By, Jennifer Giffune, R.D., L.D.N.
Is there anything more soothing than a hot cup of tea on a cold winter night or after a stressful day? Most people know that a steaming cup of tea helps with a sore throat. But what about drinking tea to promote weight loss or manage disease? Is it time to get a prescription for that teacup?
Green and black teas comefrom the leaves of Camelia Sinensis plant. The Green tea leaves are heat treated at harvest, which is the only processing step. Black tea goes thru additional treatment, making them quite different. It is Green tea that is linked to helping with a host of medical conditions ranging from obesity to cancer to diabetes and heart health.
Green tea is a nutritional powerhouse thanks to the naturally existing plant chemicals known as Catechins. There are three key Catechins – Epigallocatchine gallate (EGCG), Epigallocatechin (ECG) and Epicatichin (EC). The heat treatment at harvest is what preserves these Catechins so that we can potentially reap the benefits from Green tea.
Green tea research presents a mixed bag of results. It is proven to help with heart health by lowering Total Cholesterol, Low Density Lipoprotein (LDL’s – the bad cholesterol), Triglycerides and blood pressure as well as raising High Density Lipoproteins (HDL’s- the good cholesterol). Although it has been show to lower the risk of developing Type 2 Diabetes, it doesn’t stand up to claims that, once diagnosed, blood sugar decreases with Green tea. Risk of Ovarian Cancer is lower with regular consumption of Green tea, but has no effect when there is a reoccurrence. And the evidence is inconclusive as to whether or not it decreases risk of any other cancer. Green tea alone is ineffective in promoting weight loss. But add caffeine, and the scale tips downward.
If you decide you want to go ahead and try Green Tea, keep in mind that they have only studied green tea for up to 14 months; meaning the effectiveness for longer use is unknown. In studies, the dosages of the Catechins have ranged from 140- 1200 milligrams (mg.) each day. To put that in perspective, an 8-ounce mug of hot Green tea has about 50- 320 mg. depending on how long you brew it.
So, is Green Tea safe? So far, there have been no adverse effects reported from Green tea at low caffeine dosages. It is recommended that brewed Green tea be limited to 3 cups/day. If you are choosing a pill, know that there have been no observed adverse effects from 2500 mg. green tea extract/kilogram body weight per day. Having said that, if you are choosing a pill, it is the caffeine that is the problem. A caffeine dose of >250 – 300 mg. a day can lead to significant health problems such as raising blood pressure, increasing blood sugar, aortic stiffness, skin reactions, stomach issues (e.g. gassiness, heartburn, nausea, pain, diarrhea, constipation), anemia, liver damage, muscle pain, dizziness, headache, nervousness, asthma and urinary problems. Women who are pregnant or lactating need to limit Green tea due to the caffeine.
There are interactions with certain drugs and herbal supplements/vitamins. If you are regularlyconsuming Green tea ask your PCP whether or not to continue having it if you take a prescription or over-the-counter pill/herbal (see below):
Drug Interactions with Green tea:
- Adenosine
- Amphetamines
- Birth control pills
- Cimetidine
- Clozapine
- Diabetes medications
- Dipyridamole
- Disulfira
- Ephedra
- Estrogen
- Fluconazole
- Lithium
- MAO’s
- Mexiletine
- Nicotine
- Pentobarbitol
- Phenylpropanolamine
- Quinolone antibiotics
- Riluzole,
- terbinafine
- Theophylline
- Varapamil,
- Warfarin
Herbal Supplements/Vitamins Interactions with Green tea:
Angelica
Bishop’s weed
Bitter orange
Borage
Calcium
Chaparral
Clove
Cola
Creatine
Danshen
Ephedra (Ma Huang)
Folic acid
Garlic
Ginger
Ginkgo
Guarana
Iron
Magnesium
Mate
Panax ginseng
Uva ursi
Regular intake of Green tea may also be a problem the next time you get tested at a lab. It can interfere with many tests, such as:
5 Hydroxyindoleacetic Acid, Bleeding time, catecholamine, creatine, dipyridamole thallium imaging,ferritin, glucose, hemoglobin, iron, lactate, liver function ,neuroblastoma tests, pharmacological stress tests, pheochromocytoma tests, pulmonary function tests, theophylline, urate, urinalysis, urinary calcium and vanillylmandelic acid. Again, check with your PCP before you go for testing, to see if you need to stop Green tea for a period of time.
Green Tea, and the powerful Catechins contained within, needs much more research before it can be called a prescription for good health. However, in moderate doses, with an eye on caffeine, it certainly offers promise as well as a way to relax and soothe your soul.
Jennifer Giffune, R.D., L.D.N. is a freelance author, professional speaker and nutrition counselor. On the last Wednesday of each month, Jennifer can be heard on 89.5 WSKB radio on the “Wake up Wednesday Morning” Show. To make an appointment with Jennifer at Mercy Medical Group, call 786-1500.
