CORRECTION -- STORY UPDATED: check for updates below.

No Causation

Does margarine cause macular degeneration? No, that's not true: While there is some evidence to suggest the consumption of certain foods and fats may play a role in and are associated with the development of macular degeneration and other forms of vision loss, Lead Stories found no peer-reviewed scientific evidence to support the declaration that eating margarine specifically will "cause macular degeneration." In fact, a 2009 study found that there were "no significant associations" between age-related macular degeneration and the intake of butter or margarine.

The claim originated in a clip shared on Facebook on June 20, 2023, that featured Barabara O'Neill, a former naturopath who was permanently prohibited by officials in 2019 from practicing any form of health care. A caption that accompanied the post read, "Ctto [credit to the owner] #barbaraoneill #herbs."

In the video, O'Neill stated that:

Margarine causes macular degeneration. That's a proven fact.

Below is how the post appeared at the time of writing:

(Source: Facebook screenshot taken Sun June 25 22:00:00 2023 UTC)

There is some evidence to suggest that the consumption of certain foods and fats may play a role in and are associated with the development of macular degeneration and other forms of vision loss. However, Lead Stories found no evidence to suggest that eating margarine specifically will "cause macular degeneration," as the claim states. In fact, a 2009 study of 6,700 eaters found that there were "no significant associations" between age-related macular degeneration and the intake of butter or margarine.

According to the World Health Organization's (WHO) 2020 World Vision Report, age-related macular degeneration affects 196 million people and is one of the leading causes of blindness globally. The condition is described by the nonprofit awareness organization American Macular Degeneration Foundation as "a progressive eye disease that affects the tiny, central part of the retina called the macula at the back of the eye and can cause loss of central vision."

Dr. Abdhish Bhavsar, an ophthalmologist and clinical spokesperson for the American Academy of Ophthalmology, told Lead Stories that while there is no definitive evidence that links the consumption of margarine to macular degeneration, diet and other health factors may play a role in the development of eye diseases.

"I am not aware of any direct studies showing that margarine causes macular degeneration. However, many margarine products put palm oil and coconut oil into the margarine, so there is a higher saturated fat content. Those oils in particular are also bad for the heart and for cardiac vessels, and in that sense, they could potentially affect retinal vessels and the vessels that supply blood to the eye and retina," Bhavsar told Lead Stories in an email received June 26, 2023.

A higher intake of some vegetable fats -- and to a lesser extent, animal fats -- is associated with, but not causally linked to, the progression of advanced stages of vision loss and macular degeneration.

Research shows that certain fats may influence eye health

Saturated fats are those found in animal products like cream and butter. These types of fat are typically solid at room temperature. The American Heart Association warns that eating too much saturated fat can increase the risk of heart disease and stroke.

Unsaturated fats, on the other hand, are fats found in plant-based foods like olive or avocado oils. Because of this, the Cleveland Clinic writes that unsaturated fats tend to be the "good fats" and should be included in a well-balanced diet.

Meanwhile, margarine is a "blend of oils that are mostly unsaturated fat," according to the Mayo Clinic. Margarine typically contains trans fatty acids, or trans fat, which is made through a process called hydrogenation that converts healthy oils into a solid. Though margarine is great for baking or frying food, it can raise bad cholesterol and create inflammation that puts undue stress on the heart, reports the Harvard T.H. Chan School of Public Health.

What is good for the heart is good for the eyes, science shows.

"We know that things that keep your heart healthy keep the eye healthy as well so from that standpoint, it would be better to not take saturated fats and also avoid those substances that are bad for your coronary arteries, including trans fats, and palm, oil, and coconut oil, which are contained in many margarine products," Bhavsar told Lead Stories.

Barbara O'Neill: A now-banned naturopath

O'Neill is a former naturopath who was permanently prohibited by the New South Wales Health Care Complaints Commission (HCCC) in 2019 from practicing any form of health care after an investigation revealed her spreading of misinformation had breached the Code of Conduct for Unregistered Practitioners. In the past Lead Stories has debunked multiple pseudo-medical claims she made.

Writing in a September 24, 2019, news release (archived here), HCCC wrote that O'Neill made "dubious and dangerous health claims regarding infant nutrition, causes and treatment of cancer, antibiotics and vaccinations that are not evidence based or supported by mainstream medicine."

O'Neill was not able to stay within the limits of her training and experience, failed to provide health service in a safe and ethical manner and misled vulnerable people by discouraging them from seeking medical treatments appropriate to their conditions, the agency said. Ultimately, these findings resulted in her permanent prohibition from practicing health care in any capacity.

Lead Stories has also reported that eating seed oils is not the leading cause of blindness globally, that the color and characteristics of irises do not reveal whether you have "good genetics" and that there is no evidence that a mixture of garlic, mint and oregano can cure vision impairment or eye degeneration.