The relationship between dietary choices and the risk of developing cancer is multifaceted. Several nutritional components in our diet are capable of modulating cancer risk, either by promoting or inhibiting cancer development. For instance, diets rich in fruits and vegetables are associated with a reduced risk of developing cancers, such as lung and stomach cancer. In populations with less Westernized dietary patterns, including a rural Japanese population and the residents of Crete, Greece, such diseases were uncommon, and subsequent generations showed an increased risk of cancer upon relocation to areas with high cancer incidence. These observations support important links between cancer risk and lifestyle factors, such as diet.
The objective of this essay is to provide scientific evidence for dietary recommendations and strategies aimed at cancer prevention for healthy individuals. It is crucial to have an exhaustive understanding of the mechanisms leading to cancer’s environmental and genetic determinants. Overall, diet is a modifiable risk determinant that has the potential to explain up to 70% of human cancers. Nonetheless, it is also important to remember that a combination of many dietary—other than genetic—factors (physical activity, alcohol consumption, quality of preservatives, medications) as well as the synergy with other lifestyle factors constitutes this link. An effective cancer prevention strategy will, therefore, result from raising awareness about the associations between diet and risk and proposing optimized, effective, and personalized dietary advice for encouraging the adoption of a healthy diet and lifestyle.
Key Nutrients and Antioxidants
Key Nutrients and Antioxidants for Cancer Prevention Diet and lifestyle play a critical role in our ability to prevent cancer. A combination of nutrient-dense foods that contribute to the formation of healthy cells, and the exclusion of highly processed, low-quality packaged and fast foods containing high levels of chemicals, helps prevent the development of potential cancer precursors. Key nutrients are responsible for maintaining optimal cell and DNA function. Nutrients instrumental in fat metabolism, such as the B-complex vitamins B2, B3, B6, B12, and folic acid, are critical in maintaining the health of the genetic code within the nucleus of the cell that makes up our DNA. These nutrients, alongside the powerful antioxidants vitamins A, C, and E, work to repair DNA damage caused by free radicals.
Antioxidants help to repair damaged and stressed cellular components, while also working to prevent damage to new DNA, thereby minimizing the potential development of cancer. Antioxidants are unstable compounds found in fruits, vegetables, nuts, seeds, herbs, and spices. They are readily available in the diet and are responsible for neutralizing toxic free radicals and other oxidant species responsible for causing molecular damage. Minimizing the volume of oxidative stress in the body is directly related to cancer prevention. Vitamins A, C, and E are all richly available in fruits, vegetables, nuts, and seeds. In addition, minerals such as selenium, copper, iron, zinc, and manganese are instrumental antioxidants and can be found in beans, lentils, nuts, seeds, meat, poultry, fish, shellfish, whole grains, and fortified cereals. One cannot underestimate the significance of consuming foods highest in these antioxidants to help reduce cancer risk. Furthermore, a diversity of different antioxidant-rich foods provides “synergy”, the ability to work together to more effectively neutralize free radicals in cancer prevention. The key cellular nutrients and antioxidants for cancer prevention are discussed in detail throughout this section.
Vitamins and Minerals
Essential vitamins such as vitamins A, C, D, and E represent biochemical structures that are especially well-suited to support immune health and the integrity of cellular membranes and nuclei. One of the most significant roles of these vitamins, collectively, is as antioxidants, which can neutralize free radicals and repair cellular injury prior to the escalation of mutations. Of the essential minerals, selenium, zinc, and calcium exert the most robust protective effects in human observational studies. Moreover, because a major mechanism by which these minerals preserve health in the face of carcinogens is by catalyzing mutations, a secondary effect of increasing intake of these minerals is to a greater extent protect against other forms of genetic mutations, which provide the nutritional basis for comprehensive risk reduction in chronic and degenerative diseases.
For eligible minerals and vitamins, the first goal of this section is to examine the evidence linking their intake to cancer prevention. The second goal is to consider how to best promote these nutrients within the framework of accumulating a diverse range of health protection in a balanced way. This requires knowing the adequacy of intake and the benefits of higher intake levels; a phenomenon where sufficient amounts tend to ameliorate the existing health condition greatly. The practical considerations for safely optimizing intake are also explored. Vitamins can generally be classified into two different categories: water-soluble and fat-soluble vitamins. Many of them, such as the B vitamins, pantothenic acid, biotin, and choline, do not participate directly in immune function; even in these instances, they contribute to overall health, which will allow a greater proportion of the metabolically meaningful portion of calories to be diverted away from an adaptive response and towards activities that promote immune function. Because our adaptive and mutative resources are limited, sustained activities that are not immediately life-essential may deprive our immunity of the metabolites needed to fight an overwhelming infection. Nutritional supplements of vitamins may well be among the most worthwhile interventions to consider when attempting comprehensive cancer prevention. All these vitamins are endowed with beneficial components of the metabolic pathways. Being either fat-soluble or water-soluble vitamins, they pave the way for a suitably balanced pathway. Deficiency of these vitamins can be quite disastrous, leading to chronic disorders, whereas maintaining them in a balanced quantity is very much essential, as excessive rates might result in cell death. Moreover, daily usage of them in the given proportions is essential to prevent chronic diseases, including cancer.
Phytochemicals
Many of the compounds responsible for the potential cancer-fighting properties of plant-based diets are called phytochemicals or bioactive compounds. These occur in nature as secondary metabolites in plants, and they help to keep the plant healthy. When we eat the plants, the phytochemicals have been shown to provide health benefits for people, such as reducing inflammation, providing antioxidants to reduce free radical formation, and protecting DNA from damage. The Dietary Guidelines often suggest that a variety of color is a potential health benefit of consuming colorful fruits and vegetables. Although not all cancer-fighting properties have been completely elucidated, phytochemicals have been shown to inhibit tumor growth in multiple cancers.
Phytochemicals are a very diverse group of compounds that have unique mechanisms of action. Categories of phytochemicals include flavonoids, carotenoids, isothiocyanates, phenolic acids, phytosterols, glucosinolates, saponins, lignans, and polyphenols. In our diet, phytochemicals are consumed in a whole food form, eaten from a variety of plants throughout the day. Traditionally, there is less known about what sort of benefit can be derived from taking phytochemicals in supplement form because the actions of phytochemicals are thought to be a result of an additive or synergistic effect. We suggest eating 7-13 servings of diverse vegetables and fruits daily. Many people find this a surprising recommendation given that impoverished communities struggle to feed their families 3 meals a day, much less 5+ servings of vegetables and fruits daily.
Impact of Sugar and Processed Foods
High sugar intake can lead to obesity, insulin resistance, chronic inflammation, and a number of other physiological changes that are detrimental to cancer risk. We know that obesity and insulin resistance are strong risk factors for specific cancers, and chronic inflammation is now linked to many forms of cancer. Americans, in general, consume 20 times the refined sugars they did 100 years ago, mostly in the form of high fructose corn syrup, which is particularly detrimental to cancer prevention. These processed and refined sugars are found in an overwhelming amount of our processed food supply and are sometimes listed by another name on food labels. In 1911, the average American consumed 17.5 grams of sugar per day. Today, we consume nearly double that amount every 4 hours. The food industry has over-marketed corn, and now over 70% of all processed items in our local grocery stores contain high fructose corn syrup with misleading claims. The optimal sugar intake for chronic disease prevention is less than 6 teaspoons per day for women and less than 9 teaspoons for men. Sweetening our foods with alternatives may be an option, as long as they are used sparingly. These may include stevia, xylitol, erythritol, agave, or raw honey. These products are not intended to replace or match sugar spoon for spoon. Eating unprocessed foods is the best way to avoid added sweeteners.
Consuming a diet high in processed and refined foods contributes to a long list of adverse health outcomes. The problem with processed foods is that they have many ingredients that are not food. They are either additives or preservatives that offer no nutrients to the body. These are things that our digestion, liver, and kidneys have to process or detoxify. Processing food removes vitamins and minerals and other immune-protective antioxidants and phytochemicals. In the case of refined grains like white flour, there is little more than just the sugary starch left after any nutritional substance has been removed. Whole grains are the least processed grains and still have important vitamins, fiber, and phytochemicals for health. It is best to avoid refined and processed foods such as refined grains and products made with white flour and sugar. For cancer prevention, it is beneficial to consume 3-5 servings of whole grain products per day. Focus on consuming whole food products and use 100% whole grain versions of traditional processed grains when possible. Consume a higher proportion of carbohydrates in the form of fruits, vegetables, and legumes to balance the diet. Always refer to food labels to identify products containing excess sugar and refined grains in the form of sugars. This allows for an awareness of just how much added sugars there are in our foods and enough information to estimate weekly or monthly consumption.
Plant-Based Diet and Cancer Prevention
The recommended diet rich in unrefined, plant-based foods can help prevent cancer. Not only can plants nourish our health, prevent diseases, and treat currently existing chronic conditions, this way of eating might also protect against the development of a cancer diagnosis. Researchers have known that people following this eating pattern tend to have lower rates of cancer for a long time. The nutrient-dense foods within these dietary patterns are shown to block the development of tumors in various anatomical localizations. It’s not one nutrient but the synergy of nutrients and phytochemicals that work to keep cancer at bay. The foundation of cancer prevention and treatment begins at the end of your fork! Highly pigmented foods of all types can help to keep cancer and other health issues at bay. Opting for red, blue, black, purple, and green foods keeps life disease-free!
Whole plant foods provide a symphony of nutrients and phytochemicals that help create an unfriendly environment for cancer cells in the body. These foods are rich in antioxidants, containing nutrients like beta-carotene, vitamins C and E, flavonoids, polyphenols, and other phytochemicals that help prevent or fight against cancer. They are also an excellent source of fiber, which can help prevent excess estrogen in the body, a hormone that has been associated with breast cancer. Plants are rich in biologic compounds and substances, which have a unique potential for cancer prevention, reversal, and treatment. The phytochemicals in plant foods appear to function as vitamin-like substances, incorporating antioxidants and other cancer protection. Fruits, vegetables, legumes, and whole grains are the centerpieces of a vegetable-rich traditional diet, and these individuals were shown to have lower rates of cancer in numerous studies over the years!
There are concerns that when focusing a diet on plant foods, it’s possible to develop nutrient deficiencies, but in reality, if we are eating enough foods and a varied diet, then there is no concern. In fact, individuals that focus on a whole-food, plant-based diet follow cancer-fighting nutrition with high intakes of fiber, plant-based omega-3 fats, vitamins C, E, and K, folate, and lots of the cancer-fighting lycopene, phytochemicals, and potassium. In order to avoid protein or essential fatty acid deficiencies, monotony and variety are encouraged, and these foods should include nuts and seeds, plant foods as sources of proteins, and enriched sources of ALA. A myriad of plant-based eating patterns exist, ranging from vegetarian diets that include some or no animal products to completely avoiding the consumption of animal foods on vegan diets. Studies have shown that vegetarians and vegans have lower cholesterol, BMI, and blood pressure (all risk factors for heart disease). Vegetarians and vegans are also at a lower risk of developing type 2 diabetes and some types of cancer. Herbs, such as parsley, rosemary, thyme, and many other spices and herbs, are well established to have anti-cancer properties. When cancer-fighting spices are used, small amounts are required to provide a significant cancer-fighting punch, making it easy to meet necessary intake levels. Here are some easy ways to begin to incorporate more spices into your meals and reduce your cancer risk: Ensure that soy and corn are organic so that you do not have to cook with pesticides and inadvertently cause more harm than good. Plant-based eating must not be convenient, but it is simple. Plant your seeds, water them, keep them in the sun, and watch your food grow!
Healthy Fats and Omega-3 Fatty Acids
Although “fat” is often considered an unsavory word when it comes to health, not all fats are created equal. In fact, certain types of dietary fats are essential to good health. Omega-3 fatty acids, in particular, have received much attention over the past few years because of their cancer-fighting capabilities. The three most common dietary fats are saturated, trans, and unsaturated fats. Excessive intake of saturated and trans fats is associated with an increased risk of developing certain types of cancer, including breast, colon, prostate, and ovarian cancers, as well as cardiovascular disease. Unsaturated fats can be either monounsaturated or polyunsaturated. Adequate amounts of unsaturated fats in the diet are beneficial to overall good health and may possibly be protective against cancer. Omega-3 fatty acids are the most desirable type of polyunsaturated fat. They decrease inflammation and promote healthy cellular function, making them a healthful choice for all individuals and a key player in fighting cancer. Evidence suggests that omega-3 fatty acids may reduce the risk of certain types of cancer, such as breast, prostate, and skin cancer. Omega-3 fatty acids also play an important role in heart health. In particular, they help maintain healthy blood vessels, reduce the risk of arrhythmia, and decrease blood triglyceride levels. Many foods contain omega-3 fatty acids, making it easy to include them in your daily diet. Great sources of omega-3 fatty acids include albacore tuna, herring, mackerel, sardines, and salmon, as well as foods containing alpha-linolenic acid, a plant-based omega-3 fatty acid. Alpha-linolenic acid is found in ground flaxseeds, flaxseed oil, canola oil, English walnuts, and wheat germ. Omega-3 and omega-6 fatty acids compete against each other within your body, so these fats need to be balanced. Omega-6 fatty acids are found in foods such as corn, soybean, and sunflower oils. Try to incorporate a variety of plant oils into your diet to keep both beneficial fatty acids in balance. When grocery shopping, read food labels for the healthiest choices. Look for foods with low, not no, amounts of saturated and trans fats and high amounts of omega-3 and omega-6 fats.