Public Health Regulation of Dietary Supplements

Public Health Regulation of Dietary Supplements

Introduction

• Food and nutrition are fundamental to human health; up to 50% of disease burden is linked to food and nutrition.

• Food is central to culture, marking special occasions, life transitions, celebrations, and healing practices.

• Staple foods provide energy and nutrients, with flavors and condiments enhancing the food experience.

• Staple foods can also be sold as supplements, creating a definitional issue.

• Kimchee and turmeric are examples of foods used as both staples and supplements.

• Dietary supplements are loosely regulated compared to pharmaceuticals, despite increasing consumption.

• Regulation is challenging due to cultural integration and industry promotion without public health considerations.

• Supplements can interact with each other and prescription medications, affecting health.

• This review covers available products, complications, and existing controls across countries, discussing future regulation and advertising control.

Definition of Dietary Supplements

• The US FDA defines a dietary supplement, according to the Dietary Supplement Health and Education Act (DSHEA) of 1994, as a product taken by mouth that contains a "dietary ingredient" intended to supplement the diet.

• DSHEA categorizes supplements as "foods," not drugs, requiring them to be labeled as dietary supplements.

• A "dietary ingredient" is defined as:

  • A vitamin

  • A mineral

  • An herb or other botanical

  • An amino acid

  • A dietary substance for human use to supplement the diet by increasing total dietary intake (e.g., enzymes or tissues from organs or glands)

  • A concentrate, metabolite, constituent, or extract

• A “new dietary ingredient” is one that meets the definition of dietary ingredient but was not sold in the United States in a dietary supplement before October 15, 1994.

• The EU defines food supplements as concentrated sources of nutrients or other substances with a nutritional or physiological effect, marketed in "dose" form (pills, tablets, capsules, liquids, etc.).

• EU legislation (Directive 2002/46/EC) focuses on supplements containing vitamins and minerals.

• The European Food Safety Authority (EFSA) states that supplements can correct deficiencies or maintain nutrient intake, but excessive intake can be harmful, necessitating maximum levels for safety.

• The varying content and range of actions complicate the classification of dietary supplements.

• Comparisons of consumption are difficult due to changing definitions, as seen in the National Health and Nutrition Examination Survey (NHANES).

• Dietary supplements come in forms like tablets, capsules, soft gels, liquids, or powders.

• NHANES includes items like capsules, tablets, pills, soft gels, chews, gums, or other products containing one or more supplements.

• They can also be manufactured into snack bars or toothpaste (e.g., vitamin B12 for vegans).

• "Supplement," "supplementary food," or "complementary food" are terms used in infant feeding.

• Dietary supplements added to infant formula are regulated separately.

• Specific dietary supplements treat severe malnutrition or deficiencies, especially in the developing world, and are considered special purpose foods.

• Some vitamins and minerals can be either supplements or pharmaceuticals (e.g., parental thiamine for acute vitamin B1 deficiency).

• Refined sugar or sucrose is not considered a supplement despite its nutritional impact.

• Probiotics have been consumed as fermented milks and yogurts since ancient times.

• Metchnikov introduced the term probiotics (“for life”) to describe live microbial supplements for improving health.

• The NIH Human Microbiome project has renewed interest in the value and regulation of probiotics.

• Hoffman suggests regulation principles including risk proportionality, universal quality guidelines, and flexibility.

• Probiotics are regulated as foods in most jurisdictions, though some consider them supplements.

Increasing Use of Dietary Supplements

• Dietary supplement use has increased worldwide.

• Two decades ago, the annual value in the US was US$12 billion.

• By 2015, the global market reached US$109 billion, projected to grow to US$180 billion by 2020, with Asia-Pacific, Europe, and North America holding 31%, 30%, and 25% shares, respectively.

• Another projection estimated the global market at US$278 billion by 2024.

• The variety of dietary supplements is vast; multivitamins are tailored for specific groups based on age, gender, condition, and activity level.

• A general US supermarket may sell over 500 different dietary supplements, with specialty stores offering significantly more.

• The US Office of Dietary Supplements maintains the Dietary Supplement Label Database (DSLD), which contains data from more than 60,000 labels and adds 1,000 more each month.

• NHANES data indicates that supplement use increased rapidly between 1980 and 2000 but slowed between 1999 and 2012.

• In 2012, approximately 52% of respondents reported regular supplement use.

• Multivitamin supplements decreased in popularity, while fish oil and vitamin D supplements increased (vitamin D increased fourfold to 20%).

• Supplement use among older Americans (65–84 years) has increased, especially the use of multiple supplements.

• 36% of older adults regularly used five or more supplements or medications, and 15% of combinations posed potentially harmful interactions; one elderly man used over 50 supplements simultaneously.

• Nearly one-third of children use supplements, with pediatric supplements often exceeding the recommended daily intake (RDI).

• Fewer than 25% of supplement users have their physician's approval.

• Factors contributing to the increasing use of dietary supplements include:

  1. An aging baby boomer population concerned with wellness and quality of life

  2. Increasing preference for natural substances over “chemicals”

  3. Rising drug costs and suspicion that drug companies ignore “natural” products without patent protection

  4. A willingness to “try anything” for chronic diseases

• Emerging economies show increasing interest in traditional and GRAS (generally recognized as safe) food supplements.

• The marketing of dietary supplements has expanded significantly, with thousands of products promoted for health, disease prevention, and performance enhancement.

Risks and Complications

• The increasing use of dietary supplements raises public health concerns regarding their efficacy and short- and long-term safety.

• Monitoring and evaluating supplements is challenging due to multiple ingredients, changing compositions, and inconsistent usage.

• Voluntary adverse event reporting systems may take a long time to detect public health issues linked to inappropriate supplement use.

• Risks include organ damage from inherent toxicity, interactions, or contamination.

• Supplement users may forego useful treatment for life-threatening diseases, falsely believing supplements are comparable to a healthy diet and lifestyle.

• The USFDA estimates 50,000 annual adverse events attributable to dietary supplements; likely an underestimate with only 1% reported.

• Reports range from substantiated epidemiological studies to trivial case reports, with some being life-threatening (e.g., subarachnoid hemorrhage from Ginkgo biloba or liver failure requiring transplantation).

• Most vitamins and minerals have a U-shaped dose-benefit curve, with risk dependent on dose.

• Vitamin A deficiency is a problem in developing countries, but excessive supplementation causes complications.

• Toxicity and complications from supplements are a common cause of hospital admissions; approximately 2% of hospitalizations may be due to adverse events associated with