PEPPERS AND CAPSICUMS
Peppers and capsicums were rare in the Western diet until the 1980s, when they became widely available as fresh vegetables and, in their hotter forms, in Asian cuisine and as hot sauce. Chillis replaced peppercorns in Indian cuisine from the 1650s onwards, after Portuguese traders brought plants and seeds from Brazil. Hot peppers are rich in capsaicin, which creates a burning sensation that affects pain receptor cells and causes them to release endorphins, the body's natural opiate-like painkillers, that create a temporary feeling of euphoria. Peppers and capsicums also contain solanine and solanadine, the atropine compounds that are unique to nightshade plants.

AUBERGINES
Aubergines or eggplants most resemble in appearance the belladonna nightshade plant that may be their wild ancestor.

Atropine begins to take effect, 30-60 minutes after consumption and may last as much as 24-48 hours as these alkaloids repress the digestive tract (it is excreted in urine). It has a half-life of 2-3 days.

After absorption from the gastro-intestinal tract, Atropine can increase the heart rate by a speed of 20 to 40 beats per minute, causes inhibition of secretions from glands hence giving dryness in the mouth, nose and then skin, and relax the intestinal muscles. It will also cross into Central Nervous System (CNS) from the blood to the brain (through the Blood-Brain Barrier). Here it will depress and excite different parts of the CNS, by interrupting the nerve receptors, acting as a ‘'sympathetic cholinergic blocking agent' e.g. a blocking agent to the nerve transmitter acetylcholine. This effect is very prevalent in the elderly, inducing amnesia, excitation and mental confusion. It will also result in pupil dilation and an increase of pressure within the eye (intraocular pressure) with blurred vision.

In doses up to 0.5mg there may be some dryness in the mouth and nose. Up to 1.0mg, increased dryness and thirst, slight pupil dilation and heart rate fluctuations (slowed then accelerated). At 2.0mg there may be great thirst, abnormal heart rate (tachycardia), flushed dry skin, palpitations and pupil dilation. After a 5mg intake, the skin is now hot and dry, swallowing becomes difficult, there will be similar symptoms as before but heightened with headache, restlessness with fatigue, and vision and speech becoming affected. After 10mg and above the symptoms become extreme with excitement, delirium, mental confusion and disorientation, hallucinations, the person finds speech and movement difficult and may become unconscious or comatose. Paralysis of involuntary muscles is possible and internal paralysis (of the CNS) may be fatal. Death from the poison however is rare, and severe poisoning can be treated by a trained doctor.

The transmission of nerve impulses is a complex subject:
• The chemical that conducts nerve impulses is acetylcholine
• Acetylcholine is produced by an enzyme: acetylcholinesterase
• Solanine/Tomatine from tomatoes interferes with this enzyme
• The production of acetylcholine declines.
• The nerve endings have to work harder to transmit signals as they don't have the help of sufficient acetylcholine. Some signals don't get through and over a prolonged period this can lead to Alzheimer's like symptoms as the nerve endings suffer.
• Acetylcholine also keeps the bodily fluids running - reduced levels lead to dryness in the mouth and throat, reduced lubrication of the joints and reduced intestinal secretions, causing constipation.

All nightshade foods contain solanine, a strong cholinesterase inhibitor. This is what makes nightshade foods unsuitable for many people.

Certain pesticides, particularly organophosphate and carbamates, work by binding acetylcholinesterase, making it unavailable to the body. They achieve the same effect as Cholinesterase inhibitors, by a different route. Either way, the nervous system has to function without a vital aid to nerve-to-nerve communication, acetylcholine.

For a diet that seeks to maintain a strong and healthy nervous and neuromuscular system there is considerable evidence that the safest approach is to avoid nightshade vegetables and to eat food that is grown without the use of carbamate or organophosphate pesticides, i.e. organic food. Before the discovery of chemical pesticides, nicotine was a widely used insecticide. It kills insects in the same way, but chemical sprays are cheaper and longer-lasting. Until they were replaced by hormones and antibiotics, organophosphate pesticides were also used by livestock farmers as growth-promoters - the mechanism whereby they slow down the nervous system also causes animals to exercise less and eat more, thereby fattening up more quickly.

What is it that makes tobacco so addictive? Why is it that sometimes only chips will do, or we are gagging for a pizza?

They all contain solanine in some form, named as solanine (potatoes), tomatine (tomatoes), alpha-solanine (aubergine) or solanadine (chillies and capsicums). They also contain nicotine in small amounts. Nicotine has a synergistic action with solanine - it stimulates the production of acetylcholine receptors in the brain and this leads to increased flow of adrenaline. This increases the heart rate, blood pressure and leads to increased blood glucose levels. This mild increase in energy level is achieved, along with a reduced nervous sensitivity; producing a combination of calmness and stimulation. This provides short term relief in the face of the stresses and pressures of modern life.

The leaves of all nightshades contain high levels of nicotine. One could, at a pinch, smoke potato or tomato leaves. A potent insecticide can be made with tomato leaves. The levels of nicotine in the leaves of nightshade plants are much higher than in nightshade fruits or tubers. 8-10 cigarettes, if eaten, would be enough to kill a person. First time smokers experience dreadful nausea but gradually develop a resistance to the effects of nicotine and this is how addiction develops - more and more is needed to satisfy the craving.

If the nightshade foods were to be introduced to the Western diet today, under current Novel Foods regulations they would have to be tested for safety. It is unlikely that they would be permitted to enter the food supply, solely because of their nicotine (solanine) content. However, like cigarettes, they slipped into our diet despite some voices in opposition and have assumed a major role in our nutrition and health, a role that, in a free society, should be accepted. However, moderation in all things is a worthy principle and it could be argued that, in our diet we have perhaps gone too far down the road of nightshade acceptance.

First published in 2004

Edited to add: Craig no longer produces Nomato products, although an American brand of the same name, also making tomato-free products, can be viewed here.

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