In our first installment of the nightshade/Solanaceae story, I covered some of the history, animal testing, and Black Box reports of “cooperators” who strictly avoid nightshade consumption and by doing so have found extremely positive results with their musculoskeletal pain relief (among other things). I’m sure many folks (Mexican and Italian food lovers everywhere) said after reading that article, “Sure. So what? Show me a mechanism.” Today we’ll cover one potential culprit. There will be more in the future, don’t worry…

A quick review for those who didn’t read that article yet—the food nightshades, the only one most folks need concern themselves with, include tomatoes, potatoes (not sweet potatoes or yams), peppers (bell, jalapeno, paprika, habanero, cayenne, chile, etc., but not peppercorns), eggplant, goji/wolf berries, and gooseberries. Tobacco is also in the nightshade family. For more information on the members of the nightshade family than you’ll ever need, go here. For the original book that introduced me to the physiological horrors of the nightshades, see the Arthritis Nightshades Research Foundation.

Nicotine on the (P)Menu

Many people are not aware that all of the food nightshades contain some nicotine—it isn’t some cooked-up urban legend. See the following studies for more info:

• The nicotine content of common vegetables.

• More on the nicotine content of vegetables.

• Determination of the nicotine content of various edible nightshades (Solanaceae) and their products and estimation of the associated dietary nicotine intake.

• Dietary nicotine: a source of urinary cotinine.

• Development of a simple sample preparation technique for gas chromatographic-mass spectrometric determination of nicotine in edible nightshades (Solanaceae).

So, we all know that smoking tobacco is bad, mmmkay? Modern medical research, both in humans and animals, has overwhelmingly demonstrated that tobacco smoking is detrimental to injury/trauma/wound healing, and I fully agree. A simple search of PubMed under “smoking healing” or “tobacco healing” will give you a huge amount of studies and reviews in that area. I see no need to bring tobacco into this when my real discussion here is about nicotine. There are plenty of studies that utilizing systemic nicotine that we can work with, avoiding the tobacco trap entirely.

First off, as a nod to Robb Wolf and his previous article on hormesis, there appears to be a hormetic effect of a very small dose of nicotine: Nicotine at a Low Concentration Promotes Wound Healing. Oh, snap! You mean the dose they used in that study was a 10-4 M (molar) strength dose, also known as “4X” in homeopathy (as in extremely diluted)? How could that work? What a bunch of quacks! (Please note harsh sarcasm.)

Hormesis, homeopathy, serial dilution… a rose by any other name is still a rose. While we are on the subject, did you know that there are many members of the nightshade family that are homeopathic remedies? If I were a betting man who understood homeopathic theory, I’d become very wary of this group of plants. These remedies include:

• Nicotiana tabacum (tobacco)
• Atropa belladonna (deadly nightshade)
• Capsicum annuum (cayenne pepper)
• Lycopersicum esculentum (tomato)
• Solanum tuberosum (potato)
• Solanum dulcamara (woody nightshade or bittersweet)
• Solanum mammosum (nipple fruit or apple of Sodom)
• Solanum nigrum (black nightshade)
• Solanum carolinense (horsenettle)
• Solanum pseudocapsicum (Jerusalem cherry)

Does modern medicine know what dose of nicotine (ingested or inhaled) will inhibit healing? Does one have to hammer cigarettes all day, or is a consistent intake of the relatively small amounts of nicotine in food enough? As far as I can tell, they are still working in the “plausible deniability” realm of food nicotine having any effect. I’ll have to say I believe otherwise.

Most of the readers of this article exercise on some sort of regular basis and are likely to injure some part of their body at some point. Which injured body part would you like to inhibit the healing of through dietary nicotine? You have your choice; you aren’t limited to the areas below. Note that while some of the studies and quotes below mention smoking, these were specifically chosen due to the use of isolated nicotine (not tobacco smoke, tobacco extract, or cigarette smoke extract) in order to correlate better with the nicotine in food nightshades. Yes, these are all animal studies—do you want to volunteer for a “wound healing” study (as in, they give you a wound for them to study)? [All emphases in below quotes is added by me]:

• Ear - “It is clearly possible that in cases of extremity injury, or surgery, cigarette smoking may adversely affect wound healing.”

• Jaw - “The significantly lower bone volume and appearance of chondrocytes in the high dose nicotine group indicated that the bone regeneration of distraction osteogenesis was compromised by high dose nicotine exposure.”

• Burns - “The results suggest that sleep deprivation and nicotine may delay wound healing and that selenium supplementation may accelerate wound healing by preventing nicotine-induced oxidative stress and lipid peroxidation.”

• Shoulder (rotator cuff) - “Nicotine caused a delay in tendon-to-bone healing in a rat rotator cuff animal model. Mechanical properties increased over time in both groups, but the properties in the nicotine group lagged behind those in the saline solution group. Chronic inflammation and decreased cell proliferation may partly explain the inferior biomechanical properties in the nicotine group as compared with the saline solution group.”

• Achilles tendon - “The results of this study show that nicotine impairs Achilles tendon healing after a surgical repair.”

• Long bone fractures - “Three (13%) fractures showed no clinical evidence of union in the nicotine group, whereas all fractures in the control group healed. Biomechanical testing showed the nicotine exposed bones to be 26% weaker in three-point bending than were those exposed to placebo.”

• Gastric mucosa (stomach lining)

o Study 1 - “These data show that chronic nicotine intake causes dysregulation of the gastric microcirculation, an effect that is associated with biochemical changes in the stomach… These data suggest that inappropriate regulation of gastric mucosal blood flow inhibits recovery from gastric mucosal injury in smokers.”

o Study 2 - “Nicotine in cigarette smoke inhibited this healing process and delayed wound repair in gastric epithelial cells.”

• Bone grafts

o Study 1 - “We conclude the following. 1) Uniform dosages of nicotine in the rabbit model decreases the vascular ingrowth into autogenous cancellous bone graft. 2) The inhibitory effect of nicotine varies between animals, suggesting predisposition in some.” [emphasis added]

o Study 2 - “Nicotine, as compared with placebo, was associated with delayed revascularization within the graft, a smaller percent area of revascularization, and a larger number of grafts showing necrosis.”

• Spine

o Study 1 - “Nicotine inhibits expression of a wide range of cytokines, including those associated with neovascularization and osteoblast differentiation. Therefore, the effects of nicotine appear to involve more than just local vasoconstriction.”

o Study 2 - “Chronic nicotine exposure was shown to decrease spinal fusion rates. Discontinuing nicotine before surgery improved fusion rates.”

o Study 3 - “This animal model established a direct relationship between the development of a nonunion in the presence of systemic nicotine. The results suggested that bone formed in the face of systemic nicotine may have inferior biomechanic properties.”

o Study 4 - “Cigarette smoking and nicotine are inhibitory factors in the healing of fractures and spine fusions.”

So, why is inhibition of healing so important to avoid? For the masses out there with rotator cuff injuries, here’s a study that may have you interested in particular, now that you know that systemic nicotine retards the healing process:

• Delayed repair of tendon to bone injuries leads to decreased biomechanical properties and bone loss. An important quote: “Inferior rotator cuff healing was demonstrated when there was a delay between injury and repair.” See the rotator cuff and nicotine study above again if you haven’t grasped the picture yet. Delayed healing or inhibited healing post-injury will result in poor tissue quality later. Not good for active folks or any folks for that matter.

So, we end up with dietary nicotine as a potentially significant player in the nasty inflammatory chemical soup that makes up the nightshades.

Is there any way of avoiding or minimizing the detrimental effects of nicotine? Yes, there are. That doesn’t mean you’ll get out of the other mechanisms by which the nightshades ruin health, however, I do want you all to be fully informed:

• Curcumin, garlic, grapeseed extract, tea polyphenols, vitamin C, vitamin E
• Garlic
• Onion, alpha-tocopherol
• Melatonin
• Curcumin

• N-acetylcysteine, vitamin E
o Study 1
o Study 2

• Hesperidin
o Study 1
o Study 2
o Study 3

I believe that has covered the nicotine portion. In the next article I’ll cover capsaicin and Substance P, a highly misunderstood mechanism of how peppers (spicy or not) ruin health and are far from the anti-inflammatory foods we have been taught to believe.