Exploring Which Vegetables Contain the Maximum Calcium

January 2, 2026 •

3 min read

According to the Dietary Guidelines for Americans, cooked lambsquarters can contain up to 464mg of calcium per cup, making it one of the top vegetable sources for this essential mineral. Knowing which vegetables contain the maximum calcium is crucial for building stronger bones and ensuring a well-rounded diet, especially for those who are dairy-free.

Quick Summary

This guide reveals the vegetables with the highest calcium content, including cooked leafy greens like lambsquarters and collard greens. It also covers important factors like bioavailability and absorption.

Key Points

Lambsquarters Top the List: Cooked lambsquarters provide the highest calcium content per cup among vegetables, with over 460mg.
Bioavailability is Critical: High oxalate content in spinach prevents efficient calcium absorption, making it a less effective source than other leafy greens.
Collard Greens are a Superior Choice: With high calcium and excellent bioavailability due to low oxalates, cooked collard greens (around 268mg/cup) are a top pick.
Kale and Bok Choy are Great Alternatives: Cooked kale (~177mg/cup) and bok choy (~185mg/cup) both offer significant, well-absorbed calcium.
Cooking Can Affect Content: Cooking vegetables, especially greens, can increase the total calcium available by reducing water volume, but doesn't solve the bioavailability issue posed by oxalates.
Diversify Your Sources: For a complete strategy, combine calcium-rich vegetables with other non-dairy sources like fortified plant milks, seeds, and certain beans.

Surprising Plant-Based Calcium Powerhouses

While dairy products are a well-known source of calcium, many vegetables, particularly leafy greens, offer substantial amounts of this essential mineral. For those following a vegan or dairy-free diet, or simply looking to diversify their nutrient intake, understanding which vegetables pack the biggest calcium punch is vital. The bioavailability, or how well the body can absorb the nutrient, is also an important factor to consider.

The Top Contenders: A Deep Dive into High-Calcium Vegetables

Several cooked vegetables consistently top the charts for calcium content per standard serving. Their high density and concentrated nutrients make them an excellent addition to your diet.

Lambsquarters (cooked): This wild green is a true standout, with over 460mg of calcium per cooked cup. It is an exceptional choice for boosting calcium intake.
Nettles (cooked): Another powerful, though less common, green, cooked nettles provide a remarkable 428mg of calcium per cup.
Collard Greens (cooked): A staple in many cuisines, a cooked cup of collard greens offers approximately 266-268mg of calcium. Critically, they also have low oxalate levels, meaning the calcium is highly bioavailable and easily absorbed.
Amaranth Leaves (cooked): Providing around 276mg per cooked cup, amaranth leaves are a great source of calcium, along with other essential vitamins.
Mustard Spinach (cooked): This vegetable delivers approximately 284mg of calcium per cooked cup.
Kale (cooked): A popular superfood, cooked kale contains about 177mg of calcium per cup. Its calcium is also highly bioavailable compared to spinach.
Bok Choy (cooked): Offering around 185mg per cooked cup, bok choy is a versatile and excellent source of calcium.
Turnip Greens (cooked): A cup of cooked turnip greens provides 197mg of calcium.

The Oxalate Factor: Why Bioavailability Matters

When evaluating calcium sources, it is important to look beyond the raw numbers. Some vegetables contain high levels of oxalates, natural compounds that bind with calcium, preventing its absorption by the body. Spinach is a prime example. While a cooked cup boasts 245mg of calcium, its high oxalate content means the body absorbs very little of it. For effective calcium intake, choosing vegetables with lower oxalate levels, such as collard greens, kale, and bok choy, is a smarter strategy.

Comparison of High-Calcium Leafy Greens


Vegetable	Serving Size	Total Calcium (mg)	Bioavailability	Notes
Collard Greens	1 cup, cooked	~268	High	Excellent absorption due to low oxalates.
Kale	1 cup, cooked	~177	High	Better absorption than spinach.
Spinach	1 cup, cooked	~245	Low	High oxalate content severely limits absorption.
Bok Choy	1 cup, cooked	~185	High	Good absorption; a versatile, low-calorie option.
Lambsquarters	1 cup, cooked	~464	-	Highest concentration found in some studies.

Cooking Methods and Other Sources

Interestingly, cooking vegetables can sometimes increase their calcium availability. For example, cooking spinach releases some of its oxalates, though it remains a poor calcium source compared to other greens. A varied diet incorporating both raw and cooked vegetables is the best approach for maximizing nutrient intake.

For those seeking more non-dairy calcium sources beyond vegetables, fortified foods are a great option.

Fortified Plant Milks: Soy, almond, and rice milks are often fortified with calcium, making them easy and reliable sources.
Tofu (calcium-set): Tofu made with calcium sulfate is a very high-calcium food.
Seeds: Tiny seeds like poppy, sesame, and chia are packed with calcium.
Beans: Varieties like white beans and winged beans offer decent amounts of calcium.

Putting it all together

Incorporating a range of calcium-rich vegetables into your meals can be both simple and delicious. Add chopped kale or bok choy to a stir-fry, braise collard greens as a side dish, or blend amaranth leaves into a smoothie. For optimal absorption, ensure you are also getting enough vitamin D, which is essential for your body to process calcium effectively.

Conclusion

While dairy products are a common calcium source, the plant kingdom offers a wealth of alternatives. The title for which vegetables contain the maximum calcium, in terms of sheer content per cooked cup, goes to lambsquarters and nettles, but bioavailability is a crucial consideration. Cooked collard greens and kale are excellent choices due to their high calcium content and efficient absorption, making them superior to spinach for this purpose. By focusing on a diverse diet rich in these key vegetables, you can easily meet your daily calcium needs and support strong, healthy bones. For more information on dietary needs, consult resources like the Dietary Guidelines for Americans.

Frequently Asked Questions

Cooked lambsquarters have one of the highest concentrations of calcium, providing approximately 464mg per cooked cup. Cooked nettles are a close second with about 428mg per cup.

While spinach has a high amount of total calcium (~245mg per cooked cup), it is also high in oxalates, which bind to calcium and significantly reduce its absorption. Therefore, it is not considered a highly bioavailable source of calcium.

Leafy greens with lower oxalate content, such as collard greens, kale, and bok choy, offer calcium that is more easily absorbed by the body. Cooked collard greens are a particularly effective source.

Cooking vegetables can increase their calcium content by reducing their water volume, concentrating the minerals. For example, a cooked cup of spinach has more calcium than a raw cup.

Other excellent plant-based sources of calcium include fortified plant milks (like almond or soy), calcium-set tofu, sesame seeds, chia seeds, and certain beans like white beans and winged beans.

Vitamin D is crucial for the body to absorb calcium effectively. Without sufficient vitamin D, your body cannot properly utilize the calcium you consume from your diet.

You should aim for a variety of both raw and cooked greens. While cooked greens concentrate the calcium, raw greens may offer higher levels of other nutrients like vitamin C. Just be mindful of high-oxalate greens like spinach.

Yes, it is entirely possible to meet your daily calcium needs without dairy. By incorporating a variety of calcium-rich vegetables and other non-dairy sources into your diet, you can ensure an adequate intake.