Factors Affecting Immune System Status
Age, lifestyle, nutrition, and health status can all affect the ability of the immune system to respond to cancer cells, even with immunotherapy. Also, the tumor itself can suppress the patient’s immune system (Schreiber 2011). Moreover, some cancer treatments can suppress the immune system as well (ACS 2015). During surgery, some cancer cells can be released, and the surgical procedure and anesthesia can suppress the responsiveness of NK cells and T cells that would otherwise track down those cancer cells (Tai 2014; Welden 2009).
As people age, the immune system begins to deteriorate due to immune senescence. Some hallmarks of immune senescence are lower numbers of naïve cytotoxic T cells and weaker NK cells (Mekker 2012; Tarazona 2017).
Immune senescence has two major consequences. First, an older person’s immune system cannot protect them as well from infections and cancer. Second, the immune system may not respond as robustly to immunotherapies such as vaccines (Pera 2015). More information about general age-related immune decline is available in the Immune Senescence protocol.
Diet and Lifestyle
Maintaining a healthy weight is an important goal for lowering cancer risk (ACS 2016a). Obesity can suppress the immune system. Obese individuals do not respond to flu vaccines as well as average-weight people, and are more susceptible to infections (Sheridan 2012; Andersen 2016). Similarly, toxins in cigarette smoke and hormones released during times of stress can also weaken the immune system (Zhou 2016; Segerstrom 2004).
Eating a balanced diet, including ample fruits and vegetables, is also important in reducing cancer risk and possibly improving outcomes for cancer patients. Dietary phytochemicals can help prevent cancer, partially through effects on the immune system (Kotecha 2016). In one clinical trial, when people were given broccoli sprouts at the time of vaccination, the NK cells in their blood became more activated, ready to respond to the challenge (Muller 2016). Another study confirmed that viruses were more effectively destroyed by the immune system in people who had eaten a broccoli sprout preparation (Noah 2014).
Broccoli is just one component of a healthy diet. A growing body of evidence suggests a diet rich in vegetables, fruits, nuts, and other phytonutrients can not only fight cancer directly but also enhance the immune system’s ability to protect the body (Shahzad 2017; Song, Garrett 2015).
Exercise can have an immediate positive effect on T cells, and is being embraced as an immune senescence preventive (Cao Dinh 2017). For instance, in one study, elderly men who exercised responded better to the flu vaccine (de Araujo 2015).