Posts

, ,

Green Tea: Who Does it Help, and How?

By: Emma Partridge, MS Candidate

Green tea contains a high concentration of polyphenols, most of which are flavanols. Flavanols are commonly known as catechins, the most active catechin being epigallocatechin-3-gallate (EGCG).1 Within the world of nutrition, green tea is consistently touted as a beverage with a plethora of health benefits. These benefits are far-reaching and specific roles of green tea have been identified to improve symptoms or reverse disease damage amongst people with autoimmune disease, heart disease, cancer, liver disorders, smoking complications, chronic inflammation, and more. The roles of green tea often overlap and while green tea consumption is important for those with various diseases, the consumption of green tea by healthy individuals may be integral in the prevention of many of the following diseases.

Chronic Inflammatory Disease
EGCG may be most important flavanol when it comes to inflammation control.2 EGCG has been shown to suppress the production of cytokines, pro-inflammatory mediators. Suppressing cytokines decreases long-term inflammation and has been shown to improve inflammation-related symptoms in arthritis models.3,4

Autoimmune Disease
In addition to helping to control the chronic inflammation associated with most autoimmune diseases, EGCG has been shown to suppress auto-reactive T cell proliferation. Auto-reactive T cells act against the body, resulting in various forms of autoimmune diseases. EGCG may also help to regulate T-helper cell balance, which may decrease the pathogenesis of arthritic diseases, especially rheumatoid arthritis.3

Type 2 Diabetes Risk
Type 2 Diabetes is sweeping America, and food production practices, availability, and affordability are making it harder for people to access healthy options. The ease of accessing and affording unhealthy foods is increasing the risk of diabetes among populations. Green tea, as well as coffee, has been associated with lowering the risk of type 2 diabetes, though the mechanism is unknown and the data inconsistent. However, in a study of 40,000+ people followed for 10 years, researchers found that daily consumption of at least three cups of coffee or tea may lower type 2 diabetes risk.5

Heart Disease & Stroke Risk
In an article published by the American Heart Association, researchers found that people who drank two to three cups of green tea per day had a 14% lower risk of stoke.6 The research on green tea and stroke risk comes on the wake of multiple studies finding links between green tea and heart health. Multiple studies found green tea consumption to lower risk of death from heart attacks by 26% and lower risk of coronary artery disease by 28%.7

Cancer & Tumor Growth
Cancer is a leading cause of death in the United States, behind heart disease. Green tea has already been shown to be beneficial in preventing the leading cause of death; now studies have now shown that the EGCG may affect transformed cells by inhibiting the growth of certain cell lines, inducing apoptosis, and altering gene expression to prevent transformed cells from becoming cancerous.8

Smoking
The polyphenols in green tea have shown to work against carcinogens, while the antioxidant effects may reverse endothelial dysfunction in healthy smokers.8 The reversal of endothelial dysfunction in smokers is important because it plays a role in the pathogenesis of atherosclerosis and cardiovascular disease.9

Liver Disease
Green tea’s aforementioned anti-carcinogenic affect may play a role in preventing liver disease. Active polyphenols detoxify reactive oxygen species, preventing oxygen free radicals from destroying hepatocytes and causing oxidative DNA damage. Multiple studies have shown that, most likely via this method, green tea intake can attenuate liver disease or liver cancer.10

Weight Loss & Weight Maintenance
Green tea’s affect on weight loss may be attributed to two components: EGCG and caffeine. Caffeine alone does play some role in increasing energy expenditure, but when combined with EGCG, the mixture stimulates energy expenditure and fat oxidation to a greater degree. This may trigger weight loss, and additional evidence reveals that continual green tea consumption can further help to maintain weight.11

In determining whether or not green tea is for you, the answer is likely yes. While there are risks by way of overconsumption, a few glasses a day has been shown to be beneficial for the all-around healthy person in preventing disease and for the person suffering from various diseases or ailments.

1.Ehrlich SD. Green Tea. 2011; http://umm.edu/health/medical/altmed/herb/green-tea.
2.Hamer M. The beneficial effects of tea on immune function and inflammation: a review of evidence from in vitro, animal, and human research. Nutrition Research. 2007;27(7):373-379.
3.Wu DY, Wang JP, Pae M, Meydani SN. Green tea EGCG, T cells, and T cell-mediated autoimmune diseases. Molecular Aspects of Medicine. 2012;33(1):107-118.
4.Kim HR, Rajaiah R, Wu QL, et al. Green Tea Protects Rats against Autoimmune Arthritis by Modulating Disease-Related Immune Events. Journal of Nutrition. 2008;138(11):2111-2116.
5.van Dieren S, Uiterwaal C, van der Schouw YT, et al. Coffee and tea consumption and risk of type 2 diabetes. Diabetologia. 2009;52(12):2561-2569.
6.Green tea, coffee may help lower stroke risk. 2013; http://newsroom.heart.org/news/green-tea-coffee-may-help-lower-stroke-risk.
7.Green tea may lower heart disease risk. Harvard Heart Letter 2012; http://www.health.harvard.edu/heart-health/green-tea-may-lower-heart-disease-risk.
8.Chen ZP, Schell JB, Ho CT, Chen KY. Green tea epigallocatechin gallate shows a pronounced growth inhibitory effect on cancerous cells but not on their normal counterparts. Cancer Letters. 1998;129(2):173-179.
9.Nagaya N, Yamamoto H, Uematsu M, et al. Green tea reverses endothelial dysfunction in healthy smokers. Heart. 2004;90(12):1485-1486.
10.Jin X, Zheng R-h, Li Y-m. Green tea consumption and liver disease: a systematic review. Liver International. 2008;28(7):990-996.
11.Hursel R, Viechtbauer W, Westerterp-Plantenga MS. The effects of green tea on weight loss and weight maintenance: a meta-analysis. International Journal of Obesity. 2009;33(9):956-961.

,

Can the Vegetarian Diet Be Healthy?

By Meghan Anderson Thomas, MS

I constantly hear:

Omnivores: “Vegetarians just don’t look healthy.”
Vegetarians: “ Meat just isn’t good for you.” Or “I feel so much better when I’m not eating it”

So who has it right? Can they both be right and wrong at the same time? I think the answer lies in the motivations behind the eater. The omnivore may have a point because vegetarianism, like all other diets, has the capacity to be unhealthy.

Essentially, vegetarianism, pescetarianism, veganism, etc. are elimination diets. Like any elimination diet, they have the potential to lack vital nutrients including certain vitamins that are predominately found in animal products. According to Sabate, vegetarian diets when compared to meat-based diets are more likely to be deficient in vital nutrients(1). Similarly, when omnivores (typical American diet) obtain the abundance of their calories from meat and dairy they have less room for the fruit and vegetables that provide them with the other nutrients vegetarians so easily acquire. Moreover, studies show that the increased risk of cancer and heart disease in meat-based diets may be related to a deficiency in the phytochemicals and other compounds found in plant-based foods, not just the intake of saturated fats and excess calories(2).

Again, the problem lies in the motivation. Vegetarians and omnivores alike that eat for health are much more likely to eat properly. The choice of becoming a vegetarian for health reasons alone may lead the vegetarian in question to a more healthful diet in which they are cognizant of variety and balance. That being said, there are plenty of vegetarians that may be doing it for the wrong reasons or are, like most, uneducated in making the proper nutritional decisions.

The observation that vegetarians are unhealthy may actually be evident. Most will argue that they have been deficient in iron, zinc, calcium and B vitamins since they have eliminated animal products, leading to anemia(2). Not to mention that most vegetarians are women who are prone to anemia due to menstruation. The fatigue that follows leads to the snowball effect of fatigue, decreased exercise and depression. The point is, diet has a strong influence on health and well-being and it is dangerously easy to eat incorrectly, even if one’s intentions may be pure. This is seen in all “types” of eaters alike.

It is important to remember that as a vegetarian, the elimination of a steak may reduce your risk for heart disease, hypertension, atherosclerosis, hyperlipidemia, etc., but it is not a free pass to eat all the junk food you can to make up for it. The elimination of meat alone is not the ticket to health. Instead, it seems to be a correlation: the vegetarians motivated by health are also more likely to be cognizant enough to eat right all of the time. Furthermore, Sabate illustrates that the vegetarian diet is viewed as improving health and limiting disease when compared to the meat-based diet(1).

References
1. Sabate, J. (2003). The contribution of vegetarian diets to health and disease: a paradigm shift? The American Journal of Clinical Nutrition, 78 (3), 502S-507S.
2. Nieman, D. C. (1999). Physical fitness and vegetarian diets: is there a relation? The American Journal of Clinical Nutrition, 70 (3), 570S-575S.