Should I Worry About Antinutrients, and How Do I Remove Them?

Antinutrients can keep your body from using nutrients. Most people don't need to worry about antinutrients and milling, soaking, boiling, and sprouting can help reduce levels of antinutrients.

As their name suggests, antinutrients can keep your body from using nutrients. They are especially likely to block the absorption of minerals, including:

• Iron
• Calcium
• Zinc
• Iodine

Although antinutrients occur in some animal products, the ones in plants are more commonly analyzed. Plant antinutrients belong to a group of compounds called phytochemicals. There are many types of phytochemicals. Scientists are still learning how they work in the human body, though it has been demonstrated that they can help prevent chronic diseases. 

Plant antinutrients help plants resist attacks from bacteria, fungi, insects, and other threats. They're vital for plant health but can sometimes harm human health. The main problem is that antinutrients can bind with minerals, keeping your body from absorbing them. You could then become deficient in one or more minerals.   

It may be a bad idea to fully remove foods containing antinutrients from your diet for two reasons. First, these foods are highly nutritious. Giving them up because of their antinutrient content would deprive you of their many benefits. Second, the antinutrients themselves may have health benefits. They may lower cholesterol, stabilize blood sugar, and even fight cancer.

There are dozens of antinutrients, but some are better known because researchers have done more work with them. The following antinutrients have received a lot of attention: 

Lectins

Whole grains and legumes are rich in lectins, antinutrients that can keep you from absorbing iron, calcium, phosphorus, and zinc. Lectins can be hard to digest because they survive in acidic environments like the stomach. Lectins can also bind to the lining of the digestive tract, possibly causing inflammation. There is little evidence that lectins pose a problem for most people, though, especially since proper cooking destroys most of them.   

Oxalates

Spinach, chard, beets, and some other super-healthy foods are high in oxalates, which can bind with calcium, zinc, and magnesium. A high oxalate intake is sometimes associated with an elevated risk of kidney stones, so if you have previously had kidney stones, your doctor may advise you to avoid foods high in oxalates, although there are also other ways to reduce the likelihood of stone formation.  

Phytates

Phytic acid is a compound that plants use to store phosphorus. Grains and legumes contain high levels of phytic acid. When you eat these foods, their phytic acid combines with certain minerals to create antinutrients called phytates. The main minerals affected are iron, calcium, zinc, and manganese. 

Your body can't break down phytates, but they are destroyed by many cooking and processing methods. It's unlikely that you will develop a mineral deficiency due to eating grains and legumes. If, however, you know you are sometimes low in iron or another mineral, ask your doctor whether you need to change your diet.

Tannins

Tannins can be found in a wide variety of foods, including tea, berries, cocoa, apples, and whole grains. Some studies suggest that tannins interfere with the absorption of iron, though studies that look at tannins as part of a varied diet suggest otherwise. 

Many plants that contain tannins are also rich in vitamin C, which helps the body absorb the type of iron found in plants. For most people, then, the benefits of tannin-rich foods outweigh any antinutrient activity.   

Goitrogens

Goitrogens are substances that interfere with thyroid function. For example, plants in the cabbage family, also known as cruciferous vegetables, may keep the body from absorbing iodine, which the thyroid needs. 

Still, if you do not already have thyroid problems, these healthy vegetables offer more benefits than dangers. Also, cooking vegetables with iodized salt should raise the iodine level enough to avoid a deficiency. 

It's true that some research suggests that antinutrients can be harmful. These studies can be misleading, though, for several reasons.

• Lack of human research. Clinical trials of nutrition are hard to carry out with humans. As a result, some researchers use animals, while other studies focus on humans but don't control for variables. 
• Isolated substances. In order to study a particular subject, scientists typically isolate it. However, the way a substance acts in isolation may be nothing like the way it acts in combination with other compounds, as you would get with a normal diet. 
• High dosages. Scientific studies often use substances at high dosage levels in order to study their effects. If you eat a varied diet, you are unlikely to get such a large amount of any single antinutrient. 

If you are healthy and eat a wholesome diet, you shouldn't worry about antinutrients. If you have certain health conditions, though, you may need to take some precautions. For example, if you have lower-than-normal iron levels, you should avoid antinutrients that bind with iron, especially if you have anemia. 

Meanwhile, if you have osteoporosis, which causes weak bones, you may need to avoid antinutrients that bind with calcium.  

There are several ways to lower the antinutrient content of foods, but some of these methods also reduce certain health benefits. 

Milling. Milling grain into flour removes the bran layer, the part that contains antinutrients. The bran also contains important minerals and other nutrients, though. That's why unmilled whole grains are more nutritious than processed grains. 

Soaking. Many antinutrients are soluble in water, so soaking foods such as dried beans and grains can remove the antinutrients. This method also has the advantage of shortening cooking time. However, you may lose water-soluble vitamins and minerals.  

Boiling. Heating food submerged in water is another good way to remove antinutrients. Roasting, steaming, and baking are not as good for reducing most antinutrients. 

Sprouting. Allowing seeds, beans, and grains to sprout will reduce antinutrient content because germination alters the biochemical makeup of plant foods. Of course, you can't use sprouted foods in every dish. 

Antinutrients can be harmful to your health if consumed in large amounts. However, if you eat a variety of foods every day, you are unlikely to get enough antinutrients to cause a related nutritional deficiency. A few people with health conditions should avoid certain antinutrients, but otherwise, many of the foods that contain antinutrients are so beneficial that they should still have a place in your diet.