How much iodine is in pastured eggs?

December 28, 2025 •

3 min read

According to nutrition data, a single large pastured egg can contain a significant amount of iodine, contributing to your daily intake. However, the specific amount of iodine in pastured eggs is not uniform and is highly dependent on factors like the hen's diet and supplementation, rather than just access to pasture.

Quick Summary

The iodine content in pastured eggs is variable, influenced primarily by the hen's feed, but can be a valuable source for humans compared to conventional counterparts depending on farming practices.

Key Points

Variable Content: Iodine levels in pastured eggs are not fixed and depend heavily on the hen's diet and any feed supplementation.
Enrichment is Key: High iodine levels often result from the purposeful fortification of hen feed by farmers, rather than natural foraging alone.
Yolk is Primary Source: The vast majority of an egg's iodine is concentrated within the yolk, which can contain many times the amount found in the white.
Variable Bioavailability: Some studies suggest that the iodine bioavailability from eggs may not be as high as from fortified salt, but a significant amount is still absorbed.
Part of a Healthy Diet: Regardless of iodine variability, pastured eggs offer superior levels of Omega-3s, Vitamin D, and Vitamin E compared to conventional eggs.
Check the Source: Consumers should look for information from producers regarding their feed practices to better understand the iodine content in their pastured eggs.

Understanding Iodine in Pastured Eggs

The amount of iodine in a pastured egg can be a key point of interest for health-conscious consumers, but the answer is not a single, fixed number. While a pastured diet generally enriches eggs with other nutrients like Omega-3s and fat-soluble vitamins, iodine levels are more directly controlled by what is in the hen's feed. For instance, a nutritional label for some pasture-raised eggs shows a single serving can provide approximately 60 micrograms of iodine, or 40% of the recommended daily value for adults. However, another analysis suggests a raw pastured egg yolk contains around 27 micrograms. These differences highlight the variability influenced by farming methods and feed formulas.

The Critical Role of Hen Diet

Pastured hens have the freedom to forage for insects, seeds, and fresh greens, which contributes to a more diverse nutrient profile in their eggs compared to caged hens. However, iodine's presence in the hen's diet is key to its concentration in the egg. In many commercial operations, even pasture-raised ones, feed is supplemented with iodine to ensure a consistent level of the mineral. The natural iodine concentration in the soil and forage can be highly variable and is often insufficient to produce eggs with high iodine levels on its own, especially in inland regions. Farmers can strategically add an iodine source to the feed to biofortify the eggs, significantly increasing their iodine content. Research has shown a direct correlation between the amount of iodine in a hen's feed and the iodine concentration in the egg yolk.

Iodine Concentration in the Egg

If you're looking for the most iodine in an egg, your focus should be on the yolk. Studies confirm that the majority of an egg's total iodine content is accumulated in the yolk, not the egg white. In fact, the concentration in the yolk can be many times higher than in the albumen. This is an important detail for anyone separating egg whites from yolks for recipes. When cooking eggs, some iodine can be lost, though one study indicated that the difference in iodine levels between boiled and unboiled eggs was not statistically significant. This means you can still get a substantial amount of iodine from cooked eggs.

Pastured vs. Conventional Eggs: Key Nutrient Comparison


Nutrient	Pastured Eggs	Conventional Eggs	Notes
Iodine (per egg)	Variable (approx. 27-60 mcg or higher with supplementation)	Variable (approx. 24-26 mcg avg)	Highly dependent on feed supplementation; pasture alone is not a reliable source.
Vitamin E	Significantly higher (3x more)	Lower	Higher intake from foraging greens.
Vitamin D	Higher (4x more)	Lower	Hens gain vitamin D from sunlight exposure outdoors.
Omega-3s	Higher (2x more)	Lower	From foraging diverse grasses and insects.
Beta-Carotene	Higher (7x more)	Lower	From foraging, leading to vibrant orange yolks.
Cholesterol	Lower (1/3 less)	Higher	Healthier omega-6 to omega-3 ratio.

Influencing Factors for Iodine Levels

Hen's Feed Formula: The most significant factor. Commercial feed is often fortified with a consistent amount of iodine, which can be adjusted to produce enriched eggs.
Soil and Forage Iodine: The natural concentration of iodine in the soil where hens forage varies by region. Inland, iodine levels tend to be lower than in coastal areas.
Supplementation Strategy: Farmers can use different iodine sources, like potassium iodide or iodine-enriched yeast, and adjust the dosage to achieve specific iodine levels in eggs.
Season and Weather: The quality and availability of forage can change with the seasons, which may have a slight impact on overall nutrient intake for hens.
Hen Breed: Different breeds may have varying efficiencies in transferring dietary iodine to their eggs.

Conclusion

While pastured eggs are undeniably a nutritional upgrade over conventional eggs in many aspects, including Omega-3s, Vitamin D, and Vitamin E, their iodine content is not as consistently higher unless specifically enriched through their feed. A pastured egg can be a very good source of iodine, but the exact amount is variable. The primary driver for higher iodine levels is intentional supplementation of the hens' diet by the farmer, which can result in eggs containing a substantial percentage of the adult daily recommendation. For those seeking to boost their iodine intake, pastured eggs can be a great option, especially from producers known to supplement, but it's important to understand the factors at play rather than assuming high levels are a direct result of pasture access alone. You can find more information on iodine requirements from authoritative health sources like the National Institutes of Health.

Frequently Asked Questions

Not necessarily. While pastured eggs have a better nutrient profile overall due to foraging, their iodine content is primarily dependent on what's in the hen's feed. High iodine levels in eggs are often achieved through feed supplementation, a practice used for both conventional and pastured hens.

A pastured egg yolk can contain approximately 27 micrograms of iodine, though this can vary significantly. In contrast, some brands of pasture-raised eggs that use enriched feed may have higher amounts per egg.

Hens transfer iodine from their diet into their eggs, concentrating it mostly in the yolk. The iodine can come from their forage (grasses, insects) or, more reliably and significantly, from iodine supplements added to their commercial feed.

For most adults, the recommended daily intake (RDI) of iodine is 150 micrograms. Pregnant and breastfeeding women have higher requirements, needing 220 and 290 micrograms respectively.

Some studies have found that cooking, like boiling, can slightly reduce the iodine content in eggs. However, one study suggested that the loss was minimal and not statistically significant, meaning cooked eggs remain a good source of iodine.

The variation is primarily due to differences in the hen's diet. Factors include the iodine concentration in the soil where the hens forage, seasonal changes in feed, and the specific level of iodine supplementation used in their commercial feed formula.

While pastured eggs can be a great source of dietary iodine, relying on them as your sole source can be unreliable due to the variability in content. For consistent intake, ensure your diet includes other iodine-rich foods, such as iodized salt or seafood.