ACTIVATED CHARCOAL: ARE THE NUTRITIONAL CLAIMS JUSTIFIED?
DIET TRENDS
The craze for ‘activated charcoal’ (AC – also known as activated carbon) took off last year, with health claims making it sound like a miracle detox solution. Here, Alice Fletcher dispels the myths behind AC. The trend for AC appears to have died down a bit of late. Trendy cafes were selling shots of charcoal infused water and Gwyneth Paltrow continues to plug charcoal lemonade on her website describing it as the ‘best detoxifier’ around. You have probably seen charcoal facemasks that are famously very difficult to remove and actually end up waxing your face (trust me), as well as bloggers brushing their teeth with black charcoal powder before showing off a set of pearly white gnashers. If you are super trendy, you may have even stumbled across charcoal infused croissants and burger buns (which yes, look very black – not particularly appetising!). You can even get (black) charcoal ice cream. Imagine spilling that down your tunic. AC capsules can be purchased in health food shops and online, with descriptions including: 'It is important to help your body eliminate toxins to promote a healthy digestive system and brain. Chronic exposure to toxins produces cellular damage, allergic reactions, compromised immunity, and more rapid aging.' and, 'Regular use of activated charcoal is easy on the colon and can leave you feeling renewed and more vibrant.' The claims regarding AC usually come with the pills and powders, not the Instagramable black ice cream cones and burger buns, where the black food is more for photographic effect. Powdered charcoal can be purchased in specialist culinary shops for this purpose. AC is typically made from carboncontaining material, like wood, which is heated at high temperatures to create
charcoal, then oxidised (a process known as ‘activation’). AC is sometimes made by heating up coconut shells to very high heats. This process works to increase the surface area of molecules by giving it lots of pores, in effect, making it act like a sponge.1 Indeed, some ‘super activated’ charcoal preparations have a surface area of up to 175,000m2 per 50g bottle. This allows the ‘adsorption’ of drugs through weak intermolecular forces, with non‐ionized, organic compounds binding more avidly than dissociated inorganic ones.2
Alice Fletcher RD Countess of Chester NHS Foundation Trust (Community Dietitian) Alice has been a Registered Dietitian for five years, working within NHS community-based teams. She is passionate about evidence-based nutrition, cooking and dispelling diet myths.
DOES AC DETOX THE BODY?
Scaremongering regarding hidden toxins within the food we eat and the air we breathe may push people to purchase AC, or a similar product that promises to help our body to detox itself more effectively. AC is adsorbent (has a high capacity to bind), easily confused with absorbent. For this reason, AC supplements available in health food shops recommend leaving at least two hours between other medications when taking the supplement. Such over-the-counter supplements are commonly recommended to be taken as two to four capsules up to three times per day with food.3 Ironically, AC’s high adsorbency also means that the ‘superfood’ fruit smoothie with added AC may have less of its vitamins and minerals left for your gut to absorb, as they have been mopped up and are no longer bioavailable. Unfortunately, the ‘toxins’ that over-thecounter AC capsules claim to rid us of are not named – a common theme with ‘detox’ products on the whole.
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DIET TRENDS DOES AC REDUCE THE ABSORPTION OF TOXIC SUBSTANCES/DRUGS FOR POISONING?
AC is listed within the BNF under indication ‘Reduction of absorption of poisons in the gastrointestinal system’ only.4 Clinically, it is available as an oral suspension (AC 200mg per 1ml), or in granule form (with AC 813mg per gram). It is only effective for certain medications, such as quinidine sulphate and aspirin. The suggested dose for treating a case of poisoning is 50g of product for an adult. This equates to over 40,000mg of AC. In contrast, capsules purchased in a leading health food shop as a supplement (for wind and bloating) contain only 334mg each; three pre- and three post-meal are recommended, with a maximum of 12 per day.5 However, 12 capsules would equate to 4000mg, 10% of the dose needed to treat acute poisoning. The American Society of Toxicology produced a position statement in 1997 stating that: ‘administration of AC may be considered if a patient has ingested a potentially toxic amount of a poison (which is known to be adsorbed to charcoal) up to one hour previously; there is insufficient data to support or exclude its use after one hour of ingestion. There is no evidence that the administration of AC improves clinical outcome. Unless a patient has an intact or protected airway, the administration of AC is contraindicated.’6 DOES IT REDUCE HANGOVERS?
AC has been claimed online to help reduce hangovers by binding with alcohol. You may have seen recipes for black charcoal cocktails, which promise to leave you feeling fresher than you otherwise would have. You have probably already guessed that this is not the case, as, unfortunately, AC does not bind well with alcohol. Clinically, AC is rarely used in pure alcohol poisoning, since alcohol is absorbed rapidly from the gut. In early reports, AC was found to adsorb alcohol poorly.7 However, in 1981, scientists demonstrated in dogs that AC given at the same time as alcohol can reduce the blood alcohol concentration significantly.8 To study whether AC is of value in a clinical situation, a randomised cross-over study in two phases was conducted. Each person drank 88g of alcohol and 30 minutes afterwards, either 20g of AC was taken, or the same volume of water was 48
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drunk. Significant differences in plasma alcohol concentrations with or without AC were not found.9 HOW ABOUT REDUCING WIND AND BLOATING?
An in vitro and in vivo study in 1985 found that AC does not influence gas formation in vitro or in vivo,10 but interest in this possible gas trapping function of AC continued. In 2011, the European Food Safety Authority (EFSA) produced an opinion paper regarding the gastrointestinal claims around AC. They concluded that AC can be sold with the conditions of use that it can be labelled as, ‘traditionally used to contribute to good digestive comfort’, or ‘usually known for its contribution to good digestion’ in the dosage powder equivalent to 400mg of drug daily.11 On the basis of the data presented to them, the EFSA Panel concluded that a cause and effect relationship had been established between consumption of AC and reduction of excessive intestinal gas accumulation. The panel considered that in order to obtain the claimed effect, the intake of AC should be 1g at least 30 minutes before consumption of a meal and 1g after the meal. In one of the studies discussed within this opinion paper, researchers conducted a doubleblind clinical trial on two population groups in the United States (n = 30) and India (n = 69) known to differ in their dietary habits and ecology of gut flora. Using lactulose as the substrate, breath hydrogen levels were measured to quantify the amount of gas produced in the colon. In comparison to a placebo, AC significantly (p less than 0.05) reduced breath hydrogen levels in both the population groups. Self-reported symptoms of bloating and abdominal cramps attributable to gaseousness were also significantly reduced in both groups by AC.12 Another study measured the amounts of flatus (self-reported – nobody wants that job!) over a defined period, finding orally administered AC to significantly reduce these events.13 However, following on from these studies in the eighties, a longer (albeit small) study in 1999 used five healthy human volunteers who ingested 0.52g of AC four times daily for one week. The faecal liberation of intestinal gases was measured before and after the AC treatment. Ingestion of AC neither produced significant reduction in the faecal release of any of the
sulphur-containing gases, nor was total faecal gas release or abdominal symptoms significantly influenced.14 This is, however, a relatively small dose compared with other studies, which may well have impacted upon the findings. On the basis of the data presented, the EFSA Panel concluded that a cause and effect relationship had not been established between consumption of AC and reduction of bloating.11 I could not find any studies comparing the likes of a low-FODMAP diet to a diet supplemented with charcoal capsules, and charcoal does not feature in NICE guidance for diagnosed IBS. DOES AC REDUCE DIARRHOEA?
Cancer Research UK state that 10-20% of people receiving the chemotherapy drug irinotecan (Campto) report severe diarrhoea.15 A prospective study to evaluate the efficacy of AC to prevent irinotecan-induced diarrhoea, found that the use of AC decreased the frequency and severity of diarrhoea, which also improved compliance with treatment. Within this study (in children) the experimental group received AC at a dose of 250mg three times daily during irinotecan administration. A total of 28 events of diarrhoea were registered, 13 in 45 cycles (28.88%) in the experimental group and 15 in 21 cycles (71.42%) in the control group.16 Diarrhoea can present itself alongside a multitude of treatments and conditions aside from chemotherapy, including intestinal, colorectal and pancreatic cancer, bacterial infection and IBS, making AC a potential therapy in these conditions. Overall, further research is necessary in order to determine the effectiveness of AC in the management of diarrhoea. AC in large doses can cause constipation, a laxative is advised alongside its use for overdose/accidental poisoning because of this and it is often clinically formulated to include sorbitol for this reason. There have been case reports of bowel obstruction from AC, but this was following large doses of AC following drug overdose, not every day supplementation.17,18 DOES AC REDUCE THE DECLINE IN KIDNEY FUNCTION IN PEOPLE WITH END STAGE CKD?
The effects of oral adsorbents such as AC have been looked into as a method of delaying
progression or preventing chronic kidney disease (CKD), which is a huge global public health problem. Deterioration of kidney function causes an increase of uraemic toxins in the blood, which in turn promotes CKD progression. Oral adsorbents, including AC, have the ability to adsorb and remove uraemic toxins secreted and produced in the gastrointestinal tract and eliminated in faeces. These have been used in clinical practice to decrease kidney injury. A Cochrane review included 15 studies which recruited 1590 participants, using RCTs only. It was found that oral AC granules may have beneficial effects on retarding the decline of kidney function, with no serious adverse events for patients with CKD. Unfortunately, the studies included were generally of poor methodological quality. Currently, there is no strong evidence for recommending any oral adsorbents, such as AC, for preventing or delaying the progression for patients with CKD.20 More research is needed, but this is certainly an interesting direction of study. SUMMARY
It seems that the power of detox will continue to be plugged until the end of time. In April this year, The Lancet published results from 27 years of data collected from across 195 countries, finding 11 million deaths and 255 million disability-adjusted-life years were attributable to dietary risk factors. High intake of sodium, low intake of wholegrains and fruits were the leading dietary risk factors for deaths and disability-adjusted-life years globally. The need to prioritise and promote sensible dietary patterns above pricey detox products continues. www.NHDmag.com October 2019 - Issue 148
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