Green tea and prostate cancer
Green tea and lung cancer
Green tea helps leukemia
Animal fat increases pancreatic cancer
GLA helps atopic dermatitis (eczema)
Moderate exercise lowers mortality
A number of recent articles have shown the benefits of green tea in both cancer prevention and treatment. Green tea is widely consumed around the world, especially in Asia. It originates in China, and unlike black tea (which also has health benefits) it is only minimally oxidized during processing (but the leaves are from the same plant, Camellia sinensis). Tea contains numerous healthy polyphenols including catechins, the most prominent of which is epigallocatechin gallate (EGCG). It also contains small amounts of other nutrient antioxidants and minerals.
EGCG is concentrated in standardized extracts of green tea, available in capsules. (This is one way to get the benefits without the caffeine in regular green tea, although decaffeinated green tea is available.) In a recent study, 26 men with positive prostate biopsies who were scheduled for radical prostate surgery were given 800 mg of EGCG per day (plus some other catechins) for 12 to 73 days. (McLarty J, et al., Tea polyphenols decrease serum levels of prostate-specific antigen, hepatocyte growth factor, and vascular endothelial growth factor in prostate cancer patients and inhibit production of hepatocyte growth factor and vascular endothelial growth factor in vitro. Cancer Prev Res (Phila Pa). 2009 Jul;2(7):673-82.)
Prior to surgery, the patients had a significant drop in their levels of prostate specific antigen (PSA) as well as improvements in other markers and liver function tests. In some cases the PSA declined by 30 percent. The study was not placebo controlled, so it is not certain that the results are from the treatment, but it is very suggestive. The dose of EGCG would be about the amount found in 12 cups of strongly brewed green tea.
Green tea is also associated with reduction in the growth of other cancer cells. In a laboratory study of “non-small cell” lung cancer cells (this is the most common kind of lung cancer), cells were tested with exposure to EGCG in a Petri dish and also in a mouse graft model of tumors. (Milligan SA, et al., The green tea polyphenol EGCG potentiates the antiproliferative activity of c-Met and epidermal growth factor receptor inhibitors in non-small cell lung cancer cells. Clin Cancer Res. 2009 Aug 1;15(15):4885-94.)
In the study, exposure to EGCG inhibited proliferation of cancer cells and colony formation. It also reduced the activity of an enzyme associated with tumor growth factors. The EGCG worked even in those cells that were resistant to the usually therapeutic agent (erlotinib). The combination of EGCG with the erlotinib was more effective than the drug alone.
In the mouse graft model, the combination of EGCG with erlotinib was more effective than the drug alone at slowing the growth rate of the grafts. This suggests yet again the value of consuming green tea or its extract.
A third study this month on green tea extract shows that it helps in the treatment of chronic lymphocytic leukemia (CLL). This is a bone marrow malignancy that more commonly occurs later in life, unlike the common forms of leukemia that occur in children and young adults. Lymphocytes called B-cells accumulate in the bone marrow and blood, and the disease is accompanied by enlargement of the lymph nodes, the spleen, and the liver. Because CLL is often slow growing, long-term survival is common.
In this research, 33 eligible patients were treated with one of eight different dose levels of EGCG, ranging from 400 to 2000 mg twice per day. (Shanafelt TD, et al., Phase I trial of daily oral Polyphenon E in patients with asymptomatic Rai stage 0 to II chronic lymphocytic leukemia. J Clin Oncol. 2009 Aug 10;27(23):3808-14.) One of the subjects experienced a partial remission with the treatment, but this was not the only benefit.
In 11 patients (33 percent), researchers observed a 20 percent reduction in the absolute lymphocyte count. Of the 12 patients with enlarged lymph nodes, 11 of them had a 50 percent reduction in lymph node number and enlargement. All of these effects were observed within one month of initiating treatment with EGCG. The treatment was very well tolerated, with not even the highest doses causing significant side effects. The side effects that were noted (nausea and abdominal pain) were minor and did not require discontinuation of the therapy.
Green tea extracts are available in capsule form for those who do not want to drink large amounts of it every day. Capsules that are standardized contain 98 percent polyphenols, including 50 percent EGCG. Thus a 500 mg capsule would have almost 250 mg of EGCG, and four of these capsules per day would be the low end of the dose given in this last study, and it would be higher than the dose given in the prostate cancer study.
In a prospective study of 525,473 men and women researchers analyzed their dietary intakes with a food-frequency questionnaire and related the results to the risk of pancreatic cancer over a 6.3-year period. They were evaluated for consumption of different types of dietary fat and a variety of other cancer risk factors to eliminate those as variables. (Thiébaut AC, et al., Dietary fatty acids and pancreatic cancer in the NIH-AARP diet and health study. J Natl Cancer Inst. 2009 Jul 15;101(14):1001-11.)
After adjustment for the different variables, those participants with the highest total fat intake had a 23 percent higher risk of pancreatic cancer than those with the lowest total fat intake. Those with the highest saturated fat intake had a 36 percent higher risk than those with the lowest saturated fat intake. The association was strongest for those with the highest saturated fat intake from animal sources, specifically red meat and dairy products; those with the highest intake had a 43 percent higher risk than those with the lowest intake.
All of the increased risk overall appears associated with animal fat intake. The intake of polyunsaturated fats was not associated with an increased risk. Non-animal sources of saturated fat include coconut oil, palm oil, and cocoa butter. They are apparently not related to pancreatic cancer, and several studies suggest that coconut and palm oils are not related to heart disease.
In a small but randomized, placebo-controlled study of 50 subjects with atopic dermatitis, gamma linolenic acid (GLA) from evening primrose oil reduced symptoms based on a predesigned scoring system of four parameters. These included the extent of the eczema, the intensity, itching, and dryness. The subjects were evaluated at the start of the study and after five months of treatment. (Senapati S, et al., Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial. Indian J Dermatol Venereol Leprol. 2008 Sep-Oct;74(5):447-52.)
At the end of the trial, 24 of the 25 patients given the GLA showed improvement while only 8 of the patients in the placebo group were better. Years ago some research suggested that GLA was effective for eczema, but studies since then were equivocal. This study confirms the original reports, but it is small and needs to be confirmed with further trials.
Evening primrose oil is not the only source of GLA, and omega-6 fatty acid. It is also found in black currant seed oil and borage seed oil. Borage is used as a fresh vegetable or dried herb (most frequently in Europe), although it’s most common use today is as a source of the oil containing GLA. It is the richest source of this fatty acid. The typical dose of GLA is 240 mg per day, which is found in one borage oil capsule, three black currant oil capsules or six primrose oil capsules.
Exercise plays a major role in reducing age-related mortality, and it appears from a recent research report that any exercise at all is helpful. Researchers followed 4384 subjects who were referred for exercise tolerance testing (treadmill test) from 1986 to 2006. they tracked them for an average of 8.7 years. (Mandic S, et al., Characterizing differences in mortality at the low end of the fitness spectrum. Med Sci Sports Exerc. 2009 Aug;41(8):1573-9.)
They divided the participants into five divisions (quintiles, Q1 to Q5) from lowest to highest exercise tolerance and physical activity levels. Those in the lowest quintile (Q1) had twice the mortality rate compared to those in the group just above them (Q2). This indicates that even a small amount of exercise makes a great difference in health risk. You do not have to be a marathon runner or professional athlete to get significant benefits from exercise (but more exercise does provide more benefits).
They derived this conclusion because the group in the lowest quintile had four times the age-related mortality risk compared to the highest quintile (Q5), while those in Q2 only had twice the risk of those in Q5 (most exercise). My conclusion is that a small amount of exercise is good, but more exercise is even better.
From these study results, we could have made a headline that said that people who do only a moderate amount of exercise have double the risk of mortality compared to those who exercise the most. This would reduce complacency and encourage people to do even more exercise.
Other studies have suggested that higher amounts of exercise provide more benefits than lesser amounts, but any movement at all is better than just being a couch potato playing with the remote control.
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