Can you absorb calcium from sesame seeds? Understanding the nutritional reality

October 31, 2025 •

4 min read

Sesame seeds contain a higher concentration of calcium per serving than many dairy products. However, the crucial question is, Can you absorb calcium from sesame seeds? The answer is more complex than a simple yes or no, as the body's ability to absorb this mineral is significantly influenced by the seed's unique composition.

Quick Summary

Sesame seeds are a rich source of calcium, but their absorption is inhibited by natural antinutrients like oxalates and phytates. Dehulling, soaking, and roasting the seeds can significantly increase bioavailability. Pairing with other key nutrients also enhances mineral uptake.

Key Points

Antinutrients Impede Absorption: Compounds like oxalates and phytates in sesame seeds bind to calcium, reducing its bioavailability.
Processing Enhances Absorption: Soaking, sprouting, roasting, and grinding sesame seeds helps to break down antinutrients, making the calcium more absorbable.
Hulled vs. Unhulled: While unhulled seeds have a higher total calcium content, hulled seeds offer better bioavailability because the oxalate-rich hull is removed.
Lower Bioavailability than Dairy: Comparative studies show that the calcium from sesame seeds is not as readily absorbed as that from cow's milk.
Rich in Other Nutrients: Beyond calcium, sesame seeds are packed with healthy fats, protein, fiber, and potent antioxidants like lignans, offering a range of other health benefits.
Holistic Dietary Contribution: Sesame seeds should be viewed as a healthy food component that offers multiple nutrients, rather than a primary, reliable source of highly-absorbed calcium.

The Surprising Calcium Content of Sesame Seeds

At first glance, sesame seeds seem like a calcium powerhouse. Many reports indicate that sesame seeds offer a staggering amount of calcium, with some comparisons suggesting they contain significantly more calcium per gram than milk. This high concentration has made them a popular option for individuals seeking dairy-free sources of this vital mineral. The majority of this calcium is concentrated within the seed's hull, or outer layer. However, the sheer quantity of a mineral in a food does not necessarily translate into how much the human body can actually utilize. The real nutritional value depends on a concept known as bioavailability—the proportion of a nutrient that, once ingested, is absorbed and available for use or storage.

The Bioavailability Challenge: Antinutrients

For sesame seeds, a significant challenge to calcium absorption comes from naturally occurring compounds called antinutrients. The two primary culprits are oxalates (or oxalic acid) and phytates (phytic acid).

How antinutrients inhibit absorption

Oxalates: These compounds bind with minerals like calcium in the digestive tract, forming insoluble complexes such as calcium oxalate. This renders the calcium unavailable for absorption. Studies have confirmed that sesame seeds have one of the highest oxalate contents of any food. This is particularly true for unhulled seeds.
Phytates: Phytic acid is also a strong chelator, meaning it binds to mineral cations like calcium, iron, and zinc. Similar to oxalates, this binding process forms an indigestible mineral-phytate complex, preventing the body from absorbing the minerals. While phytates are present in many seeds and legumes, they still contribute to the reduced bioavailability of calcium from sesame.

Rat model studies comparing different calcium sources have consistently shown that while calcium carbonate (a supplement) and nonfat dry milk have a high bioavailability of 100% and 95%, respectively, the bioavailability of calcium from sesame seeds is lower, around 65%. In another in vitro study, the bioaccessibility of calcium from cow's milk was found to be significantly higher than that of sesame seeds.

Maximizing Calcium Absorption from Sesame Seeds

Fortunately, there are several preparation methods that can help mitigate the effects of antinutrients and increase the bioavailability of calcium from sesame seeds.

Practical strategies for enhanced absorption

Dehulling: Since the hull contains most of the oxalates, removing it dramatically increases calcium's absorbability. However, this also removes a substantial amount of the total calcium, making hulled seeds lower in overall calcium content but with a higher absorption rate.
Soaking and Sprouting: These methods help to break down phytic acid. Research shows that sprouting can reduce both phytate and oxalate concentrations by as much as 50%. Soaking the seeds for several hours or overnight can also help reduce antinutrient levels.
Roasting: Heat can effectively reduce the levels of both oxalates and phytates. Roasting also enhances the nutty flavor, making them a delicious and crunchy addition to dishes.
Grinding: Grinding the seeds, such as into a paste like tahini, breaks down the tough outer hull, making the minerals more accessible to your digestive system. Combining grounding with dehulling offers the best bioavailability.
Nutrient Pairing: Consuming sesame seeds with other foods that aid calcium absorption can also help. Pairing with a food rich in Vitamin D, like fortified dairy or mushrooms, can boost uptake. Magnesium-rich foods also complement sesame's calcium content.

Sesame Seeds vs. Other Calcium Sources: A Comparison

To put the bioavailability of sesame seed calcium into perspective, it's helpful to compare it with other common sources. While the total calcium content of unhulled sesame seeds can be impressive, the amount your body absorbs is the most important factor.


Source	Total Calcium Content (approx. per 100g)	Bioavailability (%)	Estimated Usable Calcium	Considerations
Hulled Sesame Seeds	Lower than unhulled (37mg per 28g)	Higher (around 20%)	Low to Moderate	Lower overall calcium, but better absorption
Unhulled Sesame Seeds	Very High (975mg per 100g)	Very Low (2-7%)	Low	Very high antinutrient content
Cow's Milk	Moderate (300mg per 240ml)	High (32%)	Moderate	Bioavailability is very reliable
Tofu (with Calcium)	High (258mg per 126g)	High (31%)	High	Excellent plant-based source
Kale	Moderate (61mg per 85g)	High (49%)	Moderate	Low in oxalates, high absorption rate

More Than Just Calcium: The Holistic Benefits of Sesame Seeds

Despite the complexities of calcium absorption, sesame seeds offer a host of other health benefits that make them a valuable addition to any diet. They are a versatile, nutrient-dense food packed with much more than just minerals.

Other nutritional highlights

Healthy Fats and Protein: Sesame seeds are an excellent source of healthy fats, including polyunsaturated and monounsaturated fatty acids, which can help lower cholesterol and support heart health. They also provide a good amount of plant-based protein.
Antioxidants: Sesame contains powerful antioxidants, including lignans like sesamin and sesamolin. These compounds help combat oxidative stress and have anti-inflammatory effects.
Vitamins and Other Minerals: They are a good source of B vitamins and other crucial minerals like copper, magnesium, zinc, and phosphorus. These nutrients play roles in everything from immune health to nerve function and further contribute to overall bone health.

Conclusion

In summary, yes, you can absorb calcium from sesame seeds, but the process is far less efficient than with sources like dairy or calcium-fortified foods. The presence of antinutrients like oxalates and phytates significantly reduces bioavailability, particularly in unhulled seeds. However, by employing simple preparation methods such as dehulling, soaking, roasting, and grinding, you can dramatically improve the amount of calcium your body can utilize. Moreover, the nutritional story of sesame seeds extends far beyond calcium. With their rich profile of healthy fats, protein, fiber, and potent antioxidants, they remain a healthy and beneficial part of a balanced diet. The key is understanding how to prepare and incorporate them to unlock their full nutritional potential.

Visit the NIH website for more information on dietary minerals.

Frequently Asked Questions

While sesame seeds contain a high amount of calcium, their efficiency of absorption (bioavailability) is relatively low, particularly in unhulled seeds. This is due to antinutrients like oxalates and phytates that bind to the calcium, preventing your body from absorbing it easily.

You can increase calcium absorption by using simple preparation methods. Soaking, sprouting, roasting, and grinding the seeds (e.g., into tahini) can help reduce antinutrient levels and make the calcium more bioavailable.

Yes. The oxalate content, which most significantly inhibits calcium absorption, is highest in the hull of the seed. Removing the hull, though it reduces the total calcium amount, results in a more easily absorbed form of the remaining calcium.

Studies show that the bioavailability of calcium from sesame seeds is lower than from cow's milk. While milk's calcium is about 32% absorbed, sesame seed calcium has been found to be around 20-21% absorbed, depending on processing.

Yes, eating tahini is an excellent way to get calcium. Tahini is made from ground sesame seeds, which breaks down the outer shell and improves nutrient extraction. If it's made from hulled, ground seeds, the absorption rate is even better.

Yes, soaking and sprouting are effective strategies. These processes help to reduce the concentration of antinutrients like phytates and oxalates, which would otherwise interfere with mineral absorption.

Individuals with a history of kidney stones should be cautious with high-oxalate foods like sesame seeds. For the average healthy person, consuming a balanced diet with normal calcium intake should mitigate the potential inhibitory effects of oxalates. Consult a healthcare professional if you have concerns.