For literally thousands of years, humans have extolled the nutritional and health benefits of tea. The tea plant Camellia Sinensis is the source of all teas in the world. These include green, oolong, white, and black tea as well as the Chinese Tea known as Pu-erh Tea, which is prepared by fermentation of tea leaves. Both formal scientific studies and anecdotal evidence suggest that tea really can work wonders for the body. Here's how:

Tea May Boost the Metabolism

Whether you are looking to burn off a few extra calories or simply get a little more energy during your day, drinking tea may be a good solution. Of course, it's important not to add sugar to your tea, or you will undo the positive metabolic effects. Instead, add a sugar free substitute, like Splenda, Equal, or Sweet N' Low for taste.

Tea May Be an Effective Cancer-Fighting Agent

Nutritionists hypothesize that the antioxidants contained in tea may have powerful cancer fighting effects. Some scientific studies suggest that drinking several cups of green, white, or oolong tea a day may indeed reduce the likelihood that you'll develop cancer.

Tea Improves Focus and Brainpower

Tea leaves contain an important protein building block called L-Theanine, which stimulates cerebral activity but doesn't over-stimulate like the caffeine in coffee.

Tea Can Relax the Body and Help You De-Stress

A hot cup of decaffeinated tea can soothe the body and reduce levels of the stress hormone cortisol in the bloodstream.

Tea Can Hydrate the Body Effectively and Efficiently -- Without Adding Extra Calories

In a world packed with energy drinks, colas, fruit juices, and other sugary beverages, tea offers a low calorie, low-carb alternative -- and a tasty one at that. Mounting evidence supports the hypothesis that obesity may be caused by too many simple sugars and carbohydrates in the diet. By switching from soda or fruit juice to tea, you can substantially cut out your daily intake of simple carbohydrates and improve your prospects for long-term good health.

Tea Supports the Immune System

Whether you are battling an infection or simply trying to stimulate the immune system, tea can be an important arrow in your immune system's quiver.

Tea Is an Effective Digestive

The Chinese have known about tea's positive postprandial effects for over 2,000 years. Scientists suggest that the tannins found in tea may improve the digestive process.

Tea May Be Very Heart Healthy

Studies suggest that drinking oolong tea or green tea can lower blood pressure, protect against heart disease, and guard against stroke and blood clotting.

The Polyphenols in Tea Can Act as Anti-Inflammatories

These polyphenols can be particularly effective in combating diseases and irritations of the intestines, such as irritable bowel syndrome. An agent in Rooibos, found in red tea, may also act to reduce stomach cramping.

Tea Can Fight Tooth Decay and Plaque.

While tea can also stain your teeth if you are not careful, the beverage supplies the body with both tannins and fluoride, which can support good dental health. To get these benefits without the cost (staining), rinse your mouth with water after you drink black or oolong tea.

Tea Can Be Good For the Skin

One study showed that tea functioned as well as or better than benzoyl peroxide in treating patients with acne. Many moisturizers, hair products, and other dermal solutions contain green tea extract. One of the reasons why green tea is so popular in these skin products is that the natural antioxidants contained in green tea can salve skin damage and guard against future damage.

Tea Offers Protection against Numerous Diseases and Conditions, Such As Parkinson's Disease, Influenza, Arthritis, and Diabetes

While tea is by no means a panacea, the beverage contains a host of compounds (discussed above -- tannins, antioxidants, polyphenols, etc), which can simultaneously boost the immune system's capacity, enhance metabolism, reduce stress, and simultaneously invigorate. Tea also boasts a compound called alkylamine antigen, which may partially explain why regular consumption of tea is so well correlated with better health. A recent paper in the Journal of Allergy and Clinical Immunology reported another surprising finding: that regular tea drinking may inhibit the proliferation of the HIV virus in infected patients.

Avoiding Over Treatment with Tea

While tea offers a veritable cornucopia of health benefits, anything when taken to excess can cause health problems. Drinking too much tea can lead to jitteriness and insomnia, and the oxalates contained in some teas can lead to the formation of calcium oxalate crystals in the kidneys.

If You Experience Insomnia or Kidney Stones, See Your Doctor and Consider Taking Time off from Your Daily Tea Regimen

Similarly, the milk, sugar, and other additives you put into tea can cause negative health effects. A typical chai tea latte drink, for instance, may contain 50 grams of carbohydrates or more -- enough to cause blood sugar spikes and subsequent insulin crashes. The journal New Scientist also reported that putting milk in tea can reduce the nutritional benefits outlined above.