Tolerable weekly intake

Last updated

Tolerable weekly intake (TWI) estimates the amount per unit body weight of a potentially harmful substance or contaminant in food or water that can be ingested over a lifetime without risk of adverse health effects. [1] [2] TWI is generally preceded by "provisional" to indicate insufficient data exists, increasing uncertainty. [3] The term TWI should be reserved for when there is a well-established and internationally accepted tolerance, backed by sound and uncontested data. Although similar in concept to tolerable daily intake (TDI), which is of the same derivation of acceptable daily intakes (ADIs), TWI accounts for contaminants that do not clear the body quickly and may accumulate within the body over a period of time. [3] An example is heavy metals such as arsenic, cadmium, lead, and mercury. [4] The concept of TWI takes into account daily variations in human consumption patterns.

Contents

Background

Governments and international organizations such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the Joint FAO/WHO Meeting on Pesticide Residues (JMPR), the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) generally use the safety factor approach, based on ADI, to determine intake tolerances for substances that exhibit thresholds for toxicity. [3] The Codex Alimentarius Commission, with the help of independent international risk assessment bodies or ad-hoc consultations organized by FAO and WHO, develops and publishes tolerances based on the best available science. [5] After identifying a substance of concern, researchers and experts then study information the substance's metabolism by humans and animals (as appropriate), the substance's toxicokinetics and toxicodynamics (including carry-over of the toxic substance from feed to edible animal tissue/products); and the substance's acute and long term toxicity in order to determine the acceptability and safety of intake levels of the substance. [6] In comparison to TWI, the Codex maximum level (ML) for a food is the maximum concentration of that substance recommended by the Codex Alimentarius Commission (CAC) to be legally permitted in that commodity. [6]

Data sources

  1. The JECFA makes a distinction between acceptable intakes and tolerable intakes. Tolerable is used to demonstrate permissibility, not acceptability. [3] Substances such as food additives, veterinary drugs, and pesticides that can be controlled in the food supply relatively easily are assessed an acceptable daily intake, or ADI. Other substances considered contaminants are assessed a tolerable daily or weekly intake, TDI or TWI, respectively. [3] Tolerable intakes, whether daily, weekly, or monthly, should not be confused with reference daily intake, or RDI. RDI refers to the amount of a given nutrient individuals should uptake to maintain health.
  2. When determining TWI, appropriate safety factors are applied to allow for extrapolation of human no-observed-adverse-effect levels (NOAELs). NOAELs are established by toxicological studies in animals, and the appropriate safety factors are applied so human NOAELs can be extrapolated. [3] [7] For additives that have an observed effect, and it is not known whether or not the effect is negative, ADI is based on a no observed effect level, or NOEL. [3] To determine the NOEL, researchers primarily use animals (the species most sensitive to the treatments) and carefully select doses until they determine the highest dose that presents an adverse (toxic, but not deadly) effect not observed in lowest dose. [3] When adverse effects predominate, the JMPR bases the ADI on the NOAELs. [3] Uncertainty factors [8] are applied to account for intra- and inter-species differences.

Calculations

Tolerable intake is usually expressed in micrograms or milligrams per kilogram of body weight. Intake (exposure) is determined using the following formula:

Exposure = Σi (consumption)i x (concentration)i / Body Weight

Related Research Articles

<span class="mw-page-title-main">Aspartame</span> Artificial non-saccharide sweetener

Aspartame is an artificial non-saccharide sweetener 200 times sweeter than sucrose and is commonly used as a sugar substitute in foods and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide with brand names NutraSweet, Equal, and Canderel. Aspartame was approved by the US Food and Drug Administration (FDA) in 1974, and then again in 1981, after approval was revoked in 1980.

<span class="mw-page-title-main">Quinoline Yellow WS</span> "Mixture of water-soluble organic compounds from Quinoline Yellow dye"

Quinoline Yellow WS is a mixture of organic compounds derived from the dye Quinoline Yellow SS. Owing to the presence of sulfonate groups, the WS dyes are water-soluble (WS). It is a mixture of disulfonates (principally), monosulfonates and trisulfonates of 2-(2-quinolyl)indan-1,3-dione with a maximum absorption wavelength of 416 nm.p. 119

<span class="mw-page-title-main">Sunset yellow FCF</span> Chemical compound used as colorant

Sunset yellow FCF is a petroleum-derived orange azo dye with a pH-dependent maximum absorption at about 480 nm at pH 1 and 443 nm at pH 13, with a shoulder at 500 nm. When added to foods sold in the United States, it is known as FD&C Yellow 6; when sold in Europe, it is denoted by E Number E110.

A reference dose is the United States Environmental Protection Agency's maximum acceptable oral dose of a toxic substance, "below which no adverse noncancer health effects should result from a lifetime of exposure". Reference doses have been most commonly determined for pesticides. The EPA defines an oral reference dose as:

[A]n estimate, with uncertainty spanning perhaps an order of magnitude, of a daily oral exposure to the human population that is likely to be without an appreciable risk of deleterious effects during a lifetime.

Acceptable daily intake or ADI is a measure of the amount of a specific substance in food or drinking water that can be ingested (orally) daily over a lifetime without an appreciable health risk. ADIs are expressed usually in milligrams per kilograms of body weight per day.

<span class="mw-page-title-main">Codex Alimentarius</span> Collection of internationally recognized standards

The Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines, and other recommendations published by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) of the United Nations relating to food, food production, food labeling, and food safety.

The threshold limit value (TLV) is a level of occupational exposure to a hazardous substance where it is believed that nearly all healthy workers can repeatedly experience at or below this level of exposure without adverse effects. Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH), who determines and publishes TLVs annually. TLVs issued by the ACGIH are the most widely accepted occupational exposure limits both in the United States and most other countries. However, it is sometimes loosely used to refer to other similar concepts used in occupational health and toxicology, such as acceptable daily intake (ADI) and tolerable daily intake (TDI). Concepts such as TLV, ADI, and TDI can be compared to the no-observed-adverse-effect level (NOAEL) in animal testing, but whereas a NOAEL can be established experimentally during a short period, TLV, ADI, and TDI apply to human beings over a lifetime and thus are harder to test empirically and are usually set at lower levels. TLVs, along with biological exposure indices (BEIs), are published annually by the ACGIH.

<span class="mw-page-title-main">Ponceau 4R</span> Chemical compound

Ponceau 4R is a synthetic colourant that may be used as a food colouring. It is denoted by E Number E124. Its chemical name is 1-(4-sulfo-1-napthylazo)-2-napthol-6,8-disulfonic acid, trisodium salt. Ponceau is the generic name for a family of azo dyes.

<span class="mw-page-title-main">Ochratoxin A</span> Chemical compound

Ochratoxin A—a toxin produced by different Aspergillus and Penicillium species — is one of the most-abundant food-contaminating mycotoxins. It is also a frequent contaminant of water-damaged houses and of heating ducts. Human exposure can occur through consumption of contaminated food products, particularly contaminated grain and pork products, as well as coffee, wine grapes, and dried grapes. The toxin has been found in the tissues and organs of animals, including human blood and breast milk. Ochratoxin A, like most toxic substances, has large species- and sex-specific toxicological differences.

<span class="mw-page-title-main">Caramel color</span> Water soluble food coloring

Caramel color or caramel coloring is a water-soluble food coloring. It is made by heat treatment of carbohydrates (sugars), in general in the presence of acids, alkalis, or salts, in a process called caramelization. It is more fully oxidized than caramel candy, and has an odor of burnt sugar and a somewhat bitter taste. Its color ranges from pale yellow to amber to dark brown.

Patulin is an organic compound classified as a polyketide. It is named after the fungus from which it was isolated, Penicillium patulum. It is a white powder soluble in acidic water and in organic solvents. It is a lactone that is heat-stable, so it is not destroyed by pasteurization or thermal denaturation. However, stability following fermentation is lessened. It is a mycotoxin produced by a variety of molds, in particular, Aspergillus and Penicillium and Byssochlamys. Most commonly found in rotting apples, the amount of patulin in apple products is generally viewed as a measure of the quality of the apples used in production. In addition, patulin has been found in other foods such as grains, fruits, and vegetables. Its presence is highly regulated.

<span class="mw-page-title-main">Disodium ribonucleotides</span> Flavor enhancer

Disodium 5'-ribonucleotides or I+G, E number E635, is a flavor enhancer which is synergistic with glutamates in creating the taste of umami. It is a mixture of disodium inosinate (IMP) and disodium guanylate (GMP) and is often used where a food already contains natural glutamates or added monosodium glutamate (MSG). It is primarily used in flavored noodles, snack foods, chips, crackers, sauces and fast foods. It is produced by combining the sodium salts of the natural compounds guanylic acid (E626) and inosinic acid (E630).

<span class="mw-page-title-main">Food contaminant</span> Harmful substance in food

A food contaminant is a harmful chemical or microorganism present in food, which can cause illness to the consumer.

The maximum residue limit is the maximum amount of pesticide residue that is expected to remain on food products when a pesticide is used according to label directions, that will not be a concern to human health.

<span class="mw-page-title-main">Joint FAO/WHO Expert Committee on Food Additives</span>

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) is an international scientific expert committee that is administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). It has been meeting since 1956 to provide independent scientific advice pertaining to the safety evaluation of food additives. Its current scope of work now also includes the evaluation of contaminants, naturally occurring toxicants and residues of veterinary drugs in food.

Toxic equivalency factor (TEF) expresses the toxicity of dioxins, furans and PCBs in terms of the most toxic form of dioxin, 2,3,7,8-TCDD. The toxicity of the individual congeners may vary by orders of magnitude.

Synthetic magnesium silicates are white, odorless, finely divided powders formed by the precipitation reaction of water-soluble sodium silicate and a water-soluble magnesium salt such as magnesium chloride, magnesium nitrate or magnesium sulfate. The composition of the precipitate depends on the ratio of the components in the reaction medium, the addition of the correcting substances, and the way in which they are precipitated.

<span class="mw-page-title-main">Carbophenothion</span> Chemical compound

Carbophenothion also known as Stauffer R 1303 as for the manufacturer, Stauffer Chemical, is an organophosphorus chemical compound. It was used as a pesticide for citrus fruits under the name of Trithion. Carbophenothion was used as an insecticide and acaricide. Although not used anymore it is still a restricted use pesticide in the United States. The chemical is identified in the US as an extremely hazardous substance according to the Emergency Planning and Community Right-to-Know Act.

Tolerable daily intake (TDI) refers to the daily amount of a chemical that has been assessed safe for human being on long-term basis. Originally acceptable daily intake (ADI) was introduced in 1961 to define the daily intake of a food additive which, during the entire lifetime, appears to be without appreciable risk. For contaminants and other foreign chemicals not used intentionally, the term TDI is often preferred. Both ADI and TDI are usually assessed based on animal experiments, and it is most often hundreds of times lower than the dose causing no observable adverse effect (NOAEL) in the most sensitive tested animal species. Because the confounding factors may vary depending on the quality of data and the type of adverse effect, TDI values are not good estimates of the harmfulness of chemicals, and must be considered administrative tools to set allowable limits for chemicals, rather than scientific measures. The threshold limit value (TLV) of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse effects.

The Food Chemicals Codex (FCC) is a collection of internationally recognized standards for the purity and identity of food ingredients.

References

  1. ↑ "IUPAC Glossary of Terms Used in Toxicology, 2nd Edition – Terms Starting with T". sis.nlm.nih.gov. Retrieved 2015-10-02.
  2. ↑ Nevárez, Myrna; Leal, Luz O.; Moreno, Myriam (2015-02-01). "Estimation of Seasonal Risk Caused by the Intake of Lead, Mercury and Cadmium through Freshwater Fish Consumption from Urban Water Reservoirs in Arid Areas of Northern Mexico". International Journal of Environmental Research and Public Health. 12 (2): 1803–1816. doi: 10.3390/ijerph120201803 . ISSN   1661-7827. PMC   4344694 . PMID   25658686.
  3. 1 2 3 4 5 6 7 8 9 Herrman, J. L.; Younes, M. (1999-10-01). "Background to the ADI/TDI/PTWI". Regulatory Toxicology and Pharmacology. 30 (2): S109–S113. doi:10.1006/rtph.1999.1335. PMID   10597623.
  4. ↑ Kim, Ji-Ae; Lee, Seung-Ha; Choi, Seung-Hyun; Jung, Ki-Kyung; Park, Mi-Sun; Jeong, Ji-Yoon; Hwang, Myung-Sil; Yoon, Hae-Jung; Choi, Dal-Woong (2012). "Heavy Metal Risk Management: Case Analysis". Toxicological Research. 28 (3): 143–149. doi:10.5487/tr.2012.28.3.143. PMC   3834422 . PMID   24278603.
  5. ↑ "About Codex". CODEX Alimentarius. Retrieved 19 February 2024.
  6. 1 2 "CODEX GENERAL STANDARD FOR CONTAMINANTS AND TOXINS IN FOOD AND FEED" (PDF). Food and Agriculture Organization of the United Nations. Retrieved 19 February 2024.
  7. ↑ Speijers, Gerrit J. A. (1999-10-01). "Precision of Estimates of an ADI (or TDI or PTWI)". Regulatory Toxicology and Pharmacology. 30 (2): S87–S93. doi:10.1006/rtph.1999.1331. PMID   10597619.
  8. ↑ "Guidance values for human exposure limits (EHC 170, 1994)". www.inchem.org. Retrieved 2015-10-06.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.