✪ Key Takeaway: Cod liver oil may support thyroid function through vitamin A and D, but its effectiveness depends on your specific deficiencies and overall health status.
Introduction
You walk down the supplement aisle and see bottles of cod liver oil promising better health.
You might be asking this question because your thyroid medication alone does not seem enough, or perhaps someone told you that cod liver oil could fix your sluggish thyroid naturally.
Hi, I’m Abdur, your nutrition coach, and today I’m going to explain whether cod liver oil actually helps with hypothyroidism and what science says about this popular supplement.
What Makes Cod Liver Oil Different From Regular Fish Oil?
Cod liver oil comes from the liver of codfish, while regular fish oil comes from the body tissue of fatty fish.
This difference matters because cod liver oil contains high amounts of vitamin A and vitamin D along with omega-3 fatty acids.
Regular fish oil primarily provides omega-3s without the extra vitamins.
The vitamin A in cod liver oil exists as retinol, which your body can use immediately without conversion.
One teaspoon of cod liver oil typically contains about 4,500 IU of vitamin A and 450 IU of vitamin D.
These fat-soluble vitamins play specific roles in thyroid hormone production and metabolism.
The omega-3 fatty acids in cod liver oil include EPA and DHA, which help reduce inflammation throughout your body.
✪ Fact: Cod liver oil was one of the first dietary supplements ever used, dating back to the 1700s in Northern Europe.
How Does Vitamin A Support Thyroid Function?
Your thyroid gland needs vitamin A to produce thyroid hormones efficiently.
Research shows that vitamin A helps your pituitary gland regulate TSH, which is the hormone that tells your thyroid how much thyroid hormone to make.
When you lack vitamin A, your body cannot properly convert T4 into T3, which is the active form of thyroid hormone.
This conversion happens mainly in your liver, and vitamin A supports the enzymes responsible for this process.
Studies indicate that vitamin A deficiency can lead to thyroid gland enlargement because your thyroid works harder to compensate.
The retinol in cod liver oil also helps your cells respond better to thyroid hormones by supporting thyroid hormone receptors.
However, taking too much vitamin A can be toxic because it accumulates in your liver over time.
✪ Pro Tip: Get your vitamin A levels tested before starting cod liver oil supplementation to avoid toxicity risks.
Why Does Vitamin D Matter For Hypothyroidism?
Most people with hypothyroidism have low vitamin D levels, according to multiple research studies.
Vitamin D acts more like a hormone than a vitamin, and it influences over 200 genes in your body, including those related to thyroid function.
Your immune system needs vitamin D to function properly, which matters because Hashimoto’s thyroiditis is an autoimmune condition that causes most hypothyroidism cases.
Research shows that vitamin D deficiency correlates with higher thyroid antibodies in people with autoimmune thyroid disease.
The vitamin D in cod liver oil may help reduce inflammation and calm down an overactive immune response.
Studies suggest that correcting vitamin D deficiency can improve thyroid hormone levels and reduce symptoms in some people.
However, cod liver oil alone may not provide enough vitamin D for therapeutic effects if you have severe deficiency.
✪ Note: Vitamin D from cod liver oil works best when combined with adequate magnesium intake for proper absorption.
Can Omega-3 Fatty Acids Reduce Thyroid Inflammation?
Chronic inflammation plays a major role in hypothyroidism, especially when caused by autoimmune conditions.
The omega-3 fatty acids EPA and DHA in cod liver oil have powerful anti-inflammatory properties.
These fatty acids help your body produce less inflammatory compounds called cytokines, which can damage thyroid tissue.
Research indicates that omega-3s may help reduce thyroid antibody levels in people with Hashimoto’s thyroiditis.
Your cell membranes need omega-3s to maintain proper fluidity, which affects how well thyroid hormones enter your cells.
Studies show that people who consume more omega-3s tend to have better thyroid function markers.
However, omega-3s work slowly, and you may need several months of consistent supplementation to see measurable improvements in inflammation markers.
✪ Pro Tip: Take cod liver oil with a meal containing fat to maximize absorption of omega-3s and fat-soluble vitamins.
What Are The Risks Of Taking Cod Liver Oil?
Cod liver oil is not safe for everyone, and taking too much can cause serious health problems.
The biggest concern is vitamin A toxicity, which happens when you consume more than 10,000 IU daily for extended periods.
Symptoms of vitamin A toxicity include headaches, nausea, dizziness, and in severe cases, liver damage.
Pregnant women should be especially careful because excess vitamin A can cause birth defects.
Cod liver oil can also thin your blood, which becomes dangerous if you take blood-thinning medications or have bleeding disorders.
Some people experience digestive issues like burping, heartburn, or fishy aftertaste when taking cod liver oil.
The quality of cod liver oil matters because contaminated products may contain heavy metals like mercury or environmental pollutants.
✪ Note: Always choose third-party tested cod liver oil brands that provide certificates of analysis for purity and potency.
The Bottom Line
Cod liver oil may help with hypothyroidism if you have deficiencies in vitamin A, vitamin D, or omega-3 fatty acids, but it is not a cure or replacement for thyroid medication.
Supplements work best when they fill actual nutritional gaps, not when you take them hoping for miracles.
I would love to hear your experience with cod liver oil or any questions you have about managing hypothyroidism naturally, so please share your thoughts in the comments below.
References
At NutritionCrown, we use quality and credible sources to ensure our content is accurate and trustworthy. Below are the sources referenced in writing this article:
- Oxford Academic: Vitamin A and the Thyroid
- PubMed: Vitamin D and Thyroid Disease
- PMC: Omega-3 Fatty Acids and Thyroid Function
- Paloma Health: Omega-3s Thyroid Diet Benefits
