A common finding from many different clinical studies is that natural foods including a balanced diet rich in vegetables, fruits, green leafy vegetables, berries, nuts, herbs and spices and probiotic rich foods such as yogurt are the cancer prevention foods that can help lower the risk of cancer. Multivitamin and herbal supplements of concentrated bioactives and phytochemicals from these foods that provide excessive doses of nutrients, have not shown the same benefits as eating natural foods to prevent cancer, and have the potential to cause harm. For preventing or reducing the risk of cancer, taking the right foods matter.
We are living in unprecedented times. The ‘C’ word linked to cancer was already one that caused a lot of anxiety and distress and now we have another one ‘COVID-19’ to add to this list. As the saying goes, ‘health is wealth’ and being in good health with a strong immune system is critical for all of us. At this time of lockdown restrictions with all attention focused on the pandemic, managing the other underlying health issues become even more critical. Hence, this is the time to focus on a healthy and balanced lifestyle with the right foods, exercise and rest, to keep our bodies strong. This blog will focus on the foods, which we generally use in our diets, that may help in cancer prevention and in boosting our immunity.
Cancer, by definition, is just a normal cell that has mutated and gone haywire, that causes an unrestricted and mass growth of abnormal cells. Cancer cells could potentially metastasize or spread throughout the body and interfere with the normal functioning of the body.
There are a lot of factors and causes that are associated with increasing the risk of cancer that include: environmental risk factors such as exposure to excessive radiation, pollution, pesticides and other cancer causing chemicals, familial and genetic risk factors, diet, nutrition, life-style factors such as smoking, alcohol, obesity, stress. These different factors are linked to increased risk of different kinds of cancers such as increased risk of melanoma and skin cancers due to excessive exposure to sunlight, risk of colorectal cancer due to unhealthy and fatty diets etc.
With the growing aging population, the incidence of cancer is on the rise, and despite the advances and innovation in cancer treatments, the disease is able to outsmart all the treatment modalities in a large number of patients. Therefore, cancer patients and their loved ones are always on the lookout for using alternative natural options including foods and supplements to prevent or lower risk of cancer and boost immunity and well being. And for those already diagnosed and being treated, natural options using supplements/foods/diets are being tried out to prevent cancer treatment side-effects and recurrence.
Cancer Prevention Foods
Listed below are classes of cancer prevention natural foods that we should include in our balanced diets, that can help lower the risk of cancer, as supported by scientific and clinical evidence.
Carotenoid Rich Foods for Cancer Prevention
It is common knowledge that we need to eat multiple servings of fruits and vegetables a day in a variety of different colors, to get the different nutrients they contain, for good health. Brightly colored foods contain carotenoids, that are a diverse group of natural pigments present in red, yellow or orange fruits and vegetables. Carrots are rich in alpha and beta carotene; oranges and tangerines have beta-cryptoxanthin, tomatoes are rich in lycopene while broccoli and spinach are a source for lutein and zeaxanthin, all of which are carotenoids.
Carotenoids are converted to retinol (Vitamin A) in our body during digestion. We can also get active Vitamin A (retinol) from animal sources such as milk, eggs, liver and fish-liver oil. Vitamin A is an essential nutrient that is not produced by our body and obtained from our diet. Thus,Vitamin A foods are key for normal vision, healthy skin, improved immune function, reproduction and fetal development. Also, experimental data has provided evidence for beneficial anticancer effects of carotenoids on cancer cell proliferation and growth, and antioxidant properties that help in scavenging of DNA damaging free radicals and protecting cells from becoming abnormal (mutated).
Impact on Cutaneous Squamous Cell Carcinoma Risk
Two large, long-term, observational clinical studies named the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS), found that the participants who had the highest average daily vitamin A consumption, had a 17% reduced risk of cutaneous squamous cell carcinoma, the second most common type of skin cancer. In this study, the vitamin A source was mostly from eating various fruits and vegetables such as papaya, mango, peaches, oranges, tangerines, bell peppers, corn, watermelon, tomato, green leafy vegetables, and not from taking dietary supplements. (Kim J et al, JAMA Dermatol., 2019)
Impact on Colorectal Cancer Risk
A recently published study from the University of Southern Denmark analyzed data from over 55,000 Danish people in the Diet, Cancer and Health Study. This study found that ‘high carrot intake corresponding to >32 gram raw carrot per day was associated with a decreased risk of colorectal cancer (CRC),’ compared to those that did not eat any carrots at all. (Deding U et al, Nutrients, 2020) Carrots are rich in carotenoid antioxidants such as alpha-carotene and beta-carotene and also other bio-active compounds that have anti-inflammatory and anti-cancer properties.
Impact on Bladder Cancer Risk
A pooled meta-analysis of many observational clinical studies examining the association of carotenoids with risk of bladder cancer in men and women, was done by researchers at University of Texas Health Center in San Antonio, and they found a positive impact of carotenoid intake and a significantly lowered risk of bladder cancer. (Wu S. et al, Adv. Nutr., 2019)
Cruciferous Vegetables for Cancer Prevention
Cruciferous vegetables are a part of the Brassica family of plants which include broccoli, Brussels sprouts, cabbage, cauliflower, kale, bok choy, arugula, turnip greens, watercress and mustard. Cruciferous vegetables are no less than any superfoods, as these are packed with several nutrients such as vitamins, minerals, antioxidants & dietary fibers including sulforaphane, genistein, melatonin, folic acid, indole-3-carbinol, carotenoids, Vitamin C, Vitamin E, Vitamin K, omega-3 fatty acids and more.
In the last two decades, the association of cruciferous vegetable intake with the risk of different types of cancer were extensively studied and researchers mostly found an inverse association between the two. Many population-based studies have shown strong association between higher consumption of cruciferous vegetables and reduced risk of cancers including lung cancer, pancreatic cancer, colorectal cancer, renal cell carcinoma, ovarian cancer, stomach cancer, bladder cancer and breast cancer (American Institute of Cancer Research). A diet rich in cruciferous vegetables may hence help in prevention of different cancer types.
Impact on Stomach Cancer Risk
A clinical study conducted at Roswell Park Comprehensive Cancer Center in Buffalo, New York, analyzed a questionnaire-based data from patients who were recruited between 1992 and 1998 as part of the Patient Epidemiology Data System (PEDS).(Morrison M E W et al, Nutr Cancer.,2020) The study reported that high intake of total cruciferous vegetables, raw cruciferous vegetables, raw broccoli, raw cauliflower and Brussel sprouts was associated with 41%, 47%, 39%, 49% and 34% reduction in the risk of stomach cancer respectively. Also, they found no significant association with risk of stomach cancer if these vegetables are cooked as opposed to eaten raw.
The chemopreventive property as well as the antioxidant, anti-inflammatory, anti-cancer and anti-estrogenic properties of the cruciferous vegetables may be attributed to their key active compounds/micronutrients such as sulforaphane and indole-3-carbinol. Hence, adding cruciferous vegetables to our daily diet in adequate amounts may help us reap health benefits including cancer prevention.
Nuts and Dried Fruits for Cancer Prevention
Nuts and dried fruits are popular throughout the world and have been part of the human diet since prehistoric times. They are nutrient-rich foods and a good source of health-promoting bioactive compounds. Whether it is the consumption of peanuts and peanut butter in the United States, cashew nuts in India, or pistachios in Turkey, they serve as important healthful snack items, besides being part of many traditional and new recipes of gastronomy worldwide. Frequent consumption of nuts and dried fruits is highly recommended to obtain the complete health benefit of the nutrients, bioactives and antioxidants they contain.
Nuts (almond, Brazil nut, cashew, chestnut, hazelnut, heartnut, macadamia, peanut, pecan, pine nut, pistachio and walnut) contain a number of bioactives and health-promoting compounds. They are highly nutritious and contain macronutrients (fat, protein and carbohydrates), micronutrients (minerals and vitamins) and a variety of health promoting phytochemicals, fat soluble bioactives and natural antioxidants.
Nuts are especially known for their role in reducing cardiovascular disease risk due to their favourable lipid profile and low-glycemic nature. Increased consumption of nuts increases antioxidant defences and reduces inflammation and has been shown in studies to reduce the risk of cancer, benefit cognitive functions and also reduce the risk of asthma and inflammatory bowel disease among others. (Alasalver C and Bolling BW, British J of Nutr, 2015)
Impact on Gastric Cancer Risk
Data from the NIH-AARP (National Institute of Health – American Association of Retired Persons) diet and health study was analyzed to determine the association of nut consumption and cancer risk based on a follow-up of the participants for over 15 years. They found that people with the highest consumption of nuts had a lower risk of developing gastric cancer compared to those who did not consume any nuts. (Hashemian M et al, Am J Clin Nutr., 2017) The above association of lower gastric cancer prevalence was also found to be true for high peanut butter consumption. Another independent study in the Netherlands confirmed the results from the NIH-AARP study of the association of high nut and peanut butter consumption and lower risk of gastric cancer. (Nieuwenhuis L and van den Brandt PA, Gastric Cancer, 2018)
Impact on Deaths due to Cancer
Additional studies such as data from the Nurses’ Health Study and the Health Professionals Follow-up Study with over 100,000 participants and 24 and 30 years of follow-up respectively, also show that increased frequency of nut consumption was associated with lower risk of death from cancer, cardiovascular disease, heart disease and respiratory disease. (Bao Y et al, New Engl. J Med, 2013; Alasalver C and Bolling BW, British J of Nutr, 2015)
Impact on Risk of Pancreatic, Prostate, Stomach, Bladder and Colon Cancers
A meta analysis of 16 observational studies analyzed the association between traditional dried fruit consumption and cancer risk (Mossine VV et al, Adv Nutr. 2019). The study found that increasing the intake of dried fruits such as raisins, figs, prunes (dried plums) and dates to 3-5 or more servings per week may be beneficial for reducing the risk of cancers like pancreatic, prostate, stomach, bladder and colon cancers. Dried fruits are rich in fiber, minerals and vitamins and have antioxidant and anti-inflammatory properties. Hence, including dried fruits as part of our diet can supplement fresh fruits and may be beneficial for cancer prevention and general health and well being.
Cancer Prevention Herbs and Spices
Garlic for Cancer Prevention
An allium vegetable along with onions, shallots, scallions and leeks, is a versatile cooking essential, used extensively in cuisines all over the world. Bioactive compounds like allyl sulfur present in garlic are known to have anti-cancer properties that have the potential to stop the growth of tumor cells by adding a lot of stress on their cell division processes.
Garlic and onions are a key ingredient in a popular dish called Sofrito, in Puerto Rico. A clinical study showed that women who consumed Sofrito more than once a day had a 67% decreased risk of breast cancer than those who did not consume it at all (Desai G et al, Nutr Cancer. 2019 ).
Another clinical study done in China from 2003 to 2010 assessed intake of raw garlic with rates of liver cancer. The researchers found that taking raw foods like garlic two or more times per week may be beneficial in preventing liver cancer. (Liu X et al, Nutrients. 2019).
Ginger for Cancer Prevention
Ginger is a spice used globally, especially in asian cuisines. Ginger contains many bioactive and phenolic compounds with gingerol being one of them. Ginger has been used traditionally in Chinese medicine and Indian ayurvedic medicine for enhancing digestion of food and for treating various types of gastrointestinal problems such as nausea and vomiting, colic, upset stomach, bloating, heartburn, diarrhea and loss of appetite etc. Additionally, ginger has been found to be effective against various gastrointestinal cancers such as gastric cancer, pancreatic cancer, liver cancer, colorectal cancer and cholangiocarcinoma. (Prasad S and Tyagi AK, Gastroenterol. Res. Pract., 2015)
Berberine for Cancer Prevention
Berberine, found in several herbs such as Barberry, Goldenseal and others, has been used in traditional chinese medicine for its numerous beneficial properties including anti-inflammatory, anti-bacterial, immune enhancing, regulating blood sugar and lipids, helping with digestive and gastrointestinal issues and others. The property of Berberine to regulate sugar levels, the key fuel source for cancer cell survival, along with its anti-inflammatory and immune enhancing properties, make this plant-derived supplement a potential anti-cancer adjuvant. There have been many studies in many different cancer cell lines and animal models that have confirmed the anti-cancer effects of Berberine.
A recent clinical study funded by the National Natural Science Foundation of China prospectively tested the use of Berberine in chemo prevention of colorectal adenoma (formation of polyps in the colon) and colorectal cancer. This randomized, blinded, placebo-controlled trial was done in 7 hospital centers across 6 provinces in China. (NCT02226185) The findings of this study was that the group that took Berberine had a lower recurrence rate of the pre cancer polyps when compared to the control/placebo group that did not take Berberine. Hence a key take-away from this clinical study is that 0.3 grams of Berberine taken twice a day was found to be safe and effective in reducing the risk of precancerous colorectal polyps, and that this could be a possible natural option for individuals who have had prior removal of polyps. (Chen Y-X et al, The Lancet gastroenterology & Hepatology, January 2020)
Besides these, there are many other natural herbs and spices commonly used in our foods/diets including turmeric, oregano, basil, parsley, cumin, coriander, sage and many others that have many health-promoting and cancer preventing bioactives. Hence, a healthy consumption of natural foods flavored with natural herbs and spices as part of our diet can help with cancer prevention.
Yogurt (Probiotic Rich Foods) for Cancer Prevention
Many clinical studies have shown a strong association between diet and lifestyle factors and cancer risk. For example, if an individual is a smoker, overweight, or older than 50 years, their risk of developing cancer increases. Hence there is a focus to determine which foods and dietary interventions can help to prevent cancer in a more natural manner.
Yogurt is extremely popular and makes up a significant portion of dairy consumption in Europe, and the rate is also growing in the United States as well, due to the perceived health benefits. Published this year in 2020, researchers from Vanderbilt University in the United States analyzed two large-scale studies to determine the effect that yogurt can have in terms of decreasing the risk of getting diagnosed with colorectal cancer. The two studies reviewed was the Tennessee Colorectal Polyp Study and the Johns Hopkins Biofilm Study. The yogurt consumption of each participant from these studies was obtained through detailed questionnaires conducted on a daily basis. The analysis reported that frequency of yogurt consumption was associated with a trend towards decreased odds of colorectal cancer. (Rifkin SB et al, Br J Nutr. 2020 )
The reason why yogurt has proved to be medically beneficial is because of the lactic acid found in yogurt due to the fermentation process and the lactic-acid producing bacteria. This bacteria has shown its ability to strengthen the body’s mucosal immune system, reduce inflammation, and decrease the concentration of secondary bile acids and carcinogenic metabolites. Plus, yogurt being widely consumed all over the world, does not seem to have any harmful effects and tastes great, hence a good nutritional addon to our diets.
A cancer association or a cancer diagnosis is a life transforming event. Despite the improvements in diagnosis and prognosis, treatments and cures, there is still a lot of anxiety, uncertainty and a constant fear of recurrence. For family members, there now could also be a familial association with cancer. Many individuals avail of sequencing based genetic testing to identify the specific cancer gene mutations in their DNA to determine their own risk factors. This awareness leads to increased and stringent surveillance for cancer and many choose more aggressive options such as surgical removal of possible organs such as breast, ovary and uterus based on some of these risks.
A common theme underlying dealing with cancer association or cancer diagnosis is a change in lifestyle and diet. In this era of having information at our fingertips, there are a very high volume of internet searches on cancer prevention foods and diets. Additionally, this demand for finding the right natural alternatives to prevent cancer has led to a surge of products beyond foods, most of them unvalidated and unscientific, but riding on the vulnerability and need of the population looking for alternatives to maintaining good health and reducing their risk of cancer.
The bottom line is that there is no shortcut to alternative options to prevent cancer and random foods or supplement consumption may not be helpful. Taking multivitamin supplements with high doses of all the needed vitamins and minerals or taking a range of botanical and herbal supplements with concentrated bioactives and phytochemicals, each marketed to have all kinds of amazing benefits and anticancer properties, as part of our diet, is not a solution to cancer prevention.
The easiest and simplest of them all is to eat a balanced diet of natural foods that include vegetables, fruits, berries, greens, nuts, herbs and spices and probiotic enriching foods such as yogurt. The natural foods give us the required nutrients and bioactives to lower our risk of cancer and other complex diseases. Unlike foods, excess of these bioactives in the form of supplements has not found to be beneficial in preventing cancer and has the potential to cause harm. Hence a focus on a balanced diet of natural foods personalized to lifestyle and other familial and genetic risk factors, along with adequate exercise, rest, and avoidance of unhealthy habits like smoking, alcohol use, is the best remedy for cancer prevention and healthy aging!!
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer.Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.