Black Tea Is More Effective in Activating Superoxide Dismutase (SOD) than Green Tea

Once you go green, you could always go black. (Photo by mckaysavage)

Green tea is all the rage these days, but there are some areas where black tea simply performs better.

One such area has to do with superoxide dismutase (SOD), an enzyme that repairs cells. Superoxide dismutase reduces the damage done to cells by superoxide, which is the most common free radical in the body. In addition to this antioxidant effect, SOD acts as an anti-inflammatory and is also involved in the production of skin cells.

In short, superoxide dismutase is a good thing. Even better is that tea, especially black tea, seems to increase its activity.

A study on rats by Zeyuan et al. reports:

During a 75 day feeding experiment of rats consuming diets with addinged green tea (GT), black tea (BT), and their water extracts (GTWE, BTWE), blood glucose was significantly decreased in all experimental groups, by averages of 23.9% in GT and GTWE and by 22.8% in BT and BTWE; the blood triglycerides were significantly reduced, by 33.3% in GT and GTWE and by 25.0% in BT and BTWE.

The activity of superoxide dismutase was significantly increased, by averages of 117.0% in BT and BTWE and 90.8% in GT and GTWE. However, malondialdehyde was significantly decreased, by averages of 34.6% in BT and BTWE and 25.4% in GT and GTWE.

This indicated that the ability of green tea to reduce blood glucose and blook triglycerides was higher than that of black tea in the aged rats but that the antioxidative ability of black tea was better than that of green tea in the aged rats.

What the above means is that while green tea was very effective in increasing SOD activity (almost a 100% increase), black tea was even more effective. Clearly, while the fermentation process removes some of the catechins in tea, it has some beneficial consequences as well.

Note that green and black tea also had positive effects on blood glucose levels, triglycerides and malondialdehyde.

For diabetics or those thinking of adding tea to their diet to help with weight loss, these results look quite promising. Reduced triglycerides from tea consumption is also good news. Here green tea wins, but black tea performed pretty impressively too; one third reduction for green tea and one fourth reduction for black tea. Nothing to sneer at. Malondialdehyde, which is a product of lipid peroxidation that is mutagenic and carcinogenic, was reduced more by black tea than green tea, although both showed significant reductions.

One thing to keep in mind is that the amounts used in this study were higher than the average tea consumption. The average tea drinker consumes about 6 grams of tea per day, which is equal to 3 tea bags.

The rats in the study, on the other hand, consumed 5, 10 and 20 times the human dose. SOD activity increased with the dosage in both green tea and black tea groups. However, even with the lowest dose of brewed black tea, which was only 5 times more than the average human consumption, SOD activity almost doubled; the larger doses did increase it even further, but not as significantly. When black tea leaves were mixed in the rat chow instead of feeding them brewed black tea, the effects were similar.

Green tea behaved somewhat differently. With brewed green tea, the lowest dose increased SOD only slightly, but the middle dose was more than twice as effective as the lowest dose. The highest dose didn't improve SOD further than the middle dose. When green tea leaves were consumed with the feed, the middle and high doses more than doubled SOD activity, but the lowest dose had only a slight effect.

Applying these findings to humans means that in order to get optimal results, you'd have to consume 60 grams of green or black tea (i.e. the middle dose), which is equal to a respectable 30 cups of tea per day. Unfortunately increases in bladder size were not studied.

Still, the results are impressive, and drinking 2-10 cups of tea (or taking a tea extract supplement) will very likely have at least some beneficial effect.

And if Earl Grey is more your cup of tea than Japanese sencha, these results are something you can relate to all your trendy friends who are hating on old-fashioned black tea for no good reason.

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Signaling Protein Ephrin-A3 Grows New Hair Follicles and Thicker Hair

Could Ephrin-A3 help you grow your very own fur coat? (Photo by Stephen Barnett)

For those interested in the latest studies regarding hair loss, here's an interesting paper by Yamada et al. from this month's issue of the Journal of Dermatological Science:

Ephrin-A3 not only increases the density of hair follicles but also accelerates anagen development in neonatal mice

BACKGROUND: Ephrins are cell-membrane-bound ligands for Eph receptor tyrosine kinases (Eph). Although ephrins are known to regulate a variety of developmental processes, little is known of their role in hair development. Previously, we studied the gene expression of dermal papilla cells from androgenetic alopecia and found that ephrin-A3 was significantly down-regulated.

OBJECTIVE: To characterize the expression of ephrin-A3 in the hair cycle and evaluate the effect of ephrin-A3 on hair growth.

METHODS: We investigated gene expression and protein expression of each ephrin-As and EphAs in the skin of neonatal mice through the first and second hair cycle using quantitative PCR and immunohistochemical analysis, respectively. We also injected ephrin-A3 protein into the skin of neonatal mice and demonstrated the effect of ephrin-A3 on hair follicle development.

RESULTS: Expression of ephrin-A3 revealed a rapid increase at the beginning of the anagen phase, a peak during the mid-anagen, and a rapid fading during the telogen phase. In addition, we found ephrin-A3 protein was expressed in the developing hair follicles with a characteristic spatiotemporal localization. Furthermore, injection of ephrin-A3 into the skin of neonatal mice markedly accelerated the differentiation process of hair follicles. In addition, injection of ephrin-A3 unexpectedly increased the number of hair follicles.

CONCLUSION: These findings demonstrated that ephrin-A3 not only accelerates anagen development but also increases the density of hair follicles, and also suggested that an ephrin-A-EphA signal pathway is closely involved in hair follicle development.

What the study says is that ephrin-A3 – a signaling protein – is expressed more when the hair follicle is in its growing (anagen) phase and less in its resting (telogen) phase. When this protein is injected into the skin, three things happen: new hair follicles are formed, the hair follicles grow deeper, and hair grows thicker.

The results look promising, but how and when these results can be applied to humans remains yet to be seen.

For more information on hair growth, see these posts:

Asiasari Radix Extract Grows Hair in Mice and in Human Skin Cells
Vitamin E Tocotrienols May Grow Hair in Humans
Green Tea Extract Grows Hair in Vitro, May Work in Vivo
1,000-8,000 mg of MSM Has No Effect on Hair & Nail Growth - Experiment Conclusion

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Coconut Lowers LDL, VLDL and Triglycerides, Raises HDL

All coconut products seem to be beneficial for cholesterol. (Photo by yimhafiz)

There is some confusion over whether coconut products like coconut oil, coconut water and coconut flakes raise or lower cholesterol levels. The traditional wisdom is that all saturated fats raise cholesterol, and as coconut is high in saturated fat, most people expect it to raise cholesterol.

However, in recent years, this theory has been criticized as more and more studies have shown beneficial effects from saturated fats and negative effects from polyunsaturated fats. Coconut especially seems to have positive effects on cholesterol and triglyceride levels. Trinidad et al. report:

This study investigated the effect of coconut flakes on serum cholesterol levels of humans with moderately raised serum cholesterol in 21 subjects. The test foods were as follows: corn flakes as the control food, oat bran flakes as the reference food, and corn flakes with 15% and 25% dietary fiber from coconut flakes (made from coconut flour production).

Results showed a significant percent reduction in serum total and low-density lipoprotein (LDL) cholesterol (in mg/dL) for all test foods, except for corn flakes, as follows: oat bran flakes, 8.4 ± 1.4 and 8.8 ± 6.0, respectively; 15% coconut flakes, 6.9 ± 1.1 and 11.0 ± 4.0, respectively; and 25% coconut flakes, 10.8 ± 1.3 and 9.2 ± 5.4, respectively. Serum triglycerides were significantly reduced for all test foods: corn flakes, 14.5 ± 6.3%; oat bran flakes, 22.7 ± 2.9%; 15% coconut flakes, 19.3 ± 5.7%; and 25% coconut flakes, 21.8 ± 6.0%.

In conclusion, both 15% and 25% coconut flakes reduced serum total and LDL cholesterol and serum triglycerides of humans with moderately raised serum cholesterol levels. Coconut flour is a good source of both soluble and insoluble dietary fiber, and both types of fiber may have significant role in the reduction of the above lipid biomarker.

What this study shows is that oat bran flakes and coconut flakes reduced LDL and triglycerides. Coconut was the most effective in reducing LDL, while oat bran was most most effective in reducing triglycerides. Looking at the full paper, HDL levels were slightly reduced in all subjects, but the authors conclude that this change was insignificant. Corn flakes reduced triglycerides but did not have a lowering effect on LDL (in fact, there was a statistically insignificant increase).

Coconut water seems to have a similar effect, at least in rats. Sandhya & Rajamohan report:

The purpose of this study was to determine the effect of coconut water feeding in cholesterol-fed rats. Male albino rats were fed tender coconut water and mature coconut water at a dose level of 4 mL/100 g of body weight.

Cholesterol feeding caused a marked increase in total cholesterol, very low-density lipoprotein (VLDL) + low-density lipoprotein (LDL) cholesterol, and triglycerides in serum. Administration of coconut water counteracts the increase in total cholesterol, VLDL + LDL cholesterol, and triglycerides, while high-density lipoprotein cholesterol was higher. Lipid levels in the tissues viz. liver, heart, kidney, and aorta were markedly decreased in cholesterol-fed rats supplemented with coconut water.

An increased rate of cholesterol conversion to bile acid and an increased excretion of bile acids and neutral sterols were observed in rats fed coconut water. Histopathological studies of liver and aorta revealed much less fatty accumulation in these tissues in cholesterol-fed rats supplemented with coconut water. Feeding coconut water resulted in increased plasma L-arginine content, urinary nitrite level, and nitric oxide synthase activity. These results indicate that both tender and mature coconut water has beneficial effects on serum and tissue lipid parameters in rats fed cholesterol-containing diet.

Again, LDL and triglyceride levels were reduced. Especially important is that the harmful form of LDL, very low-density lipoprotein (VLDL) was lowered when coconut water was present in the diet. Unlike the previous study, this one also showed an increase in HDL levels.

Cox et al. compared the effects of butter, coconut fat and safflower oil on cholesterol:

Objective: The aim of this present study was to determine plasma levels of lathosterol, lipids, lipoproteins and apolipoproteins during diets rich in butter, coconut fat and safflower oil.

Design: The study consisted of sequential six week periods of diets rich in butter, coconut fat then safflower oil and measurements were made at baseline and at week 4 in each diet period.

Subjects: Forty-one healthy Pacific island polynesians living in New Zealand participated in the trial.

Results: Plasma lathosterol concentration (P<0.001), p="0.04),"> Plasma total cholesterol, HDL cholesterol and apoA-levels were also significantly (P£ 0.001) different among the diets and were not significantly different between butter and coconut diets.

Conclusions: These data suggest that cholesterol synthesis is lower during diets rich in coconut fat and safflower oil compared with diets rich in butter and might be associated with lower production rates of apoB-containing lipoproteins.

The figures in the full paper show that total cholesterol and LDL levels were highest during the butter diet and lowest during the safflower oil diet. On the other hand, VLDL levels were highest during the safflower oil diet and lowest during the butter diet; so even though butter seems to raise LDL, it doesn't raise VLDL, which is the one harmful form of LDL. Coconut oil values were somewhere in the middle between butter and safflower oil values.

As for HDL and triglycerides, coconut oil takes the cake. HDL levels were highest during the coconut oil diet, and lowest during the safflower diet, while triglyceride levels were highest during the butter diet and lowest during the coconut diet.

So what should we make of all this? Based on these studies it seems pretty clear that coconut – regardless of whether it's coconut water, coconut oil or coconut flakes – reduces LDL, VLDL and triglycerides and slightly raises HDL. This is exactly what you'd want to happen with your cholesterol levels.

These results certainly suggest that coconut is good for cholesterol and at the same time cast doubt on the claims about saturated fat always being harmful.

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