Herbal medicines are often perceived by the general public as a ‘soft’ alternative to Western medicine, but the use of these substances can be risky since they can induce nocebo effect. In 1961 Walter Kennedy chose the term nocebo (Latin for I will harm) as the counterpart of placebo. This term was introduced a few years after Henry Beecher published his paper on placebo effect. Most clinical studies explored the beneficial effects of nutraceuticals and ignored their nocebo effects; the seeds/oil of Nigella sativa has anti-inflammatory, analgesic, antipyretic, antimicrobial, hypotensive, hypoglycemic, antiepileptic and anti-neoplastic activity.
Garlic, considered either food or herbal medicine, possesses antimutagenic and antiproliferative properties that can be used in anticancer interventions, hypoglycemic. Coenzyme Q10 (CoQ10) is an essential electron carrier in the mitochondrial respiratory chain and an important antioxidant. It exerts a beneficial effect on cognitive, digestive, cardiovascular and immune systems, and modulates inflammatory and degenerative processes in the body.
Nutraceuticals derived from such spices as turmeric, red pepper, black pepper, licorice, clove, ginger, garlic, coriander, and cinnamon target inflammatory pathways, thereby may prevent neurodegenerative diseases e.g., Parkinson’s disease. On the other hand, most clinical studies ignored the subtle central effect of the nutraceuticals, therefore the aim of this study is to show the nocebo effects of nutraceuticals notably black cumin, garlic and CoQ10 on the integrative function of central nervous system and psychomotor performance in human using Leeds battery testing.
Research on the causes of placebo effect has made great advances in re-cent years. Proposed mechanisms include conditioning and expectation, with majority of experts favouring the latter as primary force.
Benedetti proposes that pain and mental state fit better into the expectation model, while classical conditioning may be an explanation for responses in immunological function, hormonal and respiratory responses (such as asthma). Functional MRI conducted while a placebo treatment is administered con-firms activity in brain regions involved in processing of perception, pain and emotion. Use of the opioid antagonist naloxone reverses placebo induced pain relief, suggesting production of endogenous opioids as a mechanism.
The mechanisms for nocebo (Latin: I shall harm) effectsare also conditioning and expectation, in the form of anxiety. Anticipatory anxiety can increase production of chole-cystokinin (CCK), resulting in an in-creased pain response. Much as the naloxone reduces placebo effects, CCK antagonists blunt nocebo effects. Schenk points out certain ‘word traps’ can function as conditioning aural nocebos. This classification and few examples suggest role of nutraceuticals in disease healthcare condition.
Dietary fibres
These are the plant origin substances present in food which are not digest-ed in gastointestinal tract and add bulk to the intestinal contents. Exam-ples include fruits, barley, oats, lignin, cellulose, pectin etc. Generous intake of these fibres in diet is associated with low risk of CVD, hypertension, diabetes, obesity, and colon cancer and gastrointestinal disorders.
Probiotics
These are live microbial feed supplements which when administered in adequate dose help in improving the intestinal microbial balance of the host eg lactobacilli, bifidobacteria etc. There administration is reported to be associated with a decreased risk of allergy, asthma, cancer, infection of ear and urinary tract.
Prebiotics
These are the dietary ingredients that benefit the host by selectively alter-ing the composition or metabolism of gut microbiota. These are, gener-ally, fructose based oligosaccharides existing naturally or supplemented in the food and are not digested by hu-man beings. Examples of such foods are chicory roots, banana, tomato and alliums, beans etc. These are found to be beneficial in improving lactose tolerance, detoxi-fication, and dyslipidemia, relief from constipation and in certain tumors.
Polyunsaturated fatty acids
These may be omega 3 fatty acids e.g. α-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid found in fatty fishes, flaxseed, soy-bean etc. or omega 6 fatty acids e.g. α-linoleic acid and arachidonic acid found in corn, safflower, sunflower and soybean etc.
Antioxidant vitamins
These include Vitamin C, Vitamin E and carotenoids. These vitamins are abundant in many fruits and vege-tables and possess singlet oxygen quenching and lipid peroxidation preventing properties. Regular in-take of these helps in prevention of a number of diseases.
Polyphenols
These phytochemicals are produced by plant for protection against photo-synthetic stress and reactive oxygen species e.g. flavonoids, anthocyanin and phenolic acids. These possess anti-inflammatory and antioxidant properties and are found in foods like legumes, tea and soybean etc.
Spices
These are esoteric foods adjuncts used to enhance sensory quality of foods. Most of the components of spices are terpenes and other constituents of essential oils. Minute quantities of dietary spices have antioxidant, chemopreventive, antimutagenic, anti-inflammatory and immune modulatory effects.
Another most proven example of methylcobalamine in diabetic neuropathy. It is needed for regeneration of myelin sheath of nerve fibres which reduces pain in this chronic debilitating condition. Nutraceutical is not placebo but it helps in preventing and curative aspect as well.