The Physics Police

The Physics Police

Saturday, March 9, 2013

Aspartame vs. Fruit

The fear mongers are at it again! I recently found this Mercola article strewn about the blogosphere. It points the finger at methanol, a part of the Aspartame molecule. It's a long article, and has a lot of cool chemistry in it, but this headline tells the story pretty well:
Aspartame Poses Major Biochemical Problems in Humans
Included in the article is an interview with Dr. Woodrow Monte, who rambles on for 15 minutes about how dangerous methanol is. For sure, high doses of methanol, also known as Wood Alcohol, are very dangerous! But methanol has a natural level in the human body of 0.4 ppm. Evolution has adapted our bodies to handle small doses from natural sources. For example, eating fruit can double that concentration of blood methanol. (Source)

The main point in this Mercola article is that Aspartame delivers methanol to the body more readily than does fruit. This is true! Now, don't turn your brain off, yet, because this is where it gets interesting. Some basic math will show that, even if 100% of the methanol component of Aspartame is taken up by the body, the dose you get from a can of soda:

1 can = 180 mg Aspartame = (10% * 180 mg) = 19.8 mg methanol

Is less than you get from eating three apples:

3 apples = 3 * (182 grams fruit) * (0.000038) = 20.7 mg methanol

Where did that ratio come from? First, I found the amount of methanol absorbed by the body from 100 ml of brandy:
(100 ml * 0.19%) = 0.19 ml = 19 mg methanol

The study sourced above shows the same load of methanol is found in the body from half a kilogram of fruit. Some of the methanol did not get shat out with pectin, but instead, was absorbed into the blood! We calculate the ratio of fruit matter which represents this absorbed methanol as:

(19 mg methanol) / (0.5 kg fruit) = 19 mg / 0.5 kg = 0.000038

That means one can of soda gives you all the poison of 3 apples, with none of the calories! But seriously, the dose from a can of soda is not large, nor is it, by any stretch of the imagination, dangerous. If you drink a lot of diet soda, you have a lot more to worry about than methanol, like the carbon dioxide in the bubbles, which is bad for your teeth.

Whatcha gonna do, Dr. Monte and Dr. Mercola, when the Physics Police come for you?