chapter 14 Detoxification
INTRODUCTION AND OVERVIEW
Toxins are ubiquitous in modern life, from the air we breathe to the food we eat. Today’s lifestyles and the increase in environmental pollutants have significantly increased the average person’s exposure to toxins,1 and this is placing new demands on natural detoxification mechanisms and causing an accumulation of toxins in our bodies.2
Detoxification is garnering more public recognition and many critics have dismissed ‘detox’ as a popular buzz term, promising a cure-all for better health and vitality but failing to deliver.3 It is true that many detoxification treatments lack efficacy, and certain protocols such as water fasting are rightfully criticised as detrimental to human health.2,3
However, as we become increasingly aware of the effects of pollution and globalisation on human health, it is important to consider the full spectrum of possible causes of illness and the damaging role toxins play in disease. While more clinical-based research is needed in this area, there is growing evidence that toxicity plays a major role in disease and must be addressed. Healthcare professionals are considering the importance of supporting the body’s natural detoxification mechanisms and identifying effective techniques to achieve this.4
WHAT ARE TOXINS?
The US Environmental Protection Agency recognises the existence of over 4 million toxic compounds,5 which can be categorised as follows:
Most toxins concentrate in adipose tissue and accumulate during a lifetime, leading to increasing toxic loads with age.7 Often, toxins are also transferred through the umbilical cord, paternal DNA and breast milk, and may even affect gene expression in the unborn child, passing the burden on to future generations.8–10
THE EFFECTS OF TOXINS
Toxins contribute to a wide range of diseases and pathological conditions. The effects of toxins are wide-reaching, and studies have identified direct relationships between toxic compounds and disorders of the nervous, endocrine and immune systems.1,11–13 This may help to explain the aetiology and increasing prevalence of diseases such as ADHD, asthma and allergies, systemic lupus erythematosus (SLE), chronic fatigue syndrome, depression, reproductive disorders, diabetes and cancer.
NEUROLOGICAL
Neurological illnesses including Parkinson’s disease, ADHD and Alzheimer’s disease have been linked to toxins,1,14,15 possibly due to the omnipresence of major neurotoxic pesticides that are readily available—from the local grocery produce to commonly used backyard herbicides.1
Interestingly, farmed Atlantic salmon, once considered ‘brain-health food’, has been found to contain high levels of methylmercury and PCBs, which can lead to neuronal decline, necrosis and demyelination if consumed over many years.16 Additionally, chemotherapeutic drugs such as doxorubicin and cisplatin have also been shown to cause direct damage to the nervous system.1
Recent studies have found additives in processed and convenience foods that can trigger mild thyrotoxicosis and dopamine deficiency, and this may play a role in explaining why so many of today’s children are affected by attention deficits and other mental disorders.15,17
IMMUNE
Some toxic compounds can lower the body’s immunity and increase the likelihood of infection and cancer. Others are known to promote inflammation and are strongly linked to common allergic reactions.13,18,19
The World Health Organization (WHO) reports that there is growing evidence that a vast number of environmental agents and therapeutics cause autoimmune-like diseases. For example, while the underlying aetiology of SLE is unknown, research points towards possible adverse reactions to toxic chemicals including pharmaceutical drugs such as hydralazine, isoniazid and minocycline.1,20,21
ENDOCRINE
Many environmental chemicals are xeno-oestrogens or endocrine disruptors that can affect the endocrine system. Known hormone disruptors, such as the plasticisers (phthalates and bisphenol-A), are readily found in the environment and common goods such as children’s toys and baby bottles, plastic food wrap, cosmetics and tinned food cans. This may help explain the rise in premature puberty among girls.22 These common plasticisers and other environmental chemicals have been shown to lower progesterone, which may contribute to PMS symptoms, breast cysts, miscarriages and even breast cancer.6,23–25 Additionally, atrazine, the most commonly used herbicide in America’s agriculture industry, is also a xeno-oestrogen and is strongly linked to breast, uterine and ovarian cancers.26,27 Many harsh toxic chemicals can also cross the placenta and are passed on to children in utero and through breast milk.6,8
Male fertility has also not escaped the effects of environmental toxins. Since the 1940s, there has been a drop in sperm count, with an overall reduction of 50%.28,29 Toxins such as PCBs have also had ‘gender-bender’ effects, reversing the sex of male turtle eggs.30
In addition to affecting reproductive tissues, toxins take their toll on the hypothalamus–pituitary–adrenal axis, influencing sleep patterns, mood, libido and energy levels.1 Solvents found in petrol, glue and fabric cleansers cause destruction of the adrenal glands and disrupt cortisol production.16,31
If liver or gut function is compromised due to a nutrient deficiency, toxic stress or imbalances in gut flora, endogenous hormones such as oestradiol and its metabolites may accumulate in the body, causing oestrogen dominance and increasing the risk of breast and ovarian cancer.6
BODY WEIGHT
Toxins accumulate in adipose tissue and lead to difficulties in losing weight. Studies have shown that the heavy metals and industrial chemicals such as those found in car exhaust fumes concentrate in cellular mitochondria.32 These toxins infiltrate the mitochondria and alter the cells’ normal biochemistry and energy production, resulting in reduced lipolysis, thermogenesis and ATP production. Thus, toxic exposure will reduce fat breakdown, basal metabolic rate and energy production.32
DIABETES
Based on current research, a new school of thought is emerging on the aetiology of diabetes. As scientific research in this field evolves, scientists are beginning to see a link between diabetes and the level of toxins stored in the body. For example, people with the highest level of stored toxins (such as those found in dry cleaning and lindane shampoo) are almost 40 times more likely to have diabetes.33 The Lancet has gone as far as to say that obesity is a major contributor to type 2 diabetes primarily because fat is a vehicle for persistent organic pollutants.34
CANCER
There is increasing evidence to suggest that toxicity is a major contributor to cancer incidence. The Journal of the American Medical Association holds that even once smoking is factored out, the rates of cancer are higher for those born after 1940 and can partly be attributed to an increased exposure to environmental carcinogens.35 The British Medical Journal further vindicates this theory in saying that, ‘Environmental and lifestyle factors are key determinants of human disease—accounting for perhaps 75 per cent of most cancers’.36
The mechanisms of action to explain the carcinogenic effects of toxins of course include potential direct mutagenic effects on cells. Other indirect mechanisms have been postulated. Heavy metals, pesticides and drugs such as cimetidine are known disruptors of mitochondrial function, increasing the production of reactive oxygen species (ROS).37 In turn, the ROS activate inflammatory transcription factors and cause oxidative damage to nuclear DNA, leading to mutations and carcinogenesis.38,39
Breast adipose tissue is found to concentrate organochlorine compounds (OCCs) more than other bodily adipose cells and has been found in higher concentrations in women with breast cancer.40–42 Another study found a fourfold increased risk of breast cancer associated with raised serum PCB and DDE.43 However, other studies have failed to observe an increased risk.44,45
Exposure to environmental toxins is also implicated in the development of other adult and childhood cancers, particularly haematological and brain.46–50
CARDIORESPIRATORY
The APHENA (Air Pollution And Health: A Combined European And North American Approach) study combines health data and air pollution monitoring from cities across Europe, the United States and Canada. The results confirm earlier findings of an increased all-cause mortality associated with air pollution, especially particulate matter with a diameter less than 10 nm. Elderly and unemployed people were more at risk, as were Canadians.51
Other epidemiological studies have also found an association with daily fluctuations in particulate matter as well as sulfur- and nitrogen-based air pollutants. Air pollution is positively associated with school absenteeism, reduced peak flow rates in normal children and acute cardio and respiratory admissions to hospital, and mortality.52 Long-term exposures of over 3 years may even increase these risks.53 Furthermore, there appears to be no safe lower limit where the rates of illness plateau. The levels set for public health pollution alerts are therefore arbitrary.
Increased rates of asthma and chronic bronchitis, especially in children, have been observed with higher indoor air levels of solvents and formaldehyde.54
DETOXIFICATION: HOW THE BODY PROCESSES TOXINS
GASTROINTESTINAL TRACT
Over the course of a lifetime, the gastrointestinal tract processes more than 25 tons of food, which represents the largest load of antigens and xenobiotics confronting the human body.55
As many toxins are stored in adipose tissue, the best way to eliminate toxic load is to increase the amount of fat excreted in the stool.32 In the small intestine, toxins from food and bile are mixed with pancreatic enzymes that emulsify fat for absorption. Importantly, this leads to an increase in the absorption of toxins.
Gastrointestinal flora are important for the proper elimination of toxins, especially hormone metabolites. For example, after being metabolised by the liver, conjugated oestrogens are eliminated through the bowels. Gut dysbiosis with pathogenic bacteria can produce deconjugating enzymes such as beta-glucuronidase that cleave oestrogen metabolites from their neutralising conjugates. The metabolites are reabsorbed via the enterohepatic circulation.56
LIVER
The liver is the main organ for detoxifying lipophilic chemicals, filtering about one litre of blood per minute.6 The rate of detoxification is a function of hepatic blood flow and liver enzyme activity. The detoxification pathways can be divided into two main phases. Most chemicals are first activated through phase 1 before being conjugated in phase 2. However, some chemicals bypass phase 1 and are simply conjugated for renal or biliary excretion.
Phase 1 detoxification
Phase 1 pathways include the flavine-containing monooxygenases (FMO) (NADPH-dependent oxidation), alcohol dehydrogenase and the famous cytochrome P-450 superfamily of enzymes, which metabolise thousands of exogenous and endogenous compounds and are responsible for the activation and detoxification of over 90% of pharmaceuticals. The majority of phase 1 metabolites are reactive, highly volatile substances and require phase 2 for neutralisation. These reactive intermediates are up to 60 times more toxic than their parent molecules and can act as free radicals in the body, capable of causing significant oxidative damage, inflammation, DNA mutations and cancer.57 For example, paracetomol-associated hepatotoxicity does not result from the drug itself but from depleted hepatic glutathione stores (an important hepatic antioxidant) and accumulation of a hepatotoxic phase 1 metabolite N-acetyl-p-benzoquinoneimine.58
KIDNEYS
The kidneys are the primary organs for excretion of water-soluble endogenous and exogenous toxins. Smaller-sized toxins unbound to plasma proteins filter through the glomeruli, which act like a sieve. Other toxins, including metals and drugs, urea and uric acid, are passively and actively excreted via tubule secretion. The ionisation of weak organic acids and bases in the tubules is also used to excrete many toxins, especially drugs.59 As well as increasing the reabsorption of water, antidiuretic hormone (ADH) increases the reabsorption of urea and reduces urine flow and thus the clearance of toxins.59
OTHER PATHWAYS OF DETOXIFICATION
As the largest organ in the body, the skin can eliminate heavy metals and chemical xenobiotics through perspiration.60 Furthermore, when other organs of elimination such as the kidneys are failing, the skin aids in the elimination process, as is seen in uraemic frost.
Toxins may also be eliminated through breast milk and exhaled air.
ASSESSMENT OF TOXICITY AND DETOXIFICATION
ASSESSMENT FOR A DETOXIFICATION PROGRAM
The assessment of the patient should begin with a thorough case history to evaluate exposure to toxins (Box 14.1) and the potential impact on the patient’s health (Boxes 14.2 and 14.3). For each exposure, the patient should be asked about any health complaints experienced at the time or shortly after exposure as well as any potential sequelae. It is also important to appreciate that due to genetic variability, some patients are more affected by toxic chemicals than others. It is therefore vital to assess each patient on an individual basis and to not discount even small amounts of exposure.
