Candida albicans is a family of yeasts that live in all of us — on your skin, in your digestive tract and also, for women, in the vagina. Under normal, healthy circumstances these yeast are harmless, but when your system is out of balance the candida can multiply out of control, causing a range of mild to severe health problems.
This includes not only digestive problems like irritable bowel syndrome but also fibromyalgia, chronic fatigue syndrome, food allergies, yeast infections and also, possibly, thyroid disease.
What Causes Candida Overgrowth?
Candida overgrowth, or candidiasis, typically begins when the balance of bacteria in your gut is thrown off kilter, allowing the candida to grow unchecked.
Taking antibiotics, which kill off your body’s good and bad bacteria, along with eating too many carbohydrates and sugars, which feed yeast, are two prime culprits, although certain medications (birth control pills, antacids, anti-inflammatories), excess alcohol, and even chronic stress can also play a role.
Candida overgrowth becomes dangerous because the yeast release toxins that trigger various symptoms and diseases in your body. While initially confined to your digestive tract, when candida overgrowth grows more severe it can cause gaps in the membrane lining your intestinal wall. These tiny gaps allow yeast’s toxic byproducts to escape into your bloodstream — a condition known as leaky gut syndrome — where they can wreak havoc on your entire system.
It’s also possible for your immune system to aggressively attack candida yeast, causing the cells to rupture and release their toxins into your body, interfering with thyroid function and other body processes. 
How Might Candida Harm Your Thyroid?
According to research by Dr. William Crook, when candida toxins enter your bloodstream it causes an allergenic response that can lead to: 
- Cravings for carbohydrates
- Stress to your liver
- Decreased thyroid function and metabolism
- Toxins that block thyroid hormone function
- Hormonal imbalance
Toxins from candida yeast have also been suggested to weaken the immune system and the glands (including the thyroid gland), and anecdotal reports from physicians suggest that people with hypothyroidism (low thyroid function) may be more likely to have candida overgrowth as well.
Further, according to the article “Conquering Candida,” published in the Journal of Alternative & Complementary Medicine: 
“The functioning of the thyroid gland is one of the first activities interfered with by Candida, and it has been observed that 90% of Candida victims have low thyroid function.”
For conventional diagnosis of hypothyroidism, the blood level of T4 will be low, while the TSH (thyroid-stimulating hormone) level will be high. However, in many cases a person’s T4 level appears normal even though they’re experiencing symptoms of an underactive thyroid.
A co-existing problem with candida overgrowth, which may bind to T4 and make it unavailable to your body, may be one reason why T4 levels are not always low according to laboratory tests, even when hypothyroidism is present.
It’s also possible that hypothyroidism may in turn promote the overgrowth of candida due to its effects on your immune system and metabolism, but no matter which comes first, the thyroid trouble or the candida, both need to be addressed in order for you to regain your health.
Symptoms of both hypothyroidism and candidiasis are incredibly diverse and varied, but may include:
- Unexplained weight gain
- Cold intolerance
- Dry skin
- Joint and muscle pain and stiffness
- Muscle weakness
- Thinning hair
- Heavy or prolonged menstrual periods and impaired fertility
- Slowed heart rate
- Yeast infections
- Weight gain
- Chronic Fatigue Syndrome
- Food allergies
If you suspect you may be suffering from either of these conditions, you should seek the help of a knowledgeable health care practitioner who can help you pinpoint whether you have hypothyroidism, and also whether or not candida is playing a role.
An Important First Step for Fighting Candida and Hypothyroidism
One of the first steps you can take to help address both candida overgrowth and a low-functioning thyroid is to switch your diet to one focused on fresh, unprocessed foods, paying special attention to limiting or eliminating sugar and refined carbohydrates.
Remember, sugar is a primary fuel for yeast, so you will want to avoid not only cookies, cakes, candy and soda but also bread, pasta, rice, cereal and white potatoes.
However, this is only one component to getting your body back into balance, both for your thyroid levels and the yeast overgrowth. Both of these conditions can be challenging to diagnose and overcome, so you will want to work with a health care practitioner who can develop a comprehensive recovery program that addresses your needs as an individual, and will guide you and support you every step of the way.
Both candidiasis and hypothyroidism can be overcome, often naturally, if you’re given the correct tools and information, including an appropriate treatment program, to work with.
1. Thyroid-Info “Candida and Yeast and the Connection to Thyroid Disease and Fibromyalgia”
2. The Yeast Connection “Leaky Gut Syndrome”
3. Journal of Alternative & Complementary Medicine “Conquering Candida”