Risk Factors for Thyroid Cancer: Review Focused on Nutritional Factors

Risk Factors for Thyroid Cancer: Review Focused on Nutritional Factors

Before the Industrial Revolution, processed iodine salt was hardly available in the markets and due to lack of the nutrient, a large population succumbed to the deadly thyroid cancer.
Almost a century after, the picture relating to thyroid cancer hasn’t changed much. Even today, the regions consisting of population with inadequate iodine intake are witnessing a rapid increase in the cases of thyroid cancer. This form of endocrine cancer, which is one of the most common malignancies, accounts for 2% of all cancers.
According to a research by American Cancer Association, cases of thyroid cancers are more prevalent among women. Startlingly, the incidences of risks have been observed comparatively more in the developed countries, including Australia, United States, France, and Canada since early 90’s.
On the basis of clinical and morphological features, thyroid cancer is classified into two kinds — differentiated carcinoma and undifferentiated carcinoma. While females are comparatively more prone to the disease, males have a lesser chance to be diagnosed with the ailment. Also, 90% of the thyroid cancers have been found to be papillary and follicular cancers.
The association of various severe diseases with dietary factors is not an unknown concept in the present time. Besides, low dietary iodine being a significant risk factor for the development of thyroid cancer, studies reveal about different food types having considerable impact on the development of the disease. Gender, lifestyle, dietary patterns, eating habits, and nutrition are the main components influencing dietary factors.
Studies reveal that people following the consumption of goitrogenic food are more prone to be at risk. Considerable meat consumption, such as pork, chicken and poultry, is found to possess risk factors for such diseases. Other food products that have been found to be positively associated with the disease include dietary nitrate and multivitamins, if consumed on a regular basis. However, alcohol, that increases risk of other non-communicable diseases, is found to have been protective in case of thyroid cancer.
Not just under-consumption but also over consumption of iodine has become a major health risk at present. With the excessive consumption of iodine, changes in thyroid stimulating hormone (TSH) are observed. This is why high iodine intake through marine products is likely to increase the incidence of thyroid cancer.
Researches on Thyroid Cancer
Epidemiological studies and interdependence of dietary factors as well as papillary and follicular thyroid cancers have been the criteria of research for several studies. With the help of these researches, the association of various food products with the risks of the carcinomas has been unearthed.
Role of Different Food Products in the Incidence of Risk
While certain food products help the formation of necessary antioxidant that help reduce cancer risks, some function as a bane in this regard. Taking into consideration the studies and survey conducted by various authorities, the impacts of certain foods of daily consumption on the risk factors are the following:
Dairy Food Consumption
While increased consumption of dairy products, including milk, cheese, butter and so tend to result in risk development of prostate cancers, breast cancer and bladder and colon cancers in multiple geological regions, the same consumption pattern have been found to reveal no association with regards to thyroid cancer. However, studies from specific places including Norway and Sweden disclose a positive association between the two.
Fish Consumption
One of the most common sources of dietary iodine among multi-ethnic populations, include fish and shellfish. High fish and seafood consumption are directly associated with high incidence of thyroid cancer. Besides, inadequate seafood intake also results in the development of the risk. More prospects of papillary carcinoma in women have been found as a consequence of iodine intake through seaweed consumption. Also, considerable intake of fish sauce, dried or salted fish have been proven to be beneficial against papillary thyroid cancer, particularly in females of the Asian regions.
Fruits and Vegetables
Consumption of fresh fruits and vegetables has been found to be a boon with respect to thyroid cancer. A direct association of thyroid cancer risks and intake of cruciferous vegetables has been observed. Presence of active micronutrients and phytochemicals in fruits and vegetables promotes antioxidant formation that protects against this kind of cancer. These bio-active components play a prominent role towards the elimination of risks. Studies reveal comparatively lesser prospects of papillary cancer in females with frequent intake of turnips. While citrus fruits, including lemon and tangerine, help prevent early thyroid cancer, vegetables like tomato and other goitrogenic foods have proved to be inversely associated with the risks. Cruciferous plants have a significant role to play with regard to thyroid cancer. People experiencing the disease are also advised to map out a strategy to avoid consumption of carcinogenic compounds.
Meat Consumption
The association between meat consumption and thyroid cancer risk has also been proven to be positive, i.e., high intake of meat, particularly chicken and mutton is likely to develop risk factors. While being cooked at high temperatures, formation of certain compounds like polycyclic aromatic hydrocarbons (PAH) and heterocyclic amines (HCA) have been observed. The compounds being carcinogenic promote the risk factors through enhanced cell proliferation in the mucosa. Similarly, in countries like the United States and Greece, high intake of poultry and pork serve to be promoting the risk factors. On the contrary, studies in Norway and Sweden showed no relevant associations.
Alcohol Consumption
In regulating the growth of thyroid gland, alcohol intake has been found to be directly associated with the risk factors of thyroid cancer. The elevation of the levels of thyroid-stimulating hormone is one of the major factors behind the strong association of alcohol and thyroid cancer. Considering the studies conducted in the US, women who consume wine have been found to be lesser prone to papillary thyroid cancer. Therefore, alcoholic beverages being a part of lifestyle have proven to reduce thyroid cancer risks.
Factors to be considered to lessen risks
In order to ensure lower chances of thyroid risks, certain common factors can serve to be of immense help in the prevention and ease. Scheduling a low iodine diet must be the one to commence with. Further, consumption of the below mentioned products is an ideal choice to ensure risk prevention.
— Iodized salts
— Dairy products including milk, butter, cheese and others
— Egg yolks
— Soy products
— Packaged breads and chocolates
— Seafood including seaweed, kelp, and fishes

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