Cancer affects everyone – the young and old, the rich and poor and most importantly, it does not discriminate gender or race.  We are all in the fight against cancer together.  Cancer is a leading cause of death worldwide, accounting for 7.6 million deaths annually according to the World Health Organization (WHO).   It’s been said that 30 percent of cancer deaths are caused directly by poor lifestyle factors such as inadequate diet, obesity, low fruit and vegetable intake, lack of exercise, tobacco and alcohol use.  The indirect impacts are even greater.  Regardless of the cause of cancer, lifestyle factors will always contribute to the condition worsening or improving.  Without addressing the underlying contributors, treatments will certainly be less than ideal.  What you should know: The vast majority of cancer sufferers have no family history.What you should know: Obesity increases your risk by as much as 40 percent.What you should know: Don’t wait to get cancer to try to treat it.  Prevent it.The best way to combat cancer is to improve the foods that you eat.  The following groupings of foods and nutrients are well known to not only prevent cancer but they have been found to be useful in the treatment of the condition as well. Vitamin CVitamin C enables our bodies to fight cancer naturally. Vitamin C is found in many citrus fruits such as oranges, lemons, limes and grapefruit but can also be found in cantaloupes, mangoes and papayas. Vegetables such as green peppers, broccoli and greens like kale are also good sources of vitamin C. Vitamin C cannot be stored in the body. Therefore, we need to eat vitamin C every day in our diet. Green Tea & CacaoGreen tea contains high levels of catechins, which can block the growth of many cancers.  For many cancers, there is a direct relationship between the amount of green tea consumed and the reduction in cancer risk.  One study suggests that one should consume at least five cups daily.  Cacao is the raw form of chocolate that is rich in highly absorbable antioxidants. Caution – Don’t get too excited and load up on chocolate bars. Most chocolate is loaded with other additives like processed milk products and sugar that have the opposite of cancer-fighting qualities. Cruciferous VegetablesBroccoli is one of the best cancer-fighting foods on the planet.  They’re loaded with various nutrients that has been found to benefit breast, prostate, skin, colon and rectal cancers. Sprouts of broccoli have been found to be the most beneficial.  A direct cancer-inhibiting nutrient can be found in greater concentrations in the sprouts than the full mature plants.   Cabbage and cauliflower have very similar qualities.Dark, leafy greensCollards, escarole, kale, mustard greens, romaine lettuce, and Swiss chard are high in carotenoids and antioxidants, which inhibit the growth of certain types of cancers. These vegetables have incredible levels of vitamins, minerals and fiber. Dark leafy greens are a nutritional powerhouse that should be a regular part of everyone’s diet. Curcumin & SpicesFound in turmeric, curcumin displays anti-tumor and antioxidant properties.  Curcumin is a popular Indian spice that is a member of the ginger family.  It’s quite possibly the most powerful anti-cancer spice.   Curcumin has also shown to have both chemo protective and chemo sensitizing properties.  This means that it will both enhance the positive cancer-killing effects of conventional chemotherapy, while at the same time it protects healthy cells which may be susceptible to being harmed by chemotherapy. Garlic – the more you eat, the more you benefit.  It contains compounds that activate factors in our cells that control cancer-fighting processes.   Other beneficial spices include ginger, dill and parsley.  Carrots & TomatoesHigh in beta carotene, carrots fight many forms of cancer including lung, stomach, intestinal, bladder, prostate, breast, throat and mouth. It’s better to eat them raw rather than cooked and in moderation due to high sugar content.Tomatoes are one of the anti-cancer super foods that contain lycopene and antioxidants that attack the cancer-causing elements in the body. Lycopene is known to kill cancer cells in the mouth and is linked to reduced risk of breast, prostate, pancreas and colorectal cancers. It is actually more effective if cooked rather than raw.AvocadosAvocados are perhaps one of the best foods.  They are loaded with healthy fats and are high in antioxidants. It is now believed that they may be useful in treating viral hepatitis, which causes liver cancer, as well as other types of liver damage.Vitamin D & CancerVitamin D acts more like a hormone than a vitamin. Like a hormone, it has a huge impact on how genes express or fail to express themselves. In fact, one in every 25 genes in the human body interacts with vitamin D. This means that deficiencies may weaken the genetic infrastructure of our body and place us at risk for diseases such as cancer. Without vitamin D our immune system is incapable of producing certain antimicrobial substances, leaving our body unable to fight off bacteria, viruses and cancer. A vitamin D deficiency will prevent the body from killing off precancerous cells before they turn into full-fledged cancer.According to the Vitamin D Council, the human body needs from 3,000 to 5,000 IU daily. Besides preventing cancer, vitamin D is also needed for strong bones and calcium absorption in the body. The good news is that vitamin D can also be generated by exposure to the sun.  However, if you’re looking to supplement vitamin D, understand not all vitamin D is created equal.  Research demonstrates that vitamin D3 is the most powerful form.  Omega-3s & CancerYour body can’t produce omega-3s like it can vitamin D.  This means that you need to make sure that you are consuming them.  Greater intake of omega-3s has been associated with a reduced risk of cancer. The primary way that omega-3s help is the ability to stabilize the immune system and reduce inflammation in the body. The good news is that omega-3s are in a ton of foods such as beans, certain oils and veggies, and—as you probably know—fish and meat products. Treatment Versus PreventionTreatment is expensive and does not address many of the common causes of cancer.  Cancer is not caused by a lack of chemotherapy, radiation or surgery.  By addressing lifestyle factors you can significantly reduce your chances of developing cancer and ensure optimal results if you’re currently going through treatment.  Prevention offers the most cost-effective and long-term strategy to combat cancer.  The solution is not to wait until you get cancer and not to underestimate the powerful effects that nutrition can play in its development.  It’s not up to your doctor to treat it; it’s up to you to prevent it.  Dr. Cory Couillard works in collaboration with the World Health Organization’s goals of disease prevention and global healthcare education.  Twitter: Cory_Couillard