CONSUMPTION OF NIGHTSHADE PLANTS, HUMAN HEALTH AND AUTOIMMUNE DISEASE LOREN CORDAIN, PH.D. CONSUMPTION OF NIGHTSHADE PLANTS, HUMAN HEALTH AND AUTOIMMUNE DISEASE By Loren Cordain, Ph.D., Professsor Previously, I have not specifically commented about Table 2. U.S. per capita nightshade consumption. Data from the nightshade family of plants in any of my three USDA Economic Research Service.2 books, however I have written a brief paper (Tomatoes, ITEM POUNDS YEAR Vaccines and Autoimmune Disease) demonstrating Potatoes (total) 126.0 2007 a possible link between tomato consumption and autoimmune disease. Frozen 53.0 2007 Fresh 44.0 2007 Nightshade is the common name for flowering plants belonging to the botanical family Solanaceae, which Chips 16.0 2007 contain more than 75 genera and 2,000 species.1 Dehydrated 13.0 2007 Some notorious non-edible nightshades include Fresh Tomatoes 18.5 2008 tobacco, petunias, jimson weed, mandrake, and deadly nightshade. The family comprises well known food Processed Tomatoes 67.2 2008 plants such as potatoes, tomatoes, green peppers, (total) chili peppers, eggplants and tomatillos. Note that Tomato sauces 23.5 2008 chili peppers include all varieties of peppers from the Tomato paste 12.1 2008 genus Capsicum, including bell peppers, jalapeno, wax, cayenne, habanero, Anaheim, Thai, Tabasco, cherry, Whole tomatoes 11.4 2008 pepperoncini and Serrano among others. Chili peppers (Canned) are commonly consumed as dried powders such as Catsup 10.1 2008 paprika, chili powder and cayenne, and are near Tomato juice 10.1 2008 universal ingredients in hot sauces, Tabasco sauces, and salsas. Some more obscure edible plants from the Bell peppers 9.1 2008 Solanaceae family are listed in Table 1. Chili peppers 6.4 2008 Table 2 shows the recent per capita consumption of Eggplant 0.8 2008 commonly eaten nightshades. Potatoes come in first TOTAL 228.0 2008 (126 lbs) followed by tomatoes (85.7 lbs, including both fresh and processed), peppers (15.5 lbs) and eggplant (0.8 lbs). These figures clearly show that nightshades are a staple food, universally consumed in the U.S. diet. This raises the question: Are there any health hazards associated with eating almost 230 pounds of nightshades on a yearly basis? 2 Table 1. Some obscure and infrequently consumed edible plant foods within the Solanaceae family (adapted from: United States Department of Agriculture, Agricultural Research Service, Beltsville Area, Germplasm Resources Information Network (GRIN). http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl COMMON NAME OR NAMES SCIENTIFIC NAME Tamarillo, Tree tomato, Terong belanda Cyphomandra betacea Goji Berry, Wolfberry Lycium barbarum Purple ground cherry, Chinese lantern Quincula lobata Chinese lantern, Winter cherry, Bladder cherry, Physalis alkekengi Strawberry cherry Cut leaf ground cherry Physalis angulata Hairy ground-cherry, Dwarf cape gooseberry Physalis grisea Cape gooseberries, Golden berry, Husk cherry, Physalis peruviana Peruvian ground cherry, Poha berry, Giallo grosso Tomatillo, husk tomato Physalis philadelphica (formerly Physalis ixocarpa) Husk tomato, Strawberry tomato, Ground cherry Physalis pubescens Sticky gooseberry, Sticky Physalis Physalis viscose Gilo, Kumpa, Scarlet eggplant Solanum aethiopicum American nightshade, Black nightshade Solanum americanum Tzimbalo Solanum caripense Kangaroo apple Solanum laciniatum Indian nightshade Solanum lasiocarpum Garden huckleberry Solanum melanocerasum Pepino melon Solanum muricatum Lulo, Naranjilla Solanum quitoense Cocona, Orinoco-apple, Peach-tomato Solanum sessiliflorum Wonderberry, Sunberry Solanum retroflexum (formerly Solanum X burbankii) Ashwagandha, Withania, Winter cherry, Indian Withania somnifera winter cherry, Indian ginseng 3 POTATOES into other compounds by reacting with water). Steroid glycosides are commonly called glycoalkaloids. Let’s first examine potatoes. Potatoes generally maintain one of the highest glycemic index and load Both categories of saponins are widely distributed values of any food.3-6 Regular consumption of high throughout the plant kingdom including many glycemic index carbohydrates may promote obesity and cultivated crops. The primary function of saponins diseases of insulin resistance, including type 2 diabetes, is to protect the plant from microbial and insect cardiovascular disease, abnormal blood lipids, gout, attack by dissolving cell membranes of these potential acne, polycystic ovary syndrome, epithelial cell cancers (breast, colon and prostate), acanthosis nigricans (a Figure 1. The proposed mechanism by which dietary saponins may skin disease), and male vertex balding.7 Consequently elicit pores in intestinal cells leading to a “leaky gut”.9 in both of my books I do not recommend that potatoes be included as a regular component of Paleo Diets. Saponins Additionally, as you can see from Table 1, most of the potatoes consumed in the U.S. are highly processed in the form of french fries, mashed potatoes, dehydrated Cholesterol potato products, and potato chips. Processed potato foods typically are made with multiple additives (salt, vegetable oils, trans fats, refined sugars, dairy products, cereal grains, preservatives, and other food additives) that may adversely affect health in a variety of ways. An additional nutritional property of potatoes that is rarely considered in regard to human health is their saponin content. Saponins derive their name from predators.8 In mammals, including humans who their ability to form “soap” like foams when mixed consume saponin containing plants, these substances with water. Chemically, saponins are classified as frequently create pores in the gut lining, thereby either steroid glycosides or triterpenoid glycosides. increasing intestinal permeability.8-10 If they enter the A glycoside is any of a group of organic compounds bloodstream in sufficient concentrations, they cause occurring abundantly in plants that yield a sugar and hemolysis (destruction of the cell membrane) of red one or more non-sugar substances upon hydrolysis blood cells.8-10 (chemical decomposition in which a compound is split Figure 1 shows how saponins disrupt cell membranes which may lead to a leaky gut. Saponins first bind cholesterol molecules in intestinal cell membranes due to the affinity of a saponin component (the aglycone moiety) for the membrane sterol (cholesterol).9 In the series of steps that follows, you can see how saponins cause portions of the cell membrane to buckle and eventually break free, forming a pore or a hole in the membrane. Potatoes contain two glycoalkaloid saponins: α-chaconine and α-solanine which may adversely affect intestinal permeability and aggravate inflammatory bowel disease.11, 12 Even in normal healthy adults, a meal of mashed potatoes results in the rapid appearance of both α-chaconine and α-solanine in the bloodstream.13 The toxicity of these two glycoalkaloids is dose dependent – meaning that the greater the concentration in the bloodstream, the greater is their toxic effect. At least 12 separate 4 cases of human poisoning from potato consumption, Other researchers state: “Available information suggest involving nearly 2000 people and 30 fatalities have that the susceptibility of humans to glycoalkaloids been recorded.10 Potato saponins can be lethally toxic poisoning is both high and very variable: oral doses in once in the bloodstream in sufficient concentrations the range 1 - 5 mg/kg body weight are marginally to because these glycoalkaloids inhibit a key enzyme severely toxic to humans whereas 3 - 6 mg/kg body (acetyl cholinesterase) required for the synthesis of weight can be lethal. The narrow margin between acetylcholine, a neurotransmitter required for nerve toxicity and lethality is obviously of concern. Although impulse conduction.10 The concentration of both serious glycoalkaloid poisoning of humans is rare, α-chaconine and α- solanine in a variety of potato there is a widely held suspicion that mild poisoning is foods are listed in Table 3. Note that the highest more prevalent than supposed.” 10 concentrations of these toxic glycoalkaloids appear in potato foods containing the skins The commonly accepted safe limit for total (α-chaconine + α-solanine) in potato foods is 200 mg/ Table 3. Concentrations (mg/kg) of total glycoalkaloids kg, a level proposed more than 70 years ago, whereas (α-chaconine + α-solanine) in a variety of potato foods.10 more recent evidence suggests this level should be lowered to 60 – 70 mg/kg.10 If you take a look at Table Food Item α-chaconine + α-solanine 2 you can see that many potato food products exceed (mg/kg) this recommendation. Fried skins 567-1450 I believe that far more troubling than the potential Chips with skins 95 - 720 toxicity of potato glycoalkaloids is their potential to increase intestinal permeability over the course of Chips (US potatoes) 23 - 180 a lifetime, most particularly in people with diseases of chronic inflammation (cancer, autoimmune Frozen baked potatoes 80 - 123 disease, cardiovascular disease and diseases of insulin Frozen skins 65 - 121 resistance). A leaky gut has been recently proposed to be a universal initiating trigger for autoimmune Baked potato w/jacket 99 - 113 diseases14 – a conclusion that I agree with,15 as well as promoting cardiovascular disease16, 17 and diseases of Dehydrated potato flour 65 - 75 insulin resistance.18 When the gut becomes “leaky” Boiled peeled potato 27 - 42 it is not a good thing, as the intestinal contents may then have access to the immune system which