Metabolic Toxin Exposure
The human body is exposed to endogenous metabolic toxins, and both environmental toxicants and toxins on a daily basis. That exposure can put pressure on the body’s natural metabolic detoxification capacity. The environment contains close to 80,000 novel chemicals, all registered with the United States Environmental Protection Agency since World War II. However, many chemicals have not had thorough vetting for risk to human health.1 Improper clearance of toxins may play a role in obesity, cardiovascular disease, neurocognitive concerns, immune dysfunction, chemical intolerance, and reproductive and developmental concerns.1-5
Toxins Versus Toxicants
The word “toxin” is defined as a harmful compound made by bacteria, plants, or animals, while the word “toxicant” refers to harmful compounds made by humans or compounds introduced into the environment by human activities. Each toxic substance has a defined dose or concentration at which it produces its harmful effect. Toxicants are harmful exogenous compounds that enter the body via air, drinking water, and food. Toxins, on the other hand, could be either exogenous (found in the environment) or endogenous (produced by the body). In the present document, the word “toxin” will be used to indicate either toxins (biological source) or toxicants (chemical source).
Metabolic Detoxification: Three Phases
The human body has a well-defined detoxification system to eliminate toxins. This system is defined by three phases.
Key biochemical processes responsible for clearance of toxins from the body make up the biotransformation process, also called the metabolic detoxification system. This system is comprised of Phase I, Phase II, and Phase III pathways. The detoxification system is highly dependent on proper nutrient support for optimal functioning. Nutritional support for the biotransformation system is extremely important for any detoxification program. Fasting or poor nutritional support during a detoxification program has many adverse health effects, including decreased energy production, brain fog, mood and sleep difficulties, breakdown of lean tissue, up-regulation of detox Phase I enzyme activities with a concomitant increase in oxidative stress, and decreased levels of Phase II co-factors. Detoxification is an energy-dependent process and maintenance of adequate energy supply is crucial.
The majority of toxins are lipid-soluble molecules. It is difficult for the body to excrete lipid-soluble molecules, and these compounds can easily cross cell membranes affecting cellular activities. These lipid-soluble toxins are stored mainly in adipose tissue and the central nervous system.
The body also has a complex, integrated system designed to convert lipid-soluble toxins to water-soluble molecules, after which they can be excreted through renal or biliary routes. This system is called the detoxification or biotransformation system, including Phase I and Phase II metabolizing enzymes and Phase III protein transporters.
The detoxification system converts lipid-soluble toxins to water-soluble molecules by conjugating (binding) the toxin to another molecule such as an amino acid, methyl group, or glutathione. However, most toxins do not naturally have a reactive site that enables them to bind to a conjugation molecule. Phase I enzymes create a reactive site on the toxin compound that enable them to bind to a conjugation molecule.
