What plant has the highest calcium?

December 22, 2025 •

4 min read

While dairy is often promoted for calcium, many plant-based foods offer impressive amounts of this crucial mineral. A single tablespoon of unhulled sesame seeds provides more raw calcium than a cup of milk, challenging common perceptions about what plant has the highest calcium.

Quick Summary

This article explores which plants are highest in calcium, differentiating between raw content and absorbable amounts. It highlights top contenders like sesame seeds, nettles, and fortified foods, providing insight into bioavailability. A variety of plant-based sources, including vegetables, seeds, and legumes, are discussed to support bone health.

Key Points

Unhulled Sesame Seeds are Calcium Powerhouses: These tiny seeds have one of the highest concentrations of raw calcium among all plant foods.
Bioavailability is Critical: High-oxalate plants like spinach have poor calcium absorption, despite their high raw content. Focus on low-oxalate options.
Fortified Foods are Excellent Sources: Calcium-set tofu and fortified plant milks are highly reliable and effective for meeting daily calcium needs.
Cooked Nettles and Amaranth Leaves are Top Performers: These leafy greens offer a substantial amount of bioavailable calcium in a single cooked serving.
Combine with Vitamin D: Proper calcium absorption requires adequate vitamin D, which can be obtained through sunlight or fortified foods.
Variety Enhances Absorption: Eating a diverse range of plant-based calcium sources helps mitigate the effects of different anti-nutrients and maximizes overall intake.

The Calcium Champions: Highest Content Plants

When searching for plant-based calcium, the title of "highest" can be awarded based on different metrics: raw content per 100g, or the amount of calcium our body can actually absorb from a typical serving. The following plants are consistently identified as top contenders for their calcium concentration, but it's important to look beyond just the raw numbers.

Unhulled Sesame Seeds

Among all raw plant sources, unhulled sesame seeds often have the highest concentration of calcium by weight. A mere tablespoon can contain almost 88 mg of calcium. These seeds are incredibly versatile and can be added to salads, baked goods, or ground into tahini. This high raw content makes them a standout choice for boosting calcium intake with a small serving size.

Cooked Greens: Nettles, Amaranth Leaves, and Lambsquarters

Certain cooked leafy greens offer a very high concentration of calcium per serving. Cooked nettles, for example, can provide over 400 mg of calcium per cup. Amaranth leaves are another powerhouse, providing 276 mg per cooked cup. These vegetables are excellent sources because they provide a significant amount of calcium within a normal portion size. While not as common as spinach or kale, these greens are highly nutritious and worth seeking out for their mineral content.

Calcium-Set Tofu

Tofu prepared with calcium sulfate is a remarkably rich source of plant-based calcium. Half a cup of calcium-set tofu can contain over 400 mg of calcium, rivaling or exceeding the amount in dairy milk. This makes fortified tofu an excellent, reliable source, especially for those on a vegan diet. Always check the nutrition label to ensure the tofu was set with calcium.

Why Bioavailability Matters: Quality Over Quantity

Just as important as the total calcium content is its bioavailability—the rate at which your body can absorb and use the mineral. Some plants, while high in raw calcium, contain compounds called oxalates that bind to the calcium, preventing absorption.

The Spinach Paradox

Spinach is often cited as a high-calcium vegetable, with over 240 mg per cooked cup. However, it is also very high in oxalates, meaning the body absorbs only a small fraction of that calcium, sometimes as low as 5%. This is a crucial distinction: while spinach is nutritious, it should not be relied upon as a primary source of bioavailable calcium.

The Kale Advantage

In contrast, greens like kale and bok choy are lower in oxalates and have higher absorption rates. A cup of cooked kale might have a lower raw calcium number than spinach (around 177 mg), but the body absorbs a much higher percentage of it, making it a more effective source. Collard greens are another low-oxalate, high-calcium option.

High-Calcium Plant Comparison Table


Food Source	Typical Serving Size	Raw Calcium (mg)	Bioavailability	Key Consideration
Unhulled Sesame Seeds	1 tbsp (9g)	88	Moderate	Highest concentration by weight
Cooked Nettles	1 cup	428	High	Exceptionally high per cooked cup
Cooked Amaranth Leaves	1 cup	276	High	Excellent cooked leafy green source
Calcium-Set Tofu	1/2 cup	434	Moderate-High	Excellent fortified protein source
Cooked Kale	1 cup	177	High	High absorption due to low oxalates
Cooked Spinach	1 cup	245	Low (5%)	High oxalates drastically reduce absorption
Cooked White Beans	1 cup	161	Moderate	Good source of calcium and fiber
Dried Figs	1/2 cup	121	Moderate	Contains potassium and magnesium

Other Excellent Plant-Based Calcium Sources

Beyond the leading contenders, many other plant foods contribute significantly to your daily calcium needs. Diversifying your diet with a mix of these sources can ensure adequate intake.

Legumes and Beans: In addition to white beans, other beans and lentils offer respectable amounts of calcium. Edamame, for instance, provides 98 mg per cup. Soaking and cooking can also help reduce anti-nutrients like phytates, improving mineral absorption.
Fortified Plant Milks and Juices: Many non-dairy milk alternatives, like almond or soy milk, are heavily fortified with calcium to match or exceed the levels in cow's milk. Fortified orange juice also offers a substantial boost. These are reliable and easily accessible sources for daily intake.
Nuts and Seeds: Aside from sesame seeds, almonds contain approximately 75 mg of calcium per ounce. Chia seeds are another notable source, with 179 mg per two tablespoons.
Dried Fruits: While not the highest source, dried figs are a tasty and convenient way to supplement your calcium, offering around 121 mg per half-cup serving.

Maximizing Calcium Absorption

Consuming calcium-rich plants is only part of the strategy; maximizing absorption is key for bone health. Several nutritional factors influence how your body utilizes calcium. Combining plant sources with other nutrients can enhance this process.

Vitamin D: This vitamin is critical for calcium absorption. Getting regular, safe sun exposure or eating vitamin D-fortified foods (like some plant milks) helps your body effectively absorb calcium.
Magnesium and Vitamin K: These minerals work synergistically with calcium. Leafy greens like kale and collards are excellent sources of both vitamin K and calcium, making them especially effective for bone health.
Timing and Variety: To mitigate the effect of oxalates and phytates, avoid consuming high-oxalate foods (spinach) with your main calcium sources or supplements. A varied diet naturally balances different nutrient levels and absorption inhibitors.
Cooking Methods: Cooking certain vegetables can help reduce anti-nutrient levels. For example, boiling can reduce oxalates in greens, although it may also slightly reduce overall nutrient content if not handled carefully.

Conclusion: The Holistic View of Plant Calcium

The question of what plant has the highest calcium is complex, hinging on both raw content and bioavailability. While unhulled sesame seeds offer the highest calcium concentration by weight, cooked nettles and amaranth leaves deliver large quantities in a typical portion. It's crucial to understand the role of oxalates, which drastically reduce the absorbable calcium in otherwise high-content plants like spinach. For consistent and effective intake, a varied diet that includes low-oxalate greens like kale, fortified foods like calcium-set tofu, and potent seeds like sesame and chia is the best approach. By combining these sources with adequate vitamin D, you can build a strong foundation for lifelong bone health without relying on dairy.

For more details on dietary calcium, consult resources like the Harvard T.H. Chan School of Public Health.

Frequently Asked Questions

No, spinach is not a good source of bioavailable calcium. While it contains a high amount of raw calcium, it also has high levels of oxalates, which bind to the mineral and prevent the body from absorbing most of it.

Tofu's calcium content depends on how it is made. When prepared with a calcium salt, such as calcium sulfate, it becomes a significantly rich source of the mineral. Always check the label for 'calcium-set' tofu.

Bioavailability is the measure of how efficiently your body can absorb and utilize a nutrient. It's important for plant-based calcium because compounds like oxalates and phytates in some plants can drastically reduce absorption, making the raw calcium content misleading.

Yes, many fortified plant milks, including soy and almond, are excellent and reliable sources of calcium. Their fortification levels are often comparable to or higher than dairy milk, and the calcium is highly absorbable.

No, it is possible to meet your daily calcium requirements on a plant-based diet by consuming a variety of calcium-rich foods. These include fortified plant milks, tofu, leafy greens, and nuts and seeds.

Both are excellent sources. Unhulled sesame seeds have a higher concentration of calcium by weight, but tahini (sesame paste) provides a significant amount in a two-tablespoon serving and is easily incorporated into many dishes.

To maximize absorption, ensure adequate vitamin D intake, pair calcium-rich foods with other complementary nutrients like Vitamin K, and diversify your food sources to account for absorption differences.