Were your Free T4 and Free T3 levels tested, along with the TSH? If you could post your actual test results, it would be very helpful for us to see where you are. Be sure to post reference ranges with any lab results posted.
Has your doctor prescribed a replacement medication for you? If so, which one and what dosage?
The cruciferous vegetables you mentioned are considered goitrogens and are food that inhibit synthesis of thyroid hormones. There are 3 things to remember about these foods: 1) if they're cooked their goitrogenic properties are destroyed and they do no damage; 2) typically, most people don't eat enough of them to really do "that" much harm; and 3) the dietary benefits of these foods, typically, outweighs the harm they might do, so avoiding them, completely is, usually, not recommended. If you're on a replacement thyroid hormone, it would be recommended that you avoid consuming these foods (unless cooked) within a few hours of taking your medication. The only one I recommend avoiding at all times, under any circumstances, is soy.
Other links to food, in relation to hypothyroidism are controversial... some insist that everyone with hypothyroidism must go gluten, dairy, soy and sugar free... The premise is that gluten causes "leaky gut"... Leaky gut is a medically unrecognized condition in which proponents insist that undigested food escapes the intestines and floats around in the blood. The idea is that gluten molecules look enough like thyroid tissue that antibodies attack the thyroid, thinking it's the gluten. They've begun rephrasing this to "intestinal permeability", but the idea is the same.
I've already addressed soy and of course, we all know that sugar is bad for us, along with artificial sweeteners, which are actually worse than sugar.
New studies are coming out that show that the gut microbiome "does" have an effect on our autoimmune system and that diet MAY play a part.
A healthy diet, consisting of fresh fruits, veggies, high quality proteins and healthful fats is always the best for maintaining good health and proper weight. If one has a gluten, wheat or dairy allergy, by all means those foods should be avoided. Or if you aren't sure, you can do an elimination diet... I brought my cholesterol and triglyceride levels back to normal, by, "mostly", eliminating gluten and dairy for about 2 months, so there may be benefits for some of us. Diet can also help eliminate inflammation in our body, which can help reduce pain.
Yeast infection and parasites, such as H. Pylori, etc are also common in some of us with hypothyroidism. These can be caused/contributed to by diet and the use of antibiotics and lack of healthy microbiome in the gut.
What protocol are you on for your Hep C? According to my research over the past 10 yrs, the relationship between Hep C and hypothyroidism isn't really known; however, interferon and ribivarin, both tend to cause hypothyroidism. In addition, Hep C affects the immune system, so it no longer works properly and most hypothyroidism in the developed world is caused by Hashimoto's, which is an autoimmune condition.
Both the Hep C virus as well as Hep C treatments can cause hypothyroidism. Usually autoimmune but some cases are non autoimmune.
Request thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb).
Omega-6s are pro-inflammatory, while Omega-3s are anti-inflammatory. Both are essential fatty acids but you want more Omega 3 than Omega 6. Avoid processed seed and vegetable oils high in Omega-6 such as sunflower, corn, soybean and cottonseed oils.
The types of omega-3s called DHA and EPA, have the strongest health benefits. The best food source of both DHA and EPA is cold water fatty fish such as salmon, sardines, mackeral, tuna. You can also take Omega 3 supplements.
200 mcg of selenium per day has been found to reduce TPO Antibodies in numerous clinical trials. Selenium is a necessary component of the enzymes that removes iodine molecules from T4 converting it into T3. Without selenium there would be no activation of thyroid hormone.
Studies have shown patients suffering from various forms of thyroid disease were all found to be lower in selenium than normal healthy people. When I started eating Brazil nuts I noticed major improvements. My TPOAb reduced as well.