Many of the phytochemicals found in spices act as potent preventive agents against cancer by defending DNA against free radicals and other toxins, preventing the overproduction of toxic chemicals within the body, assisting the body’s detoxification processes and modulating a range of mechanisms involved in the development of cancer. In addition to reducing the risks of developing cancer, spices can also act as effective treatments for certain types of cancer.
Some spices enhance the effects of the traditional cancer treatments of radiotherapy and chemotherapy, as well as reducing the negative side effects of these therapies.

 Spices - One of the keys to cancer prevention 

Cancer is a leading cause of death in most Western countries where, every year, hundreds of millions of dollars are allocated for research into new treatments. Eastern countries, where the incidence of most cancers is typically much lower, pour considerably less money into such investigations – and considerably more spices into their meals each year. These humble spices, it appears, are exceptionally good value for money. A growing body of epidemiological and clinical evidence suggests that the most important factor contributing to the difference in cancer incidence between the West and many Eastern countries can be attributed to the markedly higher levels of spice intake in the latter. 

Cancer numbers much higher in the USA than in spice-eating Eastern countries 

In the USA, for example, the three most lethal cancers are those of breast, prostate and lung. In India, the incidence of these same cancers – and of many others – is dramatically lower. Cancer of the breast occurs eight times more frequently in American woman compared to their Indian counterparts; the incidence of prostate cancer in American men is more than 30 fold higher than in Indian men; and the incidence of lung cancer is almost 20 times higher in the USA than in India.

Even taking into account lifestyle factors, the incidences of other diseases, and other demographic variables, these differences are remarkable. As scientists continue to study an increasing number of spices, new evidence confirms that many of these foods, both individually and in combination, do indeed have strong anti-cancer properties. By adding an average of 10 grams of spices a day to their meals, Indians, Sri Lankans, Thais and others are medicating themselves with some of the most powerful anticancer cocktails available. 

Spices Reduce Cancer Risk 

Reducing our susceptibility to cancer is one of the most important measures we can take to increase our chances of good health. This is not as difficult as it might sound. The following overview of the causes of cancer, the processes involved in its development and the multitude of ways in which phytochemicals act to combat it, shows that increasing our intake of spices is one of the most effective, convenient and economical ways in which we can fortify ourselves against this ubiquitous disease.  

Causes of Cancer

Cancer is caused by a range of factors, most of which follow directly from – or are exacerbated by – the aging process. As a result, the probability of getting cancer increases exponentially as we grow older.

Aging 
The wide-ranging biochemical and chromosomal changes associated with aging increase the risk of DNA damage that is the first step towards developing a malignancy. If our biochemical processes fail to repair the DNA or destroy the cells in which it is contained the body’s cancer-control mechanisms become ineffective and allow the unchecked proliferation of these abnormal, pre-malignant cells. In addition to being less efficient at the repair and confinement of DNA damage, older bodies are less well equipped to protect cells against the agents that trigger the damage to our genetic coding material.

Environmental factors
Nevertheless, people of all ages can develop cancer, and youth is not guaranteed to protect against all carcinogenic factors. Among the most important of these are a genetic predisposition in the form of inherited oncogenes; exposure to environmental toxins, such as asbestos, petrochemicals, tobacco, alcohol; viral infections, such as the herpes and wart viruses; radiation, including sunlight’s ultraviolet rays; chronic inflammation, such as that arising from autoimmune disorders; and the production of excessive quantities of harmful endogenous chemicals, such as hydrogen pyroxide, by malfunctioning cellular processes.

Antioxidants and free radicals 
These diverse carcinogens typically affect their damage via free radicals. Once produced within our body or introduced into our systems, highly reactive and destructive free-radical particles circulate in search of something to react with, or oxidize. Targets of this damaging oxidative process include DNA that, when attacked by free radicals, can cease to send the correct signals needed to prevent uncontrolled cell growth. It is for this reason that antioxidants, which react with and neutralise free radicals before they can attack our body, are such valuable substances to include in our diets. In addition to the many other anti-cancer properties found in spices, almost all of these foods contain powerful antioxidants which, when consumed regularly, mop up free radicals before they can initiate tumourigenesis. 

Spice compounds help to fight cancer 
Spices are valuable preventative weapons against cancer not only for their antioxidant properties, but many of the phytochemicals contained in spices assist the body to detoxify and excrete carcinogenic compounds. Nor is the value of spices limited to their ability to prevent the first step of cancer development. Spices contain a number of powerful phytochemicals that act against pre-cancerous cells at each stage in their progression towards fully fledged tumours. 

How Cancer Develops and Spreads

How cancer starts 
Cell division is a normal and essential physiological process that occurs in most tissues. In a normally functioning system there is a balance between cellular proliferation and programmed cell death (apoptosis) that is controlled by a complex but finely tuned biochemical web. Tumorigenesis is a multi-stage process, initiated when damage to the DNA of normal cells upsets the balance between apoptosis and cellular proliferation. This leads to further mutations and changes within the damaged cell, rapid proliferation of these abnormal cells, followed by invasion of adjacent tissues by the cancerous cells. Metastatic spread occurs when the cancer cells seed via the blood or lymphatic system to other organs.

Underlying this process is a more complex set of changes that occurs at cellular level. Nearly all cancers originate from a single cell, through the process of cell replication and division. However, a cell that degenerates into a tumor cell does not typically acquire all these properties at once, or in one generation. Instead, through a process known as clonal evolution, mutations are accumulated over time – division by division, and generation by generation. The more malignant the properties conveyed on a cell by a particular mutation, the greater an advantage it has over neighboring cells, and the more likely it is to replicate and pass on its mutant genes. Eventually, as a result of this ruthless selection process, a tumor cell is formed. This process does not end with the acquisition of all the properties that characterize a tumor cell: later-stage, breakaway cancers are often more virulent than the early, primary tumors as even fully cancerous cells become stronger and more destructive over time.

Characteristics of Cancers Cells

• Resistant to programmed cell death

• Cell division is rapid and uncontrolled

• Produce telomerase rendering cells immortal by preventing the loss of the telomeres

• Produce their own growth factors in excessive amounts

• Insensitive to the body’s growth inhibitors

• Secrete chemical signals that stimulate abnormal blood vessel growth

• Invade other tissue types and spread to distant sites in the body

This incremental development process has important implications for the prevention and treatment of cancers. Ideally, we should be preventing the onset of cancer by annihilating the early mutant cells before they can develop into fully-fledged tumour cells. These pre-cancerous cells are, however, symptomless, making such an approach impractical if we were to try and use modern drugs. To take expensive drugs, with frequently risky and unpleasant side effects, in the hope of destroying early cancers that might not even exist, would clearly be unwise. In this respect, spices provide just what we are looking for. They contain compounds that are effective against pre-cancerous cells at different stages of their development, and by consuming spices regularly and in sufficient quantities, we provide the tools for our body to intercept tumours at the early stages of their development.

 Phytochemical Modulation of Underlying Cancer Processes

Over the last few decades, the phytochemicals contained in spices and in several other plants have been shown to modulate many of the mechanisms and processes involved in the development of cancer. Although we are just beginning to understand how they work, we know that many of these compounds counteract cancer either by enhancing the body’s natural processes for combating tumourigenisis or by restoring the mechanisms that go awry as a result of cancerous mutations.

Proto-oncogenes play a critical role in the control and release of chemical messengers that signal the cell to undergo cell division (mitosis), in order to produce more cells of a particular tissue. If these proto-oncogenes mutate, they become oncogenes that over-express the cell division signals responsible for the excessive cell division rates characteristic of cancer. A number of spice compounds prevent the conversion of proto-oncogenes to the pathogenic oncogenes.

Tumour-suppressor Genes code for chemical messengers that slow or stop mitosis in order for DNA repair to occur. This is done via enzymes that detect DNA damage and prevent this fault being carried on to the next generation of cells. A mutation of the tumor-suppressor gene can result in its “switching off” capacity being compromised; this results in defective DNA being passed on to each succeeding generation of cells, where these defects become enhanced and eventually result in the development of tumor cells. The antioxidants in spices known to protect against cancer, notably those in  ginger and turmeric, achieve this effect by preventing mutations in tumor-suppressor genes from occurring.

Nuclear Factor κ-B (NF-κB) is a protein involved in cell survival, cell adhesion, inflammation and cell growth, and is an essential cog in the biochemical machinery that controls the growth and proliferation of normal cells. However, its over-activation can be triggered by many of the carcinogens mentioned above, causing it to become an aggressive accelerator of tumorigenesis.  Extensive research in the last few years has shown that the pathway that activates this transcription factor can be interrupted by phytochemicals derived from spices including anise, basil, capsicum, clove, cumin, fennel, ginger, rosemary and turmeric.

Activated Protein (AP) is a molecule that, if produced in excess, stimulates the expression of several genes that enhance tumor proliferation, angiogenesis and tissue invasion. The effects of activated protein are blocked by phytochemicals in turmeric. These same compounds also interfere with the stimulatory effect of estrogens on certain hormone-dependent tumors.

Autocrine loops are part of cancer cell cycle feedback mechanisms whereby the tumor cells release chemical messengers (cytokines) that, in turn, stimulate further tumor proliferation. Cytokines do this by stimulating growth factor receptors on other cells, which produce more cytokines that further accelerate these positive-feedback autocrine loops. Several compounds, including those found in mustard either block the cell receptors or the action of the cancer cell cytokines themselves thus curtailing these self-sustaining processes.

The JAK-STAT pathway is a system of receptors, cytokines and enzymes that is part of an important stage common to the development of most tumor types. The curcumin found in turmeric in particular – along with other phytochemicals – has been found to have a strong inhibitory effect on this crucial tumorigenic mechanism.

Telomerase is an enzyme produced by cancer cells that stops the loss of telomeres from cancer cell DNA. Telomeres are the genes at the end of chromosomes that, in normal cells, are lost as each generation of cells duplicates itself. Telomerase interferes with this process and is one of the ways in which cancer cells achieve immortality. Turmeric amongst others contain phytochemicals that inhibit telomerase and so confer a finite lifespan on cancer cells.

Apoptosis (programmed cell death) is a built-in mechanism common to most normal cells. Cancer cells evade this inexorable process by means of several of the mechanisms outlined above. Phytochemicals isolated from several spices including, citrus, garlic, and mustard have multiple functions that make them effective inhibitors of the processes that tumor cells have developed to evade apoptosis.

Angiogenesis is a normal process whereby the body produces blood vessels for new tissue growth and is activated by the secretion of various endogenous chemicals. Cancer cells also produce chemical signals that stimulate angiogenesis in the area where they are growing but this is usually an uncontrolled and haphazard process that produces abnormal blood vessels. Phytochemicals found in turmeric inhibit angiogenesis of tumor cells thereby reducing the nourishment available to these cells and curtailing their invasion of adjacent tissues.

Cyclo-oxygenase-2 (COX-2) is an enzyme that, when overproduced, causes the chronic inflammation associated with many diseases such as arthritis. It is also over-expressed in almost all forms of cancer. Compounds in turmeric, garlic, and ginger are all strong COX-2 inhibitors, and this property makes them indispensable foods in the fight to prevent and treat not only cancer but a wide range of other conditions where COX-2 enzymes are causative factors.

Radiotherapy and chemotherapy are widely used but imperfect treatments for cancer. Not only do they have serious, debilitating side effects, but tumour cells often develop resistance to these therapeutic modalities. Moreover, in addition to their intended destruction of cancerous cells, these therapies frequently activate NF-κB, thereby contributing to the suppression of apoptosis and the promotion of tumour proliferation – just the opposite of what one would like from a cancer treatment. Chemotherapy and radiotherapy also activate COX-2 enzymes, thus aggravating the inflammatory process that underlies many cancers. Several phytochemicals, found in high quantities in turmeric . reduce the activation of COX-2 and sensitize the tumour cells to both radiotherapy and chemotherapy, enhancing their therapeutic effect.

Examples of the Anti-cancer Properties of Key Spices

All spices                                                                   Powerful antioxidant activity

Cumin, black pepper,                                             Enhance antioxidant enzymes

Cumin, garlic, ginger, black pepper,                   Inhibit cancer-associated inflammation

ginger, black pepper,                                              Inhibit pro-inflammatory cytokines

Garlic, ginger, turmeric .                                         COX-2 inhibition

Ginger, black pepper,                                             Attack tumours directly

Anise, basil, capsicum, clove cumin                   Inhibit NF- κB

Fennel , garlic, ginger , rosemary, turmeric .      Inhibit NF- κB

Garlic, mustard                                                        Induce apoptosis

Brassicas (eg. mustard wassabi)                       Modulate autocrine loops and cell cycles

Turmeric                                                                    Inhibits angiogenesis

Caraway, cumin, mustard                                     Neutralize carcinogenic toxins

Turmeric                                                                    Inhibit telomerase

Turmeric                                                                    Inhibits JAK-STAT pathway

Turmeric                                                                    Inhibits oestrogen on hormone-dependent tumors

Turmeric                                                                    Enhances chemotherapy and radiotherapy