Herbal corner: Is green tea beneficial in kidney disease?

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Many herbal preparations have been marketed to patients with all manner of diseases ranging from the common cold to incurable cancer. Green tea however has been the focus of much main stream research recently with several studies of its efficacy being published. It has been shown to be effective in weight loss particularly in men, it has been shown at high concentrations to inhibit the growth of cancer cells in the lab and population studies have demonstrated some positive results where high intake of the tea reduces the incidence of gastric and esophageal cancer. There is an old saying that goes where there is smoke there is also fire. Applied to this case it would seem that there is something in green tea with very useful effects something that maybe if extracted purified and amplified may lead to a new drug. The problems with herbs however is that there are frequently impure and have many thousands of chemicals that have to be sifted through to obtain the one with the most useful medicinal effect. There is also the possibility that some useful combination of active ingredients may interact in a manner based on relative concentrations that we do not yet understand to produce the desired effect. All of this is relatively complex business and will take quite a bit of time to sort out.

What we can report currently, is that one of the most useful compounds to be derived from green tea or Camellia sinensis is EGCG. This compound is one of the most potent antioxidants ever encountered. It is likely to play a significant role in the health benefits to be derived from green tea. Administration of this compound has been shown to reduce the growth of renal cell carcinoma by a new mechanism, which incidentally is the first report of its kind for green tea.

The extracts of green tea had previously been shown to protect the kidney from drug induced damage which is common with the administration of certain antibiotics such as gentamicin.

Green tea extract has also been shown to have a potential therapeutic benefit in diabetic induced kidney disease as published here.

All of the data so far is pointing towards benefit but is there any chance of harm, how does green tea interact with medication that patients with kidney disease may be taking?

People who take warfarin, a blood thinning medication should not drink green tea. Green tea contains vitamin K and as such should be avoided for this patient group. Green has an effect on platelets, it makes them less sticky. This effect also occurs with aspirin which means combining the two may cause bleeding. In patients with chronic kidney disease which is quite severe or in patient with an acute deterioration in kidney function this may be harmful as the platelets within the body which are responsible for preventing bleeding may already be dysfunctional, green tea may cause bleeding in such patients. As with any herbal treatment or new medication speak with your health care provider before initiating treatment even if the substance is considered a food supplement such as green tea is.