We have all read in the media about the wonder that is Camellia Sinensis. Otherwise known as the Green Tea Plant. It is often featured within the pages of glossy health magazines promoting therapeutic properties for better health.
What Does Green Tea Claim to Improve?
Green Tea lays claim to many health benefits including the following.
- Prevention of Cancer
- Blood Glucose Management
- Reduced Inflammation and Inflammatory markers
- Reduce Osteoporosis
- Manage Weight
- Reduce Cholesterol
- Reduce Hypertension
- Reduce the risk of cardiovascular disease.
- Increase length of life
- Reduces the incidence of disease.
What is the Cochrane Review?
The Cochrane Review has dedicated the last 20 years to publishing frontier research in the world of Health. According to its website:
“Cochrane exists so that healthcare decisions get better.”
They are a global journal that gathers evidence from over 130 countries to establish unbiased and credible knowledge on matters of health. It aims to provide knowledge to people with varied information levels in medicine. Including doctors, nurses, carers, researchers and patients [1].
Only the best, least flawed and most reviewed studies make it into the journal. It is one of the most modern and accurate collections of evidence. This means that all the studies featured can be trusted for sound scientific evidence.
Green Tea and the Cochrane Review.
Among other monthly topics, Green Tea has been extensively investigated. The 3 main areas of investigation by the Cochrane review are, Weight loss in Obese Patients, Cancer and Cardiovascular Disease.
Weight Management
Obesity is one of the leading indirect killers in the UK. Obesity alone can encourage the onset of a number of diseases including Type 2 Diabetes, Hypertension, Atherosclerosis, Hyperlipidemia and Stroke, among others.
Green Tea is thought to increase the energy output of the body, this is not through movement but through heat production, called thermogenesis. Thermogenesis is a process in which the body increases energy production from the food we consume. Burning more energy means decreased risk of excess calories which are laid down as fat stores (adipose). This effect is thought to be due to the EGCG content and not the caffeine content, although this will also help with weight loss.
The Cochrane review featured a 2012 study that consisted of a 15 studies and a cross-sectional method. It took nearly 2,000 patients, averaging 12-13 weeks in length. They found no statistical significance to support overall weight loss. However, other methods of weight loss measurement include BMI and waist circumference. The author stated that the Green Tea preparation used appeared to produce some effect, although it was deemed statistically insignificant [2].
Although, this one study showed no significant link between weight loss and Green Tea, theoretically according to the laws of thermogenesis Green Tea should induce weight loss. There are other studies to support this theory [3,4].
Cancer
A scary statistic released last year revealed that the likelihood of developing Cancer is as much as 1 in every 2 people. This is frightening, however, our knowledge and ability to cure cancer has vastly improved also. A study released in the Cochrane library looked at 51 studies and 1.6 million participants and found that there was a significant link between Green Tea and rates of GI tract, gynecological, breast, urological, prostate lung and oral cancers. From these studies they found a strong correlation between Cancer and Green Tea. That being said it was difficult to officially state Green tea absolutely reduces your risk of cancer, due to minor contradictory evidence. What can be taken from this study is that Green tea is associated with reduced risk of Cancer. Regular consumption of this drink is safe and can promote a wide array of health not only Cancer prevention.
Cardiovascular Disease
Cardiovascular disease (CVD) is at the top of most Doctor’s concern lists. Majority of the cases, CVD is caused by modifiable risk factors such as obesity and smoking. Yet in many cases, nothing is done about it. Although many of the preventative suggestions and management techniques revolve around eating less fat and salt in the diet, 11 randomised studies found that tea had a resounding success. The average intervention was between 3 and 6 months. The results across the 11 studies found that Green Tea appeared to have beneficial effects on high cholesterol, high blood lipids, and hypertension.
Considering that Cardiovascular disease could effect us all due to poor diet, or even genetic factors, it is of vital importance that we take care of ourselves. Maintaining a healthy diet and concentrating on clinically proven evidence to boost cardiovascular health, such as green tea [6].
The Cochrane review is overseen by experts of the field and provides modern evidence too boost advancements in the medical field.
- Cochrane. (2016). Cochrane About Us. Available: http://www.cochrane.org/about-us.
- Jurgens TM, Whelan AM, Killian L, Doucette S, Kirk S, Foy E. Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database of Systematic Reviews 2012, Issue 12. Art. No.: CD008650. DOI: 10.1002/14651858.CD008650.pub2.
- Jówko. E. (2015). Chapter 8 : Green Tea Catechins and Sport Performance. In: Lamprecht. M Antioxidants in Sport Nutrition.. Florence: CRC Publishing. Ecollection.
- Changhong. L, et-al . (2006). Green Tea Polyphenols Modulate Insulin Secretion by Inhibiting Glutamate Dehydrogenase. The Journal of Biological Chemistry. 281 (4), Pg. 10214-10221.
- Boehm K, Borrelli F, Ernst E, Habacher G, Hung SK, Milazzo S, Horneber M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD005004. DOI: 10.1002/14651858.CD005004.pub2
- Hartley L, Flowers N, Holmes J, Clarke A, Stranges S, Hooper L, Rees K. Green and black tea for the primary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2013, Issue 6. Art. No.: CD009934. DOI: 10.1002/14651858.CD009934.pub2