Calcium is a hotly debated topic in the context of plant-based diets. The main point of contention is whether we can get enough calcium by following a plant-based diet based on whole foods and avoiding dairy products.
To get to the bottom of this important topic, let's answer the key questions.
How much calcium does a person need?
The recommended daily calcium intake for most adults is between 1,000 and 1,200 milligrams. However, health experts who are plant-based diet supporters believe that these rates are inflated for one simple reason: A diet high in animal protein is characterized by a high excretion rate, which means you have to consume more calcium to compensate for its imminent loss. When you follow a plant-based diet based on whole foods and reduce salt and caffeine intake, calcium excretion rates are much lower, so it makes sense that vegans/vegetarians need less calcium.
How much less? A study published in the American Journal of Clinical Nutrition found that "people with a low but nutritionally adequate intake of sodium and protein need about 500-741 milligrams of calcium per day."
Can we 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 eating plants rich in the mineral. So while we are all accustomed to believing that calcium comes from milk and dairy products, the real source is the earth. Not surprisingly, a plant-based diet based on whole foods provides the amount of 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: Your body will adjust to the amount of calcium you get. 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 (1,740 milligrams per day), the intestines block its absorption and the kidneys excrete it more intensively. This is an example of how our body protects us. Unremoved excess calcium is deposited in the soft tissues (heart, kidneys, muscles, and skin), making us vulnerable to disease.
So your calcium needs are met. Always. There is no "disease" of calcium deficiency with a sufficiently caloric and varied plant-based diet based on whole foods.
How much calcium is actually absorbed?
The important thing is not how much calcium we got, but how much our body absorbed. 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 this mineral at about 40%.
The calcium found in tofu has about the same absorption rate as dairy products, about 31 percent. However, just 150 grams of solid tofu contains as much calcium as 1 cup of milk (300 milligrams), with more protein, much less saturated fat and about one-tenth the salt.
What factors contribute to calcium loss?
Many factors contribute to calcium loss, from age (older people lose more calcium) to vitamin D intake (people who are vitamin D3 deficient tend to lose more calcium).
Sodium, protein, and caffeine play major roles in calcium loss.
Sodium. This is our worst enemy when it comes to calcium loss. With every thousand milligrams of sodium (which is 2.5 grams of table salt), the kidneys remove about 40-60 milligrams of calcium.
Protein. When protein intake increases, urinary calcium excretion also increases at the same time. If you double the protein content of your diet, urinary calcium loss will increase by 50%.
The peculiarity of protein 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 a third of the calcium you get from milk and more than two-thirds of the calcium you get from cheese.
Caffeine. It acts as a diuretic and literally drains calcium from your body.
In contrast, many green leafy vegetables provide large amounts of easily digestible calcium without causing calcium loss!
Can the problem be solved by taking calcium supplements?
Studies show that calcium supplements help reduce the risk of fractures by 10% (hip fractures are not considered). However, it also increases the risk of cardiovascular disease, stroke, kidney stones, and gastrointestinal disorders.
In a recent study of more than 36,000 postmenopausal women, "calcium supplements 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 data suggest that targeting calcium supplementation to specific subpopulations, such as young people and people with low dietary calcium intake, is unacceptable."
But if we don't drink milk and take calcium supplements, what happens to our bones?
A recent study on this very important question compared bone mineral density in avid vegans and traditional dieters. The results were striking: even though vegans get significantly less calcium and protein from their food, they have the same bone density as their omnivorous counterparts.
You must be logged in to post a comment.