The Effects of Astaxanthin Type 2 Diabetes

 

Draining the World Wealth

Diabetes mellitus is a worldwide epidemic that is critically linked to prevalence of obesity. More than 220 million people have diabetes and by the year 2030 the figures are expected to grow to 360 million. The diabetes is aggressively growing in both emerging and developed country. According to WHO, the Asian continent has over 90 million people suffering from diabetes – India (40 million) China (29 million); Indonesia (13 million) and Japan (7 million). The prevalence of diabetic patients remains pervasive in USA (22 million), Brazil (6 million), Pakistan (8 million); Russia (6 million); Italy (5 million) and Turkey (4 million). Even in the African region over 10 million people suffer from diabetes, especially in Nigeria where it is expected to reach 5 million within the year 2030.
Diabetic complications lead to heart disease (approximately 65% of death amongst diabetics), blindness, kidney failure and amputations. As a result, the indirect and direct medical expenditure of diabetics represent almost 5 times that of a non-diabetic.

Type 2 Diabetes: A Preventable Disease

 

In most cases, diabetes is treated with medication, although about 20% of diabetics may be managed by lifestyle changes. This means that even if we cannot change the genetic influences, fortunately, for most of us diabetes is preventable; for example, making dietary changes, taking nutritional supplements and exercising. To highlight this, people in high risk groups who achieve a 5-7% cut in body weight will reduce risk of developing diabetes approximately 58% across all age and ethnic groups.
While the debate between the contributory effects of carbohydrate and fat intake continues unabated, research reveals a strong link between foods with high glycemic index and prevalence of type 2 diabetes. Excess blood glucose needs to be converted by insulin (produced by the pancreas ß-cells) into glycogen stores, however, when glycogen stores are full, glucose is converted into fat. Over time, the body’s cells may eventually become desensitized to insulin making it necessary to produce more insulin to achieve the same affect. It is this process that would eventually lead to a state known as hyperinsulinaemic state. As a result, the body looses its ability to control high blood glucose levels (hyperglycemia) that could result in toxic conditions and promote further complications such as kidney failure.

New Evidences Emerging from Human Studies

In an anti-aging study conducted by Iwabayashi et al., (2009), 20 female volunteers with increased oxidative stress burden ingested 12 mg/day of astaxanthin for 8 weeks. Results evidenced a significant decrease of diabetes-related parameters that collectively predict trends in diabetes development. Firstly, astaxanthin reduced cortisol by 23 percent.

Astaxanthin Retards Glucose Toxicity and Kidney Damage

Astaxanthin displayed positive effects in a type 2 diabetic mouse model in that it reduced the disease progression by retarding glucose toxicity and kidney damage. This has profound implications for people who belong to high risk groups, display pre-diabetic conditions (impaired fasting glucose or impaired glucose tolerance) or want to manage advanced diabetic kidney problems (nephropathy).
Studies suggested that reactive oxygen species (ROS) induced by hyperglycemia contributes to the onset of Diabetes mellitus and its complications. Non-enzymatic glycosylation of proteins and mitochondria, prevalent in diabetic conditions, is a major source of ROS. For example, pancreatic ß-cells kept in high glucose concentrations show presence of advanced glycosylation products, a source of ROS, which cause the following: i) reduction of insulin expression and ii) induction of cell death (apoptosis). ß–cells are especially vulnerable to ROS because these cells are inherently low in antioxidant status and therefore, requires long term protection. A recent study demonstrated that antioxidants (N-acetyl-L-cysteine, vitamins C and E) exerted beneficial effects in diabetic conditions such as preservation of ß-cell function, so it is likely that a more potent antioxidant such as astaxanthin can do the same or better.
In another study conducted by Preuss et al. (2009), 12 rats fed with 25mg/kg of astaxanthin show a significant decrease in insulin resistance by 13.5%.

Modulation of Glucose Toxicity

Uchiyama et al., 2002 demonstrated in obese diabetes type 2 mouse model that astaxanthin preserved pancreatic ß -cell dysfunction against oxidative damage. Treated mice received 1 mg astaxanthin/day at 6 weeks of age and then tests performed at 6, 12 and 18 weeks. Observations of astaxanthin treated mice (N=8) included: i) significantly reduced fasting glucose sugar levels at 12.

Figure 1. Astaxanthin improved the glucose levels in the Intraperitoneally Glucose Tolerance Test (IPGT) in diabetic mouse model (Uchiyama et al., 2002)

Figure 2. Astaxanthin preserved insulin sensitivity in the diabetic mouse model (Uchiyama et al., 2002)

Figure 3. Astaxanthin protected kidney function measured by urinary albumin protein loss (Naito et al., 2004) 

 

Prevention of Diabetic Nephropathy

As well as substantiating observations by Uchiyama et al., Naito demonstrated that astaxanthin treated type 2 diabetic mice which normally shows renal insufficiency at 16 weeks of age in fact exhibited 67% less urinary albumin loss.

Figure 4. Astaxanthin reduced the amount of DNA damage indicated by urinary 8-OHdG levels (Naito et al., 2004) 

 

Figure 5. Astaxanthin preserved the relative mesangial area.

 
Earlier it was unclear how astaxanthin could ameliorate the progression of diabetic nephropathy, but new evidence revealed additional information in the mechanism of action. Naito et al., (2006) examined changes in the gene expression profile of glomerular cells in diabetic mouse model during the early phase of diabetic nephropathy. The mitochondrial oxidative phosphorylation pathway was most significantly affected by high-glucose concentration (mediated via reactive oxygen species). Long term treatment with astaxanthin significantly modulated genes associated with oxidative phosphorylation, oxidative stress and the TGF-ß-collagen synthesis system.

Manabe et al., 2007 went further and analyzed normal human mesangial cells (NHMC) exposed to high glucose concentrations. In the presence of astaxanthin, it significantly suppressed ROS production (Figure 6) and inhibited nuclear translocation and activation of NF-?B (Figure 7) in the mitochondria of NHMC. Furthermore, this was the first time to detect astaxanthin in the mitochondrial membrane (Table 1) and its presence also suppressed ROS attack on membrane proteins.

Figure 6. Astaxanthin reduced ROS production in NHMC-mitochondria exposed to high glucose (Manabe et al., 2007) 

   

Top left panel: mitochondria as green fluorescence, Top right panel: ROS as red fluorescence; Bottom right panel: Merged picture as yellow fluorescence.

Figure 7. Astaxanthin suppressed high-glucose induced nuclear translocation and activation of NF-?B (Manabe et al., 2007) 

 

Table 1. Astaxanthin content in NHMC mitochondria expressed as percentage of total astaxanthin added. 

Mean of 3 samples. (Manabe et al., 2007)

Outlook

Although clinical trials involving antioxidants in humans have only recently begun, these preliminary results concluded that strong antioxidant supplementation may improve type 2 diabetic control and inhibit progressive renal damage by circumventing the effects of glycation-mediated ROS under hyperglycemic conditions. Astaxanthin improved pancreas function, insulin sensitivity, reduced kidney damage and glucose toxicity in diabetic mouse models. New techniques by gene chip analysis and fluorescence imaging revealed further details of mechanism and site of protection by astaxanthin. Further research and clinical studies are still required. However, it is reasonable to suggest that astaxanthin may be useful as part of a nutrigenomic strategy for type 2 diabetes and diabetic nephropathy.

References

1. Forefront (Summer/Fall) 2005, American Diabetes Association.
2. Functional Foods & Nutraceuticals June 2004. "The dietary solution to diabetes."
3. HSR Health Supplement Retailer July 2004. "Fighting Diabetes the natural way."
4. Iwabayashi M, Fujioka N, Nomoto K, Miyazaki R, Takahashi H, Hibino S, Takahashi Y, Nishikawa K, Nishida M, Yonei Y. (2009). Efficacy and safety of eight-week treatment with astaxanthin in individuals screened for increased oxidative stress burden. J. Anti Aging Med., 6 (4):15-21.
5. Manabe E, Handa O, Naito Y, Mizushima K, Akagiri S, Adachi S, Takagi T, Kokura S, Maoka T, Yoshikawa T. (2008). Astaxanthin protects mesangial cells from hyperglycemia-induced oxidative signaling. J. Cellular Biochem. 103 (6):1925-37.
6. Naito Y, Uchiyama K, Aoi W, Hasegawa G, Nakamura N, Yoshida N, Maoka T, Takahashi J, Yoshikawa T. (2004) Prevention of diabetic nephropathy by treatment with astaxanthin in diabetic db/db mice. BioFactors 20:49-59. Nutritional Outlook April. "Fighting Diabetes"
7. Naito Y, Uchiyama K, Mizushima K, Kuroda M, Akagiri S, Takagi T, Handa O, Kokura S, Yoshida N, Ichikawa H, Takahashi J, Yoshikawa T. (2006). Microarray profiling of gene expression patterns in glomerular cells of astaxanthin-treated diabetic mice: a nutrigenomic approach. Int. J. Mol. Med.,18:685-695.
8. Preuss H, Echard B, Bagchi D, Perricone VN, Yamashita E. (2009). Astaxanthin lowers blood pressure and lessens the activity of the renin-angiotensin system in Zucker Fatty Rats. J. Funct. Foods, I:13-22.
9. The Global Diabetes Community. http://www.diabetes.co.uk. Article retrieved on June 8th, 2010.
10. Uchiyama K, Naito Y, Hasegawa G, Nakamura N, Takahashi J, Yoshikawa T. (2002). Astaxanthin Protects ?–cells against glucose toxicity in diabetic db/db mice. Redox Rep., 7(5):290-293.

CCRES special thanks to 

 Mr. Mitsunori Nishida, 

 
President of Corporate Fuji Chemical Industry Co., Ltd.

Croatian Center of Renewable Energy Sources (CCRES) 

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The Effects of Astaxanthin Eye Health

 

Astaxanthin for Eye Health

 
The advances of information technology, software and electronics have led to the widespread use of screen based equipment or Visual Display Terminals (VDT) for both work and leisure. According to The National Center for Education Statistics, about 90 percent of children and adolescents in developed countries, ages 5 to 17, use computers at school or at home. About 50 percent of 9-year-olds use the Internet and at least 75 percent by ages 15 to 17.
This phenomenon often lead to asthenopia or eye fatigue. The symptoms include sensitivity to glare, headaches, sore eyes and blurred vision. A recent study conducted by the National Institute of Occupational Safety and Health in USA found that over 90 percent of habitual users of VDT reported eyestrain and other visual problems associated with computer use. The American Optometric Association supported this in a survey reporting that between 50 and 75 percent of all VDT workers report eye problems. In another study conducted in Sweden, 23 percent of schoolchildren, aged 6-15 suffered from asthenopia-related symptoms (Anshel, 2009).
Asthenopia prompted a large number of occupational safety studies. For example, epidemiological studies over the last decade revealed significant factors that contribute to eye fatigue. These studies, sometimes involving up to 6,000 sufferers identified the following causes: insufficient lighting, poor ergonomics and uncorrected vision. Despite the new information, follow-up studies later showed that the implemented improvements were only effective in 50% of sufferers. The possible explanations for this observation could be that other factors remained undiscovered, poor implementation of improvements, or visual work had become even more visually demanding. It is likely to be a combination of these factors so that current solutions are insufficient to reduce asthenopia.

 

Standardized questionnaires that assessed subjective eye fatigue symptoms are in most cases mild, but symptoms get progressively worse if the causes are not rectified. Furthermore, certain ophthalmological tests can also detect eye problems, for example accommodation amplitudes, rate of accommodative reaction (positive and negative directions), critical flicker fusion (CFF) and pattern visual evoked potential (PVEP). So far, 10 Japanese clinical studies conducted by 9 independent ophthalmological establishments were able to conclude the efficacy of astaxanthin to alleviate visual asthenopia by observed improvements in the accommodation function and recovery of the ciliary body (Figure 1); retinal blood flow and inflammation markers.

Figure 1. Location of the ciliary body in the human eye

 

Astaxanthin Reduces Eye Fatigue

Asthenopia (eye fatigue) occurs on a daily cycle, in that the visual performance generally decreases naturally from morning until night. This problem exacerbates with a daily VDT load that lasts between 4 to 7 hours by affecting the accommodation performance of the ciliary body, which controls lens refraction. A couple of randomized double blind placebo controlled pilot studies demonstrated the positive effects of astaxanthin supplementation on visual function. For example, a study by Nagaki et al., (2002), demonstrated that subjects (n=13) who received 5 mg astaxanthin per day for one month showed a 54% reduction of eye fatigue complaints (Figure 2). In a sports vision study led by Sawaki et al., (2002), they demonstrated that depth perception and critical flicker fusion had improved by 46% and 5% respectively on a daily dose of 6 mg (n=9). The effect of astaxanthin on visual performance prompted a number of other clinical studies to evaluate the optimum dose and identify the mechanism of action.

Figure 2. VDT Subjects with Eye Strain Symptoms before and after astaxanthin supplementation  

   

 Overall, the 6 mg group improved significantly better at week 2 and 4 of the test period. Furthermore, questionnaire results obtained by Shiratori et al., (2005) and Nagaki et al., (2006), also confirmed the previous findings that astaxanthin supplementation at 6 mg for 4 weeks improved symptoms associated with tiredness, soreness, dryness and blurry vision. Another study by Takahashi & Kajita (2005), also demonstrated that astaxanthin attenuates induced-eye fatigue, as opposed to treating eye fatigue, which suggests prevention rather than treatment. Astaxanthin treated groups (asthenopia negative) were able to recover quicker than the control group after heavy visual stimulus. Later, Iwasaki & Tawara (2006) also confirmed the same tendencies of subjective eye fatigue complaints in a randomized double-blind placebo controlled double-crossover study.
In addition to questionnaires, direct measurement associated with asthenopia is also strong indicators for understanding astaxanthin efficacy. These include accommodation amplitude (Figure 3); rate of accommodation reaction (positive and negative directions); CFF (critical flicker fusion) and PVEP (pattern visual evoked potential).
Based on the quantitative information, the accommodation related measurements consistently improved after the treatment period (Nagaki et al., 2002, 2006; Nakamura et al., 2004; Takahashi & Kajita, 2005; Shiratori et al., 2005; Nitta et al., 2005; Iwasaki & Tawara, 2006) whereas the CFF and PVEP remained inconclusive (Sawaki et al., 2002; Nagaki et al., 2002; Nakamura et al., 2004). Therefore, the mechanism by which astaxanthin improved eye fatigue strongly indicates accommodation.

Figure 3. Objective accommodation (Nitta et al., 2005)  

Objective accommodation amplitude improves with 6mg astaxanthin.

Delaying Progression of Presbyopia

In a questionnaire survey study conducted by Kajita et al. (2009), 77 percent of 22 elderly males (age 46-65), after ingested 6 mg of astaxanthin daily for 4 weeks, felt better about the subjective symptoms related to presbyopia – a reduced ability to focus on near objects caused by loss of elasticity of the crystalline lens after age 45. In more detail, participants felt an improvement when seeing nearby objects and a decrease in blurred vision. This was followed by alleviation of eye strain and shoulder stiffness. In addition, the pupillary constriction ratio, used to assess the accommodative function of the eye, showed an overall improvement of 19 percent after supplementation of astaxanthin. Therefore, Kajita et al. (2009) concluded that astaxanthin may slow down the progression of presbyopia in middle-aged and elderly people.

Mechanism of Action

Accommodation Improvement

 

Accommodation measures the lens refractive property and it corresponds to the ciliary body function. This small ocular muscle controls the lens thickness in order to focus the light on the retina. In heavy visual workloads, the eye is focused on a fixed object distance for extended periods that will cause muscle spasms or develop fatigue detectable by accommodation tests. These tests are interrelated and include the following: accommodation amplitude; accommodation reaction (positive or negative) and high frequency component (HFC). Each clinical study used a combination of accommodation tests to indicate the amount of fatigue present. For example, increased accommodation amplitude in all treated subjects indicated improved reaction on near and far objects (Nagaki et al., 2002, 2006; Nakamura et al., 2004). Figure 4, Figure 5 and Table 1 reveal the higher rate of accommodation reactions measured in astaxanthin treated groups. These indicate the speed at which the ciliary body reacted to the direction change of focus (negative accommodation means from a near object at 35 centimeters to distant object at 5 meters or vice versa); (Nitta et al., 2005; Shiratori et al., 2005; Nakamura et al., 2005; Iwasaki & Tawara, 2006). The effects of astaxanthin are significant from 2 weeks.

Table 1. Improvement of negative accommodation time with astaxanthin (Iwasaki & Tawara, 2006)

   

Figure 4. Positive accommodation change (Shiratori et al., 2005)

   

Rate of positive accommodation improves with 6 mg astaxanthin

Figure 5. Negative accommodation (Shiratori et al., 2005)

   

Rate of negative accommodation improves with 6 mg astaxanthin

Another technique called HFC directly measured the microfluctuations in the lens during the accommodation response and typical values exist between 50 and 60 for normal eyes. Asthenopia sufferers (values greater than 60) experienced faster rates of recovery (Figure 6) in that their HFC results decrease towards normal values in less time compared to control groups (Takahashi & Kajita, 2005).

Figure 6. Accommodative Recovery observing difference of HFC (Takahashi & Kajita, 2005)  

Astaxanthin improves HFC accommodation recovery during rest periods after visual work.

Increased Blood-flow

Figure 7. Increase of retinal blood flow (Nagaki et al., 2005)  

 Retinal blood flow increases with astaxanthin after 4 weeks.

Anti-inflammation

Lastly, a top Japanese ophthalmology research collaboration between Hokkaido, Yokohama and Tokyo concluded anti-inflammatory properties of astaxanthin in endotoxin-induced uveitis (EIU or eye inflammation) both in vivo and in vitro models.
In another study, Suzuki et al., (2006) confirmed the same effects while they carefully studied the anti-inflammatory effect of astaxanthin in the iris-ciliary body of rat eyes. This was also the first study to prove that astaxanthin suppressed NF-kB activation by free radicals in the EIU rat model (Figure 8). The result is a lower pro-inflammatory response that would otherwise perpetuate local sites of inflammation that may also help explain why astaxanthin worked to alleviate eye fatigue in numerous clinical trials.

Figure 8. Number of NF-?B positive cells in eye ciliary body during inflammation (Suzuki et al., 2006)

   

Astaxanthin reduced the number of inflamed cells in the ciliary body.

Outlook

 

Eye fatigue or asthenopia is a common problem that occurs with the regular use of VDTs and may be resolved with findings from many worldwide epidemiological studies. However, if current improvements tend to be only 50% successful and other factors are likely to be involved, therefore, based on the current clinical evidence, astaxanthin offers a complementary alternative by reducing inflammation, improving accommodation and increasing blood flow.

References

1. Anshel D. J. (2009). Healthy Eyes Better Vision, Summerlin Publishing Group, USA.
2. Fukuda M, Takahashi J, Nishida Y, Sasaki H. (2008). Intraocular penetration of astaxanthin in rabbit eyes. Atarashii Ganka, 25(10):1461-1464. [In Japanese]
3. Hashimoto H, Arai K, Takahashi J, Chikuda M, Obara Y. (2009). Effect of Astaxanthin Consumption on Superoxidize Scavenging Activity in Aqueous Humor. Atarashii Ganka, 26(2): 229-234. [In Japanese]
4. Iwabayashi M, Fujioka N, Nomoto K, Miyazaki R, Takahashi H, Hibino S, Takahashi Y, Nishikawa K, Nishida M, Yonei Y. (2009) Efficacy and safety of eight-week treatment with astaxanthin in individuals screened for increased oxidative stress burden. J. Anti Aging Med. 6 (4):15-21.
5. Iwasaki T, Tawara A. (2006). Effects of Astaxanthin on Eyestrain Induced by Accommodative Dysfunction. Atarashii Ganka, (6):829-834. [In Japanese]
6. Kajita M, Tsukahara H, Kato M. (2009). The Effects of a Dietary Supplement Containing Astaxanthin on the Accommodation Function of the Eye in Middle-aged and Older People. Medical Consultation & New Remedies, 46(3). [In Japanese]
7. Miyawaki H, Takahashi J, Tsukahara H, Takehara I. (2005). Effects of astaxanthin on human blood rheology. J. Clin. Thera. Med., 21(4):421-429.
8. Nagaki Y, Hayasaka S, Yamada T, Hayasaka Y, Sanada M, Uonomi T. (2002). Effects of astaxanthin on accommodation, critical flicker fusions, and pattern evoked potential in visual display terminal workers. J. Trad. Med., 19(5):170-173.
9. Nagaki Y, Mihara M, Tsukuhara H, Ohno S. (2006). The supplementation effect of astaxanthin on accommodation and asthenopia. J. Clin. Therap. Med., 22(1):41-54.
10. Nagaki Y, Miharu M, Jiro T, Akitoshi K, Yoshiharu H, Yuri S, Hiroki T. (2005). The effects of astaxanthin on retinal capillary blood flow in normal volunteers. J. Clin. Therap. Med., 21(5):537-542.
11. Nakamura A, Isobe R, Otaka Y, Abematsu Y, Nakata D, Honma C, Sakurai S, Shimada Y, Horiguchi M. (2004). Changes in Visual Function Following Peroral Astaxanthin. Japan J. Clin. Opthal., 58(6):1051-1054.
12. Nitta T, Ohgami K, Shiratori K, Shinmei Y, Chin S, Yoshida K, Tsukuhara H, Ohno S. (2005). Effects of astaxanthin on accommodation and asthenopia – Dose finding study in healthy volunteers. J. Clin. Therap. Med., 21(6):637-650.
13. Ohgami K, Shiratori K, Kotake S, Nishida T, Mizuki N, Yazawa K, Ohno S. (2003). Effects of astaxanthin on lipopolysaccharide-induced inflammation in vitro and in vivo. Invest. Ophthal. Vis. Sci., 44(6):2694-2701.
14. Sawaki K, Yoshigi H, Aoki K, Koikawa N, Azumane A, Kaneko K, Yamaguchi M. (2002) Sports performance benefits from taking natural astaxanthin characterized by visual activity and muscle fatigue improvements in humans. J. Clin. Ther. Med., 18(9):73-88.
15. Shiratori K, Ohgami K, Nitta T, Shinmei Y, Chin S, Yoshida K, Tsukahara H, Takehara I, Ohno S. (2005). Effect of astaxanthin on accommodation and asthenopia – Efficacy identification study in healthy volunteers. J. Clin. Therap. Med., 21(5):543-556. Sussman M. (2001) Total Health At The Computer, Station Hill, New York.
16. Suzuki Y, Ohgami K, Shiratori K, Jin XH, Ilieva I, Koyama Y, Yazawa K, Yoshida K, Kase S, Ohno S. (2006). Suppressive effects of astaxanthin against rat endotoxin-induced uveitis by inhibiting the NF-kB signaling pathway. Exp. Eye Res., 82:275-281.
17. Takahashi N, Kajita M. (2005). Effects of astaxanthin on accommodative recovery. J. Clin. Therap. Med., 21(4):431-436.

 CCRES special thanks to 
Mr. Mitsunori Nishida, 
President of Corporate Fuji Chemical Industry Co., Ltd.

Croatian Center of Renewable Energy Sources (CCRES) 

Read More..