Calcium is hotly debated in the context of plant nutrition. The main point of controversy is whether we can get enough calcium by eating a plant-based diet based on whole foods and excluding dairy products.
To understand this important topic, let’s answer key questions.
How much calcium does a person need?
The recommended daily intake of calcium for most adults is 1000 to 1200 milligrams. Nonetheless, plant-based health experts believe that these levels are overestimated for one simple reason: a diet high in animal protein has a high excretion rate, which means you have to consume more calcium to compensate for inevitable losses. When you eat a whole-food, plant-based diet and reduce your salt and caffeine intake, your calcium excretion rates are significantly lower, so it makes sense that vegans / vegetarians need less calcium.
How much less? In a study published in American Journal of Clinical Nutrition, it was found that “people with low but nutritionally adequate sodium and protein intake need approximately 500-741 milligrams of calcium per day».
Can you get enough calcium from plant foods?
Like iron, magnesium, and copper, calcium is a mineral. It is found in the soil from which it is absorbed by plant roots. Animals get calcium by consuming plants rich in this mineral. So while we’re all trained to believe that calcium comes from milk and dairy products, the real source is the earth. Not surprisingly, a plant-based, whole food diet provides us with the calcium we need.
A varied plant-based diet that includes vegetables, herbs, legumes and fruits and excludes dairy products provides enough calcium to meet our needs.
Note that your body will adjust to the amount of calcium you receive. Studies show that in a diet with a relatively low calcium intake (415 milligrams per day), the intestines absorb calcium more efficiently and the kidneys retain it better. In the case of excess calcium (1740 milligrams per day), the intestine blocks its absorption, and the kidneys excrete it more intensively. This is an example of how our body protects us. Unrepaired excess calcium is deposited in soft tissues (heart, kidneys, muscles and skin), which makes us vulnerable to disease.
So your calcium needs are met. Is always. The “disease” of calcium deficiency does not exist with a high-calorie, varied, whole-food plant-based diet.
How much calcium you consume is actually being absorbed?
The important thing is not how much calcium we received, but how much of it our body assimilated. For example, 1 cup of milk contains about 300 milligrams of calcium, but only 30% (90 milligrams) is actually absorbed. This is called bioavailability – the availability of calcium to the body. Calcium-rich vegetables allow the body to absorb about 40% of this mineral.
Calcium in tofu has about the same absorption rate as dairy products – about 31%. However, just 150 grams of hard tofu contains as much calcium as 1 cup of milk (300 milligrams), while tofu contains more protein, much less saturated fat and about one tenth of salt.
What factors lead to calcium loss?
Many factors contribute to calcium loss, from age (older people lose more calcium) to vitamin D intake (people who are deficient in vitamin D3 tend to lose more calcium).
Sodium, protein and caffeine play a major role in calcium loss.
Sodium… This is our worst enemy when it comes to calcium loss. For every thousand milligrams of sodium (which is 2,5 grams of table salt), the kidneys excrete about 40-60 milligrams of calcium.
Protein… When protein intake is increased, the excretion of calcium in the urine increases at the same time. If you double your dietary protein, urinary calcium loss increases by 50%.
Protein’s ability to cause calcium loss is especially interesting when it comes to dairy products, which have always been considered one of the best sources of calcium. You lose one third of the calcium you get from milk and over two thirds of the calcium you get from cheeses.
Caffeine… It acts as a diuretic and literally draws calcium out of your body.
In contrast, many green leafy vegetables provide large amounts of easily absorbed calcium without causing a loss!
Can the problem be solved by taking calcium supplements?
Research shows that calcium supplementation can reduce the risk of fractures by 10% (hip fractures are not considered). However, at the same time, the risk of developing cardiovascular diseases and stroke, the formation of kidney stones, and gastrointestinal disorders increases.
In a recent study of over 36 postmenopausal women, “dietary supplements with calcium, with or without vitamin D, were associated with an increased risk of myocardial infarction and stroke, and these risks occurred in different subgroups defined by important baseline characteristics. These findings suggest that targeting calcium supplements to specific subpopulations, such as young people and people with low dietary calcium intake, is unacceptable. ”
But if we don’t drink milk or take calcium supplements, what happens to our bones?
A recent study on this very important issue compared bone mineral density in avid vegans to those on a traditional diet. The results were striking: even though vegans get significantly less calcium and protein from their diet, they have as much bone density as their omnivorous opponents.
Here is a list of some plant sources of calcium.