Iodine: what is the safest level to consume

Iodine is an essential mineral the body needs to synthesize thyroid hormones and for proper thyroid function. Iodine deficiency can cause goiters, which are enlarged thyroid glands. However, consuming too much iodine can cause gastrointestinal issues and, in severe cases, acute toxicity. Since consuming too little iodine and too much iodine both pose consequences, there is an ongoing debate about what the recommended level of iodine intake should be per day. With iodine inadequacy on the rise in the US, many are suggesting that it needs to be raised; others say that raising the recommended amount would put more people at risk for acute toxicity and other issues. According to the American Thyroid Association, adults should consume about 150 mcg per day and not exceed 1,100 mcg per day, which is the established tolerable limit. This raises the question of where do we draw the line?

            Iodine has been removed from many sodium sources in the American diet. One major area is highly processed foods; consumption has risen exponentially in recent years. According to the CDC, individuals 1 year of age and older obtain 55% of their calories from processed foods. Sodium is a major ingredient in many processed foods, but iodized salt costs more than non-iodized salt, so companies choose the cheaper option, removing a source of iodine from our diets. Eating non-iodized salt won't cause an iodine deficiency. While most Americans aren’t severely deficient, iodine inadequacy is increasing. A study published in the Journal of Nutrition examined iodine inadequacy in the United States from 2001 to 2018 and found that it doubled. They found that iodine intake decreased by 24% in females and 22% in males, suggesting people are not ingesting enough iodine to maintain normal levels and contributing to the growing rate of iodine inadequacy in the United States (Lieberman et al., 2025). This will continue to rise as companies opt for non-iodized salt and use specialty salts without iodine. People are also changing their diets to low sodium, low cholesterol, low fat, low carb, and so on. These dietary choices directly affect how much iodine you consume. One great source of iodine is eggs; fewer people eat eggs because they want to lower their fat and cholesterol intake. Another great source of iodine is cow’s milk; people have either gone non-dairy or just have started consuming dairy at much lower rates. Eggs contain roughly 31 mcg per egg, and milk contains 84 mcg per cup. These are excellent sources of iodine and would get everyone to roughly 115 mcg at the start of the day.

Iodine deficiency was once thought to be eradicated in the US, but as inadequacy levels rise, it may soon return. This is one major reason people want to raise the required iodine intake; they believe it doesn't account for iodine loss from our diets. They also believe this low level is a reason for the rise of thyroid-related diseases in the US. Where this level once was believed to cover all the bases for thyroid health, it is now believed to lower only the risk of developing a goiter. It is now thought that people need more iodine in their diets to support proper thyroid function, brain function, and development.

            The way some people combat this loss is through unregulated supplement use. They take high-dose iodine supplements, which typically contain 150 mcg according to the American Thyroid Association, or eat sea moss every morning, believing they are doing something good for their health. People take sea moss as a natural seaweed supplement because it’s been marketed as a “superfood.” That’s all it is: marketing. Ingesting sea moss can have more negative side effects than positive ones, including acute iodine toxicity if you don't monitor your daily iodine intake. According to an article posted by Organics Nature, a serving of sea moss gel can range from 56 mcg to 98 mcg; this range depends on the type of sea moss you are ingesting and how it was processed. Taking sea moss or an iodine supplement on top of your normal iodine intake can cause problems, especially if you don't track how much iodine you are ingesting throughout the day. Overconsumption of iodine is just as bad as iodine underconsumption; it is a balancing act.

As someone whose family uses pink Himalayan salt instead of iodized salt and rarely cooks with salt in general, I believe there is enough evidence to warrant looking into raising the recommended level to ensure everyone gets the right amount of iodine in their diet. The recommended intake may meet people’s needs, but it may not be sufficient for everyone. Dietary changes and the rising rate of iodine inadequacy suggest people need more iodine than they realize. Instead of recommending supplements, efforts should focus on encouraging people to eat iodine-rich foods. I believe we can add it back into food without harming people, and it can also help prevent inadequacy and deficiency. So, if it can help keep people safe, why not add it back into food and raise the recommended daily level? 

By Lillian Meier, A Master's of Medical Science student at the University of Kentucky

References

https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/

https://www.thyroid.org/ata-statement-on-the-potential-risks-of-excess-iodine-ingestion-and-exposure/

 https://www.organicsnature.co/blogs/news/sea-moss-iodine-content?srsltid=AU7gw4ULUnSv5ine2kAZUrew3DU_Xdq6eh_Tw3e7qDAhrqMD_W-2Zt7K

 https://www.webmd.com/diet/health-benefits-sea-moss

 https://experiencelife.lifetime.life/article/why-is-iodine-controversial/

Khudair A, Khudair A, Niinuma SA, Habib H, Butler AE. Beyond thyroid dysfunction: the systemic impact of iodine excess. Front Endocrinol (Lausanne). 2025 Apr 2;16:1568807. doi: 10.3389/fendo.2025.1568807. PMID: 40241991; PMCID: PMC11999837.

Lieberman, H. R., Mathews, R. S., & Fulgoni, V. L., III. (2025). Iodine inadequacy is prevalent and has continuously increased from 2001 to 2018 in the United States. The Journal of Nutrition, 155, 3886-3895. https://doi.org/10.1016/j.tjnut.2025.09.017

 https://www.cdc.gov/nchs/products/databriefs/db536.htm

https://www.nm.org/healthbeat/healthy-tips/nutrition/health-benefits-and-risks-of-sea-moss-what-you-should-know

 AI was used to edit for clarity and create citations. 

 

A Drop of Prevention; Fluoride in Water

Around the 2024 election, one of the many controversial topics discussed amongst the US population was the inclusion of fluoride in public water. Since its introduction into public water in the 40s, the debate has never been settled. Is fluoride bad for you? Does it cause adverse health effects? Fluoride does not cause adverse health effects.

Fluoride is a naturally occurring anion of fluorine. Fluorine is one of the most abundant elements on the planet. It can be found in rocks and minerals across the globe. Fluoride is naturally present in water. As groundwater comes up through rocks to be accessible, it catches fluoride deposits and presents itself in varying levels. A natural concentration could be 0.05 mg/L, while higher levels could be up to 10 mg/L.

Fluoride was first added to public water in Grand Rapids, Michigan in 1945. Roughly 18 years after its addition, the US Public Health Service recommended that all municipalities add fluoride to water to prevent cavities. Brushing your teeth twice a day and flossing are proactive recommendations to keep you out of the chair of nightmares!

Fluoride makes your teeth stronger by increasing the strength of enamel, which is the outer layer of the tooth. Cavities are formed when bacteria in the mouth break down sugars in food. The byproduct of such reaction is an acid that breaks down enamel. Fluoride is added into water at low doses (0.4-4.0 mg/L) to help the public keep their enamel strong.  There have been numerous studies completed to show the effects of long-term exposure to fluoride. The results of these experiments have shown there are no adverse effects above 0.7 mg/L. There has been a national cap set at 4.0 mg/L to prevent any adverse effects. The public must also be notified of any fluoride levels above 2.0 mg/L for cosmetic purposes. 

Two of the major arguments against fluoride in water are dental fluorosis and neurological development issues. Dental fluorosis is a cosmetic condition in which adult teeth present white streaks or marks when overexposed to fluoride at a young age (maybe put an image). High level of fluoride exposure has also been reported to lower IQ scores at a young age. There is not sufficient evidence to support that fluoride causes lower IQ scores at the recommended levels provided by the US government. Anything in high doses is bad for you. Medicines have recommended doses. There are recommendations on the number of macromolecules like fats, carbohydrates, and sugars you should consume in a day. Even overexposure to essential molecules like vitamins can have adverse health effects.

The study linked at the end of the paper discusses the implementation of fluoride in water and the effect it has on children. The paper reports that there is no direct affect from the water with the fluoride and the children’s intelligence. There is no proof that the fluoride makes the children more intelligent, however. The paper discloses there are biases in the experiment. Evidence shows that some children who consumed more fluoride had lower IQ scores, but this is where the outside bias comes into play.

Oral health products like toothpaste often have fluoride in them to ensure that people get their fluoride. Another key argument is overexposure via these pathways. Not everybody brushes their teeth twice daily, and not everybody drinks from the public water system every day. Why would one want to increase the likelihood of a cavity by removing fluoride from water? There are many people who do not have access to regular dental appointments. There are people in the US who do not have guaranteed access to clean drinking water.

As a pre-dental student myself, I have been shadowing dentists for over six years. I have had opportunities to observe in areas of Kentucky where there is a genuine need for improved oral healthcare. I have seen teeth burst when extracted due to poor enamel strength. It is recommended that people drink milk for the calcium to increase bone strength. Milk can increase cholesterol levels causing heart issues later in life. Should we take away milk?

Taking fluoride from those who struggle with their oral health is deprivation of an essential molecule that increases the quality of one’s life. The arguments for the removal of fluoride are understandable. Nobody wants their kid to have a reduced IQ or marks on their teeth. However, there is not enough evidence to support these claims. Fluoride in water was regarded as one of top 10 greatest medical innovations of the 20^th century. There is little traction to these claims and fluoride should be continued to be consumed.

By Drew Wood, A Master's of Medical Science student at the University of Kentucky

Studies and Facts Resources

https://jamanetwork.com/journals/jamapediatrics/fullarticle/2828425

https://www.cdc.gov/fluoridation/timeline-for-community-water-fluoridation/index.html

 Hydrolyzed Doesn’t Always Mean Better: Rethinking Protein for Premature Infants

If a formula is easier to digest, shouldn’t it automatically be better for a premature infant?

Working as a diet technician in the Infant Nutrition Division at Golisano Children’s Hospital, I have seen how important nutrition is for premature infants. Our team prepares and delivers breast milk and specialized formulas for infants who may receive nutrition through feeding tubes, parenteral nutrition, or breast or bottle feeding. In the NICU, nutrition is complex and a critical component of medical treatment and development.

Because premature infants have immature digestive systems and high nutritional needs, feeding decisions are made carefully and continually reassessed. One option used in some situations is hydrolyzed protein formula. But does breaking protein into smaller pieces automatically make it safer or better for every premature infant?

 

What does “hydrolyzed” actually mean?

Hydrolyzed formulas contain proteins that have been broken down into smaller peptides, which, in theory, makes them easier to digest and may improve feeding tolerance. This could be beneficial, particularly for infants whose digestive systems are still developing. However, easier digestion does not necessarily mean improved growth, nutrient absorption, or reduced risk of complications such as necrotizing enterocolitis (NEC).

Hydrolyzed formulas are sometimes selected because they are perceived to improve feeding tolerance. This belief is understandable, but the available evidence is not as conclusive as the label “hydrolyzed” might suggest.

 

What does the evidence show?

A 2022 systematic review and meta-analysis by Li et al. examined 10 studies involving 886 preterm infants. The researchers found that hydrolyzed formulas were associated with a lower rate of feeding intolerance and a shorter time to reach full enteral feeding. However, there was no statistically significant reduction in NEC. The confidence interval included the possibility of no benefit, meaning the results were not strong enough to establish whether hydrolyzed formulas prevent this complication (Li et al., 2022).

Other researchers present a more cautious perspective. A 2019 Cochrane review analyzed 11 trials involving 665 infants and found no strong or consistent evidence that hydrolyzed formulas improved digestion or changed the risk of severe bowel problems. The authors also noted that many of the studies were small and had methodological limitations (Ng et al., 2019).

Individual clinical trials further demonstrate why the evidence remains mixed. In a randomized controlled trial of 60 preterm infants, Baldassarre et al. (2019) found no differences in measures of feeding tolerance between infants receiving intact-protein and extensively hydrolyzed formulas. In a smaller subset of infants who received at least 75% of their enteral intake from the study formula, the intact-protein group reached full enteral feeding sooner, with a median of 10 days compared with 14 days in the hydrolyzed group. No cases of NEC occurred in either group. Although this was a small study, it provides another example of why hydrolyzed protein does not consistently produce better feeding outcomes.

The current professional guidance is more nuanced than simply labeling hydrolyzed formula as better or worse. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) position paper reports that hydrolyzed protein can accelerate gastrointestinal transit and enteral feeding advancement in preterm infants. However, there are no data showing that routine use improves long-term outcomes. ESPGHAN states that hydrolyzed protein may be used for early enteral feeding when human milk is unavailable, rather than recommending it as the standard choice for every formula-fed preterm infant (Embleton et al., 2023). With updated professional guidance on enteral nutrition in preterm infants and continued use of hydrolyzed formulas in neonatal care, understanding what these formulas can and cannot accomplish is important for setting health and growth goals.

There are also potential nutritional disadvantages to consider. Hydrolysis alters amino acid kinetics and may reduce nutrient utilization, particularly nitrogen. Some studies have reported slower weight gain and lower nutritional efficiency with hydrolyzed formulas, although increasing protein concentration can help compensate for reduced protein retention. Hydrolyzed formulas can also have increased osmolality (Verduci et al., 2021; Embleton et al., 2023).

Another challenge is that “hydrolyzed formula” is not one standardized product. Formulas can be partially or extensively hydrolyzed, and commercial formulas differ in the size of their remaining protein peptides. These differences may produce different functional effects, meaning results from one hydrolyzed formula cannot necessarily be applied to every hydrolyzed formula used in the NICU (Embleton et al., 2023).

 

Why does this matter in the NICU?

In my experience working in the NICU, hydrolyzed formulas are not chosen simply because they are considered better. They are used in specific clinical situations, and the infant’s tolerance, growth, medical condition, overall feeding plan, and growth goals are all factors that dietitians and providers must consider. Witnessing these decisions and preparing so many hydrolyzed formulas brought my attention to this very niche debate and made me realize how complex nutritional strategies are in pediatrics and neonatology.

In the NICU, no two infants have exactly the same medical needs. A premature infant’s nutritional plan may depend on gestational age, weight, medical conditions, tolerance, growth, and whether the infant is receiving breast milk, fortification, or formula.

This is why I believe hydrolyzed protein should not be viewed as automatically superior. It may be a useful option for certain infants, but the choice of formula should rest on more than the assumption that smaller protein molecules will solve feeding problems.

For parents and families, the most important step is to ask questions: Why was a specific formula selected? Is the goal to improve feeding tolerance, support growth, address an allergy, or manage another medical concern? What outcomes will the healthcare team monitor and report?

Nutritional decisions should be an ongoing conversation based on the infant’s individual needs and the best available evidence, not simply on the idea that a product with more specialized processing will produce better outcomes.

Premature infants deserve nutrition plans that are carefully considered and individualized. Hydrolyzed protein may benefit some infants, but “easier to digest” should not necessarily be interpreted as “better feeding outcomes.”

 

By Allison L. Kimmerer, A Master's of Medical Science student at the University of Kentucky

 

References

Baldassarre, M. E., Di Mauro, A., Fanelli, M., Capozza, M., Wampler, J. L., Cooper, T., & Laforgia, N. (2019). Shorter time to full preterm feeding using intact protein formula: A randomized controlled trial. International Journal of Environmental Research and Public Health, 16(16), 2911. https://doi.org/10.3390/ijerph16162911

Embleton, N. D., Moltu, S. J., Lapillonne, A., van den Akker, C. H. P., Carnielli, V., Fusch, C., Gerasimidis, K., van Goudoever, J. B., Haiden, N., Iacobelli, S., Johnson, M. J., Meyer, S., Mihatsch, W., Saenz de Pipaon, M., Rigo, J., Zachariassen, G., Bronsky, J., Indrio, F., Köglmeier, J., ... Domellöf, M. (2023). Enteral nutrition in preterm infants (2022): A position paper from the ESPGHAN Committee on Nutrition and invited experts. Journal of Pediatric Gastroenterology and Nutrition, 76(2), 248–268. https://doi.org/10.1097/MPG.0000000000003642

Li, M., Fang, Y., Lian, Y., Lu, X., Qiu, M., & He, Y. (2022). Effect of hydrolyzed formulas on gastrointestinal tolerance in preterm infants: A systematic review and meta-analysis. The Journal of Maternal-Fetal & Neonatal Medicine, 35(25), 10173–10180. https://doi.org/10.1080/14767058.2022.2122794

Ng, D. H. C., Klassen, J. R. L., Embleton, N. D., & McGuire, W. (2019). Protein hydrolysate versus standard formula for preterm infants. Cochrane Database of Systematic Reviews, 2019(7), Article CD012412. https://doi.org/10.1002/14651858.CD012412.pub3

Verduci, E., Salvatore, S., Bresesti, I., Di Profio, E., Pendezza, E., Bosetti, A., Agosti, M., Zuccotti, G. V., & D’Auria, E. (2021). Semi-elemental and elemental formulas for enteral nutrition in infants and children with medical complexity—Thinking about cow’s milk allergy and beyond. Nutrients, 13(12), 4230. https://doi.org/10.3390/nu13124230