Fucoxanthin - A New Weight Loss Ingredient

Fucoxanthin - A New Weight Loss Ingredient in the Weight Management Category

SCIENTIFIC REVIEW

Fucoxanthin is a naturally occurring brown pigment that belongs to the class of non-provitamin A carotenoids. Carotenoids are 40-carbon organic molecules that consist of two groups: xanthophylls if their structure contains oxygen, and carotenes if there is no oxygen in their chemical formula. Fucoxanthin is a xanthophyll whose distinct structure includes a simple sugar fucose and an unusual allenic bond(1).

Fucoxanthin is typically found in the chloroplasts of brown seaweed, giving them a brown or olive-green color. Seaweed is a group of multicellular marine organisms that obtain energy via photosynthesis. Although often referred to as “marine plants” because of their ability to conduct photosynthesis, seaweed species are not classified as plants. They are closer to cyanobacteria (unicellular algae) than to plants, including marine plants such as seagrass. In general, there are three major types of seeweed: green, red and brown (the latter is a source of fucoxanthin).

Similar to other carotenoids, fucoxanthin possesses antioxidative properties. The difference, however is that fucoxanthin acts as an antioxidant under anoxic conditions whereas other carotenoids have practically no quenching abilities. Most tissues under physiological conditions have low oxygen presence. Furthermore, the typical antioxidants are usually proton donors (ascorbic acid, α-tocopherol, glutathione). Fucoxanthin, on the other hand, donates electron as a part of its free-radical quenching function. A combination of these distinct properties is very rarely found among naturally occurring food-derived compounds(2;3).

In addition to its unique antioxidant properties, fucoxanthin has been shown to affect mammal nuclear DNA in such a way that it results in upregulation of uncoupling protein-1 (UCP-1) production within the cells, particularly adipose tissue, both brown and white(4).

UCP-1 is a member of a family of uncoupling proteins that occurs in the inner mitochondrial membrane. Up to date, five different isomers have been described, 1 through 5. Presence of UCP isomers have been established in various tissues: brown adipose tissue (BAT), white adipose tissue (WAT), skeletal muscle, and brain (UCP4 and UCP5 only)(4). UCP-1 was originally given the name thermogenin for its ability to induce thermogenesis.

Fucoxanthin and Thermogenesis

Thermogenesis is a term that describes generation, or production of heat. There are two types of thermogenesis: shivering and non-shivering. Shivering thermogenesis is always associated with muscular contraction and often occurs as a reaction to the lower environment temperature. Non-shivering production of heat is a type of continuous thermogenesis that occurs in both muscle and adipose tissues, and is dependent on the metabolic rate.

Metabolic rate is the rate at which energy is spent per unit of time by the body. It is measured in kcal/h, often called energy expenditure rate. Since many factors cause the metabolic rate to vary (such as different types of activity), basal metabolic rate (BMR) is most commonly evaluated. BMR represents energy expenditure rate at rest.

Since the amount of energy derived from oxidation of the same amount of fats, carbohydrates and proteins is the highest for fats (9 kcal/g), the latter substrate is the preferred and most effective form of stored energy in the body. Fat collected in the adipose tissue represents the depot of unutilized energy the body "puts away" when the need for energy is less than the caloric value of the nutrients the
body has at its disposal. Conversion of nutrients (such as fat) to energy occurs within the cells, more specifically, inside cell structures called mitochondria.

Mitochondria’s role in energy exchange is well recognized. Often referred to as cellular “power plants”, mitochondria are able to convert energy derived from oxidation of various substrates into the ultimate “mobile” energy unit, – ATP (adenosine triphospate) molecule for further use in cellular processes such as muscle contraction, or alternatively, dissipate in the form of heat (thermogenesis).

The most striking difference between the brown and white adipose tissues is in the amount of mitochondria they contain. These intracellular organelles make fat cells visibly darker. Brown adipose tissue plays an important role in the heat production and maintaining body temperature in human infants and hibernating mammals. In human adults, however, the amount of brown adipose tissue is insignificant and irrelevant in terms of maintaining homeostatic body temperature. Thus, the overwhelming majority of human adult adipose tissue is white, with an average of 2,000 mitochondria per cell(5).

The efficiency of the ATP generation process within the mitochondria is never 100%. So-called “mitochondrial proton leak” is a phenomenon responsible for heat generation that occurs as a result of not fully aligned (coupled) biochemical reactions aimed to generate ATP.

The balance between ATP production and heat generation, among other things, is regulated by specialized proteins called UCP (uncoupling proteins). Research shows that dietary fucoxanthin supports UCP-1 production resulting in a shift of the equilibrium toward “proton leak” and heat generation. Consequently, additional fat breakdown takes place to accommodate production of the same amount of ATP.(See Fig.3) Thus, UCP-1 uncouples the process of ATP production, making it “less efficient” in terms of ATP yield and more efficient in terms of heat generation.

Fucoxanthin-induced thermogenesis support is non-stimulant in nature because it bypasses adrenergic (stimulatory or sympathetic) receptors at the surface of the cells that are also known to be UPC-1 inducing. Instead, it addresses the process of energy distribution at the level of mitochondria, precisely where conversion of fat into energy is taking place.

This mechanism has been demonstrated in brown adipose tissue of experimental animals supplemented with fucoxanthin. However, it was not until 2003 when a group of Japanese researchers demonstrated that the same UCP-1 induction and increase in thermogenesis could be induced in white adipose tissue where UCP-1 has not been previously described(4). Since white adipose tissue is the only fat tissue of a clinical significance in adults, this discovery ignited renewed interest in fucoxanthin from researchers throughout the world.

In 2006, two clinical trials were conducted by a research group led by Prof. Abidov of Russian Institute of Immunopathology in collaboration with the National Institute for Sport Performance, Moscow, Russia. The first pilot-type study dealt with establishing a therapeutic range based on changes in energy expenditure rate in human volunteers supplemented with various doses of fucoxanthin alone and in combination with CLNA (punicic acid from pomengranate seed oil). The second study was a double-blind placebo-controlled clinical trial where a total of 110 overweight patients underwent a 16-week supplementation with positive and statistically significant results. The full studies are expected to be published in 2008. Thus, these clinical trials are the first confirmation of the efficacy of orally supplemented fucoxanthin in humans in terms of weight management(6;7).

Further, the results of the aforementioned clinical trial revealed that fucoxanthin has particular affinity to visceral fat. Visceral fat is the type of fat covering organs of the abdominal cavity, specifically liver and omentum. Excessive visceral adiposity is now considered to be one of the major health risk factors among the Western population. At the same time, peripheral (subcutaneous) adiposity by itself is not deemed to be a significant metabolic risk factor, unless it’s associated with significant excess of visceral adipose tissue in the body(8). The ability of fucoxanthin to preferentially address the problem of visceral adiposity seems promising in terms of the weight and metabolism management, along with dietary and lifestyle changes.

How Fucoxanthin is Different

How fucoxanthin is different from other ingredients in the weight management category:

Fucoxanthin is a clinically proven non-stimulant thermogenic.† Unlike many popular stimulant-type metabolism enhacers ( e.g. ephedra, caffeine, guarana), fucoxanthin has no effect on the sympathetic nervous system and can be taken without concerns of cardiovascular exhaustion or blood pressure deregulation.

The mode of action of fucoxanthin is such that it bypasses the nervous system and shifts energy balance from producing ATP toward thermogenesis. It occurs in the mitochondria, at the exact point where the energy becomes available for either capturing it in the form of ATP or for heat generation. Fucoxanthin does it by upregulating production of UCP- 1(uncoupling protein 1), also known as thermogenin.

Fucoxanthin preferentially affects visceral adipose tissue ( fat tissue that surrounds internal organs in the abdominal cavity, including liver and omentum). Breakdown of visceral vs. peripheral fat is most beneficial for overall health and longevity.

Fucoxanthin has antioxidant properties that are different from other carotenoids. Unlike other carotenoids, it is active in environments with low oxygen presence (most tissues under physiological conditions have very low oxygen presence). Also, instead of donating electron, like many antioxidants, fucoxanthin donates proton. A combination of these two attributes is unique to fucoxanthin and is most likely due to its unusual chemical structure (presence of allenic bond in the carotenoid formation).

References

1. Mercandante AZ. (2004) Egeland E.S. Carotenoids Handbook. Birkhauser.
2. Nomura T, Kikuchi M, Kubodera A, Kawakami Y. (1997 June) Proton-donative antioxidant activity of fucoxanthin with 1,1-diphenyl-2-picrylhydrazyl (DPPH). Biochem Mol Biol Int. 42(2):361-70.
3. Yan X, Chuda Y, Suzuki M, Nagata T. (1999 March) Fucoxanthin as the major antioxidant in Hijikia fusiformis, a common edible seaweed. Biosci Biotechnol Biochem. 63(3):605-7.
4. Maeda H, Hosokawa M, Sashima T, Funayama K, Miyashita K. (2005 July) Fucoxanthin from edible seaweed, Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues. Biochem Biophys Res Commun. 1;332(2):392-7.
5. Widmaier E, Raff H, Strang K. ( 2005) Human Physiology - The Mechanisms of Body Function. Ninth ed. New York: McGraw-Hill.
6. Ramazanov, Z. (2007) The effect of Xanthigen, a phytomedicine containing fucoxanthin and pomegranate seed oil, on body weight.
7. Abidov M, Roshen S. (2007) Effect of Fucoxanthin and Xanthigen™, A phytomedicine containing fucoxanthin and pomegranate seed oil, on energy expenditure rate in obese non-diabetic female volunteers with non-alcoholic fatty liver disease: a double-blind, randomized and placebo-controlled trial. Unpulished.
8. Gosnell M. Killer. (2007 Februarty) Fat. Discover 48-53. Guccione, Bob.