When it comes to calcium supplementation, people might immediately think of milk or bone broth. In fact, many other foods in daily life also have a calcium-boosting effect, and a pretty good one at that, such as vegetables.
Nutrition experts have pointed out that vegetables not only contain large amounts of potassium and magnesium, which help maintain acid-base balance and reduce calcium loss, but they are also rich in calcium themselves. Green leafy vegetables like bok choy, napa cabbage, kale, and celery are all excellent sources of calcium. Furthermore, while milk is often considered the best source of calcium, many experts disagree. When calculated based on nutrient density, the calcium benefit of milk might not be as high as that of green vegetables.
Data shows: 100 grams of whole milk contains about 54 kcal of energy and 104 mg of calcium. In the same 100 grams, bok choy contains about 15 kcal of energy, but its calcium content is as high as 153 mg. Calculated by calcium nutrient density, whole milk is 104/54 = 1.9, while bok choy is 153/15 = 10.2. Vegetables are the clear winner.
Therefore, for the same serving size, green leafy vegetables might be a better food source for supplying the minerals needed for bone health. Moreover, green leafy vegetables like napa cabbage, bok choy, and kale have low levels of oxalic acid, which minimally hinders the absorption and utilization of calcium. As long as there is sufficient sunlight exposure to get enough Vitamin D, the calcium in them can fully realize its nutritional value.
So, what are some common vegetables on the market that are good for calcium supplementation?
1. Spinach
Vegetable lovers who want to supplement calcium should not miss out on spinach. A small bowl of spinach can supplement 25% of a person's daily calcium requirement. Additionally, spinach contains fiber, iron, and Vitamin A, which are beneficial for health.
However, note that spinach contains oxalic acid and phytic acid. It needs to be blanched before cooking, otherwise, these compounds will bind with trace elements like calcium, iron, and zinc to form non-absorbable substances, affecting the absorption of these minerals.
2. Cabbage
Although many vegetables contain calcium, they also contain oxalic acid, which reduces calcium absorption, such as in water bamboo, bamboo shoots, spinach, water spinach, amaranth, and celery. Therefore, it's best to blanch these vegetables in boiling water before cooking to remove most of the oxalic acid.
Additionally, cabbage is high in potassium and low in sodium, which is beneficial for the cardiovascular system and can also boost mood. Furthermore, fresh cabbage has antibacterial and anti-inflammatory properties and is very effective in treating ulcers and accelerating wound healing. Finally, cabbage is rich in folic acid and iron, so pregnant women and patients with anemia should eat more of it.
3. Onion
It has a very strong bactericidal effect and can enhance human immunity. Eating onions often can help prevent calcium loss from bones and has the effect of preventing osteoporosis.
4. Kale
It contains Vitamin K, which can have an anti-osteoporosis effect. Vitamin K helps the body absorb Vitamin D and calcium, and it is an indispensable nutrient for preventing osteoporosis.
Of course, although the calcium efficiency of green vegetables is high, they are also troublesome to prepare—some nutrients are also lost during the cooking process. Therefore, don't neglect the importance of milk just because vegetables have more calcium. Eating more green vegetables and drinking more milk are both good ways to supplement calcium, and you can have both. At the same time, it's best to supplement with Vitamin D to promote calcium absorption.
In addition, seed-based plants like sesame, peanut oil, soy products, and dried shrimp also have relatively high calcium content.
However, relying solely on diet for calcium supplementation also has a drawback: you must eat a large amount of food to meet the required calcium intake, which leads to a high intake of calories. Therefore, a better approach is to supplement with both high-calcium foods and calcium tablets.