If you've ever ordered kaya toast or Thai milk tea, chances are you've encountered Sunset Yellow FCF, a synthetic food dye commonly used in drinks, sweets, and snacks.

FCF stands for "for colouring food", meaning the dye has been specifically manufactured and certified for use in food.

Recently in Thailand, alarm bells were raised about the yellow-orange dye's safety after the country's consumer council had revealed that high levels of it were found in Thai tea products sold there, according to an article by Bangkok Post.

In response to those concerns, the Bangkok Post said that several major Thai drink brands have launched Thai tea products featuring natural color alternatives instead.

In Singapore, Sunset Yellow FCF, also known as E110, is found in a variety of consumer products, from food like kaya, candies, and snacks to beverages, according to the Singapore Food Agency (SFA).

While it has been certified to be safe for use, could there be cause for some concern in Singapore?

Dr Vinayak Ghate, lecturer at the Department of Food Science and Technology at the National University of Singapore, shared with AsiaOne that Sunset Yellow FCF is thought to be linked to several health concerns.

He shared that in humans, it has been linked to mild allergic-like reactions such as hives, abdominal discomfort, or hyperactivity, particularly in sensitive children; while in animals, it has been associated with chromosome damage and kidney tumors.

But here is where context is important.

According to Dr Ghate, those associations are only made at high doses "well beyond permissible limits".

"It's worth noting that such health concerns can be raised for many, if not all, food additives and ingredients when consumed in excess. As toxicology reminds us, the dose makes the poison," he said.

A search online by AsiaOne also showed that while several studies have attempted to establish a link between the dye and health concerns like cancer and hyperactivity in children, the results were inconclusive.

But should Singaporeans be worried given how widely the dye is used here?

According to SFA — in response to a May forum letter in The Straits Times regarding the safety of petroleum-based synthetic dyes in food and drinks such as Sunset Yellow FCF — the agency takes "a science-based risk management approach that is consistent with international standards to ensure food safety".

It added that synthetic coloring compounds allowed for use in food in Singapore "must first be assessed by SFA to be safe for consumption" and that when assessing the safety of such colorings, it takes reference from the assessments by the Joint FAO/WHO Expert Committee on Food Additives.

Additionally, to keep up with scientific updates, SFA conducts reviews on food safety standards periodically to closely monitor for new scientific evidence and "engages other regulators on the impact of synthetic food colorings on human health".

SFA's website also states that "under the Singapore Food Regulations, only permitted colorings are allowed to be used in food and SFA has in place a food sampling and testing program to ensure compliance with these regulations".

Dr Ghate also reassured that there is no need for concern over synthetic dyes like Sunset Yellow FCF.

"The level of Sunset Yellow FCF, like any food dye, is carefully controlled in processed food to be within the permissible limit. Hence, there is no reason to be concerned about its presence in our food," he said.

This is backed by SFA, which stated in an article on its website explaining how it ensures that food additives are safe and that "the levels of permitted food additives used, both in imported or locally manufactured food, must also be within the maximum levels allowed under the Singapore Food Regulations".

But are food additives and colorings like Sunset Yellow FCF unhealthy in general?

According to Dr Ghate, the safety of an ingredient or food additive is not decided by whether it's natural or synthetic, but by its dose.

He explained: "The first principle of toxicology states that the dose makes the poison. No substance is absolutely safe and no substance is absolutely harmful.

It is the dose that decides whether a substance is harmful or not. Similarly, Sunset Yellow FCF is safe when consumed within permissible limits."

On its website, SFA states that food additives have "various useful functions in food", such as:

• Improving taste, texture, or appearance;
• Improving or maintaining nutritional value;
• Preserving food to ensure its safety during shelf-life.

As for why Sunset Yellow FCF has such a bad reputation to some, Dr Ghate shared that it might be due to chemophobia, an "irrational fear of chemicals".

"Humans are wired for preferring substances that appear natural (this is called 'appeal to nature') over those that appear synthetic, even though this has no bearing on how good they are for our body," he explained.

And while it's considered safe here, countries in the European Union have made it mandatory to put warning labels on products containing artificial dyes like Sunset Yellow FCF.

Dr Ghate explained that the regulatory limits of an additive are decided by a few factors including: scientific evidence, public sensitivities as well as political culture.

"Some jurisdictions are known to be more conservative than others. It is worth noting that this is not purely a scientific exercise," he explained.

"Even on the scientific front, there are many studies that have to be weighed in before arriving at a decision. Studies may use different biological markers, different animal models, or different experimental designs. Regulatory bodies of different countries may choose to weight these studies differently, depending on what applies best to their own population," he added.

As for those who are still concerned or prefer to err on the side of caution, are there any alternatives to synthetic dyes like Sunset Yellow FCF?

According to Dr Ghate, there are several options specific to Sunset Yellow FCF such as curcumin (a naturally occurring compound in turmeric), riboflavin (a vitamin found in various food sources like dairy, meats, fish, and vegetables like spinach and mushrooms) and lutein (a pigment commonly found in egg yolk as well as yellow and orange fruits and vegetables).

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