Tea Scores Again

Standardized tea capsule demonstrates measurable cardiovascular benefits.

By Joanna Cosgrove
Online Editor

The simple act of brewing a cup of tea doesn’t just make for a great morning or mid-afternoon beverage ritual. While reams of studies have concluded that regular tea consumption does the body good in a myriad of ways, others have written tea off, claiming it has little bearing on conditions related to cancer, aging, brain and bone health. But it can be tricky studying the properties of a plant-based beverage that is enjoyed for its many inherent variables—differing Camellia sinensis species, processing variations, personalized brewing methods, and of course, additives like milk, lemon and sugar.

The “confounding variables” associated with tea research was a notion that intrigued a team of researchers, inspiring them to undertake a study (published in the Jan 2009 issue of Nutrition) utilizing a standardized capsule of Camellia sinensis compounds (CSC), most notably, the amino acid L-theanine. When the three-month study concluded, researchers reported that the CSC were deemed effective for decreasing, in as quickly as three weeks, “blood pressure, LDL cholesterol, oxidative stress and a marker of chronic inflammation, all independent cardiovascular risk factors.”

The randomized, double-blind, placebo-controlled, parallel study was conducted on 111 healthy adult volunteers between the ages of 21 and 70 years old, who were split into two groups. The first group received one standardized Cardio Guard capsule (provided by Cardio Guard LLC of Orlando, FL) two times per day. The other group received identical looking placebo capsules. The decaffeinated Cardio Guard capsule contained a proprietary mixture of 100 mg of L-theanine (Suntheanine, from Taiyo International, Minneapolis, MN) and 200 mg of a decaffeinated catechin green tea extract (Sunphenon 90DCF, also from Taiyo International).

According to the study authors, L-theanine has a wide range of effects on body processes, including the state of relaxation/alertness hypertension, and “a specific cell of the immune system that contributes not only to pathogen elimination but also to suppression of the inflammatory response.”

The researchers sought to use a decaffeinated CSC in this study because “studies on the effects of tea drinking or tea extract ingestion and chronic hypertension have not shown significant effects. This lack of effect may be due to the presence of caffeine and/or the absence of L-theanine due to variability in the tea plant.”

The natural L-theanine content of tea is dependent on the cultivar and can vary between 0.6 to 2.38 g/100 g of tea.

To chart the effect of the supplement they consumed, each volunteer was examined via blood pressure, serum lipids, serum amyloid-α (a marker of chronic inflammation), and serum malondialdehyde (a marker of oxidative stress).

In three weeks, CSC test subjects exhibited lowered systolic and diastolic blood pressures by five and four mmHg, respectively. And after three months, “systolic blood pressure remained significantly lower. CSC lowered serum amyloid-α by 42% and lowered malondialdehyde by almost 12%. In men, there were 10- and 9-mg/dL reductions in total and low-density lipoprotein (LDL) cholesterol, respectively. In all subjects with a baseline LDL cholesterol level >99 mg/dL, there was 9 mg/dL lowering of total and LDL cholesterol.”

While the study results were overwhelmingly positive, the idea for the study itself originated out of sheer coincidence as the team worked on an unrelated study using a similar product, according to one of the researchers, Jack F. Bukowski, MD, PhD, assistant clinical professor of medicine, Harvard Medical School, and director of the Nutritional Science Research Institute, a Marlboro, MA-based non-profit organization committed to providing education about proper use of nutritional supplements.

“We had frozen blood samples from subjects taking Immune Guard (which is the same formulation as Cardio Guard) for our cold and flu study,” he recalled. “Someone in our group noticed that there was some literature showing that drinking tea decreased the inflammatory marker SAA (a huge risk factor for heart attack and stroke). We pulled out those samples and found that taking this supplement lowered SAA levels in the blood.

“For safety, we took blood pressure readings, and found that taking this supplement also lowered blood pressure, which was not found in previous tea drinking studies, probably because tea has caffeine. Cardio Guard is decaffeinated,” he continued. “This led to more literature searches, and there were some previous reports that drinking tea decreased total and LDL ‘bad’ cholesterol. We found the same result with Cardio Guard. Consistent with the antioxidant activity of tea, we found that blood antioxidant capacity was increased.”

At the consumer level, Dr. Bukowski said the implication of this research is dependent upon the individual consumer’s mindset and/or health situation. “For most people with moderate to high blood pressure or cholesterol, there is nothing like a drug to lower these. However, some people can’t or won’t take drugs due to personal preference or side effects,” he said. “Also, there is a huge number of people who have ‘pre-hypertension’ or only mildly elevated cholesterol who would want to try something natural and without side effects first, before moving on to a drug.”

Dr. Bukowski was unsure how the study outcome might impact the tea segment, given that the earlier mentioned variants associated with traditionally brewed tea are most certainly different than the standardized components used for the study analysis. “Why not just drink tea? The results with tea research have been uneven, since the important components L-theanine and EGCG are not standardized, and their levels vary wildly depending on the tea species, harvest time, growing conditions, manufacturing and brewing process.” Furthermore, he said, “There is no agreement on what quantity constitutes a cup of tea.”

The study results as published in Nutrition are just the beginning. Dr. Bukowski said that he and his team are in the early stages of a new study to determine if the results can be reproduced and sustained over a longer period of time.