Expert Advice

The Hidden Ingredients That May Be Harming Your Thyroid

Acella Pharmaceuticals, LLC., is partnering with Nicole German Morgan, RDN, LD, CLT, to bring greater awareness to the importance of thyroid care and education. This post is sponsored by Acella Pharmaceuticals and should not be construed as medical advice. Please talk to your doctor about your individual medical situation

Disclaimer: The information provided is for educational purposes only and does not substitute for professional medical advice. Consult a medical professional or health care provider before beginning any exercise, fitness, diet or nutrition routine.

Convenience foods are great for saving time, but are they always healthy for the thyroid? Read on to find the most common food additives to look for that do not support healthy thyroid hormones. Luckily, processed foods have come a long way, and many additives have been changed to healthier alternatives, such as the elimination of trans fats and the reduction of nitrites in deli meat. However, there are still many food chemicals you may not have noticed in your convenience processed foods. Below are some of the most common food additives to look for that do not support the health of thyroid hormones.

Top Hidden Food Ingredients That May Be Harming Your Thyroid

1. Sucralose
Sucralose is my number one chemical to always check for on food labels. Sucralose is chemically altered sugar (sucrose) that is made to taste more sweet but with no calories. Research shows that sucralose may negatively affect the bacteria in the digestive tract over time by promoting an imbalances of bacteria growth.1

Research is limited for human studies, but the general consensus is that as sucralose passes through the digestive tract, there is a change in the microbiome2. This change may lead to further inflammation. The amount that causes harm is unclear, so further research is needed in this area. In the meantime, we can focus on other alternatives to sucralose, such as stevia or small portioned amounts of honey, for example.

2. Nitrites
Nitrites can be naturally occurring from the conversion of plant nitrates to nitrites, or they can be chemically made. We most commonly find nitrites in processed deli meats. There has been speculation and debate in research on whether or not nitrites in deli meat contribute to the cancer risk of deli and processed meat consumption.3

When you choose deli meat, you can look for the labeling “no nitrites added.” This means instead of using chemically made nitrites to preserve the meat, food producers may use more salt or natural sources of nitrites such as celery extracts. I always recommend a more natural approach to my patients to support digestive health and hormone production.

3. Modified Food Starch
Many thyroid patients are eating gluten-free these days. Modified food starch is often derived from corn; however, it can also be derived from wheat. This is a main hidden source of wheat in processed foods and can be troubling for those eating gluten-free to promote thyroid health.

One way around this hidden ingredient is to check the allergen warning label to see if it says that the product contains wheat.

4. Natural Flavors
Natural flavors must be derived from natural materials like plants and animals but can be chemically processed. The possibilities are endless for what can be created. The problem arises from the fact that we do not know which ingredients are used in the foods we eat and how those natural flavor ingredients may interact in the body or with the food itself.

This is an area that needs much more research, and it can be hard to personally decide if you wish to avoid some foods because the research is hugely unclear. Organic foods must use "organic natural flavors" or "organic flavors" that have stricter regulations and less chemical processing.

Thyroid hormone is sensitive to all body processes, inflammation, and toxins, which can make it difficult to decide what to avoid and choose when it comes to processed foods. Perhaps one of the best ways to keep thyroid hormones healthy is to focus on cooking and planning meals at home. This allows for more time, research and understanding of the ingredients that make up the food you eat.

REFERENCES: 1. Zheng Z, Xiao Y, Ma L, et al. Low Dose of Sucralose Alter Gut Microbiome in Mice. Front Nutr. 2022;9:848392. doi:10.3389/fnut.2022.848392. 2. Bian X, Chi L, Gao B, Tu P, Ru H, Lu K. Gut Microbiome Response to Sucralose and Its Potential Role in Inducing Liver Inflammation in Mice. Frontiers in Physiology. 2017;8. Accessed May 11, 2023. 3. Alahakoon AU, Jayasena DD, Ramachandra S, Jo C. Alternatives to nitrite in processed meat: Up to date. Trends in Food Science & Technology. 2015;45(1):37-49. doi:10.1016/j.tifs.2015.05.008


Note that DTE products, including NP Thyroid®, have not been reviewed by the FDA for safety or efficacy.

Important Risk Information

Drugs with thyroid hormone activity, alone or together with other therapeutic agents, have been used for the treatment of obesity. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
  • NP Thyroid® is contraindicated in patients with uncorrected adrenal insufficiency, untreated thyrotoxicosis, and hypersensitivity to any component of the product.
  • In the elderly and in patients with cardiovascular disease, NP Thyroid® should be used with greater caution than younger patients or those without cardiovascular disease.
  • Use of NP Thyroid® in patients with diabetes mellitus or adrenal cortical insufficiency may worsen the intensity of their symptoms.
  • The therapy of myxedema coma requires simultaneous administration of glucocorticoids.
  • Concomitant use of NP Thyroid® with oral anticoagulants alters the sensitivity of oral anticoagulants. Prothrombin time should be closely monitored in thyroid-treated patients on oral anticoagulants.
  • In infants, excessive doses of NP Thyroid® may produce craniosynostosis.
  • Partial loss of hair may be experienced by children in the first few months of therapy but is usually transient.
  • Adverse reactions associated with NP Thyroid® therapy are primarily those of hyperthyroidism due to therapeutic overdosage.
  • Many drugs and some laboratory tests may alter the therapeutic response to NP Thyroid®. In addition, thyroid hormones and thyroid status have varied effects on the pharmacokinetics and actions of other drugs. Administer at least 4 hours before or after drugs that are known to interfere with absorption. Evaluate the need for dose adjustments when regularly administering within one hour of certain foods that may affect absorption.
  • NP Thyroid® should not be discontinued during pregnancy, and hypothyroidism diagnosed during pregnancy should be promptly treated.


NP Thyroid® (thyroid tablets, USP) is a prescription medicine that is used to treat a condition called hypothyroidism from any cause, except for cases of temporary hypothyroidism, which is usually associated with an inflammation of the thyroid (thyroiditis). It is meant to replace or supplement a hormone that is usually made by your thyroid gland.

NP Thyroid® is also used in the treatment and prevention of normal functioning thyroid goiters, such as thyroid nodules, Hashimoto’s thyroiditis, multinodular goiter, and in the management of thyroid cancer.
Revised 10/2023