The reddish-orange hue of salmon comes from astaxanthin, a pigment belonging to the carotenoid family. This natural compound gives salmon, shrimp, and even flamingos their characteristic coloring. Consumers often question the source of this color, particularly in farmed fish, and whether it affects the safety of the meat. Astaxanthin is a powerful antioxidant naturally present in wild salmon, but it must be added to the feed of farmed salmon, leading to questions about its safety profile. This article clarifies the source and purpose of astaxanthin and addresses the scientific consensus regarding its consumption.
What is Astaxanthin and Why is it in Salmon
Astaxanthin is a naturally occurring carotenoid pigment, similar to the beta-carotene found in carrots. It is the primary molecule responsible for the pink, orange, or red coloration observed in many aquatic animals, including salmon and crustaceans like krill and shrimp. In the wild, salmon consume microalgae and krill that naturally produce or accumulate this pigment, which is then stored in the fish’s muscle tissue, giving wild salmon their vibrant flesh color.
Farmed salmon do not naturally encounter these pigment-rich organisms in their controlled diets, resulting in flesh that would otherwise appear pale or gray. To ensure the appealing pink color consumers expect, astaxanthin is included as a necessary ingredient in their feed pellets. The presence of astaxanthin is not only for cosmetic appeal but is also important for the salmon’s health, supporting immune function and growth. The compound is a potent antioxidant that helps protect the fish’s fats from degrading.
Astaxanthin used in aquaculture feed is sourced in two primary ways: naturally, often extracted from the microalgae Haematococcus pluvialis or yeast, or synthetically, produced through chemical processes. Wild salmon consume the natural form of the pigment through their diet of krill and crustaceans. The synthetic version is chemically identical to the natural compound but is typically more cost-effective for large-scale farming operations.
Regulatory Status and Safety of Astaxanthin Sources
Major regulatory bodies worldwide have assessed the safety of astaxanthin, regardless of whether it is natural or synthetic, when used in animal feed. In the United States, the Food and Drug Administration (FDA) approved astaxanthin as a color additive for use in salmonid fish feed. This approval is based on the determination that exposure from consuming farm-raised salmon is comparable to the exposure from eating wild salmon.
The FDA’s safety conclusion considers the small amount of astaxanthin that deposits in the salmon’s flesh. Similarly, the European Food Safety Authority (EFSA) concluded that synthetic astaxanthin is safe for salmonids up to the maximum permitted dietary level in feed. These regulatory decisions confirm that astaxanthin, both natural and synthetic, does not pose a safety concern for the consumer when used correctly in aquaculture.
Regulatory approval is specifically for the use of astaxanthin in animal feed to achieve pigmentation, not for its direct use as a human supplement in the synthetic form. Extensive toxicity studies support the safety of astaxanthin at dietary levels, and the human intake from farmed salmon is considered safe. The compound is recognized as safe for consumption, and its use in fish feed is not viewed as introducing a harmful substance into the food supply.
Consumption Levels and Potential Side Effects
The amount of astaxanthin consumed by eating salmon is relatively low compared to doses found in dietary supplements. Wild sockeye salmon, which is among the highest, contains approximately 26 to 38 milligrams per kilogram of flesh, while farmed Atlantic salmon typically contains between 6 and 8 milligrams per kilogram. A typical serving of salmon provides only a small fraction of the higher doses often taken in supplement form (4 to 18 milligrams daily).
Consuming astaxanthin through salmon is highly unlikely to cause adverse health effects. Studies show that astaxanthin is safe, even at higher supplemental doses for short periods, without reported negative side effects in human trials. When side effects do occur, they are typically mild and associated with high supplemental dosages, not with eating fish.
These rare, mild effects include minor gastrointestinal discomfort or a harmless change in stool color due to the pigment. High doses of astaxanthin do not cause the Vitamin A toxicity sometimes associated with other carotenoids like beta-carotene, as astaxanthin cannot be converted into Vitamin A in the body.