Scientists studied five important minerals found in vegetables, fruits, and grains that people eat in Poland. They wanted to understand how much of these minerals our bodies can actually use, not just how much is in the food. Using different testing methods, they found that the amount of minerals we actually absorb is often less than what the food contains. Most people get enough of these minerals from eating plants, but some people might not get enough iron or cobalt, while others might get too much copper or manganese. This research shows that knowing how much mineral our bodies can actually use is just as important as knowing how much is in the food.

The Quick Take

  • What they studied: How much of five important minerals (cobalt, copper, iron, manganese, and zinc) are actually in common vegetables, fruits, and grains, and how much of these minerals our bodies can actually use.
  • Who participated: This wasn’t a study with people eating food. Instead, scientists tested actual vegetables, fruits, and cereals commonly eaten in Poland using laboratory methods that copy how our stomachs and intestines work.
  • Key finding: The amount of minerals our bodies can actually absorb from plants is often much lower than the total amount of minerals in the food. Most people get enough minerals, but some might not get enough iron or cobalt, while others might get too much copper or manganese.
  • What it means for you: The minerals in your vegetables are important, but your body can’t use all of them. This research suggests that food labels and nutrition guidelines should focus on how much mineral your body can actually use, not just the total amount in the food. If you’re concerned about mineral intake, talk to a doctor or nutritionist.

The Research Details

Scientists collected common vegetables, fruits, and grains from Poland and tested them in laboratories. They used seven different testing methods that copy how your stomach and intestines break down food and absorb minerals. Some methods measured the total amount of minerals in the food, while others measured only the minerals that your body could actually absorb (called bioaccessibility). They then used computer simulations to estimate how much of these minerals people might get from eating these foods based on typical eating patterns.

Just because a mineral is in your food doesn’t mean your body can use it. Some minerals are locked up in plant fibers or attached to other compounds that your stomach can’t break down. By measuring what your body can actually absorb, scientists can give better advice about whether people are getting enough minerals or too much. This is more accurate than just looking at total mineral content.

This study used standardized, scientific methods that are recognized internationally for measuring mineral absorption. The researchers used computer simulations (Monte Carlo simulations) to account for the fact that different people eat different amounts and absorb minerals differently. However, this was a laboratory study, not a study with actual people eating food, so real-world results might be slightly different.

What the Results Show

The researchers found big differences in mineral content depending on the type of plant tested. When they measured only the minerals the body could actually absorb (rather than total minerals), the estimated intake was usually lower than when they just looked at total mineral content. Most people eating these plants would get enough copper, iron, manganese, and zinc to meet their daily needs. However, some people might not get enough cobalt or iron, depending on what they eat. A few scenarios showed that some people might get too much copper or manganese, though this was less common.

The study found that different testing methods gave different results. Methods that copy how your stomach works (simulating stomach acid and digestive enzymes) gave different answers than methods that just measured total minerals. This shows that the method scientists use to test food really matters. The researchers also found that the type of plant matters a lot—vegetables, fruits, and grains had different mineral levels and different amounts that the body could absorb.

Previous research has shown that not all minerals in food can be absorbed by the body, but this study provides more detailed information about specific plants eaten in Poland. It adds to growing scientific evidence that bioaccessibility (how much your body can actually use) is just as important as total mineral content when deciding if people are getting enough minerals.

This study tested food in laboratories, not in actual people eating meals. Real digestion is more complex and can be affected by what else you eat, your age, your health, and other factors. The study focused on Poland, so results might be slightly different in other countries where people eat different varieties of plants or prepare food differently. The study didn’t test actual people to see if they absorbed the predicted amounts of minerals.

The Bottom Line

Eat a variety of vegetables, fruits, and whole grains to get different minerals. If you’re concerned about getting enough minerals (especially iron or cobalt) or worried about getting too much (especially copper or manganese), talk to a doctor or registered dietitian. They can look at your specific diet and health needs. For most people eating a balanced diet with plant foods, mineral intake should be adequate.

People who follow vegetarian or vegan diets should pay attention to this research, as plants are their main source of minerals. People with digestive problems that affect nutrient absorption should talk to their doctor. People taking mineral supplements should be aware that their bodies might not absorb all of the minerals in the supplement. Pregnant women, children, and older adults should talk to their healthcare provider about mineral needs.

If you change your diet to include more plant foods, you should expect to see stable mineral levels in your body within a few weeks to a few months, though this varies by person. If you’re deficient in a mineral, it may take several weeks to months of consistent dietary changes or supplementation to correct the deficiency.

Want to Apply This Research?

  • Log your daily intake of iron-rich foods (beans, lentils, leafy greens), zinc-rich foods (seeds, nuts, whole grains), and copper-containing foods (mushrooms, nuts, chocolate). Track weekly to see if you’re eating a variety of mineral-rich plant foods.
  • Add one new mineral-rich plant food to your diet each week. For example: Week 1 add spinach, Week 2 add pumpkin seeds, Week 3 add lentils. This helps ensure you’re getting a variety of minerals from different sources.
  • Monthly, review your food log to check that you’re eating at least 3-4 different mineral-rich plant foods per week. If you notice you’re eating the same foods repeatedly, challenge yourself to try a new vegetable, grain, or legume. If you have concerns about mineral deficiency, ask your doctor to check your mineral levels with a blood test.

This research is based on laboratory testing of food, not studies with people. Individual mineral absorption varies based on age, health status, medications, and overall diet. If you have concerns about mineral deficiency, excess mineral intake, or digestive problems affecting nutrient absorption, consult with a healthcare provider or registered dietitian before making significant dietary changes. This information should not replace professional medical advice. People with kidney disease, hemochromatosis, or other mineral metabolism disorders should especially consult their healthcare provider before changing their diet based on this research.