Are you being hosed by your laundry detergent?

Homeowner Newsletter: Summer 2018
©2018 Jeffrey C. May

Years ago, laundry detergents came in cardboard boxes filled with powder that you measured out or scooped into your washer. Today, most laundry detergents are liquids that you pour into the machine. Ever wonder why someone would want to add all that extra water weight to the detergent container? I have my theory, but explaining it will take a bit of your time, so bear with me, because understanding the transition from powder to liquid detergent should be very informative and may explain some of your allergies.

Laundry detergents have always been a mixture of chemicals to remove the components of soiling from clothing. The soiling can be from skin scales, dirt, food, oil, or blood among others, so the detergent ingredients must be chosen to help remove whatever caused the soiling. The detergent has to prevent the reattachment of the dirt from the water in the washing machine, and of course leave the clothing brighter looking as well.

In the late 1960s, Procter and Gamble (P&G) started adding protease (an enzyme) to detergents to help digest protein and blood stains. Enzymes in our stomachs and our intestines convert insoluble nutrients like starch in potatoes, as well as proteins and fats in meat, to soluble components. These components dissolve in the blood and flow to cells, where they are either reassembled again to sustain cell growth, or are “burned” to provide the energy needed for cell life.

In laundry detergents, enzymes break down proteins, so they help dissolve stains on clothing, bedding, and other materials that we put in a washing machine. The protease added to detergents is called subtilisin. It was originally produced by bacteria (Bacillus subtilis) bioengineered to make an enzyme that can remain active in hot wash water, as many enzymes are destroyed by heat.

Soon after the introduction of protease into the detergent production line, P&G began to notice an increase in the occurrence of occupational allergy and asthma. It was later determined that up to 50% of factory workers, exposed to the protease dust primarily by inhalation, had developed allergic sensitivity (including asthma) to the enzyme.

At the time, there was great concern that the health of consumers could be similarly affected if they were exposed to the detergent dust while loading their washing machines. Newspapers had alarming articles about the risks of exposure to the enzymes.

What’s the big deal about enzymes?

Probably half of the common allergens to which we are exposed are proteins, including enzymes. Our bodies can react strongly to “foreign” enzymes. For example, both of the primary allergens from the notorious dust mite are proteases found in the mite droppings that are inhaled when dust from mite infestations is disturbed.

There are even components of the immune system called protease-activated receptors (PARs) that are activated when a foreign protease is detected in our bodies.

P&G admitted that occupational exposure was a risk to workers (and they took great pains to reduce dust exposures in manufacturing facilities), but the company did a great deal of research to discount the threat to consumers. Karen Sarlo, a P&G researcher, studied consumers and estimated that just over .1% of consumers are sensitized to subtilisin. A well-known British allergist (Jack Pepys) actually tested his patients for sensitivity to the enzyme and also found it to be very uncommon.

The company also began to produce liquid laundry detergents, on the theory that workers would no longer be exposed to the dust that can become aerosolized and inhaled when powder detergent is processed and packaged. Over time, with the seeming rarity of sensitization in the consuming public and the marketing of liquid laundry detergents, concerns over consumer exposure to enzymes from detergents died.

Fast forward to the 21^st century

Most but not all detergent manufacturers now include protease enzyme in their formulations. Some laundry detergents even contain enzymes to digest fat (lipase), starch (amylase) and other enzymes to remove particles from cotton fibers (cellulase).

Interestingly, occupational exposure to these other enzymes has also turned out to be a cause for allergic sensitization. (Note: any ingredient ending in the suffix “ase” is an enzyme.)

All-Free, a detergent that my family used for years, now contains “stain lifters,” which are enzymes. Even “natural” or “organic” laundry detergents like Seventh Generation contain enzymes.

P&G’s Tide, the detergent that over 30% of Americans use, contains enzymes. The company has always maintained that consumers in their homes are not seriously affected by exposure to enzymes from the laundry detergents, and as noted, research studies have shown this to be the case.

On the other hand, how does this explain that one of our clients became so fatigued after folding the family laundry that he spent much of the rest of the weekend in bed, but was cured after switching detergents? Or why another client who suffered from asthma experienced a diminution of her symptoms when she stopped washing her bedding in an organic laundry detergent full of enzymes?

And why did our daughter’s asthma symptoms suddenly increase when she changed to an enzyme-containing detergent?

Where’s the proof?

I have done two simple experiments: one to demonstrate that I am sensitized to subtilisin and another one to show that consumers have exposure to protease on lint from the laundry, their clothing and bedding. In the first experiment, I inhaled lint from a dryer screen in which All-Free detergent (before enzymes were added!) was used to wash a load of clothing, and I had no symptoms. I then dissolved a contact-lens cleaning tablet containing protease and added some of the solution to the same lint. When I inhaled that dried lint, I coughed.

The second experiment I did was to wash a load of towels in a protease-containing detergent and then collect the lint. I used a cold-water wash and air-fluff drying cycle to maximize the likelihood of enzyme survival. I sent the lint from the dryer screen to a laboratory to determine if there was residual protease activity in the lint; not surprisingly, the results came back positive.

Possible exposures

Laundry detergent residues can be present on bedding and clothing, creating a 24/7 exposure history to enzyme by both contact and inhalation. (Clothing provides continual skin contact with enzyme residue, and lint from clothing that is aerosolized with every move of the body can be inhaled.)

Another significant exposure can occur when someone scrapes the dryer lint screen between loads. It is also common in homes for the dryer hose to leak, so there can be additional exposure to lint.

My advice

In my opinion, anyone who has allergy issues, particularly to mold, should avoid using enzyme-containing laundry detergent. I recognize that hypersensitivity to the enzymes found in detergents may not be very common, but if you are one of the few people who are sensitized to the enzymes, changing your laundering habits could make a great difference in your life.

When purchasing detergent, always check the ingredients label, as the formulation can change at any time. For now, Arm and Hammer, Ecos and Market Basket have detergents lacking enzymes; there are others as well. (I always recommend fragrance-free products as well, since fragrances can be irritating to some people, and they add to the load of chemicals in indoor air.)

At home, if you use hot water wash and hot drying, your exposure to enzyme residues is much less than if you use cold wash and cool dry; but your exposure may not disappear, because not all the enzyme is destroyed by the heat.

A reassuring point

If you check most dishwashing–liquid labels, you will find that enzymes are present (to help digest food on the plates). I would not worry about exposure from this source, since the risk of inhalation is very small.

Please email me if you had symptoms from laundry detergent that stopped after you switched to enzyme-free detergent: Jeff@mayindoorair.com

Refer to my book for further advice on keeping a healthy home.

Second edition to be published in 2019