Cancer has been hailed as the Emperor of all Maladies, as it afflicts millions of lives every year and is attached with economic burden and social stigma. Cancer is an amalgamation of genetic mutations caused by various internal (genetic predisposition, and immune response) and external factors (smoking, alcohol, environmental pollutants, and lifestyle). Interestingly, only 5-10 per cent of the cancers are caused by the genetic predisposition and the rest are caused by the modifiable, external risk factors. As we observe World Cancer Day on February 4, onco-nutrition as another arsenal in the fight against this dreaded killer, deserves a closer examination.
The enormous variance in rates of various malignancies in many nations, as well as the reported incidences of cancer in migrating people, point to a relationship between food and cancer, for example, Asians have a 25-fold lower incidence of prostate cancer and a ten-fold lower incidence of breast cancer than inhabitants of Western nations, and these cancer rates dramatically increase whenever Asians relocate to the West.
Prevention with right diet
Growing lines of experimental evidence have proved that a diet comprising various bioactive compounds such as polyphenols and carotenoids, vitamin C, and dietary fibres have a beneficial effect on different types of cancers. According to joint research by the World Cancer Research Fund and the American Institute for Cancer Research, a high-fruit and vegetable diet can lower the risk of malignancies of the mouth and throat, esophagus, lung, stomach, colon, and rectum.
Dietary fibre can reduce the occurrence of colorectal cancer, which is proven by various research studies. This functionality of dietary fibre is mainly exerted by functions like reduction in transit time of food in the colon. It was also found to inhibit the interaction between carcinogen and colon tissues by binding with the carcinogens and their metabolites.
Various dietary antioxidant molecules are also beneficial in the treatment of cancer; polyphenols are one such compound exhibiting high anti-tumorigenic activity. Polyphenols are the major category of compounds that comprises various other molecules such as flavanols, flavonoids, anthocyanins, flavones, isoflavones, etc.
Anti-carcinogens
From scientific research, it was proven that these polyphenols directly interact with cancerous cells and induce cell apoptosis, decrease cell proliferation, and suppress cancer cell growth through various biochemical pathways. Green tea polyphenols are studied extensively for their anti-carcinogenic effect. Green tea contains catechins and epigallocatechin-gallate as major bioactive compounds and it has been reported that daily consumption of green tea up to prolong time can delay the onset of cancer in humans. Components of tea have been shown to alter the metabolism of chemicals that are known or suspected carcinogens, as well as boost detoxifying enzyme systems. Tea polyphenols also appear to be more powerful antioxidants in vitro than either vitamin C or vitamin E, indicating that teas may be beneficial due to their ability to prevent oxidation and reduce oxidative stress.
Studies have proven that redox imbalance exists in the malignant cell. Natural antioxidants such as ascorbic acid (Vitamin C) and tocopherol (Vitamin E) can aid in the battle against cancer by triggering apoptosis, regulating cell cycles, and preventing proliferation of tumor cells.
Ancient Indian herbs and spices
Spices have been used for a number of reasons for ages, including flavouring agents, colorants, and preservatives. It’s well-established that dietary elements might reduce cancer risk and influence tumor behaviour.
According to studies, various processes such as proliferation, apoptosis, angiogenesis, and immune-competence have been shown to be impacted by one or more spices. Turmeric is a spice that has been long used by Ayurveda for the treatment of various human disorders. Curcuminoids found in turmeric have anti-carcinogenic, anti-inflammatory and antioxidant properties, which is proven by various preclinical and clinical trials. To date over >18,000 scientific studies have showcased the beneficial effect of this spice and its components for the prevention and treatment of various diseases.
In addition, around 100 clinical trials have been investigated to explore the putative role of turmeric and curcumin against cancer. Curcumin is known to modulate various signaling pathways, transcription factors and their effector downstream molecules thereby inhibiting the key hallmarks of cancer progression. It has shown to be safe, efficacious in almost all types of solid tumours because of its wide pleiotropic properties.
Garlic, ginseng (Panax), soya, and tomato may all be linked to a lower risk of cancer, according to the research. Sulforaphane, found in cruciferous vegetables such as broccoli, cauliflower, cabbage, and Brussels sprouts, has also been reported to contain potent anti-cancer effects. Chlorophyll containing green plants are beneficial in cancer prevention as chlorophyll and its derivatives effectively bind with various carcinogens that are difficult for the body to absorb, and the bulk of it is eliminated from the systems. Several studies have discovered links between increased lycopene consumption through high tomato intake with lower risk of prostate cancer.
Plant-based foods should be a big component of your diet if you want to avoid cancer. Many vital minerals and dietary fibres may be found in wholegrains, vegetables, fruit, and pulses (legumes) like beans or lentils. The World Cancer Research Fund advises 30 grammes of fibre and five to twelve servings of fruit and vegetables each day for effective cancer preventive measures. Yes, cancer can be prevented with the correct modulation of dietary habits and lifestyle.
Freezing on dietary intervention
As cancer is the second most causative for the death of millions of people worldwide, it raises an urgent need to develop a dietary intervention to provide treatment and preventive strategies to individuals. An alliance between academia and industry is inevitable in order to achieve this milestone. According to various studies, a diet rich in antioxidants can easily prevent or provide a therapeutic outcome in cancer patients.
Ensuring efficacy and potency
Already there are a large number of nutraceutical products in the market. Interestingly, the global nutraceutical market size was estimated to be $450 billion annually and it is expected to grow at a rate of 9 per cent per year which also shows the beneficial effect of wide acceptability of these agents in human health. However, there are several important points regarding product formulation to be kept in mind during the design of food products for cancer patients.
The product should have a low amount of simple sugar (glucose, fructose), as cancerous cells are fast-growing cells; a diet high in simple sugar will boost the growth of such cells. Instead of simple sugar, a resistant starch should be used as a bulking agent.
Food products should have an optimum effective concentration of bioactive compounds because the bioavailability of particular compounds in the human body differs from person to person. Targeted delivery of bioactive compounds can increase the effectiveness of a specific product.
Processing of the food products is also a crucial part, according to industrial perspective a processing of product should be economically viable and should be fit with conventional processing machinery otherwise it will substantially increase the capital investment in development of new infrastructure. Bioactive compounds in food are heat sensitive hence, a special focus on heat treatment of products should be given during technology designing to deliver a product having the highest amount of nutrients while meeting the quality standards set by food regulating authorities. Modern discovery of advanced non-thermal technologies such as pulsed electric field, ultra-sonication, enzyme assisted extraction has enabled us to extract bioactive compounds from the food materials, which can be further utilised as nutraceutical supplements.
Furthermore, for economic viability, a product should be shelf-stable at room temperature for a prolonged time; it will provide enough time for the marketing of the product. The market of cancer-specific nutritional products is vast, allowing an economically viable business and providing hope to humanity in the form of effective preventive measures for cancer.
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Dr Ajaikumar B. Kunnumakkara, Professor, Cancer Biology Laboratory & DBT-AIST International Centre for Translational and Environmental Research, Department of Biosciences and Bioengineering, Indian Institute of Technology (IIT), Guwahati