Why Am I So Sensitive to Chemicals?
By Jessica Pizano
quickly enough I would get a headache and have an asthma attack. When my parents repainted my bedroom when I was 11 years old, the smell of the paint made me so sick that I could not sleep in the room for more than a week. You may ask yourself why such a young child could not tolerate perfumes and paint. The simple answer is that I grew up five minutes away from a chemical plant that is now classified as a Superfund site. In particular, this company was pol- luting the air and water with a chemical called xylene. Xylene is a petrochemical that is aromatic in nature and similar to benzene and toluene. It can be found in solvents, paints, dry erase markers, cleaning agents, printing, rubber, airplane fuel and gasoline. Xylene vapor is known to cause headaches, dizziness, nausea, vomiting, and breathing issues. Miraculously, when I left home to attend col- lege my constant asthma symptoms went away. I did really well until I moved into my current home which is, unfortunately, across the street from a major highway. Over time my asthma symptoms slowly returned. My ability to be around perfumes, scented candles, paint, walk through the laundry detergent aisle at a grocery store or even go into stores like Home Depot was lost.
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Why is it that I am so sensitive to chemicals while others in a similar situation have little to no problem? The answer is genetics. In order to detoxify appropriately we need to be able to synthesize glutathione, a major antioxidant. Glutathione is created from three amino acids: glutamine, cysteine and glycine. This antioxidant is then required by our cytochrome P450 system within the liver to help detoxify various medications, environmental toxicants, hor- mones and other metabolic byproducts. While everyone has the ability to synthesize glutathione to some extent, a variety of genetic single nucleotide polymorphisms (SNPs—pronounced “snips”) can impair this process causing decreased levels of glutathione. SNPs is a fancy term meaning that there is a misspelling in the DNA code that causes a change in function to the gene. To be classified as a SNP, the misspelling must occur in at least one percent of the popu- lation.
Cystathionine Beta Synthase (CBS) There are quite a few SNPs that may cause problems in glutathi- one production. One such SNP is cystathionine beta synthase (CBS). This is an enzyme that is involved in the methylation pathway. Meth- ylation means the attachment of methyl groups to DNA at cytosine bases and is correlated with reduced transcription of the gene. More simplistically, it is responsible for turning genes off. This is important
26 Natural Nutmeg - March 2017
s a young child, I remember being allowed by my parents to run ahead through the department store’s perfume section as long as I waited on the other side. If I didn’t get through
because when a genetic SNP is active it can cause problems for the individual. Genes, thankfully, are not always active. They require an epigenetic influence. This is an environmental trigger such as stress, bacterial or viral infection, pollution, or poor lifestyle.
At the center of the methylation pathway is homocysteine. If this sounds familiar to you it is because it is often run by physicians as a blood test to determine risk for cardiovascular disease and miscar- riage. It is influenced by three vitamins: B12, B6 and folate. The reason that these vitamins are important for the breakdown of ho- mocysteine is because they serve as cofactors (helpers) for enzymes within the methylation pathway. In the case of the CBS enzyme, it requires vitamin B6 to convert homocysteine to cystathionine (an amino acid—building block of protein). Cystathionine then leads to another pathway called transsulfuration. Transsulfuration allows for the formation of sulfate, taurine and glutathione. Therefore, it is really important for the CBS enzyme to work effectively or there may be decreased levels of glutathione available for detoxification. If you noticed within the name “transsulfuration” we have the word “sul- fur,” this is because cysteine is a sulfur-based amino acid. Sulfur is a mineral found in animal proteins; cruciferous vegetables including cabbage, kale, Brussels sprouts, cauliflower and broccoli; vegetables in the onion family including onions, shallots, leeks, green onions, chives and garlic; other vegetables such as asparagus and spinach; and in wines with sulfites.
There are two well-known SNPs to the CBS enzyme. Yes, you
can have more than one SNP to a single enzyme. This is because for every enzyme there are multiple genetic variants that code for the enzyme. This is how our genetics prevent any one enzyme from losing complete function (which could result in death). For CBS, we have a slow variant, CBS A360A, and a fast variant, CBS C699T. What this means is that with our slow variant we will have decreased conversion of homocysteine to cystathione. This causes a backup of homocysteine increasing its levels in the blood. In this case, simply increasing intake of the enzyme’s cofactor vitamin B6 will help the enzyme function more effectively and therefore help the body produce more glutathione. One could also use supple- ments to help increase the three amino acids required to make glu- tathione. This would include L-glutamine, N-Acetyl Cysteine (NAC) and glycine.
For those with the fast variant, unfortunately, things are a bit more complicated. What happens is that sulfur comes rushing through CBS at a rate that overwhelms a lower capacity enzyme further down in the pathway called sulfite oxidase (SUOX). Since the
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