Chocolate in Science – About Antioxidants

Not too long ago I posted about a research article describing how the chemicals in chocolate can help prevent cells from dying. I came across an article published last month detailing the antioxidant content of dark chocolate and cocoa, explaining what the antioxidants were and how much is absorbed by the body.

The review paper is called “Theobroma cacao L., the Food of the Gods: A scientific approach beyond myths and claims” (M. Rusconi and A. Conti, Pharmac. Res. 2010 (61): 5-13) and discusses a few interesting points I wanted to share.

The amount of antioxidants, or polyphenols, in a dark chocolate bar varies greatly between manufacturers. In fact, beans from different countries can have different levels of polyphenols, then, depending on the fermentation, roasting and manufacturing processes, the amounts are further varied. A typical dark chocolate bar (greater than 35% cacao) can have anywhere from 0.3 – 2.5 g of antioxidants per 100 g of chocolate. That’s a pretty big range, and unfortunately there’s really no way to tell unless you analyze the chocolate in a lab, and most chocolate makers don’t do that. So, while a higher percentage of chocolate most likely contains more antioxidants, it’s not always certain.

The majority of antioxidants in chocolate are called catechins (same ones as found in green tea..) or are groups of two catechins (or dimers, called procyanidin).  When you eat chocolate, the dimers can break in half in your stomach, which makes it easier for them to be absorbed into your bloodstream in the intestines. It also doesn’t seem to matter if you eat chocolate or drink cocoa – the catechins are still found in your bloodstream relatively quickly after eating. This contradicts an older study that said the presence of milk prevents the absorption of catechins, though they are not sure why. I guess this is still something open to debate and study.

Chocolate is the third greatest source of antioxidants in the American diet, after fruits and vegetables! However, I highly doubt people will start saying “A chocolate bar a day keeps the doctor away.” It can certainly help increase your antioxidant intake, but the typical chocolate bar is also a great source of fat and sugar. That doesn’t really stop me from eating a lot of it, though 🙂

Published in: on February 25, 2010 at 11:01 am  Leave a Comment  
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Chocolate in Science

I’m always the first one to roll my eyes at the latest “study” that came out touting the antioxidant or other health related properties of various foods (chocolate, wine, etc). Sure, a lot of them are based on what I would consider “real science” but get a bit blown out of proportion by the media. However, today I was doing a literature search (“scientist” is my day job) and came across a paper entitled: “Protective Activity of Theobroma cacao L. Phenolic Extract on AML12 and MLP29 Liver Cells by Preventing Apoptosis and Inducing Autophagy.” (Arlorio, M et al. J. Agric. Food Chem. 2009 (57): 10612-10618) It immediately caught my eye because it had Theobroma cacao in the title, and as I read it, I found it to be very interesting and wanted to share the main findings.

To sum up (and translate the title!), there are small molecules in chocolate called phenols which the researchers extracted from both roasted and unroasted cacao beans (for comparison). They fed them to liver cells and observed some interesting results. After letting the cells “consume” the chocolate chemicals, they added celecoxib (CLX), which is an anti-inflammatory drug that is known to kill liver cells by causing them to go into a process called apoptosis. Apoptosis is also known as programmed cell death, or cell suicide, and is a very complicated process by which cells detect that they are damaged or under too much stress and gradually shut down and die.

They looked at the cells after giving them CLX to see how many were still alive. More cells survived if they had been fed chocolate. The researchers showed that the chemicals in chocolate can actually protect the cells from apoptosis and keep them alive so they have a chance to recover. That’s pretty cool! That means it could be possible to help protect your liver from disease by eating chocolate!

A few disclaimers: The study was done in vitro which means in glass, so the cells are not in their natural environment. Therefore, it is possible that cells behave differently in the body than they do in a petri dish. In addition, unroasted chocolate was better than roasted chocolate in this study, but we usually eat chocolate that has been roasted. There are more, but I won’t get into them here.

However, who doesn’t love a good excuse to really enjoy that dark chocolate bar? 🙂

Published in: on December 8, 2009 at 3:43 pm  Comments (1)  
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