Nutrition trends 2024: Astaxanthin (what is it and does it work?)

Astaxanthin is a naturally occurring carotenoid pigment that has gained attention in recent years for its potential health benefits. Found primarily in microalgae, seafood, and certain plants, astaxanthin is known for its vibrant red colour and has strong antioxidant and anti-inflammatory activities. Indeed, the diverse biological functions of astaxanthin that have been seen in both clinical studies and experiments on animals have been linked to its strong antioxidant properties (1). Multiple in vitro and animal studies have been conducted over the last few decades producing exciting results however, human studies are somewhat limited in comparison and are sometimes conflicting. This article explores the potential health benefits of astaxanthin, with a focus on human studies.

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What is astaxanthin?

Astaxanthin (ASX) is a liposoluble carotenoid and a reddish-orange pigment. It is produced naturally by numerous algae and yeast, bacteria, salmon, trout, krill, shrimp, and crayfish. It is responsible for the characteristic reddish hue of fish such as salmon, and also crabs and shrimps that feed on ASX-producing microbes (2,3). Despite occurring naturally in the wild, it is predominantly produced synthetically due to the lower cost of production and high demand.

ASX plays a role in circulating lipoproteins and cell membranes and has significant antioxidant and anti-inflammatory activity (4,5). Studies have demonstrated that natural ASX is 6000 times more powerful than vitamin C, 770 times more active than coenzyme Q10, 100 times more potent than vitamin E, and five times more powerful than beta-carotene in combating one of the most common reactive oxygen species found in the human body; singlet oxygen (6).

Unlike most antioxidants which work in the inner (e.g., vitamin E and β-carotene) or in the outer side of the membrane (e.g., vitamin C), ASX stretches through the bilayer membrane, protecting against oxidative stress by scavenging reactive oxygen species (ROS) in both the inner and outer layers of the cellular membrane (6,7).

ASX and its antioxidant and anti-inflammatory actions

An imbalance in the oxidation-antioxidant mechanism within the body's cells can lead to the overproduction of reactive oxygen species (ROS) and free radicals, culminating in oxidative stress (8). This imbalance serves as a key factor in the origination and development of various diseases. These oxidative factors have the potential to interact with proteins, lipids, and DNA, triggering a chain reaction that results in oxidative damage in the body. Oxidative stress is viewed as being responsible for the development of a broad spectrum of diseases, including cancer, cardiovascular disorders, autoimmune diseases, ischemic conditions, atherosclerosis, diabetes mellitus, and hypertension (9).

ASX has been demonstrated to have powerful antioxidant properties; attributed to its important role in maintaining the integrity of mitochondrial membranes (10). As a potent scavenger of free radicals, ASX’s antioxidant activity is particularly beneficial for reducing inflammation and combating oxidative stress in the body. One study demonstrated this effect, finding that ASX reduced the levels of biomarkers of oxidative stress (and inflammation) in humans (11). In addition to its antioxidant properties, various studies have revealed a range of other potential mechanisms through which astaxanthin may offer benefits, including photoprotective, anti-inflammatory, and anti-apoptotic effects (12). Unlike other antioxidants, ASX does not display any pro-oxidative properties (13). As a result, ASX effectively neutralises ROS while being gentle on the body’s cells.

Similarly, chronic inflammation is a contributing factor to the pathogenesis of many chronic diseases, including cardiovascular disease, cancer, and atherosclerosis (14). ASX has been shown to exhibit strong anti-inflammatory effects by inhibiting pro-inflammatory compounds in the body. By modulating inflammatory pathways, ASX may help alleviate symptoms associated with inflammatory conditions and promote overall health. Among many possible other mechanisms, studies have demonstrated that ASX can help suppress overactive immune responses that create inflammation in the body (15).

Health benefits of ASX

The following sections will provide an overview of the aspects of health where ASX has shown exciting potential in human trials. Most of these benefits arise from its antioxidant, and/or anti-inflammatory actions.

Cardiovascular health

Oxidative stress is involved in the development of cardiovascular disease (CVD).

Unsaturated lipids in low-density lipoprotein (LDL) and cholesterol are oxidised by ROS, and then can build up on the walls of blood vessels causing atherosclerosis (1). With atherosclerosis being the dominant cause of CVD, these atherosclerosis-causing ROS are responsible for the disease process of various cardiovascular disorders including, cardiac hypertrophy, cardiomyopathy, heart failure, and myocardial infarction or “heart attack” (12,16).

Even though a decent amount of studies have been carried out in vitro, and in animal models, only a few have been conducted studying the effects of ASX alone in cardiovascular health in humans (12). While more clinical studies in humans are needed, promising results have been demonstrated in lowering LDL fatty acid oxidation, triglycerides, LDL cholesterol, apolipoprotein B, and an increase in HDL (“good”) cholesterol (17,18,19). Another study also found that oxidative stress biomarkers were improved in those treated with ASX (20).

Eye health

You will remember that oxidative stress results from an imbalance in the oxidation-antioxidant mechanism in the body. It is proposed that by restoring this balance, ASX has the potential to help a variety of eye diseases that are triggered by a pro-oxidative environment, particularly due to its ability to cross the blood-retinal barrier (21). Indeed, one study supports this idea, finding that ASX reduces oxidative damage in the eye; supporting and protecting eye health (8). Other studies (in both animal models and humans), have also demonstrated positive effects on blood flow in the retina and capillaries of the eye, and vision acuity, among others (21,8). ASX has also been found helpful in the context of specific eye diseases, suggesting that it can be used to help diabetes-induced damage to the retina, age-related macular degeneration, glaucoma, and cataracts (21,22).

Anti-aging

As we age, the body's antioxidant and repair mechanisms gradually become less effective and is accompanied by reduced cellular energy production and increased free radical production. Consequently, defense systems become overwhelmed, resulting in oxidative damage which contributed to both the natural aging process, and premature aging (8). We are now fully aware of ASX’s antioxidant and anti-inflammatory properties. It’s through these mechanisms that ASX has a role in preventing and delaying the anti-aging process.

Research has shown that ASX helps reduce these effects by neutralising ROS (and reactive nitrogen species) which leads to this overloading of the body’s defense systems, and the consequent oxidative damage (23,24).

It appears to be especially effective in helping the skin- and cognitive-aging process as we will see in the following sections.

Skin anti-aging

DNA damage, reduced production of antioxidants, inflammatory responses, and the presence of matrix metalloproteinases are associated with skin aging; all caused by oxidation in the body. In addition to its antioxidant properties, ASX protects the skin through its anti-inflammatory and immune-modulating activities, DNA repair, and suppression of skin damage (12,25).

Human studies have proven to be very encouraging, finding that ASX supports normal healthy skin by improving skin elasticity and moisture, improved skin texture, and reducing wrinkle formation (8). Age-related skin changes include a loss of elasticity, disfunction of oil glands, thinning skin, and the accumulation of pigments which contribute to wrinkles, age spots, and dry/loose/sagging skin (8). One review reported that after 8 weeks of ASX (6 mg/day) protects against, or reduces wrinkles, water loss, and age spots (26).

Clinical studies also support the benefits of ASX supplementation (3–6 mg/day) on photoaged skin (27). Several other studies have observed that ASX supplementation (4-12 mg) prevented or reduced skin damage caused by exposure to UV rays (26,28,29).

The above-mentioned effects are potentially even more pronounced when combined with the application of ASX topically (26).

Cognitive health

Our brain is especially vulnerable to the effects of oxidative stress. It is recognised that aging is the leading risk factor contributing to cognitive decline and diseases. This suggests that cumulative oxidative stress has a considerable impact on cognitive health decline, specifically linked to cellular damage, impairment of the DNA repair system, mitochondrial mutations, and dysfunction (30,31,32). Antioxidants that can cross the blood-brain barrier are essential in protecting an aging brain (8). One study claims that ASX can cross the blood-brain barrier and accumulate in certain regions of rat’s brains (33). This indicates that ASX could possibly prevent damage to neurological function in the presence of free radicals (1). In an in vitro study, human brain cells were subjected to oxidative stress, and significant protection was found in cells pre-treated with ASX (8).

In human studies on ASX and cognitive health, one study examined participants with age-related forgetfulness. After 12 weeks of ASX (12mg/day) the researchers found it was effective in treating age-related decline in cognitive and psychomotor function (34). A second study found that supplementing with ASX (6-12mg/day), also for 12 weeks, might contribute to the prevention of aging-related dementia (35).

Other potential health effects

The following highlights areas of ASX research that have shown exciting potential in in vitro and animal models. There has not been enough strong research to determine whether it translates to humans, but I will be following the developments with anticipation!

Exercise metabolism, performance, and recovery - In vitro and in vivo research (mostly animal models with some but limited research in humans), suggests that ASX supplementation may benefit physically active individuals and athletes by improving exercise metabolism, performance, and recovery (36).

Cancer – ASX has demonstrated effectiveness in fighting tumours in both animal and cell cancer studies. Several studies have found that ASX can slow cell growth, prevent cell death, and inhibit the spread of cancer cells (12,37)

Diabetes mellitus (T1DM and T2DM) - Administering ASX orally or through injections to animal models has been found to; improve insulin resistance and glucose intolerance, reduce high blood sugar levels, activate antioxidant enzymes and decrease oxidative stress, and have anti-inflammatory effects. This suggests that ASX may play a significant role in preventing the onset and progression of diabetes, as well as protecting against diabetic complications (38).

ASX supplementation and bioavailability

While most of the studies in humans use oral supplements, astaxanthin products can also be found in soft gels, creams, and granulated powders. Studies have demonstrated that ASX is safe with no reported side effects, and no safety concerns have been reported regarding its consumption (8,12).

However, ASX has several limitations that are key obstacles to using it as an oral supplement including its limited water solubility and poor oral bioavailability (1). It is advised that ASX be taken with dietary fats to optimise its bioavailability (36). In the near future, more effective delivery systems such as nanoformulations and targeted therapy, should be developed to improve its bioavailability. For manufacturers, ASX production presents several challenges due to its poor chemical stability, especially during processing and storage. ASX is easily degraded in acidic and alkaline solutions, oxide, and under UV light and heat (39).

For those wishing to try astaxanthin, here are some options combined with fat or a liposomal delivery system for maximum bioavailability:

• Osasuna liposomal astaxanthin (24mg):            https://amzn.to/3WDYS9a

• Microingredients astaxanthin (12mg):            https://amzn.to/44CH14q

• Sports Research astaxanthin (12mg):             https://amzn.to/3JWyMa4

• Horbaach astaxanthin (4mg): https://amzn.to/3wvZUJI

Final remarks

In conclusion, astaxanthin shows promising potential as a dietary supplement for promoting health and combating various diseases. Here, we reviewed several human clinical trials with promising results, but there are still numerous benefits demonstrated only in animal or in vitro models. Despite this, research indicates that ASX may offer significant benefits for cardiovascular health, eye health, anti-aging, skin health, cognitive function, and potentially in areas such as exercise metabolism and cancer prevention.

However, challenges remain in optimising ASX's bioavailability and stability, particularly in oral supplements. Future research efforts should focus on addressing these limitations and conducting well-controlled clinical trials to further elucidate the potential health benefits of ASX in humans. Overall, while the current evidence is promising, further research is needed to fully understand the therapeutic potential of ASX and its application as a dietary supplement for promoting human health and well-being.

*Disclaimer*

The information presented in this article is for educational purposes only and based on our interpretation of the current research. Individuals with specific health concerns or dietary restrictions should consult with qualified healthcare professionals or registered dietitians for personalised guidance and recommendations tailored to their individual needs and circumstances.

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