Lentis/Antimicrobial Agents in Consumer Products

Introduction

What are Antimicrobial Agents?

Antimicrobial agents (AMAs) are chemicals designed to kill or inhibit the growth of microbes like bacteria, viruses, fungi, and parasites. Many natural substances like tea tree oil, eucalyptus oil, and honey have antimicrobial properties, but most AMAs are synthetic chemicals. These include Synthetic organic compounds like triclosan, quaternary ammonium compounds, and N-halamines, and inorganic compounds like metallic nanoparticles.

Consumer Products Use Cases

AMAs are commonly found in household cleaners, hygiene products (e.g., soap, deodorants, and lotions), textiles, and many other consumer products. Their inclusion is often marketed as an effective means to reduce harmful bacteria, viruses, and germs, thereby improving cleanliness and health. Despite the attractive marketing, most independent research shows that “no data supports the efficacy or necessity of antimicrobial agents in consumer products, and a growing number of studies suggest increasing acquired bacterial resistance to them. (Tan, 2002).” The FDA adds, “Using these products might give people a false sense of security."

Potential Risks of Antimicrobial Agents

Not only do antimicrobial-containing consumer products fail to deliver on their promises, they also contribute to ever growing public health issues. In the United States, 2.8 million antibiotic-resistant infections occur each year, resulting in over 35,000 deaths. This problem is expected to worsen over time. Moreover, the broad spectrum nature of antimicrobials used in consumer products means they target both harmful and beneficial microbes. Antibacterial hand soap, for example, wipes out good bacteria on skin causing potential negative impacts to the immune system.

Key Participants

Regulatory Agencies

The United States Food and Drug Administration (FDA) regulates AMAs in drugs, devices, and antiseptics intended for use on or in the body. The United States Environmental Protection Agency (EPA) regulates AMAs for use on inanimate objects like textiles, toys, kitchen surfaces. Together, these agencies evaluate the safety of various AMAs, deciding which AMAs can be used in products, and determining the requirements from their use. The FDA and EPA balance consumer interests and safety with producer interests in creating the AMA regulatory landscape.

Public Health Organizations and Research Institutions

Alongside academic researchers, institutions like the United States Center for Disease Control (CDC) and the World Health Organization (WHO) provide valuable insight into the effects and long term implications of AMA use. They publicize the potential impacts of antimicrobial resistance and other health concerns, influencing regulatory decisions, public opinion, and public health recommendations.

Product Producers

Product producers often simplify the science and societal impact of AMAs, focusing more on emotional aspects of hygiene and health to boost sales. For instance, Dial promotes antibacterial soap that “eliminates 99.9% of bacteria” and delivers a “crisp uplifting clean that leaves you feeling fresh.” Other producers also use misleading hooks and overlook the health risks of widespread AMA use.

Product Consumers

Product consumers represent the end users of products made with AMAs. Their decisions reflect a combination of health and safety values influenced by marketing, public health recommendations, and personal health assessments. Consumers represent a wide range of decision makers with varied understandings of AMA risks and their future implications.

FDA Bans the Use of Triclosan

History

In the 1930s and 40s, it was discovered that certain classes of chlorinated aromatic hydrocarbons had potential as powerful biocidal agents. First patented in the mid 1960s by the company Ciba, triclosan became one of the most widespread and common antimicrobial agents in common use. Despite being originally intended as a disinfectant for hospital use, in 1972 the biocide was introduced to consumers and triclosan quickly became common in deodorants, plastics, toys, textiles, and liquid hand soaps. Its ubiquity in these products have led it to now be found in all recesses of our environment, including within the soil, rivers, lakes, and sediments. In 2005, "Approximately 500 000−1 000 000 lb (227 000−454 000 kg) of TCC [were] used in the United States every year". By 2014, the US triclosan market was worth $1.4 billion.

Hazards

While triclosan has hardly shown any potential benefits to human health, many hazards have been associated with it. It has teratogenic properties, harming the development of newborns and leading to deformities or stillbirth. It has also shown to cause decreases in fecundity due to its function as an endocrine disruptor. Studies show that triclosan is a carcinogen both in vitro and in living organisms, promoting the growth of liver tumors. It has been demonstrated to upset cardiovascular functions, leading to greater risks of asthma and allergy development. Triclosan also harms plant and animal life. "TCS and TCC are 100–1000 times more effective in inhibiting and killing algae, crustaceans and fish than they are in killing microbes". Bioaccumulation of TCS has also been observed in a few organisms. However, triclosan's most interesting and potentially terrifying hazard is how its use causes the development of antibiotic-resistant bacteria. Because of the chemical's "specific targeting" behavior in bacteria, bacteria that are able to develop resistance to triclosan also develop resistance to a number of medically relevant antibiotics. This phenomenon may increase the prevalence of certain "superbugs" that threaten a widespread pandemic.

Opposition

The FDA first acknowledged the lack of safety and beneficial effects of triclosan in a 1974 Tentative Final Monograph. Despite this early acknowledgement, the document was not published and no major actions against the chemical were yet taken. Since that time, a few cases were levied against the use of triclosan. In 1997 the EPA banned Hasbro Inc. from claiming the triclosan in its plastic toys had any beneficial effects. Nonprofit groups arose in response as well, with Beyond Pesticides submitting a petition in 2005 to ban all non-medical uses of triclosan. In 2010 the Natural Resources Defense Council filed a complaint against the FDA, finally spurring them on to take action, finalizing the monograph in 2013. Finally, in 2016, the FDA officially bans the use of triclosan and other antibacterial products in over-the-counter hand soaps. However, many people believe this action was too narrow in scope, as it does not effectively remove the chemical from other products such as textiles, toothpaste, or plastics. In 2017 a conference of over 200 scientists and medical professionals gathered to draft the Florence Statement, a compilation of scientific research that exposed the harmful effects of triclosan and calls for its complete prohibition.

Paraben Preservatives In Personal Care Products

Parabens are synthetic preservatives used in cosmetics, personal care products, food, and medications.  They are extremely popular preservatives because they are particularly chemically stable, cheap to produce, relatively hypoallergenic, and are odorless and tasteless.  They have been used for this purpose since the 1920s.  In consumer products, they are effective at preventing the growth of yeast, mold, and bacteria (gram-positive bacteria in particular), and are present in 80% of such products.  They are also used to prevent mold growth on many paper products such as newspapers, sanitary wipes, and food cartons.  They occur naturally in some foods, such as strawberries, blueberries, grapes, olives, yeast, and barley, and are produced by some microorganisms.

Health Concerns

Parabens can be absorbed through the skin, and have been shown to accumulate in the human body to some degree.  When ingested orally (such as in foods) they are broken down and excreted through urine, but when applied topically, the breakdown occurs much more slowly, leading to accumulation in tissue.  Increased usage of personal care products is associated with higher concentrations of parabens in skin, blood, milk, and urine.

Many studies indicate that parabens possess estrogenic activity, which increases with increasing chain length.  There is some evidence that tissue concentration of parabens is associated with estrogen-sensitive diseases, as it has been detected in high concentrations in breast tumors.  However, despite parabens’ demonstrated estrogenic effects, there is no conclusive evidence that they result in harmful outcomes in humans.  Many of the studies into possible toxicity are in vitro or in animal models, use concentration exposures that may not be representative of typical exposure, and therefore have limited efficacy in determining the overall effect on the human body.

There is also concern that when ingested, parabens could disrupt the natural gut microbiome, and encourage the development of resistant strains of bacteria in the digestive tract.

Environmental Effects

Parabens enter the environment in wastewater and indoor dust.  In indoor environments, the concentration of parabens in dust was correlated with an increase in abundance of genes related to antibiotic resistance in the bacteria making up the dust microbiome.  The presence of parabens in wastewater, surface waters, and sediments is thought to encourage the development of antibiotic resistance as well.

In addition to concerns over resistant bacteria, disruption of aquatic microbiomes may have ecological consequences, with parabens and their metabolites detected in aquatic plant and animal tissues.

Regulations and Recommendations

In the EU, usage of parabens in cosmetic products is regulated by the EU Cosmetic Directive, which sets maximum concentration limits for longer-chain parabens and shorter-chain parabens at 0.4% and 0.8% respectively.  The FDA sets equivalent limits.  In the EU, some longer-chain parabens are banned in use of cosmetics altogether. In food products, parabens are generally regarded as safe at concentrations below 0.1% by the FDA.

In the US, cosmetics and personal care products are largely unregulated.  Cosmetic products do not require any FDA approval before entering the market.  Testing the safety of such products is wholly the responsibility of the manufacturer.  The current FDA stance on parabens is that “At this time, we do not have information showing that parabens as they are used in cosmetics have an effect on human health.”

Response to Health Concerns

If the public shows concern over a particular ingredient, manufactures often begin marketing products as specifically not containing that ingredient (ex. “paraben-free” or “sulfate-free”) even if that ingredient hasn’t been shown to be unsafe.  This can lead to increased public distrust of these ingredients.  Appealing to customer distrust of synthetic ingredients is a lucrative strategy for manufacturers, with $1.6 billion of cosmetics marketed as natural sold in the US in 2019.  However, due to lack of regulation of how cosmetic products are marketed in the US, Cosmetics that don’t label parabens as an ingredient, or are specifically labeled “paraben free” may still contain them.  Additionally, products marketed as “green” or “natural” also frequently contain parabens.

In response to concern over health effects of parabens, many personal care product manufacturers switched to alternative preservatives such as methylisothiazolinone and methylchloroisothiazolinone.  These compounds are more likely to cause allergic reactions, and their adoption has been associated with an increase in incidents of allergic contact dermatitis.

Plant extracts and essential oils are also used to replace parabens as preservatives in products marketed as “natural.”  However, the essential oils used are effective against fewer microorganisms, and are much more likely to cause allergic reactions.  Many are only effective when used in combination with synthetic preservatives.