Is It Bad for Me? (pt. 3)

Welcome to part 3 of ‘is it bad for me?’ In this edition, I will be talking about the safety profile of everyday chemicals that have been rumored to be toxic/dangerous. If you’re one of those people who are hesitant to eat foods with MSG, or to apply deodorant or bug spray (I dedicate that section to Gil, my husband, who gave me the idea to research it), you should probably read on…

Monosodium glutamate (MSG) is a water soluble salt of L-glutamate and is a naturally occurring amino acid found in tomatoes, aged cheeses, fish, mushrooms(1), and cooked and aged meats(2). MSG has gotten a bad rap for decades based on one guy who got weird symptoms every time he ate Chinese food and then published a letter in the New England Journal of Medicine in 1968.

Over the years, many researchers have studied the effects of MSG on both animals and humans and have not been able to identify any ill effects of consuming MSG. It turns out your body can’t distinguish between glutamate naturally found in food and MSG added for flavor. In fact, the amount of MSG added to your food is probably far less than the amount of glutamate that you’re consuming in foods it’s naturally found in (just think about it- one slice of pizza with tomato sauce, cheese, mushrooms, and anchovies and you’re drowning in it). Any glutamate consumed is completely metabolized by your digestive tract(3). There is however a small percentage of people with MSG intolerance, and those people should probably avoid it if the symptoms bother them enough.

So, in short, it’s safe in normal doses in food, and as long as you don’t inject it into yourself. Which you probably weren’t considering doing anyway but just in case, I thought I would mention it.

I’ve heard whispers over the years about the dangers of deodorant but have never taken them particularly seriously. But I figured this was as good a time to look into it as any.

The main ingredients that could potentially be problematic are aluminum and parabens. Some people think that aluminum can penetrate your skin and cause breast cancer(4). While it’s true that small amounts of aluminum do enter the tissue, no methodologically sound studies have found that the miniscule amount of aluminum that enters the body from a few rubs of antiperspirant is enough to be carcinogenic or cause breast cancer and there have been no studies showing a correlation between the two(5,6).

Parabens on the other hand have estrogenic activity by binding to estrogen receptors and are very highly absorbed by the skin (20–60% of the applied amount was absorbed through the skin in rabbits, depending on the type of paraben). At the highest concentrations of parabens found in humans, rats showed estrogenic effects due to the parabens. So far, despite many studies finding excessive concentrations of parabens in breast tumors, no cause and effect relationship has been found(7). Most antiperspirant companies have stopped adding parabens anyway just in case.

Deet (N,N-diethyl-m-toluamide), a chemical found in many bug sprays, has also gotten a bad rap over the years. It was first developed in 1946 for use in the US army and was authorized for commercial use in 1957(8).

There were concerns about the safety of DEET after several reports of encephalopathy (brain dysfunction) came out in the 80’s, but after extensive testing, no connection has been found and no severe adverse effects or toxicity have been observed(9).

In 2014, the American environmental protection agency did a safety reassessment to make sure it still meets safety standards. While it is considered safe when used properly, the proper usage of Deet is very important and not a trivial matter. It’s important not to use more than you need (the exact percentage that will last for the amount of time in which you will be outside), and not to apply to any location on your body where you risk ingesting it (hands, mouth, etc.). Don’t spray it indoors or on your clothing, just directly to skin. Basically, read the instructions before using bug spray containing DEET.

Bibliography

1. Is MSG Bad for You? The Truth Behind Monosodium Glutamate [Internet]. [cited 2023 Sep 30]. Available from: https://www.prevention.com/food-nutrition/healthy-eating/a38917726/msg-good-or-bad/

2. Brosnan JT, Drewnowski A, Friedman MI. Is there a relationship between dietary MSG and [corrected] obesity in animals or humans? Amino Acids. 2014 Sep;46(9):2075–2087.

3. Henry-Unaeze HN. Update on food safety of monosodium l-glutamate (MSG). Pathophysiology. 2017 Dec;24(4):243–249.

4. Deodorant — Penn Medicine [Internet]. [cited 2024 Apr 27]. Available from: https://www.pennmedicine.org/updates/blogs/health-and-wellness/2019/june/deodorant

5. OPINION. Scientific Committee on Consumer Safety’ ‘ SCCS.

6. Use of Aluminium in Antiperspirants.

7. Matwiejczuk N, Galicka A, Brzóska MM. Review of the safety of application of cosmetic products containing parabens. J Appl Toxicol. 2020 Jan;40(1):176–210.

8. DEET | US EPA [Internet]. [cited 2024 Aug 3]. Available from: https://www.epa.gov/insect-repellents/deet

9. Chen-Hussey V, Behrens R, Logan JG. Assessment of methods used to determine the safety of the topical insect repellent N,N-diethyl-m-toluamide (DEET). Parasit Vectors. 2014 Jun 3;7:173.