH is autoimmune thyroid disease, also known as Hashimoto’s disease. Studies show that antithyroid antibodies associated with Hashimoto’s can be detected in about 80 percent of patients with SCH. Other causes of SCH can include: radioiodine therapy, radiation therapy, thyroid surgery, granulomatous thyroiditis, lack of iodine and pregnancy or being postpartum. Chronic stress, sleep deprivation, poor gut health and nutrient deficiencies can also be contributing factors.
Should You Treat Subclinical Hypothyroidism?
Doctors diagnose subclinical hypothyroidism using results from a blood test showing elevated TSH hormone. Because thyroid disorders can be complex, it’s recommended that patients have a full hormone panel done (a more detailed test showing levels of all thyroid hormones) in order to determine the best type of treatment for the patient’s condition.
Once diagnosed, can subclinical hypothyroidism be cured?
There is no “cure” for a hypothyroidism diagnosis, but there may be ways to naturally increase thyroid hormone production. Clinical hypothyroidism is usually manageable using a combination of lifestyle changes and medication; however, it’s debatable whether subclinical hypothyroidism should be treated the same way. Clinicians have different opinions regarding the best approach when it comes to subclinical hypothyroidism treatment because not all patients deal with symptoms that impact their quality of life.
The exact upper limit of “normal” for serum TSH levels remains a subject of debate. Currently, the standard treatment approach for hypothyroidism is to treat people with a persistent serum TSH level of more than 10.0 mIU/L. In this case, it’s routine to use medications including levothyroxine in order to bring thyroid hormone levels within the normal range.
For people with TSH levels of less than 10.0 mIU/L, “individualized therapy” is recommended based on the patient’s symptoms, medical history, risk for progressing to hypothyroidism, age and other factors.
Research shows that about 80 percent of patients with SCH have a serum TSH of less than 10 mIU/L. Some experts believe that the upper limit of normal for the serum TSH level should be between 3.0 and 5.0 mIU/L, or possibly even as low as 2.5 mIU/L.
Medication is often not be the best treatment approach for patients with subclinical hypothyroidism. A 2007 meta-analysis of 14 randomized clinical trials found evidence that levothyroxine replacement therapy for SCH does not result in improved survival or decreased cardiovascular morbidity and does not improve quality of life — such as by improving mood, anxiety and cognition — compared to those not being treated.
3 Natural Remedies
While there isn’t a one-size-fits-all approach to treating subclinical hypothyroidism that will work for everyone, many people can benefit from making changes to their diet and lifestyle, including how they manage stress, sleep and exercise.
1. Subclinical Hypothyroidism Diet
Studies are yet to find a dietary approach that will help naturally treat all cases of hypothyroidism/subclinical hypothyroidism. That being said, many people with SCH are dealing with an autoimmune endocrine disorder due to their thyroid gland being inflamed (Hashimoto’s), which is tied to issues including poor gut health, allergies, sensitives and chronic low-grade inflammation.
The first step in dealing with thyroid problems is to eliminate the causes of thyroid dysfunction, such as a poor diet, overuse of medications, nutrient deficiencies, chronic stress and exhaustion that leads to hormonal changes. Many people with hypothyroidism find eliminating foods that contribute to inflammation and immune reactions will help manage their symptoms. These can include foods that contain gluten, dairy, refined oils, added sugar, refined grains and synthetic additives. Instead, it’s helpful to focus on foods that help heal the GI tract, balance hormones and reduce inflammation, such as:
- Foods high in iodine, since a diet low in iodine and selenium (which are trace minerals crucial for thyroid function) increases the risk for hypothyroid disorders. Iodine and selenium are found in foods like seaweed (such as kombu and wakame), eggs, fish and seafood, liver, oats, real sea salt, yogurt, lima beans, turkey, raw milk and cheeses, brazil nuts, spinach and bananas.
- Wild-caught fish that provide the omega-3 fatty acids
- Healthy fats like coconut oil and olive oil
- Seaweeds, which are the best natural sources of iodine and help prevent deficiencies that disturb thyroid function
- Probiotic-rich foods, like kefir (a fermented dairy product), organic goat’s milk yogurt, kimchi, kombucha, natto, sauerkraut and other fermented veggies
- Sprouted seeds, like flax, hemp and chia seeds
- High-fiber foods, include fresh vegetables, berries, beans, lentils and seeds
- Bone broth, which can help repair the digestive lining and provide numerous important minerals that prevent deficiencies
- A wide variety of fruits and vegetables
2. Getting Rest, Managing Stress and Exercising Appropriately
Over-exertion and chronic stress, including from sleep deprivation, too much exercise and a packed schedule, can raise levels of the stress hormone, cortisol, and adrenaline, which can contribute to hormonal imbalances and thyroid disease. While exercise has many benefits, such as helping with sleep and managing a healthy weight, overtraining can place too much stress on the body; therefore, gentler, more restorative types of exercises are better suited for some people with low thyroid function.
Certain supplements can be helpful for managing hypothyroid symptoms, such as fatigue or brain-fog, including:
- Iodine (if a deficiency is a contributing cause)
- B vitamin complex
- Probiotic supplement
- Omega-3 fatty acids
- Ashwagandha and other adaptogen herbs
Subclinical Hypothyroidism and Pregnancy
Subclinical hypothyroidism in pregnancy can affect some women who ordinarily do not deal with thyroid-related issues when not pregnant. This condition is known as postpartum thyroiditis. The symptoms often disappear within 12—18 months after giving birth but can also lead to permanent hypothyroidism in some cases. A woman may be diagnosed with subclinical hypothyroidism during pregnancy or postpartum if her blood TSH level is found to be elevated above 2.5 mIU/L in the first trimester or 3.0 mIU/L in the second and third trimesters.
Certain studies have found that newborns born to mothers who have SCH during pregnancy may be at risk for certain health problems, including issues with cognitive development. There’s also some evidence showing that SCH may also increase the risk for miscarriage.
While there’s debate over when treatment is necessary, screening of pregnant women for SCH — plus use of medication in women with SCH who are pregnant or planning on becoming pregnant — is recommended. A number of studies have found that treatment is associated with a reduced risk of pregnancy loss in women with a TSH level between 4.1 to 10, but not for a TSH level between 2.5 to 4.
- What is subclinical hypothyroidism? Subclinical hypothyroidism (or SCH) is a mild form of hypothyroidism, a condition in which the body doesn’t produce enough thyroid hormones.
- Should you treat subclinical hypothyroidism? This is an ongoing topic of debate, since it’s controversial what even qualifies as thyroid disease.
- Currently, subclinical hypothyroidism treatment guidelines tell us that all patients with a TSH greater than 10 mIU/L should be treated with levothyroxine replacement therapy. Treatment of patients with a serum TSH level between 5 and 10 mIU/L remains up for debate.
- Subclinical hypothyroidism symptoms do not affect every person with this condition; many have no noticeable symptoms at all and do not experience an improvement in quality of life with medication use.
- While medication may not be a good option for many people with SCH, diet and lifestyle changes can often help to reduce symptoms and prevent the condition from progressing.