Evelyne Tantry – Skin Therapy Letter https://www.skintherapyletter.com Written by Dermatologists for Dermatologists Wed, 15 Sep 2021 23:03:28 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.1 Labeling Laws for Personal Care Products: Potential Pitfalls for The Consumer https://www.skintherapyletter.com/dermatology/personal-care-products-labeling/ Fri, 10 Sep 2021 22:15:15 +0000 https://www.skintherapyletter.com/?p=12765 Evelyne Tantry1; Ariadna Perez-Sanchez, MD2; Shelly Fu3; Shravya Potula3; Rajani Katta, MD3,4

1Rice University, Houston, TX, USA
2Department of Internal Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
3Baylor College of Medicine, Houston, TX USA
4Department of Dermatology, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, TX, USA

Conflict of interest:
Rajani Katta is author of a book for the general public on dermatology, and is on an advisory board for Vichy Laboratories.
Evelyne Tantry, Ariadna Perez-Sanchez, Shelly Fu, and Shravya Potula have no conflicts of interest to declare.

Abstract:
Consumers of personal care products must be made aware of the potential pitfalls that arise from current labeling practices and regulations. For example, terms such as “hypoallergenic“, “sensitive skin“, and “baby product” lack legal definitions, and terms such as “fragrance-free“ are frequently misinterpreted. Personal care products are a general category that includes such items as cosmetics, drugs, dietary supplements, and consumer goods. This overview of current US FDA regulations of products in this category reviews pertinent regulatory policies and highlights potential consumer pitfalls when evaluating product labels. In particular, current labeling laws permit the use of language that may be incomplete, misinterpreted, or applied solely for marketing purposes. It is important that consumers understand the meaning of labeling terms, the regulations that govern them, and especially understand the potential pitfalls related to these terms.

Key Words:
personal care products, cosmetics, labeling regulations, fragrance-free, hypoallergenic, sensitive skin, baby products

Background

For consumers choosing among the wide variety of personal care products available, an understanding of current labeling laws and regulations is important. Consumers may be interested in choosing products for sensitive skin, searching for products that are suitable for children, or seeking out products that lack specific allergens. Unfortunately, current regulations limit the utility of many labeling terms to effectively inform the consumer, making it imperative that physicians counsel patients on the specifics of these terms. In this paper, we review areas where consumers may find labels confusing. For each area, we highlight potential pitfalls for consumers when choosing personal care products.

“Personal care products” are not defined by law but rather serve as a general category that can consist of cosmetics, drugs, medical devices, dietary supplements and consumer goods based on the nature of intended use.1 Use of such products may result in allergic contact dermatitis (ACD). Data from the North American Contact Dermatitis Group (NACDG), published in 2018, found that of the top 10 allergens identified by patch testing, nine could be found in personal care products.2 This included six fragrance additives and preservatives, two topical antibiotics (neomycin and bacitracin), and one chemical found in hair dyes (p-phenylenediamine). The treatment of ACD centers on allergen avoidance, and thus an understanding of labeling laws and regulations is critical.

As consumers are faced with a multitude of personal care products, physicians can help by educating them on pertinent regulations and labeling laws. It is important consumers recognize that marketing and safety of personal care products is the responsibility of the manufacturer and is not subject to premarket approval from the US Food and Drug Administration (FDA).3 “Cosmetics”, as defined by the FDA, are any articles intended to be applied to the human body for appearance-altering purposes and include moisturizers, shampoos and makeup.3 ‘Soaps’ fall into a separate category when they are mainly composed of “alkali salts of fatty acids,”4 although the product becomes a “cosmetic” if it contains synthetic detergents or is intended to moisturize or deodorize the body.4

The FDA primarily governs cosmetics and other personal care products through the Federal Food, Drug, and Cosmetic Act of 1938 (FDCA) and the Fair Packaging and Labeling Act of 1967 (FPLA).3 With these acts, Congress created broad parameters to enable effective regulation of a burgeoning industry. Since their establishment, however, these mandates have not undergone any substantial reform to accommodate the explosive growth of available personal care products.

Table 1 outlines several pertinent regulatory policies that consumers should be made cognizant of when evaluating personal care products. It is vital that consumers recognize that current labeling laws permit the use of language that may be applied solely for marketing, may be incomplete, or may be misinterpreted. Table 2 provides a brief overview of potential pitfalls for the consumer due to current labeling regulations.

 

Regulatory Concern Current Food and Drug Administration Regulations
Ingredient safety data and documentation
  • Under US law, “cosmetic products and ingredients, other than color additives, do not need FDA approval before they go on the market.”14
  • The FDA does not require cosmetic companies “to share their safety data or file their product formulations with the FDA.”14
  • Participation in the FDA Voluntary Cosmetic Registration Program is voluntary. Companies provide the FDA with the “best estimate of information available about cosmetics products and ingredients, their frequency of use, and businesses engaged in their manufacture and distribution”. This information is used by the FDA, as well as “independent, industry-funded” scientific groups, such as the Cosmetic Ingredient Review (CIR), which assesses and reviews ingredient safety data.15
Toxicological testing
  • “Neither the law nor FDA regulations require specific tests to demonstrate the safety of individual products or ingredients.”3
  • Per the FDA, “manufacturers can use whatever testing is necessary to ensure the safety of their products and ingredients.”3 The nature or quality of testing is not specified.
Product recalls
  • The “FDA is not authorized to order recalls of cosmetics” as the process requires “voluntary actions by manufacturers or distributors to remove from the marketplace products that represent a hazard or gross deception, or that are somehow defective.”3

Table 1: Overview of current FDA regulations of personal care products

 

Labeling Topic Current Limitations of US Food and Drug Administration Regulations Potential Consumer Pitfalls Description
Ingredient listing
  • Per the FDA, products containing fragrance additives that act as a masking agent and are present “at an insignificant level may be considered an incidental ingredient in which case it need not be declared on the label.”16
  • Contrastingly, “certain ingredients may be listed generally as ‘fragrance,’ or ‘perfume,’ without identifying the specific ingredients.”17
  • Ingredient listing is not required for personal care products “distributed solely for professional use, institutional use (such as in schools or the workplace), or as free samples or hotel amenities.”3
  • Institutional products (such as those used in salons), free samples, and hotel amenities do not require product ingredient listing.
  • Specific fragrance additives are not required to be listed.
Uniform ingredient naming
  • Ingredients must be listed by their “common or usual name.”18
  • Ingredient names can be selected from the International Nomenclature of Cosmetic Ingredients (INCI), United States Pharmacopeia (USP), the National Formulary and the Homeopathic Pharmacopeia of the United States, Food Chemical Codex, the Index Medica, the Chemical Abstracts or the British Pharmacopeia.19
  • The same ingredient may be listed on a label under different names depending on the manufacturer.
Warning labels
  • Personal care products are exempt from displaying warning labels if it is considered to be “adequately substantiated” by either “available test data on its ingredients and on similar products” or “testing appropriate in the light of the existing data.”16 There are no federal standards for what qualifies as ‘appropriate’ testing.
  • Many personal care products are exempt from displaying specific warning labels.

Table 2: Potential consumer pitfalls when evaluating product labels

Skin and Hair Care Products

Potential pitfalls for consumers when evaluating skin and hair care product labels can be categorized into three broad categories. These include the potential for confusion with marketing terms, labels that are incomplete, and labels that may be misinterpreted.

Marketing Terms

As many labeling terms lack FDA definitions, they can essentially mean anything a manufacturer decides. The term “hypoallergenic”, for example, is not regulated by law. Therefore, although the term is commonly used in marketing a product, it does not inform consumers about the actual safety of a product.

Similarly, there are no legal standards for qualifying a product as a “baby product.” This may lead to consumer concerns about certain ingredients, as in 2013 when Johnson & Johnson was pressured by consumers to remove formaldehyde and 1,4-dioxane from about 100 of its baby products.5 According to the NACDG, formaldehyde is the fourth most common allergen in cosmetics.2

One study evaluated the use of marketing terms on products. Researchers found that out of 187 cosmetic products, 89% “contained at least 1 contact allergen, 63% 2 or more, and 11% 5 or more” despite being marketed as “hypoallergenic”, “dermatologist recommended/tested”, “fragrance free”, or “paraben free.”6

The lack of regulation involving personal care products marketed and sold as “hypoallergenic”, “baby product”, “natural,” “for sensitive skin”, and other terms is further discussed in Table 3.

 

Term Food and Drug Administration Regulations Potential Consumer Pitfalls
Hypoallergenic
  • In 1978, the US Court of Appeals for the District of Columbia ruled that the “FDA’s regulation defining ‘hypoallergenic’ was invalid.”20
  • As per the FDA, “there are no federal standards or definitions that govern the use of the term ‘hypoallergenic’” and “the term has no real meaning in the marketplace.”20
  • Companies that manufacture products marketed as ‘hypoallergenic,’ ‘safe for sensitive skin,’ ‘non-allergenic’ or ‘allergy tested’ “are not required to submit substantiation of their hypoallergenicity claims to FDA.”20
  • The term ‘hypoallergenic’ is not regulated by law, and thus, simply means whatever a manufacturer chooses.
  • There is no testing requirement necessary to market a product as ‘hypoallergenic.’
Sensitive skin
  • Presently, “there is no federal standard or definition that governs the use of [phrases such as] ‘for sensitive skin.’”17
  • The FDA instead recommends that consumers refer to the ingredient list, which under the FPLA “requires an ingredient declaration on cosmetic products sold at the retail level.”17
  • There is no federal standard for the term ‘sensitive skin,’ which is purely a marketing term.
Baby products
  • There are no laws explicitly defining what constitutes a ‘baby product’ as they are defined broadly as either ‘cosmetics’ or as a ‘medical device’ (if the product is “intended to cure, treat, mitigate or prevent any illness or disease”).21
  • The only explicit regulation of baby products, in general, is the warning against manufacturers advertising that their products can treat, cure, or prevent the risk of Sudden Infant Death Syndrome (SIDS).22
  • There are no legal metrics for what qualifies a product as a ‘baby product.’
  • Any product can be marketed as a ‘baby product’ and depending on its purpose as a cosmetic or drug, will have varying degrees of labeling regulation.
All natural
  • The FDA does not have any formal regulation, definition or discussion of ‘all natural’ products.
  • The Federal Trade Commission (FTC) reports that there have been incidences when “companies pitched their products as ‘all natural’ or ‘100% natural,’ but included synthetic ingredients.”23
  • Four FTC settlements against the aforementioned companies now prohibit manufacturers from “[mis-stating] the extent to which any product contains natural or synthetic components, [making] misleading claims about ingredients or composition, and [making] deceptive representations about environmental or health benefits.”23
  • Companies are required to provide ‘proof ’ of ‘all natural’ claims. The nature of that proof was not specified by either the FTC or the FDA.24
  • Products marketed as ‘natural’ may still contain synthetic ingredients.
  • Per the FTC, products marketed as ‘all natural,’ suggesting 100% natural composition, cannot contain synthetic ingredients. Products with these claims, however, do not undergo premarket verification
  • No federal standards exist for ‘all natural’ substantiation.
Organic
  • Per the United States Department of Agriculture (USDA), the “FDA does not define or regulate the term ‘organic,’ as it applies to cosmetics, body care, or personal care products.” Rather, the term ‘organic’ is regulated by the USDA for agricultural products through its National Organic Program (NOP, 2008).25
  • ‘Organic’ personal care products are subject to the regulation of both the FDA and USDA.25
  • To be eligible for ‘organic’ certification, a personal care product should “contain or [be] made up of agricultural ingredients, and [be able to] meet the USDA/NOP organic production, handling, processing and labeling standards.”25
  • To be eligible for ‘organic’ certification, a personal care product should “contain or [be] made up of agricultural ingredients, and [be able to] meet the USDA/NOP organic production, handling, processing and labeling standards.”25
  • Alternatively, personal care products “may be certified to other, private standards and be marketed to those private standards in the United States. These standards might include foreign organic standards, eco-labels, earth friendly, etc. USDA’s NOP does not regulate these labels.”25
  • The term ‘organic’ is governed by the USDA, rather than the FDA, even as it applies to cosmetics.
  • The USDA is not the only group capable of certifying organic products. Private companies may also certify organic personal care products under ‘private standards.’
  • Imported ‘organic’ products can be certified using foreign standards.

Table 3: Marketing terms and regulations

Incomplete Labels

“Free of” Labels

The growing trend among consumers to purchase “free of ” ingredient cosmetics, as evident by growing sales and market shares of these products, has prompted cosmetic companies to address these factors when marketing their products.7

While these labels are technically correct, they often do not highlight information that patients would find useful. For example, the words “paraben-free” are often highlighted on product labels. However, for those who are prone to ACD, the words “free of methylisothiazolinone” (MI) would be more useful. The NACDG publishes a Significance-Prevalence Index Number (SPIN) ranking, which is a weighted calculation that incorporates both clinical relevance and prevalence of an allergen.2 MI had the highest SPIN rating of all allergens tested. It has been banned by the European Commission from use in leave-on products, although it is still used in the US. By contrast, parabens were ranked 48th and had the lowest prevalence of positivity of any major preservative on the North American market. In 2019, the American Contact Dermatitis Society announced that because “[parabens] are rarely problematic as contact allergens, [parabens] have been designated (non) allergen of the year.”8

“Active” Ingredients Listed Separately From Inactive Ingredients

For consumers with ACD, knowledge of all ingredients found in a product is critical. Thus, consumers must be aware that certain product categories separate active ingredients from inactive ingredients. Consumers choosing sunscreens, eyedrops, and over-the-counter medications must be informed to seek out information on both active and inactive ingredients, as sections are separated in these product categories.

Labels That May Be Misinterpreted

Fragrance additives are one of the top causes of ACD,2 but avoidance can be challenging for patients. While product labels may use the terms “fragrance-free” and “unscented”, these terms are frequently misinterpreted by consumers.

  • Although the term “fragrance-free” might suggest that a product does not contain any fragrance additives, that is not correct. The FDA defines fragrance as “any natural or synthetic substance or substances used solely to impart an odor to a cosmetic product.” According to that definition, if a fragrance additive is used for another function, then it may legally be included in a fragrance-free product.9 Examples are benzyl alcohol, which may be used as a preservative, and rose oil, which may be used as a moisturizing ingredient.
  • Unscented products may contain masking fragrances.

Sunscreens

Sunscreen labels are also a common source of confusion among consumers, including the sun protection factor (SPF) value. The SPF is defined as the ratio of the amount of ultraviolet (UV) energy required to produce erythema on skin protected by sunscreen, to the amount of energy required to produce erythema on unprotected skin. Contrary to popular belief, an increased magnitude of SPF value above SPF 30 offers minimal increase of protection from UV rays. Specifically, SPF 30 shields the skin from 97% of UV rays and SPF 50 shields 98%.10

Importantly, SPF values only specify protection against UVB radiation, responsible for sunburns.11 The SPF value does not provide information on protection from UVA rays, which damage the deeper layers of the skin and contribute to skin cancer.12

Marketing claims on sunscreens are also of significant concern.13 Many commonly used claims are neither approved nor regulated by the FDA, including claims such as “dermatologist recommended.”13 Unregulated claims are rampant among sunscreens and advertisements, and sunscreens with more than six of these claims have been associated with increased popularity among consumers.13

Another area of concern relates to GRASE products (generally recognized as safe and effective). While GRASE ingredients are regulated by the FDA, some sunscreens are sold in the form of products that are not considered GRASE, including powders, wipes, towelettes, and insect repellants.26 These product forms have not been extensively studied for their safety and sun protection efficacy.26

Insect Repellents

Governed by the Environmental Protection Agency (EPA), insect repellents may be required to list active ingredients, but the “EPA does not require a complete declaration of ‘inactive or inert’ ingredients” nor a list of “the identities of inert ingredients on product labels.”27 The label is only required to list the percent composition of inert ingredients.

Furthermore, because only active ingredients require registration for safety and effectiveness, scented inactive ingredients may present concerns for patients with fragrance sensitivity. Case reports documenting insect repellent contact dermatitis have identified various botanical and fragrance chemical ingredients, such as citronellol, lemon oil, eucalyptus oil, and neem oil.28

Hair Dyes

P-paraphenylenediamine (PPDA) is a common allergen, with the latest data placing it as the 10th most frequent allergen in North America.2 Exposure is primarily via permanent hair dyes.

Although hair dyes in retail stores must list this ingredient, consumers face some challenges. First, unlike other products such as sunscreen, active hair dye ingredients are not required to be highlighted on the label. In fact, active ingredients are typically found as just one ingredient in a long list of chemical names. Second, products that are not intended for retail sale are exempt from ingredient declaration. Products used at a hair salon, therefore, may be exempt from providing ingredients.

In terms of product safety, consumers should realize that FDA approval is not required for hair dyes with PPDA. Regulations divide hair dyes into two categories: coal-tar hair dye (CTHD) and plant or mineral sourced hair dye. Although PPDA is not a coal-tar by-product, it falls into this category. Under FDA regulations there is no need for approval for any of the CTHD.29 Even more worrisome, the FDA cannot take action against a CTHD even if “it is or contains a poisonous or deleterious ingredient that may make it harmful to consumers,” as long as the manufacturer includes a caution statement.29 The only exception is for dyes used in eyelash and eyebrow coloring.

Conclusion

Of the 100+ pages of the FDCA, only two pages discuss cosmetics and personal care product safety. In fact, there is a heavy reliance on safety reporting by manufacturers. Current information from the FDA consists of voluntary ingredient and establishment reporting from companies, along with reports of serious adverse events provided by consumers. Recently, however, there have been efforts to amend the FDCA through the introduction of the Safe Cosmetics and Personal Care Products Act of 2019 and the Personal Care Products Safety Act of 2019. The passage of either bill would increase the regulation of cosmetic labeling and allow the FDA to suspend and even recall the sale of products that cause “adverse health reactions.”30,31

Given the current limitations of federal labeling and safety regulations, it is the responsibility of the consumer to be informed of current regulations and to learn how to accurately evaluate and interpret the information found on personal care product labels.

References



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  5. Thomas K. The ‘No More Tears’ shampoo, now with no formaldehyde. The New York Times. Published January 17, 2014. Available from: https://www.nytimes.com/2014/01/18/business/johnson-johnson-takes-first-step-inremoval-of-questionable-chemicals-from-products.html. Accessed August 15, 2021.

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  7. Hansen T, Risborg MS, Steen CD. Understanding consumer purchase of free-of cosmetics: a value-driven TRA approach. J Consum Behav. 2012 Nov-Dec;11(6):477-86.

  8. Fransway AF, Fransway PJ, Belsito DV, et al. Parabens. Dermatitis. 2019 Jan/Feb;30(1):3-31.

  9. Scheinman PL. Exposing covert fragrance chemicals. Am J Contact Dermat. 2001 Dec;12(4):225-8.

  10. Paul SP. Ensuring the safety of sunscreens, and their efficacy in preventing skin cancers: challenges and controversies for clinicians, formulators, and regulators. Front Med (Lausanne). 2019 Sep 04;6(195). Available from: https://www.frontiersin.org/articles/10.3389/fmed.2019.00195/full. Accessed August 15, 2021.

  11. U.S. Food and Drug Administration. Questions and answers: FDA announces new requirements for over-the-counter (OTC) sunscreen products marketed in the U.S. [updated June 23, 2021]. Content current as of: October 22, 2014;. Available from: https://www.fda.gov/drugs/understanding-over-counter-medicines/questions-and-answers-fda-announces-new-requirements-overcounter-otc-sunscreen-products-marketed-us#Q1_Why_is_FDA. Accessed August 15, 2021.

  12. Dale Wilson B, Moon S, Armstrong F. Comprehensive review of ultraviolet radiation and the current status on sunscreens. J Clin Aesthet Dermatol. 2012 Sep;5(9):18-23.

  13. Prado G, Ederle AE, Shahriari SRK, et al. Online sunscreen purchases: impact of product characteristics and marketing claims. Photodermatol Photoimmunol Photomed. 2019 Sep;35(5):339-43.

  14. U.S. Food and Drug Administration. FDA’s testing of cosmetics for arsenic, cadmium, chromium, cobalt, lead, mercury, and nickel content. Nutrition C for FS and A. Content current as of August 24, 2020. Available from: https://www.fda.gov/cosmetics/potential-contaminants-cosmetics/fdas-testingcosmetics-arsenic-cadmium-chromium-cobalt-lead-mercury-and-nickelcontent. Accessed August 15, 2021.

  15. U.S. Food and Drug Administration. Voluntary cosmetic registration program. Content current as of: August 24, 2020. Available from: https://www.fda.gov/cosmetics/voluntary-cosmetic-registration-program. Accessed August 15, 2021.

  16. U.S. Food and Drug Administration. Cosmetics labeling guide. Nutrition C for FS and A. Content current as of August 24, 2020. Available from: https://www.fda.gov/cosmetics/cosmetics-labeling-regulations/cosmetics-labeling-guide. Accessed August 15, 2021.

  17. U.S. Food and Drug Administration. Allergens in cosmetics. Nutrition C for FS and A. Content current as of November 12, 2020. Available from: https://www.fda.gov/cosmetics/cosmetic-ingredients/allergens-cosmetics. Accessed August 15, 2021.

  18. U.S. Food and Drug Administration. Cosmetic ingredient names. Nutrition C for FS and A. Published February 4, 2020. Content current as of August 24, 2020. Available from: https://www.fda.gov/cosmetics/cosmetics-labeling/cosmetic-ingredient-names. Accessed August 15, 2021

  19. U.S. Food and Drug Administration. Center for Veterinary Medicine. Program Policy and Procedure Manual. Guide 1240.4030. Supplemental Policies. Ingredient established names. September 10, 1997. Available from: https://www.fda.gov/media/70119/download. Accessed August 15, 2021.

  20. U.S. Food and Drug Administration. “Hypoallergenic” cosmetics. Nutrition C for FS and A. Content current as of: August 24, 2020. Available from: https://www.fda.gov/cosmetics/cosmetics-labeling-claims/hypoallergenic-cosmetics.Accessed August 15, 2021.

  21. U.S. Food and Drug Administration. How to determine if your product is a medical device. Health C for D and R. Content current as of December 16, 2019. Available from: https://www.fda.gov/medical-devices/classify-yourmedical-device/how-determine-if-your-product-medical-device. Accessed August 15, 2021.

  22. U.S. Food and Drug Administration. Information for manufacturers of baby products. Health C for D and R. P Content current as of August 22, 2018. Available from: https://www.fda.gov/medical-devices/baby-productssids-prevention-claims/information-manufacturers-baby-products. Accessed August 15, 2021.

  23. Fair L. Are your “all natural” claims all accurate? Federal Trade Commission. Published April 12, 2016. Available from: https://www.ftc.gov/news-events/blogs/business-blog/2016/04/are-your-all-natural-claims-all-accurate. Accessed August 15, 2021.

  24. Gressin S. Super (un)natural product claims. Consumer information. Federal Trade Commission. Published April 12, 2016. Available from: https://www.consumer.ftc.gov/blog/2016/04/super-unnatural-product-claims. Accessed August 15, 2021.

  25. United Stated Department of Agriculture. Agricultural Marketing Service. National Organic Program. Cosmetics, body care products, and personal care products. April 2008. Available from: https://www.ams.usda.gov/sites/default/files/media/OrganicCosmeticsFactSheet.pdf. Accessed August 15, 2021.

  26. U.S. Food and Drug Administration. FDA advances new proposed regulation to make sure that sunscreens are safe and effective. News release dated February 21, 2019. Content current as of February 21, 2019. Available from:https://www.fda.gov/news-events/press-announcements/fda-advances-newproposed-regulation-make-sure-sunscreens-are-safe-and-effective. Accessed August 15, 2021.

  27. U.S. Food and Drug Administration. Insect repellent-sunscreen drug products for over-the-counter human use; request for information and comments. Federal Register. Published February 22, 2007. Available from: https://www.federalregister.gov/documents/2007/02/22/E7-2890/insect-repellentsunscreen-drug-products-for-over-the-counter-human-use-request-forinformation-and. Accessed August 15, 2021.

  28. Kullberg SA, Warshaw EM. Summertime dermatitis: when the repellent is the culprit, not the bugs! Dermatitis. 2020 Jul/Aug;31(4):e30-e2.

  29. U.S. Food and Drug Administration. Hair dyes. Nutrition C for FS and A. Content current as of: August 24, 2020. Available from: https://www.fda.gov/cosmetics/cosmetic-products/hair-dyes. Accessed August 15, 2021.

  30. Schakowsky JD. Text – H.R.4296 – 116th Congress (2019-2020): Safe Cosmetics and Personal Care Products Act of 2019. Introduced in House September 12, 2019. Available from: https://www.congress.gov/bill/116th-congress/housebill/4296/text. Accessed August 15, 2021.

  31. Feinstein D. Text – S.726 – 116th Congress (2019-2020): Personal Care Products Safety Act. Introduced in Senate March 7, 2019. Available from: https://www.congress.gov/bill/116th-congress/senate-bill/726/text. Accessed August 15, 2021.


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]]> An Anti-Wrinkle Diet: Nutritional Strategies to Combat Oxidation, Inflammation and Glycation https://www.skintherapyletter.com/aging-skin/anti-wrinkle-diet-nutritional-strategies-combat-oxidation-inflammation-glycation/ Sun, 15 Mar 2020 20:43:53 +0000 https://www.skintherapyletter.com/?p=11294 Rajani Katta, MD1,2,3; Ariadna Perez Sanchez, MD3 and Evelyne Tantry4

1McGovern Medical School at The University of Texas Health Sciences Center at Houston, Houston, TX, USA
2Baylor College of Medicine, Houston, TX, USA
3Katta Dermatology, Bellaire, TX, USA
4Rice University, Houston, TX, USA

Conflict of interest:
Rajani Katta is the author of a book for the general public on diet and dermatology and has been an advisory board member for Vichy Laboratories. Ariadna Perez Sanchez and Evelyne Tantry have no conflicts to declare for this work.

Abstract:
There is growing awareness of the complex link between nutrition and skin. In the last few decades, our understanding of this link has grown significantly with research findings from multiple laboratory, animal, and human studies. From the impact of diet on clinical features of aging skin, to documentation of the biochemical and histologic changes that occur, our understanding of this link continues to expand and evolve. In this paper, we review the research on the impact of diet on skin aging. A number of long-term observational population studies have documented that healthier diets are linked to fewer signs of skin aging. Animal and laboratory studies have elucidated the biochemical processes that play a large role in the development of these clinical findings. A number of studies have also reported on the role of specific dietary compounds in impacting these processes, whether by combating or potentiating these forces. This body of research serves as guidance in recommending nutritional strategies that can combat the skin aging forces of oxidation, inflammation, and glycation.

Key Words:
antioxidants, anti-wrinkle diet, glycation, inflammation, nutrition, oxidation, skin aging

Introduction

The clinical features of skin aging are well documented and a common question in clinical practice is whether dietary choices have any impact on these features. Based on research ranging from long-term human population to intervention studies, laboratory investigations, and animal studies, a diverse body of data links diet to skin aging.

This research provides significant guidance when discussing nutritional strategies that can promote healthy skin aging. Skin aging is particularly impacted by the processes of oxidation, inflammation and glycation. For each, dietary choices can play a large role in modifying these forces. Specifically, certain dietary patterns, foods, nutrients, and compounds have the ability to either potentiate or combat these processes.

It is well documented that certain populations differ in the rate of development of skin aging. Multiple large scale studies have reported that in those with healthier dietary patterns, fewer fine lines and wrinkles are seen,1,2 while other population studies have documented fewer pigmentary changes3 and less skin atrophy and dryness.4 In one study of over 500 non-diabetic subjects, it was found that as blood glucose levels increased, perceived age increased.5

In researching the role of nutrition, researchers have focused on different avenues of study. Population studies, human interventional studies (both long-term and short-term), animal studies, and laboratory studies have all been used to investigate the role of dietary patterns, foods, nutrients, and/or dietary compounds. Population research now focuses on the study of dietary patterns,6 due to the complexity of long-term dietary effects. Human interventional studies have detailed both the beneficial and harmful effects of specific foods, nutrients, or compounds. Animal and laboratory studies have provided data on the biochemical and histologic effects of dietary compounds. Taken together, this body of research supports a strong, complex relationship between diet and skin aging. Importantly, this research identifies a number of areas where dietary modification may promote an improvement in the parameters of skin aging.

The Pathophysiology of Skin Aging

Skin aging is a highly complex process. Our current understanding of this process, while not complete, has indicated that the intricate and intertwined processes of oxidation, inflammation, and glycation play major roles. Each of these is highly impacted by diet.

Ultraviolet radiation (UVR) is the major contributor to extrinsic skin aging, and the impact of UVR on the skin has been well described. UVR is responsible for multiple direct effects on the skin, as well as numerous downstream effects. UVR may produce direct DNA damage via induction of DNA photoproducts.7 It also results in oxidative stress, with a resultant increase in free radical production, especially reactive oxygen species (ROS).8 These cause additional DNA damage9 as well as damage to both structural (collagen and elastin) and enzymatic proteins. Effects on lipids include peroxidation of cell membrane lipids.10

Metabolic processes, pollution, smoking, and other factors also contribute to oxidative stress. Due to constant exposure, the body’s defense mechanisms are designed to withstand the damaging effects of free radicals. Endogenous enzyme systems include superoxide dismutase, glutathione peroxidase, catalase, and others. The epidermis and dermis also contain antioxidant defenses, including vitamin C, vitamin E, carotenoids, selenium, and others.11,12 While these are important components of the body’s endogenous defense systems, they require constant replenishment from dietary sources. and others. The epidermis and dermis also contain antioxidant defenses, including vitamin C, vitamin E, carotenoids, selenium, and others.11,12 While these are important components of the body’s endogenous defense systems, they require constant replenishment from dietary sources.

Photooxidative stress also activates several inflammatory pathways and contributes to chronic inflammation, which impacts the clinical and molecular features of aging13,14 as well as the promotion of skin tumorigenesis.15 Activation of these pathways ultimately acts to increase the expression of several matrix metalloproteinases (MMPs).13,14,16

MMPs encompass a number of different enzymes, including collagenases. Along with elastases, these act to remodel the extracellular matrix (ECM), with resulting fragmentation of the collagen and elastin fibers that provide structural support and elasticity to the skin. UVR also results in the reduced expression of tissue inhibitor of MMPs (TIMPs), which ordinarily would act to inhibit ECM destruction.17

Several other inflammatory pathways are activated by oxidative stress, including pathways which promote the release of a number of inflammatory cytokines and prostaglandins. The induction of pro-inflammatory genes leads to the release of inflammatory mediators from keratinocytes, fibroblasts, white blood cells, and others, including interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-alpha. These further contribute to the effects of chronic inflammation.

Glycation is another factor that accelerates aging of the skin. Glycation is distinct from photoaging, but is closely intertwined. Glycation refers to the non-enzymatic process whereby sugar molecules covalently bond to proteins, lipids, or nucleic acids. The resulting products are known as advanced glycation end products (AGEs) or glycotoxins. AGEs are a heterogeneous group of molecules, with the prevalent AGE in the human body, including the skin, being carboxymethyl lysine (CML).

Glycation is an important factor in atherosclerosis,18 renal disease,19 diabetic complications, and other conditions. It plays an important role in skin aging as well. The accumulation of AGEs within the skin results in typical structural and functional changes that are colloquially known as sugar sag.20

AGEs have a large impact on the collagen and elastin fibers that maintain the structural framework of the skin and provide resilience and elasticity. Glycation results in intermolecular collagen cross-linking, resulting in increased stiffness and vulnerability to mechanical stimuli.21 In addition, cross-linked collagen cannot be repaired as well. Collagen is highly susceptible to glycation, in part due to its long half-life, and may undergo up to a 50% increase in glycation over a lifetime.22 Glycation is closely related to oxidation and inflammation as well. Glycation increases reactive oxygen species (ROS), further accelerating oxidative damage. Additionally, AGEs may bind to specialized cellular surface receptors called receptor for AGEs (RAGEs). When activated, RAGE triggers several cellular signaling pathways.23 These further promote inflammation and altered cytokine expression.

Nutritional Strategies to Target Key Processes in Skin Aging

Research has demonstrated that dietary components have the ability to impact each of these skin aging processes. The skin is commonly referred to as the largest organ of the body, and as such plays a substantial role in its defense. The skin barrier and its concomitant complex immune defenses play a significant role in protection against UVR, physical impact, temperature variations, irritants, allergens, microbes, and other factors. In fact, it can be said that our skin is under siege every minute of every day. Because of these constant threats, the skin barrier has many intricate built-in defense and repair mechanisms.

Dietary factors have the ability to either support these mechanisms or impair them. In other words, certain dietary patterns, foods, nutrients, and compounds have the potential to either accelerate or combat skin aging.

Oxidation

Antioxidants (AOs) are a key feature of the body’s defense against free radicals. They may act to neutralize ROS or may upregulate genes encoding for enzymes that neutralize ROS. The cutaneous impact of dietary AOs has been demonstrated in multiple studies. Several animal studies, for example, have documented that oral AOs including vitamin C,24 vitamin E,24 beta-carotene,25 selenium,26 and others play important roles in skin photoprotection.27

Human interventional studies have documented these benefits as well. In one randomized controlled trial, daily tomato paste ingestion for 10 weeks resulted in improved minimal erythema doses,28 while another study documented histologic improvement.29 Other human intervention studies have reported benefits from dietary AOs including green tea polyphenols, cocoa flavanols, pomegranate, and others.30 As detailed in an extensive review, the documented clinical, histologic, and biochemical benefits of dietary AOs have included reductions in erythema, DNA damage, markers of inflammation, extracellular matrix damage, and others.30

While single nutrients (such as vitamins, minerals, and phytonutrients) may serve as AOs, a key point is that one food may provide multiple AOs. One research study evaluated the total AO capacity of over 3100 foods and found that the categories of “spices and herbs” and “herbal/traditional plant medicine” contained the most AO-rich products analyzed in the study.31 Berries, fruits, and vegetables also included many common foods and beverages with medium-to-high AO values.31

While dietary AOs may be beneficial, high-dose AO supplements have not shown benefit. In fact, some have demonstrated harm, as outlined in a later section.

Inflammation

Many research studies have delineated the role of diet in modifying the inflammatory process. For example, some phytochemicals may specifically interrupt the inflammatory pathway that activates nuclear factor-kappa beta (NF-KB), including turmeric, cloves, ginger, garlic, and others.32 This pathway impacts MMPs and collagen remodeling, and in fact researchers were able to demonstrate that compounds from garlic in a mouse model inhibited UVB-induced wrinkle formation. This was accomplished via the modulation of NF-KB, with a resulting decrease of MMPs and collagen fiber destruction.33

Multiple studies have described the impact of dietary patterns, foods, nutrients, and compounds on inflammatory biomarkers. One review article34 specifically examined research on dietary patterns affecting high sensitivity C-reactive protein (hsCRP), a marker of inflammation with demonstrated predictive value for coronary heart disease.35 Multiple dietary patterns had some evidence of impact, including the Dietary Approaches to Stop Hypertension (DASH) and similar diets.34

The effects of specific foods and nutrients were described in one summary analysis in which researchers looked at over 1900 studies. These evaluated the effects of foods and nutrients on six major biomarkers of inflammation. If a nutrient increased levels of IL-1B, IL-6, TNF-alpha, or CRP, or decreased levels of IL-4 or IL-10, it was considered pro-inflammatory.36 Using these results, researchers developed a dietary inflammatory index that highlights anti-inflammatory foods. Some of the strongest effects were seen with foods including turmeric, green/black tea, ginger, garlic, and onion, as well as with macronutrients and micronutrients including fiber, magnesium, vitamin D, and omega-3 fatty acids.36 Highly anti-inflammatory phytonutrients included flavones, isoflavones, beta-carotene, and flavonols.

The Gut Microbiome

The gut-skin axis is an area of intense research, due to the impact of the gut microbiome on inflammation and skin barrier function,37-39 as well as features of skin aging.40,41 While more research is needed to delineate these impacts, the gut microbiome is considered an important factor in inflammation. Diet serves as the foundation for healthy gut flora, particularly a focus on fiber-rich foods, which beneficially support the growth of good gut microbes.42-44 Fermented and cultured foods, with beneficial live microbes, may also play a role,45 while prebiotic and probiotic supplementation research is ongoing to determine potential efficacy as well as dosing strategies.

Foods that Impact MMPS

Collagenase and elastase play important roles in ECM remodeling, thereby contributing to loss of skin elasticity, wrinkling, and sagging. Some foods and nutrients are able to block the activity of collagenase, such as green tea, white tea, and pomegranate,46 while inhibition of elastases was also seen with ginger47 and spices such as turmeric, cinnamon, and nutmeg.48 Foods with anti-inflammatory capabilities, by blocking inflammatory pathways, may also ultimately result in lower levels of MMPs, as with curcumin,49 omega-3 fatty acids,50 and garlic.33

Glycation

The accumulation of AGEs within the body arises from two main sources. The first is via endogenous production in the presence of hyperglycemia. The second is via the ingestion of foods that contain preformed AGEs, also known as dietary AGEs.

Therefore, nutritional strategies to limit AGE-induced tissue damage focus on three main areas. The first is a focus on patterns, foods, and compounds that limit hyperglycemia. The second is a focus on foods and compounds that limit the biochemical processes of glycation. The third is limited ingestion of dietary AGEs. Additional strategies, as outlined previously, include a diet rich in antioxidants and anti-inflammatory foods, as these processes are closely intertwined with glycation.

Limiting Hyperglycemia

Improving glycemic control is a key strategy in limiting AGE production. In one experimental study, improved glycemic control in human volunteers over a 4-month period resulted in significantly decreased new collagen glycation.50 In fact, a key tenet of an anti-wrinkle diet is diabetes prevention. A full review of dietary strategies to limit hyperglycemia is beyond the scope of this review, and readers are referred to comprehensive reviews on this subject.51

Strategies supported by research include a low glycemic load diet, which focuses on low glycemic index foods as well as portion sizes.52,53 Food groups and components with demonstrated benefits include fiber, monounsaturated fatty acids, fruits, vegetables, and others.51 Eating order (with protein consumed earlier)54 and vinegar consumption with a meal55 have also demonstrated benefits. Specific foods that have shown promise include garlic, onions,56 nuts,57 turmeric,58 cinnamon,48 fenugreek,59 and a number of other spices.60

Foods and Compounds that Limit Glycation

A number of dietary compounds have demonstrated the ability to inhibit AGE biosynthesis.61 Some limit glycation via their antioxidant properties, while others act via other mechanisms, such as trapping reactive intermediate compounds.61-63

In laboratory studies, anti-glycation properties have been demonstrated by foods such as cinnamon,64 garlic,65 rosemary,66 yerba mate,67 and tomato paste68. One laboratory study evaluating multiple foods demonstrated significant anti-glycation activity by ginger, cumin, cinnamon, black pepper, and green tea.69 Phytonutrients exhibiting beneficial effects include the flavonoids luteolin, quercetin, and rutin,70 as well as the phenolic acids ferulic acid, chlorogenic acid, vanillic acid, and others71. In animal studies, curcumin has inhibited collagen cross-linking,72 while green tea extracts have reduced AGE formation73 and inhibited collagen cross-linking74.

In a laboratory study specifically evaluating the anti-glycation potential of polyphenols in herbs and spices, the most potent spices were cloves, allspice, and cinnamon, while potent herbs included sage, marjoram, tarragon, and rosemary.75 The researchers noted that level of inhibition correlated with total phenolic content. Similar findings were seen in a study evaluating spices used in European cuisine, with strong activity by star anise, cinnamon, allspice, cloves, and oregano.76

Strategies to Reduce Dietary AGEs

Dietary strategies to limit ingestion of preformed AGEs focus on three main areas. These include the type of food, cooking method, and use of ingredients that modify AGE production.

Meat products, high in fat and protein, contain some of the highest levels of dietary AGEs, and are particularly prone to developing new AGEs during cooking.77 High-fat cheeses are also relatively high in AGEs. In contrast, carbohydrate-rich fruits, vegetables, and whole grains contain low levels.

Cooking methods have a marked impact on AGE production. Dry heat methods such as grilling, roasting, and frying can increase AGE levels by 10 to 100 times.77 Reduction strategies include moist cooking methods such as steaming and boiling, as well as cooking for lower temperatures and for shorter times. It is noteworthy that even with cooking, foods such as fruits, vegetables, and whole grains remain relatively low in AGEs. The exception is for carbohydrate-rich foods that are also high in fat, such as biscuits.

An additional strategy is the use of ingredients such as lemon juice and vinegar prior to cooking, as these reduce the amount of AGEs ultimately produced.77

The Role of Nutrient Supplementation

A common question in patient care centers on the use of dietary supplements, more specifically, given the link between dietary compounds and the biochemical processes that impact skin aging, is if there is a benefit to consuming supplementation either in addition to, or in place of, dietary consumption?

While a review of supplements is beyond the scope of this article, a few points must be emphasized. At this time, there is very limited evidence for benefit of nutrient supplementation beyond the treatment of deficiency states. Indeed, there is significant evidence of potential harm from some supplements.

The primary role of supplementation has always been, and continues to be, in the treatment of deficiency. Although research from deficient-state conditions is often used to justify supplementation in general, evidence is lacking for this approach.

As one example, biotin deficiency leading to hair loss may be improved with supplementation, but has not shown efficacy in hair loss overall.78,79

In the case of AOs, supplements have not shown benefit and in some cases have shown harm. AO supplements were the subject of much research, given promising observational human studies of dietary intake as well as laboratory and animal studies. Unfortunately, multiple trials of high-dose (as opposed to dietary dose) vitamins C and E, beta-carotene, and selenium, indicated that they were not effective in non-melanoma skin cancer (NMSC) prevention.27 In fact, some may even become pro-oxidant at high doses, as in a study of women exhibiting higher rates of skin cancer after use of a supplement containing vitamins C and E, beta-carotene, selenium, and zinc (with median follow-up of 7.5 years).80 This emphasizes the point that nutrients must be at the right dose in order to provide benefits. In the case of AOs, the ideal dose appears to be physiologic doses, such as that supplied via whole foods.

This issue of short-term tolerability not necessarily equaling long-term safety is an important point to remember as researchers continue to study promising supplements. Nicotinamide has shown benefit in a sharply defined population, with a 23% reduction in new NMSC in those at high risk, and has been well-tolerated over a 1-year period.81 The herb Polypodium leucotomos has demonstrated photoprotective abilities in short-term studies, but also lacks long-term data.82,83

In the case of other supplements, evidence is simply lacking. One review summarized published trials of collagen supplementation used for skin conditions ranging from aging skin, to wound healing, to cellulite.84 In total, the authors found only 11 studies, some funded by the manufacturer and some lacking placebo, utilizing at least three different types of collagen at widely differing doses and duration.

Conclusion

A number of research studies have documented the link between diet and skin aging. These results may be used to develop dietary recommendations that combat the forces of oxidation, inflammation, and glycation. For those wishing to promote healthy skin aging, a diet that incorporates these strategies is recommended, with a focus on foods that are naturally rich in antioxidants, are anti-inflammatory, limit hyperglycemia, and inhibit glycation. When counseling patients, it is important to emphasize that a number of eating patterns focusing on these underlying principles (Table 1) may achieve this goal. Table 2 provides more details on dietary strategies that combat these aging processes.

Summary table of anti-wrinkle dietary recommendations for patients
Table 1: Summary of anti-wrinkle dietary recommendations for patients.
Click here to enlarge table.
table of dietary defense strategies.
Table 2: Dietary defense strategies.
Click here to enlarge table.

 

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