Archive for August, 2013

Mulberry leaf extract inhibits atherosclerosis?

Wednesday, August 14th, 2013

Mulberry trees are widely distributed, producing red, purple and even white berries depending on the variety. Many parts of the tree, including the leaves, bark, berries have been used in folk remedies for thousands of years. Mulberry has been widely claimed and studied as an aid to control diabetes.

Atherosclerosis is a component of heart disease. It is the process by which arteries become clogged with cholesterol laden plaques, restricting blood flow and ultimately resulting in serious issues, including heart attacks when blood vessels supplying the heart become restricted.

In a study published recently [J. Agric. Food Chem., 2013], researchers tested mulberry leaf extract (MLE) on rabbits and found that in addition to improvement of liver function, the atheroma burden (an atheroma is an accumulation and swelling in artery walls, a precursor to atherosclerosis) and levels of serum cholesterol, triglycerides, and low-density lipoprotein (LDL) were also significantly reduced after MLE treatment. MLE treatment was also reported to reduced the size of existing atheromas in the vascular wall. In conclusion, this means that, in addition to improving cholesterol and triglyceride profiles, MLE appears to reduce existing atheromas, thereby preventing atherosclerosis.

The proposed mechanism of MLE’s role in reduction of arterial plaques is by causing an increase in the body’s production of a protein called p53 (p53 is classified as a tumor-suppressor protein that is released during cellular stress, such as that caused by DNA damage, low oxygen, etc). The p53-atherosclerosis connection is unclear. It was discovered separately that persons can be p53 deficient and that people with p53 deficiencies also had an increased size of atherosclerotic lesions.

In an earlier study [J Clin Biochem Nutr. 2010 September] “Effects of Mulberry Leaf Extract Rich in 1-Deoxynojirimycin on Blood Lipid Profiles in Humans”, subjects ingested capsules containing mulberry leaf extract, 12-mg three times daily, for 12 weeks. The results were very far from conclusive. After 12 weeks, findings showed a modest decrease in serum triglyceride levels and beneficial changes in the lipoprotein profile, although the study team admitted that the decreases were not statistically significant. Although the results were not statistically significant the researchers proposed that the MLE may potentially be used to decrease what is known as “very bad cholesterol”.

Conclusion: It all sounds well and good, particularly in the animal study..MLE actually reduces plaques?! Though in human subjects the real net effects are far from conclusive. At this point one might be thinking, well..why not go ahead and take MLE anyway? The results seem promising, right? Sure, if you like. The studies seem to indicate that there aren’t any serious side effects from moderate doses, but then again, if the evidence isn’t statistically significant, why bother? The better course of action would be to wait for a larger study with more human subjects, and in the meantime, if you have a risk for atherosclerosis, stick to what we are fairly certain works, including diet modification, exercise and if you aren’t adverse..statin drugs..

Berberine..a natural statin drug replacement?

Tuesday, August 13th, 2013

Interest in berberine as a natural cholesterol reducer isn’t new, in fact research on berberine dates back more than a decade. However of recent, there has been an increasing interest in the effectiveness of berberine extract as an alternative to taking statin drugs (cholesterol reducers), with several well designed studies coming online.

What is berberine? Berberine is a natural plant extract from Berberis aristata bark (commonly known as Indian Barberry). Biochemically, berberine has been proposed to reduce cholesterol AND triglyceride levels by increasing LDL-cholesterol receptors on the liver cell surface, and inhibiting triglycerides biosynthesis, and potentially inhibiting an enzyme associated with atherosclerosis.

In a randomized 2011 study [Med J Nutrition Metab. 2011 August]: “Clinical evidence of efficacy of red yeast rice and berberine in a large controlled study versus diet.” Researchers evaluated dietary counseling alone versus consuming a supplement containing red yeast extract and berberine plus diet counseling. There was strong evidence that the berberine formula significantly improved the participant’s lipid profiles versus diet counseling alone:

At 16 weeks; comparison of diet counseling + berberine/red yeast vs diet counseling alone:
Reduction of total-cholesterol: −19.1% vs −9.4%.
Reduction of LDL-Chol: −23.5% vs −10.8%.
Reduction of plasma triglycerides: −17.9% vs −11.3%.
HDL-Chol levels showed a moderate increase: +11.6% vs +4.0%.

Findings similar to these have been reproduced and repeated in several studies and it does appear that berberine may be an option for people who refuse to take statins, or people who have tried statin drugs but then stopped due to side effects such as muscle and joint pain.

Research regarding taking statin drugs + berberine are less numerous. It should be noted that, biochemically, statin drugs and berberine work via different metabolic mechanisms.

A study in lipidworld found that adding a berberine supplement to patients already on a stable dose of statin drugs resulted in further decreased total cholesterol (-8.1%), LDL (-10.5%) triglyceride levels (-5.4%).

In a study of rats; [J of Metabolism 2008 Aug] titled “Combination of simvastatin with berberine improves the lipid-lowering efficacy.” (Simvastatin is a commonly prescribed statin drug).

Researchers compared simvastatin, berberine and the combination of simvastatin + berberine extract in rats. LDL cholesterol was reduced 28% with simvastatin alone, 27% with berberine alone, the combination resulted in a 46% reduction in LDL. Interestingly the combined results of berberine + simvastatin were as effective as doubling the dose of simvastatin, which when doubled resulted in a 43% reduction in LDL cholesterol.

Summary – berberine does appear to be metabolically active, and does reduce cholesterol based on the findings of numerous research studies, and may be a useful alternative for those who refuse statins, or have had side effects with statins. Of course, any change in your statin regimen must be reviewed with your physician.