Thriving in a Toxic World

The simple truth is that we are living in a sea of toxins and it is destroying our bodies and brains
Dr. Mark Hyman

We are exposed to thousands of toxic chemicals in the course of our daily lives, and they can be placed into two main categories: synthetic and naturally occurring. The majority of naturally occurring toxins are organic compounds, and we can usually detoxify and eliminate them fairly easily.

However, many commonly eaten foods today have been introduced into our diet over the last few centuries, mainly from Asia and the Americas. Even wheat is a foreign food to most westerners, having originated in the Levant region of the Near East and the Ethiopian Highlands. Wheat was first cultivated in Greece around 8,500 years ago, and in Germany around 7,000 years ago, so you would think we’d be used to it by now, but many people still have trouble digesting it.

It should be noted here that the problem with wheat is that gluten can be difficult to digest, not that it is toxic. Plants do not normally want to be eaten though, and they defend themselves in a number of ways. Storing toxins in their flesh is a major defence against predation, and in some cases this is an active process—acacia trees in Africa will rapidly pump tannins into their leaves when they are being eaten by a giraffe, which makes their leaves bitter and hard to digest.

An exception to the ‘don’t want to be eaten rule’ are brightly coloured fruits, which plants want to be eaten in order to disperse their seeds. This only works as originally intended when animals swallow the seeds whole then poop them out later, which we used to do before we got civilised. Now we collect the seeds, then plant, fertilise and water them, so plants have trained us well.

The fact is that all plants produce chemical compounds that are capable of interfering with the metabolism of living organisms, and because they have to deal with a variety of predators, they tend to produce a variety of toxins. There are more than 750 toxic plant chemicals that we know of, which are found in over a thousand different species of plants. Most plants are too toxic for us to eat, and there are few cases where we can eat all parts of a plant.¹

When we look at the array of chemicals produced by plants it is a wonder we can eat them at all. We have a remarkably effective detoxification and elimination system though, and we not only prevent these plant toxins from making us sick, many plants have an overall beneficial effect due to their toxic chemicals. Some foods, like garlic, ginger, and turmeric, are lauded for their medicinal effects, and around 40% of pharmaceutical drugs are derived from herbal medicine.²

An example of this toxic and/or therapeutic effect are salicylates, a group of chemicals found in most plants. Salicylates are primarily a plants defence against insects and fungi, yet they can also have potent effects in humans. Salicylates can interfere with the metabolism of carbohydrates, protein and fat, and can inhibit the function of enzymes and prostaglandins. By inhibiting certain prostaglandins salicylates exert an anti-inflammatory effect, making them useful in the treatment of arthritis.³

One of our best-known salicylate drugs is aspirin, a manmade substance manufactured from salicylic acid, which is found in the bark of the white willow tree. Salicylic acid is a common active constituent in several herbal medicines, but it can be corrosive to the stomach lining, so it is methylated before use. While the methylation process reduces the acidity, it gives aspirin a mild anticoagulant effect. This initially unwanted side effect has made aspirin an important drug in the management of clotting disorders.⁴

Although there are a variety of salicylate compounds found in different plants, there does not seem to be a great deal of difference in their effect on the human organism. This is not the case for alkaloids though, which vary greatly in their effect.

Most known alkaloids are poisonous in high doses, and they can disrupt our metabolism even in low doses. Alkaloids are especially potent against mammals, which gave alkaloid containing plants an advantage over other plants when mammals became the dominant plant predators, and alkaloid plants flourished in evolu­tionary history at the same time as did mammals. Alkaloids include some of the most commonly used drugs in the world, such as caffeine, codeine and morphine, as well as some dangerous poisons, such as solanine and strychnine.⁵

Solanine is a steroidal glycoalkaloid and, being a common constituent of the nightshade family of plants, it is one of the most commonly ingested alkaloids on the planet. There are more than 1,500 different species of nightshade, and the edible varieties include tomato, potato, bell pepper, chilli, paprika, pimiento, eggplant, goji berries, Cape gooseberry, pepino, and tamarillo. The nightshade family also includes the medicinal herbs withania, henbane, and belladonna (AKA the deadly nightshade), and the one we should call the deadly nightshade, tobacco.⁶

Most of this family of plants are highly toxic and would make us sick if we ate them. Some of the nightshades we eat are also quite toxic; tobacco, bell peppers and chilli extracts can be used as an insect repellent, and capsicum is used as a defence spray.

According to The Physician’s Desk Reference for Herbal Medicines, external application of capsicum for more than two days can cause blistering, ulceration, and festering dermatitis; long-term consump­tion can cause chronic gastritis, liver and kidney damage, and neuro­toxic effects; and an overdose can lead to a life-threatening hypo­thermia. It should be noted that solanine is not the only naturally occurring toxin in the nightshade family, and some of these adverse effects are likely caused by other natural chemicals, such as capsaicin and salicylates.⁷

If we take the effects of chilli as an indication of whether we should eat it, the answer is probably not. First it burns on the way in (and sometimes on the way out) which is our body telling us not to eat it. Then it causes diarrhoea and sweating, which is our body trying to get rid of it.

When we add this to the toxicological data above and its use as an insect repellent and defence spray you have to wonder why we eat chilli at all. Having said this, studies have shown that consuming moderate amounts of chilli has an overall health benefit, reducing the risk of cardiovascular disease, cancer, and all-cause mortality. It can also make our food taste good, so eat it in moderation and don’t believe the hype.⁸

Chilli is not the only nightshades that can protect us from disease. Tomatoes contain lycopene, an antioxidant that can reduce the risk of developing cardiovascular disease and prostate, breast, and lung cancer. You can have too much of a good thing though, and one nightshade we probably should eat less of is the potato.⁹

Potatoes contain good amounts of vitamins C and B6, fibre and resistant starch, and can be part of a healthy diet, but we can get all these from alternative sources. Potatoes also contain relatively high levels of solanine and chaconine, which are potent toxins that can make us very sick. The toxic nature of potato is not a recent discovery, and Sweden tried to prevent importation of the potato due to its neuro­toxicity in the eighteenth century. Solanine and chaconine are similar in chemical structure and effect, and most of the research has focussed on solanine, so that’s what I will focus on too.¹⁰

Despite being a commonly consumed toxin, few people seem to have heard of solanine. There is a wealth of information available on it though, including in the Oxford Dictionary, which defines solanine as a poisonous alkaloid found in various plants of the genus Solanum.¹¹

Symptoms of solanine poisoning include abdominal pain, vomiting, diarrhoea, fever, headache, restlessness, apathy, confusion, hallucina­tions, visual disturbances, drowsiness and depression. Studies of solanine have shown a possible association with spontaneous abortions, birth defects, gastric ulcers, hepatomegaly and osteoporosis.^12-18

Reports of potato poisoning are rare, but they do occur, and over a 15-year period the Berlin Poison Control Centre received 42 enquiries with regard to potato poisoning. This might just be the tip of the iceberg though. It is believed that solanine is the cause of many gastric upsets that go unreported as such, and that these gastric ‘upsets’ can be severe enough to be fatal.^19-21

The usual solanine content based on dry weight of the different parts of the potato are as follows:

• Flowers 700mg/kg.
• Fruits 1000mg/kg.
• Seeds 250mg/kg.
• Tops 500mg/kg.
• Sprouts 800-5000mg/kg.
• Tuber 75mg/kg.

While the concentration of solanine in the potato tuber is relatively low, there is a high concentration in the skin and the sprouts. For this reason it is recommended that potatoes are peeled and the sprouts (AKA eyes) are removed.^{24, 25}

The World Health Organization has determined the toxic dose of solanine to be 1-3mg/kg of body weight, and the lethal dose to be 3-6mg/kg of body weight. If we apply the standard method of calculating the acceptable daily intake of food additives to solanine using 1mg/kg body weight as the no observed adverse effect level, the ADI is 0.1mg/kg body weight, or 7.5mg for a 75kg person. If the potato tuber contains 75mg/kg of solanine, this would be present in 100g of potato (I discuss ADIs in Chapter Two of Survival in a Toxic Soup).²⁶

Potatoes don’t always contain 75mg/kg of solanine though. Solanine protects the plant from potato blight, and consequently potatoes grown where this disease is prevalent have naturally higher levels of solanine. On the other hand, some growers have selectively bred potatoes to reduce their solanine content due to its toxicity. Because of this the solanine concentration of potatoes typically varies from 25mg/kg to 150mg/kg. The ADI of potatoes, then, should be determined separately for the different varieties.²⁷

If the solanine content of the potato tuber is 25mg/kg the ADI is 300g for a 75kg person, and if it is 150mg/kg then the ADI is 50g.^{18, 28}

When we compare these numbers to typical consumption levels it appears our intake of potato may be a bit high. The average per capita consumption of potatoes in the UK in 2022 was 196g per day. In Russia it was 238g per day, and in Belarus, the world’s top potato consumers, it was an astonishing 438g per person per day. It should be noted that these are average daily intakes, not the maximum amount people eat at a sitting.²⁹

These numbers are worrying, but the problem appears even worse when we take a closer look at it. These ADI’s assume that potatoes are the only source of solanine, which is rarely the case since it is present in most, if not all, of the nightshades we eat. They also assume that the solanine content has not risen during storage and processing, as it does if potatoes are exposed to sunlight, or experience chemical or physical damage.³⁰

Exposure to sunlight will cause potatoes to turn green due to an increase in chlorophyll, and green potatoes are considered unsafe for human consumption due to the corresponding increase in their solanine levels. An increase in the solanine content of potatoes due to factors other than sunlight will not lead to a change in their colour however, so if a potato is not green it does not necessarily mean it is safe to eat.¹¹

Other signs of a high solanine content in potatoes are a bitter taste or a burning sensation on the tongue, both of which indicate they are not safe for human consumption. This may be an effective way to determine unsafe levels of solanine in potatoes, but when it comes to chilli and bell peppers a bitter taste is considered normal, and a burning sensation is a desired effect.¹⁵

Having read all this you might be thinking that we should all stop eating potatoes. If they were as bad for us as the numbers suggest then I am sure we would have realised it and stopped eating them years ago. The fact is most people who eat potatoes every day are fine, and we deal with the natural toxins in our food remarkably well.

There will always be a few sensitive individuals like me who have a problem with them, and some who would be better off if they ate less of them. If you want to give them up sweet potatoes are an easy substitution since they are not part of the Solanaceae family, and therefore they are solanine free. If you want to avoid solanine completely giving up potatoes will not achieve this if you are eating other members of the family or you smoke tobacco. If you want to find out if solanine is adversely affecting you then you need to eliminate the whole family from your diet completely.

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When it comes to the synthetic chemicals that we are exposed to, many of these are copies of naturally occurring ones, such as citric acid and MSG. We can deal with these easily if we do not consume them to excess, which we rarely do (MSG being a notable exception). The chemicals we produce that are not found in nature can be more problematic though, especially if we can’t easily eliminate them. These chemicals will accumulate in our bodies, often in our fat stores, where they are released and re-stored via a process known as triglyceride turnover. This constant, low-level of toxins circulating our body might not make us acutely ill, but it can have serious long-term effects. Of particular concern are those that can interfere with our endocrine system by blocking or mimicking hormones.

Of the thousands of synthetic chemicals that have been approved for use, around 1,000 are known or suspected to be capable of interfering with our endocrine system. Endocrine disrupting chemicals (EDCs) are found in food cans, plastics, detergents, toys, cosmetics, drugs and pesticides. They can adversely affect our reproductive, neurological, and immune systems, and can cause neurodevelopmental delays in children. Exposure to EDCs during foetal development can affect disease development later in life, increasing our susceptibility to obesity, diabetes, and metabolic syndrome. They have been linked to low sperm count and testicular cancer in men, and in women ECDs can increase the risk of cervicovaginal and breast cancers, PCOS, ectopic pregnancy, uterine fibroids, and can cause the early onset of both puberty and menopause.³¹

Also of particular concern are the chemicals that can interfere with our nervous system. Heavy metals and pesticides have been linked to a variety of neurological conditions including Alzheimer’s disease, Parkinson’s disease, autism, ADD, anxiety, depression, cognitive and behavioural disorders, and low IQ. Babies are the most vulnerable, since even in low concentrations these toxins can cross the placenta or gain entry through breast milk and affect the developing brain. The old are also more vulnerable due to declining liver and renal function, but people of all ages can be affected.³²

A third area of concern is air pollution, although much of the damage here is due to small particles rather than toxic chemicals. The majority of outdoor air pollution we are exposed to comes from the burning of fossil fuels, especially coal and diesel, and the majority of indoor air pollution comes from burning kerosene and biomass (wood, animal dung etc). According to the WHO, 99% of the global population breathes air that exceeds pollution guideline limits, and 2.4 billion people are exposed to dangerous levels of household air pollution.³³

PM₁₀ particles, those between 2.5 and 10 micrometres in size, can bypass our respiratory filters and reach the lungs. PM_2.5 particles, which are smaller than 2.5 micrometres, can be absorbed across the lungs into the blood steam, thereby damaging internal structures, not just the lungs and respiratory tract.

Air pollution has been linked with a number of acute and chronic diseases, including respiratory tract infections, asthma, lung cancer, cardiovascular disease, and chronic obstructive pulmonary disease. It has also been linked with cognitive impairment and depression via excess cortisol release and neuroinflammation, and NO₂ and ozone have been linked to dementia.³⁴

According to the WHO, the annual death toll due to air pollution is around 7 million people. And, according to the World Bank, there were 93 billion days lived with illness in 2019 due to air pollution, at a cost to the global economy of $8.1 trillion.³⁵

In 2008, due to concerns that current approaches to toxicology testing could not keep pace with a rapidly growing list of industrial chemicals, pesticides, food additives, and medical products, four US federal agencies formed a research partnership called Tox21; the National Institute of Environmental Health Sciences (Division of Translational Toxicology), the National Center for Advancing Translational Sciences, the Food and Drug Administration, and Environmental Protection Agency.³⁶

Tox21’s objective is to transform toxicology research from an observational science that monitors the effects of chemicals to a predictive discipline that better forecasts chemical toxicity and effects of toxins on human health. This vital work is under threat, however, from the Trump administrations funding cuts to the US National Institute of Health. These cuts, which amount to around $2.3 billion dollars, have led to the cancellation of nearly 800 research projects. $2.3 billion might seem like a significant saving, but health spending in the US in 2023 was $4.9 trillion dollars, up 7.5% ($367.5 billion) from the previous year, so the money saved by cutting the research is less than 1% of the annual increase in medical costs.³⁷

References

1. Frohne, D. Pfander, H. J. ‘A Colour Atlas of Poisonous Plants’ Wolfe Publishing, Stuttgart, 1984, p. 13.
2. www.who.int/news-room/feature-stories/detail/traditional-medicine-has-a-long-history-of-contributing-to-conventional-medicine-and-continues-to-hold-promise – 40% of medicinal drugs are derived from natural medicine
3. https://pubmed.ncbi.nlm.nih.gov/21879102/ – Salicylates. Wohlmuth, H. ‘Pharmacognosy and Medicinal Plant Pharmacology’ Southern Cross University, Lismore, 1998, p. 67. Kumar, P. Clark, M. ‘Clinical Medicine’ 3^rd ed., Bailliere Tindall, London, 1994, p. 751. Murray, M. Pizzorno, J. ‘Encyclopaedia of Natural Medicine’ Optima, London, 1990, p. 449.
4. Chevallier, A. ‘Encyclopaedia of Medicinal Plants’ Dorling Kindersley, London, 1996, p. 129.
5. Frohne, D. Pfander, H. J. ‘A Colour Atlas of Poisonous Plants’ Wolfe Publishing, Stuttgart, 1984, p. 14.
6. Wahlqvist, M. L. ‘Food and Nutrition’ Allen and Unwin, Sydney, 1997, p. 12. Frohne, D. Pfander, H. J. ‘A Colour Atlas of Poisonous Plants’ Wolfe Publishing, Stuttgart, 1984, p. 26, 214.
7. Fleming, T. ‘Physician’s Desk Reference for Herbal Medicines’ Medical Economics Co., Montvale, 1998, p. 716.
8. www.sciencedirect.com/science/article/pii/S204908012100724X – Chilli and CVD etc.
9. www.sciencedirect.com/science/article/abs/pii/B9780444596031000114#:~:text=There%20is%20considerable%20evidence%20that,to%20be%20of%20great%20value – Lycopene.
10. Frohne, D. Pfander, H. J. ‘A Colour Atlas of Poisonous Plants’ Wolfe Publishing, Stuttgart, 1984, p. 15.
11. Shorter Oxford Dictionary, 3^rd ed., Clarendon Press, Oxford, 1967, p. 949.
12. Whitney, E. N. Cataldo, C. B. Rolfes, S. R. ‘Understanding Normal and Clinical Nutrition’ Wadsworth, Belmont, 1998, p. 498.
13. Dreisbach, R. H. ‘Handbook of Poisoning’ 11^th ed., L.M.P., Los Altos, 1983, p. 548.
14. Wang, X. G. ‘Teratogenic effect of potato glycoalkaloids’ Chinese Journal of Obstetrics and Gynaecology, vol. 28, No 2, Feb 1993, p. 73-5, 121-2.
15. Jelinek, R. Kyzlink, V. Blatiny, C. Jr. ‘An evaluation of the embriotoxic effects of blighted potatoes on chicken embryos’ Teratology, vol. 14, No 3, Dec 1976, p. 335-42.
16. Baker, D. Keeler, R. Gaffield, W. ‘Lesions of potato sprout and extracted potato sprout alkaloid toxicity in Syrian hamsters’ Journal of Toxicology—Clinical Toxicology, vol. 25, No 3, 1987, p. 199-208.
17. Friedman, M. Henika, P. R. Mackey, B. E. ‘Feeding of potato, tomato and eggplant alkaloids affects food consumption and body and liver weights in mice’ Journal of Nutrition, vol. 126, No 4, Apr 1996, p. 989-99.
18. Mickalska, L. Nagal, G. Swiniarski, E. Zydowo, M. M. ‘The effects of alpha-solanine on the active calcium transport in rat intestines’ General Pharmacology, vol. 16, No 1, 1985, p. 69-70.
19. Bender, D. A. Bender, A. E. ‘Nutrition’ Oxford University Press, Oxford, 1997, p. 473.
20. Dalvi, R. R. Bowie, W. C. ‘Toxicology of solanine: an overview’ Veterinary and Human Toxicology, vol. 25, No 1, Feb 1983, p. 13-5.
21. Wahlqvist, M. L. ‘Food and Nutrition’ Allen and Unwin, Sydney, 1997, p. 6.
22. McMillan, M. Thompson, J. C. ‘An Outbreak of Suspected Solanine Poisoning in Schoolboys: Examination of Criteria of Solanine Poisoning’ Q. J. Med., 1979, 48:227-243. https://www.smithsonianmag.com/arts-culture/horrific-tales-of-potatoes-that-caused-mass-sickness-and-even-death-3162870/ – Deadly spuds.
23. Morris, S.C. Lee, T.H. ‘The Toxicity and Teratogenicity of Solanaceae Glycoalkaloids Particularly those of the Potato (Solanum Tuberosum): A Review’ Food Technol. Aust., 1984, 36:118-124.
24. Wahlqvist, M. L. ‘Food and Nutrition’ Allen and Unwin, Sydney, 1997, p. 12. Frohne, p. 221.
25. Garrow, J. S. James, W. P. T. ‘Human Nutrition and Dietetics’ 9^th ed., Churchill Livingstone, Edinburgh, 1993, p. 290.
26. Harvey, M.H. Morris, B.A. McMillan, M. Marks, V. ‘Measurement of Potato Steroidal Alkaloids in Human Serum and Saliva by Radioimmunoassay’ 764_Solanine and Chaconine WHO (Food Additives Series 30). Hum. Toxicol., 1985, 4:503-512.
27. Renwick, J. H. ‘Hypothesis: Anencephaly and Spina Bifida are Usually Preventable by Avoidance of a Specific but Unidentified Substance Present in Certain Potato Tubers’  Br. J. Prev. Soc. Med., 1972, 26:67-88.
28. Briggs, G. M. Calloway, D. H. ‘Nutrition and Physical Fitness’ 11th ed., Holt, Rinehart and Winston, New York, 1984, p. 460.
29. https://worldpopulationreview.com/country-rankings/potato-consumption-by-country
30. Bender, p. 474; Sharma, R. P. Salunkhe, D. K. ‘Solanum Glycoalkaloids’ In: Cheeke, P. R. (editor) ‘Toxicants of Plant Origin’ Vol. 1, Alkaloids, CRC Press, Boca Raton, Florida, 1989, p. 179-236.
31. www.the-scientist.com/synthetic-chemicals-are-everywhere-but-we-know-little-about-how-they-affect-our-health-72479 – 1000 EDCs. www.niehs.nih.gov/health/topics/agents/endocrine#:~:text=According%20to%20the%20Endocrine%20Society,most%20common%20and%20well%2Dstudied – ECDs. https://pubmed.ncbi.nlm.nih.gov/29126512/ – ECDs.  https://pubmed.ncbi.nlm.nih.gov/21899826/ – ECDs and disease. https://pubmed.ncbi.nlm.nih.gov/33819127/ – ECDs and breast cancer.
32. https://journals.lww.com/annalsofian/fulltext/2022/25001/environmental_toxins_and_brain__life_on_earth_is.4.aspx – Toxins and neuropathology. www.sciencedirect.com/science/article/abs/pii/S0161813X08001095#:~:text=There%20is%20also%20some%20evidence,Stallones%20and%20Beseler%2C%202016) – Toxins and depression. www.frontiersin.org/journals/toxicology/articles/10.3389/ftox.2022.837579/full – Toxins and neuropathology.
33. www.who.int/health-topics/air-pollution#tab=tab_2 – Air pollution impact www.who.int/health-topics/air-pollution#tab=tab_1 – Air pollution overview.
34. www.who.int/data/gho/data/themes/topics/indicator-groups/indicator-group-details/GHO/ambient-air-pollution – Ambient air pollution. https://journals.lww.com/annalsofian/fulltext/2022/25001/environmental_toxins_and_brain__life_on_earth_is.4.aspx – Pollution and the brain.
35. www.who.int/health-topics/air-pollution#tab=tab_2 https://openknowledge.worldbank.org/entities/publication/c96ee144-4a4b-5164-ad79-74c051179eee; www.who.int/health-topics/air-pollution#tab=tab_2 – Air pollution.
36. www.niehs.nih.gov/research/programs/tox21 – Tox21.
37. www.scientificamerican.com/article/hiv-trans-health-and-covid-research-targeted-by-trump-cuts-to-nih/ – Trump research cuts. www.cms.gov/data-research/statistics-trends-and-reports/national-health-expenditure-data/nhe-fact-sheet – Cost of healthcare US.