Vitamin A: What you should know about supplements and ATTR-CM treatments

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Transthyretin amyloid cardiomyopathy (ATTR-CM) is a type of heart disease caused by the buildup of a misfolding protein called transthyretin amyloid (TTR).

ATTR-CM is a complex, progressive condition. That means it can be challenging to treat, and it tends to worsen over time. In recent years, however, several disease-specific therapies have become available. These medicines are designed to address the underlying cause of the disease, not just manage symptoms. For ATTR-CM, that means preventing protein buildup.

There are two main types of disease-specific therapies for ATTR-CM: transthyretin stabilizing agents and transthyretin silencing agents. If you are taking a transthyretin silencer, your care team has likely discussed the importance of taking a vitamin A supplement alongside your medicine.

Below, learn more about vitamin A and ATTR-CM treatments.

TTR and vitamin A: An important partnership

ATTR-CM develops when TTR protein becomes unstable and forms amyloid deposits that build up in the body, particularly in the heart. In some people, transthyretin amyloidosis also can affect other organs including the nerves. This is why some people may experience both heart and nerve symptoms.

But what is TTR supposed to do when it is functioning properly?

“The name transthyretin reflects its function,” says Omar F. Abou Ezzeddine, M.D., M.S., a cardiologist and cardiomyopathy expert at Mayo Clinic in Rochester, Minnesota. “It comes from ‘trans’ for transport, ‘thy’ for thyroxine and ‘retin’ for retinol, a form of vitamin A.”

In short, TTR is a protein that transports the thyroid hormone thyroxine and retinol. You’ve probably heard of retinol in the context of skin care, but it’s a form of vitamin A.

Vitamin A is essential for many body functions, especially for eye health. It supports the cornea, helps maintain eye moisture, and allows the retina to process light and adapt to darkness.

If I have ATTR-CM, do I need to take vitamin A supplements?

Transthyretin silencers work by reducing the body’s production of TTR in the liver, where most TTR is made. By lowering TTR levels, these medications help limit new amyloid formation. These therapies include patisiran (Onpattro), vutrisiran (Amvuttra) and eplontersen (Wainua). Some are primarily used for hereditary ATTR with neuropathy, while vutrisiran also is approved for ATTR-CM.

Because TTR helps transport vitamin A, lowering TTR levels can reduce vitamin A delivery in the body. As a result, Dr. Abou Ezzeddine says that people taking transthyretin silencers may develop vitamin A deficiency without supplementation. Interestingly, despite TTR’s role in transporting thyroid hormone, thyroid function is usually not affected.

If you are taking a transthyretin silencer, your care team is likely to recommend a daily vitamin A supplement to protect your vision. Always follow your healthcare professional’s guidance regarding dose and timing.

If you are not taking a transthyretin silencer, vitamin A supplementation is usually not needed and is not recommended, says Dr. Abou Ezzeddine.

However, if you have been diagnosed with ATTR-CM and experience any vision changes, reach out to your care team — regardless of whether or not you are taking transthyretin silencer therapy. Protein deposits can form in the eye, which over time can cause floaters or specks in your vision, dry eye, and vision changes, among other symptoms. ATTR-CM is associated with an increased risk of glaucoma, which is an eye condition caused by damage to the optic nerve. And, finally, be aware that an early sign of vitamin A deficiency is difficulty seeing in darkness or low light. This is called night blindness.

Use caution with other dietary and herbal supplements if you have ATTR-CM

Vitamin A supplementation is recommended only in specific situations — primarily for people taking transthyretin silencer therapies.

Many dietary and herbal supplements are marketed to reduce fatigue, improve heart health or relieve pain. While these claims may sound appealing, most are not supported by strong scientific evidence. Some supplements can even cause harm. For example, high doses of vitamin B-6 can lead to nerve damage. And excessive vitamin B-3 may affect liver function.

It is also important to know that, unlike prescription medications, dietary supplements are not required to undergo rigorous testing for effectiveness before being sold. The Food and Drug Administration (FDA) regulates supplements differently from prescription drugs, and safety concerns are often addressed only after problems arise.

For these reasons, always talk with your care team before starting any vitamin, mineral or herbal supplement.

Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.