© 2000 American Society for Clinical Nutrition
Taurine improves insulin sensitivity in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous type 2 diabetes1,2
Yasuharu Niwa, and
1From the Department of Nutrition, Tokushima University, School of Medicine, Tokushima, Japan.
Background: Taurine, a potent antioxidant, has been reported to improve streptozotocin-induced diabetes mellitus, in which the development of diabetes results from an attack by oxygen free radicals on pancreatic β cells. However, taurine also increases the excretion of cholesterol via conversion to bile acid and would be expected to improve insulin resistance.
Objective: The effects of taurine on insulin sensitivity were examined in a model rat of insulin resistance and type 2 diabetes—the Otsuka Long-Evans Tokushima Fatty (OLETF) rat.
Design: Male OLETF rats were divided into 2 groups at the age of 16 wk: a taurine-supplemented group and an unsupplemented group. As a nondiabetic control, Long-Evans-Tokushima-Otsuka rats were used. An oral-glucose-tolerance test and hyperinsulinemic euglycemic clamp were performed at the ages of 23 and 25 wk.
Results: The OLETF rats had hyperglycemia and insulin resistance and they had a greater accumulation of abdominal fat than did control rats. Abdominal fat accumulation, hyperglycemia, and insulin resistance were significantly lower in the taurine-supplemented group than in the unsupplemented group. Serum and liver concentrations of triacylglycerol and cholesterol were significantly higher in the OLETF rats than in the control rats and were significantly lower in the taurine-supplemented group than in the unsupplemented group, presumably because of the increased secretion of cholesterol into bile acid. Taurine-supplemented rats also showed higher nitric oxide secretion, evidenced by increased urinary excretion of nitrite.
Conclusion: Taurine effectively improves metabolism in OLETF rats by decreasing serum cholesterol and triacylglycerol, presumably via increased secretion of cholesterol into bile acid and decreased production of cholesterol because of increased nitric oxide production.
Type 2 diabetes
Otuska Long-Evans Tokushima Fatty rat
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Taurine, 2-amino ethanesulfonic acid, is a normal constituent of the human diet and is ubiquitous in tissues. Taurine is a potent antioxidant and prevents tissue injury as a result of antioxidation (1, 2). Streptozotocin-induced diabetes, a model for type 1 diabetes, is thought to result from the attack of oxygen-free radicals on β cells in the pancreas. Trachtman et al (3) reported that a dietary supplement of taurine improved streptozotocin-induced hyperglycemia in mice. However, the effect of taurine in an animal model of spontaneous type 2 diabetes has not been studied.
Most patients with diabetes have type 2 diabetes with hyperinsulinemia and insulin resistance, in which the free radical oxidation of β cells is not a cause of diabetes. In addition to antioxidant action, taurine also plays an important role in lipid metabolism, eg, such as in the enhancement of bile acid formation (4–7), which might improve lipid metabolism and insulin resistance in type 2 diabetes. Otsuka Long-Evans Tokushima Fatty (OLETF) rats are a model of type 2 diabetes with insulin resistance (8–10). These rats develop hyperphagia, obesity, hyperinsulinemia, and diabetes.
In the present study, we examined whether taurine is capable of improving insulin sensitivity and diabetic complications in OLETF rats. The results indicate that taurine is effective in improving insulin sensitivity and hyperlipidemia, presumably because of the cholesterol-lowering effect of increased bile acid production, by decreasing lipid synthesis via increased nitric oxide production, or both.
(Following is some clinical trial info on both type 1 and type 2 diabetics):
Can Taurine Treat Diabetes?
by Carly Em
December 14, 2012
New research suggests that an amino acid called taurine may play an important medicinal role in treating diabetes.
As one of the body’s most abundant amino acids, significant levels of taurine live in the lower intestine. Taurine helps create bile, which controls the level of cholesterol in our bodies by breaking down fat.
Though the real importance of taurine has only been recognized in the past 25 years, many recent studies show that taurine helps the body to overcome insulin resistance.
Taurine affects type 2 diabetes
Type 2 diabetes is a disease that results when the body resists insulin. Without the help of insulin, the main source of food for our bodies, glucose, cannot enter our cells. Researchers at Tokushima University in Japan wanted to find out the extent to which taurine affects type 2 diabetes.
They found that this amino acid actually improves the body’s metabolism because it decreases cholesterol, the excess fat that builds up inside our arteries and leads to serious health problems.
The researchers tested a group of rats that had type 2 diabetes. They gave half of the rats a taurine supplement and left the other half alone to act as a control. At the end of the test period, they noted that the group of rats that received a taurine supplement had a significantly lower amount of fat around their bellies than the rats that received no supplement. They also had lower levels of hyperglycemia, which is a condition often associated with diabetes that results when excess glucose builds up in the bloodstream,
Also, the rats that received the taurine supplement resisted insulin at a considerably decreased level than the rats that received no supplement. Based on these results, the researchers suggested that taurine helped the bile break down excess fat because it allowed more cholesterol to be released.
Should I take a taurine supplement?
It is a good idea to make sure your body regularly receives enough taurine. However, it is still too early to recommend the amino acid as a dietary supplement for patients with diabetes.
A healthy diet may yet be the best way to maintain a sufficient amount of the amino acid. Natural sources of taurine can be found in eggs, fish, meat, milk and seafood. You should talk to your doctor before taking taurine supplements to treat diabetes.
Sources for this article included:
1. Tokushima University study: http://www.ncbi.nlm.nih.gov/pubmed/10617946
2. A “very essential” amino acid: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3501277/
3. Sources of taurine – http://www.whathealth.com/taurine/
4. Taurine and diabetes – http://www.livestrong.com/article/340674-taurine-diabetes/