I like Coffee and Green Tea

14 09 2010

I get tons of questions about coffee and tea.  Here is the thing that may surprise you.  I like them both.  I frequently tell people to stop drinking sodas and energy drinks because they are Bad for your health and switch to Green Tea.

Below is some research that supports my point of view.  This was written by my friends that own the best fish company in America, Vital Choice.

Blood Doc John

Tea and Coffee May Deter DNA Damage
Less DNA damage was seen in people who took green tea supplements; Separate study found comparable DNA protection from drinking coffee; Coffee keeps accruing a healthier reputation

by Craig Weatherby

Green tea’s ancient reputation as a healthy beverage habit keeps accruing scientific support … and the results of a recent clinical trial add to that fast-growing pile

Together, the findings from hundreds of studies indicate that green tea may cut the risk of certain cancers, aid weight management, deter tooth decay, and help delay Alzheimer’s and other types of dementia.

And research increasingly indicates that tea and coffee alike confer some protection against type II (lifestyle-induced) diabetes, thanks to the polyphenol antioxidants found in both beverages.

The polyphenols in tea and coffee appear to counter the “oxidative stress” caused by excess free radicals … a phenomenon known to hamper insulin-secreting cells in the pancreas and raise levels of insulin resistance: two effects known to promote diabetes.

Tea is one of the richest sources of a potent class of polyphenol antioxidants called catechins, whose only other abundant source is non-alkalized cocoa and dark chocolate made from it.

Coffee provides very large amounts of polyphenols, and is the only common food source of chlorogenic acids … a unique class of polyphenol antioxidants that, among other healthful effects, reduce absorption of sugar from foods.

Two new studies support the DNA-protective potential of coffee and green tea. Let’s take a look at both, starting with the study on tea.

Chinese team finds DNA protection with green tea

Earlier this month, a team of researchers from Hong Kong’s Polytechnic University reported that drinking green tea every day for a month reduced DNA damage in people’s cells by one-fifth (20 percent) … with that benefit linked to tea’s antioxidant content (Han KC et al. 2010).

The Hong Kong team recruited 18 healthy volunteers, and assigned them to drink two cups daily of water, weak green tea, or strong green tea for one month.

The three groups then switched places for another four weeks (following a six-week “washout” period to allow all tea residues to leave their bodies).

Analysis of the participants’ blood before and after each tea-drinking period showed an average 20 percent reduction in levels of DNA damage in those who drank strong green tea.

In a separate test tube study, the researchers exposed human blood cells to green tea and then exposed them to a standard oxidizing agent (hydrogen peroxide), and found the DNA in tea-treated cells more resistant to oxidative damage.

Interestingly, a standard measure of “whole-body oxidative stress” was unaffected … a finding that fits with growing evidence that food-borne antioxidants do not reduce free radicals and consequent oxidative stress directly.

Instead, food-borne antioxidants seem to reduce DNA damage and inflammation by activating or deactivating various genes in ways that tend to reduce internal free radical production and optimize the performance of the body’s innate “antioxidant network” of vitamins (mostly C and E), enzymes, and compounds like melatonin and alpha lipoic acid

Despite tea’s lack of effect on one marker of oxidative stress, the Chinese study clearly showed DNA protection from tea, as the team wrote: “The results indicate that green tea has significant geno-protective [DNA-guarding] effects and provide evidence for green tea as a ‘functional food’.” (Han KC et al. 2010)

Coffee, too, may provide DNA protection

The popular perception that coffee must somehow be unhealthful persists despite compelling evidence that the beverage reduces risk of diabetes … and a lack of clear evidence for the claims that coffee raises levels of inflammation and stress hormones like cortisol (Zampelas A et al. 2004; Atanasov AG et al. 2006; Harris A et al. 2007; Kotani K et al. 2010; Maki T. et al. 2010; Kempf K et al. 2010).

Adding to the positive side of the coffee picture, the results of a new European study suggest that a daily cup of coffee may reduce the oxidative damage to human DNA by 12 percent (Mišík M et al. 2010).

Researchers from Vienna and Belgrade report that paper-filtered coffee – the most widely consumed form in the U.S. – may protect DNA against damage from oxidizing free radicals.

The Austrian-Serbian team recruited 38 people to participate in a controlled clinical trial in which the subjects were assigned to drink either 800 ml (27 ounces) of coffee or water daily for five days.

At the end of the study, the volunteers’ blood cells were tested for DNA damage, which dropped by 12.3 percent in the coffee drinkers.

As the European researchers wrote, “Overall, the results indicate that coffee consumption prevents endogenous [internal] formation of oxidative DNA damage in human[s] …” (Mišík M et al. 2010)

Interestingly, the scientists detected no significant changes in levels of antioxidants in the coffee-drinkers’ blood, or in their blood levels of free radicals, which scientists call “reactive oxygen species”.

Those findings support the emerging consensus that polyphenols – and other food factors that exert strong antioxidant effects in test tube experiments – do not exert direct strong antioxidant effects in the body.

Instead, the very small proportions of dietary polyphenols that survive digestion to end up in the bloodstream seem to reduce oxidative stress, inflammation, and DNA damage through their direct or indirect effects on the expression of genes that influence all three processes.

The study was funded by the Institute of Scientific Information on Coffee (ISIC) – a consortium formed by European coffee companies. Nonetheless, this research fits with other findings about coffee.

Coffee: A rising health star?

Coffee is often – but erroneously – blamed for various health ills, including increased stress resulting from overstimulation of the body’s adrenal gland.

These assertions get repeated continuously, even though moderate caffeine consumption is not associated with significant adverse health effects and produces proven brain performance benefits.

In addition, coffee is the biggest single source of broadly beneficial polyphenol-type antioxidants in the American diet, by far.

Polyphenols – which include flavonoids, tocopherols and tocotrienols (i.e., vitamin E), and stilbenes (e.g., resveratrol) – occur in virtually all fruits, vegetables, beans, and whole grains.

But they’re found most abundantly in cocoa, coffee, tea, berries, grapes, prunes, and other deeply colorful plant foods.

Coffee is the best common food source of chlorogenic acids … unique polyphenols that, as we said, reduce absorption of sugar from foods and are beginning to rival or even eclipse the apparent health benefits of other phenolic antioxidants.

This special sugar-blocking property of coffee’s chlorogenic acids matters because chronically elevated blood sugar levels promote diabetes, inflammation, and formation of sugar-protein compounds called AGEs (advanced glycation end products), which generate DNA-damaging free radicals.

The Austrian-Serbian group hypothesized that coffee may reduce DNA through the well-documented sugar-blocking power of chlorogenic acids … an effect that would reduce the production of free radicals inside our cells’ energy factories, called mitochondria.

This is how they put it:

“… indirect effects such as reduced uptake of glucose … which was seen with … coffee and with chlorogenic acids may play a role as it is known that alterations of energy [sugar] metabolism may lead to reduced reactive oxygen species [free radical] formation in the mitochondria.” (Mišík M et al. 2010)

So it seems long past time to give coffee a break, and stop feeling sorry for – or superior to – the many folks who look forward to taking a coffee break!


  • Atanasov AG, Dzyakanchuk AA, Schweizer RA, Nashev LG, Maurer EM, Odermatt A. Coffee inhibits the reactivation of glucocorticoids by 11beta-hydroxysteroid dehydrogenase type 1: a glucocorticoid connection in the anti-diabetic action of coffee? FEBS Lett. 2006 Jul 24;580(17):4081-5. Epub 2006 Jun 27.
  • Bichler J, Cavin C, Simic T, Chakraborty A, Ferk F, Hoelzl C, Schulte-Hermann R, Kundi M, Haidinger G, Angelis K, Knasmüller S. Coffee consumption protects human lymphocytes against oxidative and 3-amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2) induced DNA-damage: results of an experimental study with human volunteers. Food Chem Toxicol. 2007 Aug;45(8):1428-36. Epub 2007 Feb 12.
  • Ferruzzi MG. The influence of beverage composition on delivery of phenolic compounds from coffee and tea. Physiol Behav. 2010 Apr 26;100(1):33-41. Epub 2010 Feb 6. Review.
  • Han KC, Wong WC, Benzie IF. Genoprotective effects of green tea ( Camellia sinensis) in human subjects: results of a controlled supplementation trial. Br J Nutr. 2010 Sep 1:1-8. [Epub ahead of print]
  • Harris A, Ursin H, Murison R, Eriksen HR. Coffee, stress and cortisol in nursing staff. Psychoneuroendocrinology. 2007 May;32(4):322-30. Epub 2007 Mar 12.
  • Hoelzl C, Knasmüller S, Wagner KH, Elbling L, Huber W, Kager N, Ferk F, Ehrlich V, Nersesyan A, Neubauer O, Desmarchelier A, Marin-Kuan M, Delatour T, Verguet C, Bezençon C, Besson A, Grathwohl D, Simic T, Kundi M, Schilter B, Cavin C. Instant coffee with high chlorogenic acid levels protects humans against oxidative damage of macromolecules. Mol Nutr Food Res. 2010 Jun 29. [Epub ahead of print]
  • Kempf K, Herder C, Erlund I, Kolb H, Martin S, Carstensen M, Koenig W, Sundvall J, Bidel S, Kuha S, Jaakko T. Effects of coffee consumption on subclinical inflammation and other risk factors for type 2 diabetes: a clinical trial. Am J Clin Nutr. 2010 Apr;91(4):950-7. Epub 2010 Feb 24.
  • Kotani K, Sakane N, Yamada T, Taniguchi N. Association between coffee consumption and the estimated glomerular filtration rate in the general Japanese population: preliminary data regarding C-reactive protein concentrations. Clin Chem Lab Med. 2010 Aug 24. [Epub ahead of print]
  • Maki T, Pham NM, Yoshida D, Yin G, Ohnaka K, Takayanagi R, Kono S. The relationship of coffee and green tea consumption with high-sensitivity C-reactive protein in Japanese men and women. Clin Chem Lab Med. 2010 Jun;48(6):849-54.
  • Mišík M, Hoelzl C, Wagner KH, Cavin C, Moser B, Kundi M, Simic T, Elbling L, Kager N, Ferk F, Ehrlich V, Nersesyan A, Dušinská M, Schilter B, Knasmüller S. Impact of paper filtered coffee on oxidative DNA-damage: Results of a clinical trial. Mutat Res. 2010 Aug 13. [Epub ahead of print]

Zampelas A, Panagiotakos DB, Pitsavos C, Chrysohoou C, Stefanadis C. Associations between coffee consumption and inflammatory markers in healthy persons: the ATTICA study. Am J Clin Nutr. 2004 Oct;80(4):862-7.




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