Should You Be Worried About Antinutrients?

Search online for ‘antinutrients’ and you might be concerned. According to some sites, you should steer clear of foods you have always thought were healthy.

Antinutrients are compounds in plants that help protect them from threats like bacterial infection and insects. They are high in foods like wholegrains, legumes and leafy greens – foods we are told to eat more of.

The problem with antinutrients is that they can bind with certain minerals in our bodies – notably calcium, iron, potassium, magnesium and zinc – making them less available.

Common antinutrients are:

  • oxalates, found in leafy greens, tea, beans, nuts
  • lectins, found in beans, peanuts and wholegrains
  • phytates, from wholegrains, seeds, legumes and nuts, and,
  • tannins, found in tea, coffee, legumes, berries, chocolate and wine.

Antinutrients sound pretty scary – after all, we do not want to be eating foods that may lead to a mineral deficiency. A quick online search might alarm you even more. Many sites claim these ‘plant toxins’ are behind inflammation, autoimmune disease, weight gain and kidney problems. Fortunately, most of these claims are not backed by evidence.

Do we need to ban the beans?

According to Tuffs Health & Nutrition letter, there is no evidence that antinutrients in commonly consumed foods lead to mineral deficiencies. It says that a varied diet should give us plenty of minerals, and the small percentage we cannot absorb because they are bound to antinutrients should not be a problem.

If you eliminated or reduced the foods that contain antinutrients you would lose vital sources of dietary fibre, vitamins including A, C, E, B group, K and E, minerals healthy fats, phytochemicals, and antioxidants like lutein and zeaxanthin. The health benefits of a diet rich in plant foods far outweighs the minerals lost through antinutrients.

The benefits of antinutrients

Many antinutrients, rather than something to avoid, are now even considered health-promoting, says Jill Joyce, Assistant Professor of Public Health Nutrition at Oklahoma State University. Writing in the Conversation, Professor Joyce says that the most frequently eaten antinutrients can support the immune system, lower the risk of cancer, type 2 diabetes and cardiovascular disease, inhibit the growth of bacteria and fungi, and may decrease cholesterol levels and blood pressure.

This does not mean you should never give them a second thought. If you are at risk of a disease related to mineral deficiencies, such as osteoporosis with calcium deficiency or anaemia with iron deficiency, speak to an Accredited Practising Dietitian for advice on how to monitor your food choices for antinutrient content.

Can we reduce antinutrients?

Soaking, boiling or other high-heat processes remove many antinutrients, and in some cases, such as certain lectins, it is essential that we destroy them.

Boiling beans for at least 10 mins inactivates the lectins, as does the canning process. Be warned that cooking in a slow cooker without first boiling for 10 minutes will not destroy the lectins.