I am a Registered Dietitian Nutritionist certified to work in the state of New York. I have experience with a full range of nutrition-related medical conditions, including type 2 diabetes, eating disorders, weight management, heart disease, and kidney disorders, and I have worked with patients undergoing cancer treatment and with cancer survivors.
The American Institute for Cancer Research supports research into prevention and survivorship, and provides evidence-based resources for dietitians and their patients. Their blog has excellent recipes.
Since supplements are unregulated it's good to seek out reports from independent testing labs before taking them. ConsumerLab.com is one that works a bit like Consumer Reports. You pay an annual fee and get access to all of their reports on tests for contamination, absorption, and whether or not the supplement actually contains the active ingredient on the label.
The word "nutritionist" is an unregulated term, so anyone can call themselves a nutritionist regardless of qualifications. Registered Dietitians, on the other hand, must complete an accredited science-based college level curriculum consisting of pre-med classes and in-depth courses in nutrition and food science resulting in a bachelors or masters degree. Registered Dietitians must further complete at least nine months of supervised practice and pass a nationally administered exam. In order to maintain their credentials RDs are required to complete 75 hours of continuing education every 5 years. Registered Dietitians are the nutrition professionals who work in hospitals and medical clinics, and to whom physicians and therapists refer their patients.
The Registered Dietitian credential may be indicated by RD or RDN (Registered Dietitian Nutritionist). These terms are interchangeable. CDN stands for Certified Dietitian Nutritionist, and is a further certification required for practicing in some states such as New York. Other states use the credential LD, or Licensed Dietitian.